[Federal Register Volume 88, Number 155 (Monday, August 14, 2023)]
[Proposed Rules]
[Pages 55220-55274]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-17023]



[[Page 55219]]

Vol. 88

Monday,

No. 155

August 14, 2023

Part III





Environmental Protection Agency





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40 CFR Part 257





Alabama: Denial of State Coal Combustion Residuals Permit Program; 
Proposed Rule

  Federal Register / Vol. 88, No. 155 / Monday, August 14, 2023 / 
Proposed Rules  

[[Page 55220]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 257

[EPA-HQ-OLEM-2022-0903; FRL 11262-01-OLEM]


Alabama: Denial of State Coal Combustion Residuals Permit Program

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of availability; request for comment.

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SUMMARY: Pursuant to section 4005(d) of the Resource Conservation and 
Recovery Act (RCRA), the Environmental Protection Agency (EPA or the 
Agency) is proposing to deny the Alabama Department of Environmental 
Management's (ADEM or Department) Application for approval of the 
Alabama coal combustion residuals (CCR) permit program (Application). 
After reviewing the State CCR permit program Application submitted by 
ADEM on December 29, 2021, and additional relevant materials, and based 
on extensive discussions with ADEM regarding its Application, EPA has 
preliminarily determined that Alabama's CCR permit program does not 
meet the standard for approval under RCRA. This document announces that 
EPA is seeking comment on this proposal during a 60-day public comment 
period and will be holding an in-person public hearing on EPA's 
proposed denial of Alabama's CCR permit program.

DATES: 
    Comments due. Comments must be received on or before October 13, 
2023.
    Public Hearing: EPA will hold an in-person public hearing on 
September 20, 2023, and a virtual public hearing on September 27, 2023. 
Please refer to the SUPPLEMENTARY INFORMATION section for additional 
information on the public hearing.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OLEM-OLEM-2022-0903, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov/ 
(our preferred method). Follow the online instructions for submitting 
comments.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Office of Land and Emergency Management (OLEM) Docket, Mail 
Code 28221T, 1200 Pennsylvania Ave. NW, Washington, DC 20460.
     Hand Delivery or Courier (by scheduled appointment only): 
EPA Docket Center, WJC West Building, Room 3334, 1301 Constitution 
Avenue NW, Washington, DC 20004. The Docket Center's hours of 
operations are 8:30 a.m.-4:30 p.m., Monday-Friday (except Federal 
holidays).
    Instructions: All submissions received must include the Docket ID 
No. for this rulemaking. Comments received may be posted without change 
to https://www.regulations.gov/, including any personal information 
provided. For detailed instructions on sending comments and additional 
information on the rulemaking process, see the ``Public Participation'' 
heading of the SUPPLEMENTARY INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: Michelle Lloyd, Office of Resource 
Conservation and Recovery, Materials Recovery and Waste Management 
Division, U.S. Environmental Protection Agency, 1200 Pennsylvania 
Avenue NW, MC: 5304T, Washington, DC 20460; telephone number: (202) 
566-0560; email address: [email protected]. For more information 
on this notice please visit https://www.epa.gov/coalash.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Public Participation
    A. Written Comments
    B. Participation in In-Person Public Hearing
    C. Participation in Virtual Public Hearing
II. General Information
    A. Overview of Proposed Action
    B. Background
    C. Statutory Authority
III. The Alabama CCR Permit Program Application
    A. Alabama CCR Units and Resources
    B. Alabama CCR Regulations
    C. Alabama Authority To Regulate CCR
    D. Alabama Permits
    E. Summary of EPA Communications With Alabama
IV. EPA Analysis of the Alabama Application and Basis for Denial
    A. Legal Authority To Evaluate State CCR Program Submittals
    1. The Statute Requires EPA To Consider a State's CCR Permits 
When Determining Whether To Approve the Program if the Information 
Is Available
    2. EPA Is Not Required To Approve a Deficient State Program and 
Then Redress the Deficiencies Through RCRA's Program Review 
Provisions
    B. EPA's Analysis of the Alabama CCR Regulations
    1. Adequacy of Technical Criteria
    2. Review of Generally Applicable Alabama CCR Permit Program 
Statutes and Regulations
    C. EPA's Analysis of Alabama's Permits Issued Under the State 
CCR Regulations
    1. Colbert Fossil Plant
    2. Plant Gadsden
    3. Plant Gorgas
    4. Plant Greene County
    5. EPA conclusion About Alabama's Implementation of the CCR 
Regulations
V. Proposed Action

List of Acronyms

ACM Assessment of Corrective Measures
ADEM Alabama Department of Environmental Management
ASD alternative source demonstration
BGS below ground surface
CBI Confidential Business Information
CCP coal combustion product
CCR coal combustion residuals
CD Consent Decree
CFR Code of Federal Regulations
CY cubic yards
eFile electronic filing system
EPA Environmental Protection Agency
EPRI Electric Power Research Institute
FR Federal Register
GWMCA groundwater monitoring and corrective action
GWMP Groundwater Monitoring Plan
GWPS groundwater protection standard
HSWA Hazardous and Solid Waste Amendments
ICR Information Collection Request
MCL maximum contaminant level
MNA Monitored Natural Attenuation
MSL mean sea level
NOPV Notice of Potential Violation
NPDES National Pollutant Discharge Elimination System
RCRA Resource Conservation and Recovery Act
RTC Response to Comments
SSI statistically significant increase
SSL statistically significant level
TSD Technical Support Document
TVA Tennessee Valley Authority
USGS U.S. Geological Survey
USWAG Utility Solid Waste Activities Group
WBWT waste below the water table
WIIN Water Infrastructure Improvements for the Nation

I. Public Participation

A. Written Comments

    Submit your comments, identified by Docket ID No. EPA-HQ-OLEM-OLEM-
2022-0903, at https://www.regulations.gov (our preferred method), or 
the other methods identified in the ADDRESSES section. Once submitted, 
comments cannot be edited or removed from the docket. EPA may publish 
any comment received to its public docket. Do not submit to EPA's 
docket at https://www.regulations.gov any information you consider to 
be Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Multimedia submissions (audio, 
video, etc.) must be accompanied by a written comment. The written 
comment is considered the official comment and should include 
discussion of all points you wish to make. EPA will generally not 
consider comments or comment contents located

[[Page 55221]]

outside of the primary submission (i.e., on the web, cloud, or other 
file sharing system). For additional submission methods, the full EPA 
public comment policy, information about CBI or multimedia submissions, 
and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.

B. Participation in In-Person Public Hearing

    EPA will begin pre-registering speakers for the hearing upon 
publication of this document in the Federal Register. To register to 
speak at the hearing, please use the online registration form available 
on EPA's CCR website (https://www.epa.gov/coalash) or contact the 
person listed in the FOR FURTHER INFORMATION CONTACT section to 
register to speak at the hearing. The last day to pre-register to speak 
at the hearing will be September 18, 2023.
    EPA will make every effort to follow the schedule as closely as 
possible on the day of the hearing; however, please plan for the 
hearings to run either ahead of schedule or behind schedule. 
Additionally, requests to speak will be taken the day of the hearing at 
the hearing registration desk. EPA will make every effort to 
accommodate all speakers who arrive and register, although preferences 
on speaking times may not be able to be fulfilled.
    Each commenter will have five (5) minutes to provide oral 
testimony. EPA encourages commenters to provide EPA with a copy of 
their oral testimony electronically by emailing it to the person listed 
in the FOR FURTHER INFORMATION CONTACT section. EPA also recommends 
submitting the text of your oral comments as written comments to the 
rulemaking docket. If EPA is anticipating a high attendance, the time 
allotment per testimony may be shortened to no shorter than three (3) 
minutes per person to accommodate all those wishing to provide 
testimony and who have pre-registered. While EPA will make every effort 
to accommodate all speakers who do not pre-register, opportunities to 
speak may be limited based upon the number of pre-registered speakers. 
Therefore, EPA strongly encourages anyone wishing to speak to pre-
register. Participation in the public hearing does not preclude any 
entity or individual from submitting a written comment.
    EPA may ask clarifying questions during the oral presentations but 
will not respond to the presentations at that time. Written statements 
and supporting information submitted during the comment period will be 
considered with the same weight as oral comments and supporting 
information presented at the public hearing.
    Please note that any updates made to any aspect of the hearing are 
posted online at EPA's CCR website at https://www.epa.gov/coalash. 
While EPA expects the hearing to go forward as set forth above, please 
monitor our website or contact the person listed in the FOR FURTHER 
INFORMATION CONTACT section to determine if there are any updates. EPA 
does not intend to publish a document in the Federal Register 
announcing updates.
    If you require the services of an interpreter or special 
accommodations such as audio description, please pre-register for the 
hearing with the person listed in the FOR FURTHER INFORMATION CONTACT 
section and describe your needs by September 6, 2023. EPA may not be 
able to arrange accommodations without advance notice.

C. Participation in Virtual Public Hearing

    EPA will begin pre-registering speakers for the hearing upon 
publication of this document in the Federal Register. To register to 
speak at the virtual hearing, please use the online registration form 
available on EPA's CCR website (https://www.epa.gov/coalash) or contact 
the person listed in the FOR FURTHER INFORMATION CONTACT section to 
register to speak at the hearing. The last day to pre-register to speak 
at the hearing will be September 25, 2023.
    EPA will make every effort to follow the schedule as closely as 
possible on the day of the hearing; however, please plan for the 
hearing to run either ahead of schedule or behind schedule. 
Additionally, requests to speak will be taken the day of the hearing 
according to the procedures specified on EPA's CCR website (https://www.epa.gov/coalash) for this hearing. The Agency will make every 
effort to accommodate all speakers who arrive and register, although 
preferences on speaking times may not be able to be fulfilled.
    Each commenter will have five (5) minutes to provide oral 
testimony. EPA encourages commenters to provide EPA with a copy of 
their oral testimony electronically (via email) to the person listed in 
the FOR FURTHER INFORMATION CONTACT section. If EPA is anticipating a 
high attendance, the time allotment per testimony may be shortened to 
no shorter than three (3) minutes per person to accommodate all those 
wishing to provide testimony and who have pre-registered. While EPA 
will make every effort to accommodate all speakers who do not pre-
register, opportunities to speak may be limited based upon the number 
of pre-registered speakers. Therefore, EPA strongly encourages anyone 
wishing to speak to pre-register. Participation in the virtual public 
hearing does not preclude any entity or individual from submitting a 
written comment.
    EPA may ask clarifying questions during the oral presentations but 
will not respond to the presentations at that time. Written statements 
and supporting information submitted during the comment period will be 
considered with the same weight as oral comments and supporting 
information presented at the public hearing. Verbatim transcripts of 
the hearings and written statements will be included in the docket for 
this action.
    Please note that any updates made to any aspect of the hearing will 
be posted online on EPA's CCR website at https://www.epa.gov/coalash. 
While EPA expects the hearing to go forward as set forth above, please 
monitor our website or contact the person listed in the FOR FURTHER 
INFORMATION CONTACT section to determine if there are any updates. EPA 
does not intend to publish a document in the Federal Register 
announcing updates.
    If you require the service of a translator, please pre-register for 
the hearing and describe your needs on the registration form by 
September 13, 2023. If you require special accommodations such as audio 
description or closed captioning, please pre-register for the hearing 
and describe your needs on the registration form by September 13, 2023. 
Alternatively, registrants may notify the person listed in the FOR 
FURTHER INFORMATION CONTACT section of any special needs. We may not be 
able to arrange accommodations without advanced notice.

II. General Information

A. Overview of Proposed Action

    On April 17, 2015, EPA published a final rule, creating 40 CFR part 
257, subpart D,\1\ that established a comprehensive set of minimum 
Federal requirements for the disposal of CCR in landfills and surface 
impoundments (80 FR 21302) (``Federal CCR regulations''). Section 2301 
of the 2016 Water Infrastructure Improvements for the Nation (WIIN) Act 
amended section 4005 of RCRA, creating a new subsection (d) that 
establishes a Federal CCR permit program that is similar to the permit 
programs under RCRA

[[Page 55222]]

subtitle C and other environmental statutes. See 42 U.S.C. 6945(d).
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    \1\ Unless otherwise specified, all references to part 257 and 
part 239 in this notice are to title 40 of the Code of Federal 
Regulations (CFR).
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    RCRA section 4005(d) also allows states to seek approval for a 
State CCR permit program that will operate in lieu of a Federal CCR 
permit program in the State. The statute provides that within 180 days 
after a State submits an application to the Administrator for approval, 
EPA shall approve the State permit program if the Administrator 
determines that the State program requires each CCR unit located in the 
State to achieve compliance with either the Federal requirements or 
other State requirements that EPA determines, after consultation with 
the State, are at least as protective as those included in the Federal 
CCR regulations. See, 42 U.S.C. 6945(d)(1)(B).
    On December 29, 2021, ADEM submitted its State CCR permit program 
Application to EPA Region 4 requesting approval of the State's partial 
CCR permit program.2 3 ADEM established State CCR 
regulations that mirrored the provisions in the Federal CCR regulations 
with additional State-specific provisions and clarifications. Though 
ADEM primarily adopted the language in the Federal CCR regulations, EPA 
reviewed both proposed and final permits Alabama issued under its CCR 
program and concluded that ADEM was interpreting its State regulations 
in a manner inconsistent with the plain language of the Federal 
requirements, and that, as a result, the permits for CCR units in the 
State contain permit terms that are neither the same as, nor as 
protective as, the Federal CCR regulations. Specifically, EPA 
identified deficiencies in ADEM's permits with respect to the closure 
requirements for unlined surface impoundments and the associated 
groundwater monitoring network and corrective action requirements. EPA 
discussed these issues with ADEM, and, despite EPA's concerns, the 
State declined to modify the existing permits and proceeded to issue 
another CCR permit with the same deficient provisions. Further, ADEM 
failed to adequately explain how the permits ensured that each CCR unit 
would achieve compliance with either the Federal requirements or other 
State requirements that are at least as protective as the requirements 
in the Federal CCR regulations.
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    \2\ Alabama Department of Environmental Management. Application 
For CCR Permit Program Approval. December 2021.
    \3\ In the December 29, 2021 Application, Alabama sought a 
partial program approval (rather than full program approval) of the 
State's CCR permit program because it is not seeking approval for 
some of its CCR regulations. Specifically, ADEM is not seeking 
approval for six items that are listed in Unit IV.B.1.b of this 
preamble and in the Technical Support Document Volume III. See 
Volume III: Technical Support Document for the Proposed Notice to 
Deny Alabama's Coal Combustion Residuals Permit Program, EPA 
Analysis of Alabama CCR Permitting and Technical Regulations. U.S. 
Environmental Protection Agency, Office of Land and Emergency 
Management (5304T), 1200 Pennsylvania Avenue NW, Washington, DC 
20460. August 2023.
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    EPA is proposing to deny Alabama's request for approval of its CCR 
permit program Application pursuant to RCRA section 4005(d)(1)(B), 
because the State's program does not meet either standard for approval. 
42 U.S.C. 6945(d)(1)(B).

B. Background

    CCR are generated from the combustion of coal, including solid 
fuels classified as anthracite, bituminous coal, subbituminous coal, 
and lignite, for the purpose of generating steam to power a generator 
to produce electricity or electricity and other thermal energy by 
electric utilities and independent power producers. CCR, commonly known 
as coal ash, include fly ash, bottom ash, boiler slag, and flue gas 
desulfurization materials.
    As noted above, on April 17, 2015, EPA published a final rule that 
established a comprehensive set of minimum Federal requirements in 40 
CFR part 257, subpart D for the disposal of CCR in landfills and 
surface impoundments. The rule created a self-implementing program that 
regulates the location, design, operating criteria, and groundwater 
monitoring and corrective action for CCR units, as well as the closure 
and post-closure care of CCR units. The rule also includes requirements 
for recordkeeping and notifications for CCR units. EPA has since 
amended 40 CFR part 257, subpart D (81 FR 51802, August 5, 2016), (83 
FR 36435, July 30, 2018), (85 FR 53516, August 28, 2020), (85 FR 72506, 
November 12, 2020). More information on these rules is provided in the 
Technical Support Document (TSD) Volume III.

C. Statutory Authority

    EPA is issuing this proposed action pursuant to sections 4005(d) 
and 7004(b)(1) of RCRA. See 42 U.S.C. 6945(d) and 6974(b)(1). As stated 
above, section 2301 of the WIIN Act amended section 4005 of RCRA, 
creating a new subsection (d) that establishes a Federal CCR permitting 
program similar to permit programs under RCRA subtitle C and other 
environmental statutes. See 42 U.S.C. 6945(d).
    Under RCRA section 4005(d)(1)(A), 42 U.S.C. 6945(d)(1)(A), states 
seeking approval of a permit program must submit to the Administrator, 
``in such form as the Administrator may establish, evidence of a permit 
program or other system of prior approval and conditions under [S]tate 
law for regulation by the State of coal combustion residuals units that 
are located in the State.'' EPA shall approve a State permit program if 
the Administrator determines that the State program requires each CCR 
unit located in the State to achieve compliance with either: (1) The 
Federal CCR requirements at 40 CFR part 257, subpart D; or (2) Other 
State criteria that the Administrator, after consultation with the 
State, determines to be ``at least as protective as'' the Federal 
requirements. See 42 U.S.C. 6945(d)(1)(B). The Administrator must make 
a final determination, after providing for public notice and an 
opportunity for public comment, within 180 days of determining that the 
State has submitted a complete application consistent with RCRA section 
4005(d)(1)(A).\4\ See 42 U.S.C. 6945(d)(1)(B). EPA may approve a State 
CCR permit program in whole or in part. Id. Once approved, the State 
permit program operates in lieu of the Federal requirements. See 42 
U.S.C. 6945(d)(1)(A). In a State with a partial permit program, only 
the State requirements that have been approved operate in lieu of the 
Federal requirements, and facilities remain responsible for compliance 
with all remaining non-State approved requirements in 40 CFR part 257, 
subpart D.
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    \4\ See U.S. Environmental Protection Agency. Coal Combustion 
Residuals State Permit Program Guidance Document; Interim Final, 
August 2017, Office of Land and Emergency Management, Washington, DC 
20460 (providing that the 180-day deadline does not start until EPA 
determines the application is complete).
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    As noted above, the Federal CCR regulations are self-implementing 
and that means that CCR landfills and surface impoundments must comply 
with the terms of the rule even prior to obtaining a Federal permit or 
permit issued by an approved State, and noncompliance with any 
requirement of the Federal CCR regulations can be directly enforced 
against the facility. Once a final CCR permit is issued by an approved 
State or pursuant to a Federal CCR permit program, however, the terms 
of the permit apply in lieu of the terms of the Federal CCR regulations 
and/or requirements in an approved State program, and RCRA section 
4005(d)(3) provides a permit shield against direct enforcement of the 
applicable Federal or State CCR regulations (meaning the permits terms

[[Page 55223]]

become the enforceable requirements for the permittee).
    In addition, RCRA section 7004(b) applies to all RCRA programs, 
directing that ``public participation in the development, revision, 
implementation, and enforcement of any. . .program under this chapter 
shall be provided for, encouraged, and assisted by the Administrator 
and the States.'' 42 U.S.C. 6974(b)(1).

III. The Alabama CCR Permit Program Application

    On December 29, 2021, ADEM submitted its revised CCR permit program 
Application to EPA Region 4.\5\ The Application requested approval of 
the State's partial CCR permit program.\6\ Alabama's first CCR 
regulations were promulgated in 2018 and continued to be revised over 
the next several years in response to public comment, discussions 
between ADEM and EPA, and changes to the Federal CCR regulations in 40 
CFR part 257, subpart D.
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    \5\ Application to USEPA Region IV for CCCR Permit Program 
Approval in Accordance with Section 4005 of the Resource 
Conservation and Recovery Act (RCRA) Alabama Department of 
Environmental Management Land Division-Solid Waste Branch. December 
2021.
    \6\ ADEM previously submitted CCR permit program applications on 
July 12, 2018, and February 26, 2021. For purposes of this proposed 
action, EPA reviewed the most recent Application submitted on 
December 29, 2021.
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    EPA conducted an analysis of the Alabama CCR permit program 
Application, including a thorough analysis of ADEM's statutory 
authorities for the CCR program, as well as regulations at Alabama 
Administrative Code Chapter. 335-13-15, Standards for the Disposal of 
Coal Combustion Residuals in Landfills and Impoundments. This analysis 
is discussed in Unit IV.B.2.b of this preamble and in the TSD Volume 
III. EPA also reviewed Alabama's permitting regulations, as well as 
recent and ongoing permit decisions ADEM was making under its CCR 
regulations.

A. Alabama CCR Units and Resources

    In the Program Narrative in the Application, ADEM identified 16 
units that are currently, or have been, used for disposal of CCR (3 
landfills and 13 surface impoundments) in Alabama. ADEM stated that it 
has the personnel and funding to administer a CCR permit program. The 
State also indicated that its program is funded from three sources: 
tipping fees collected for the disposal of solid waste, permitting 
fees, and civil penalties from enforcement orders.

B. Alabama CCR Regulations

    ADEM Administrative Code Chapter 335-13-15 largely replicates the 
requirements of 40 CFR part 257, subpart D, for the portions of those 
regulations for which the State is seeking approval. In addition to the 
technical criteria at ADEM Chapter 335-13-15, ADEM has adopted State-
specific permitting requirements, including public participation 
requirements, at ADEM Administrative Code Chapter. 335-13-05. ADEM also 
has additional reporting and approval requirements for CCR units, as 
described in the TSD Volume III.

C. Alabama Authority To Regulate CCR

    ADEM derives its authority to operate the Solid Waste Program, 
which includes CCR, in Alabama pursuant to the following statutory 
provisions of the Code of Alabama, 1975: (1) Section 22-22A-5 provides 
the Department with the authority to administer and enforce the State's 
Solid Wastes and Recyclable Materials Management Act, to adopt and 
promulgate rules, regulations, and standards through the Environmental 
Management Commission, and to develop environmental policy for the 
State; and to serve as the State Agency responsible for administering 
federally-approved or federally-delegated environmental programs; (2) 
Section 22-27-9 provides ADEM with authority over the management of 
solid waste in the State (except for the collection and transportation 
of nonhazardous and nonmedical solid waste) and the permitting and 
operation of solid waste management facilities; and (3) Section 22-27-
12 provides ADEM with the authority to promulgate and adopt rules 
establishing requirements for the management of solid waste and to 
issue permits with conditions regarding the management of such solid 
waste.

D. Alabama Permits

    Unlike Georgia, Texas, and Oklahoma (currently the only three 
States with EPA approval for State CCR permit programs), Alabama had 
already begun implementing its State CCR permit program and issuing 
permits prior to its submittal of an Application for EPA approval of 
the State's CCR permit program. At the time of submission of ADEM's 
December 29, 2021 Application, ADEM had issued permits for the 
following CCR facilities: (1) the James H. Miller Electric Generating 
Plant (Permit #37-51; issued December 18, 2020); (2) Greene County 
Electric Generating Plant (Permit #32-03: issued December 18, 2020); 
(3) Gadsden Steam Plant (Permit #28-09, issued December 18, 2020); (4) 
James M. Barry Electric Generating Plant (Permit #49-35, issued July 1, 
2021); (5) E.C. Gaston Electric Generating Plant (Permit #59-16, issued 
May 25, 2021); and (6) Charles R. Lowman Power Plant (Permit #65-06, 
issued August 30, 2021). At the time of submission of the December 29, 
2021 Application, permits were under development by ADEM at two other 
facilities: the William C. Gorgas Electric Generating Plant and 
Tennessee Valley Authority (TVA) Plant Colbert. Since the submission of 
ADEM's Application, ADEM has proceeded to issue both the Plant Gorgas 
Permit (Permit #64-12 issued February 28, 2022) and the TVA Colbert 
Permit (Permit #17-11, issued October 25, 2022).

E. Summary of EPA Communications With Alabama

    As part of EPA's review of State CCR permit programs, the Agency 
engages the State both before and after submittal of a State CCR permit 
program application. These discussions serve a number of purposes; for 
example, EPA engages in these discussions to help the State determine 
the scope of the CCR permit program it wants to adopt (e.g., full or 
partial program) and to ensure the State establishes the necessary 
State CCR regulations prior to submitting the request for program 
approval. EPA also assists the State in determining what to include in 
the Narrative Statement component of its permit program application, 
which serves as a roadmap to the State's CCR permit program. EPA also 
uses these discussions to clarify questions raised during the public 
comment period about the State program. To the extent the State 
implements its CCR regulations prior to EPA's determination of State 
program adequacy, EPA will also discuss the State's interpretation and 
implementation of its program to ensure that EPA fully understands the 
program and to determine which of the two statutory standards EPA will 
use to evaluate the State program. EPA took the same approach with 
Alabama as with other states seeking approval, and, as detailed below, 
EPA and ADEM have had extensive discussions about the State's CCR 
permit program.\7\
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    \7\ EPA has attempted to identify all the interactions between 
EPA and ADEM with respect to the State's CCR permit program. A 
summary of the interactions between EPA and ADEM is included in the 
docket to this notice in Volume II: Technical Support Document for 
the Proposed Notice to Deny Alabama's Coal Combustion Residuals 
Permit Program, Communication Between EPA and ADEM. U.S. 
Environmental Protection Agency Office of Land and Emergency 
Management (5304T). August 2023. In addition, copies of emails and 
letters between EPA and ADEM can be found in the docket.

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[[Page 55224]]

    EPA began telephone calls and meetings with ADEM about its 
development of an Application for a CCR permit program in January 2018 
and continued them through July 2022. In the early calls, EPA and ADEM 
discussed the process for EPA to review and approve State CCR permit 
programs, ADEM's plans for formally adopting CCR regulations, its 
anticipated timeline for submitting a CCR permit program Application to 
EPA, and ADEM's permit requirements. During these calls, EPA reviewed 
ADEM's submission and sent comments to ADEM on those documents. The 
frequency of calls between EPA and ADEM varied depending on the stage 
of ADEM's efforts to develop and submit (or re-submit) its CCR permit 
program Application. For example, during ADEM's public comment periods 
associated with State rulemaking, or during periods of re-working 
regulations or documents, calls were held less frequently. When ADEM 
had questions or requested EPA input, calls were held more often.
    After ADEM's initial CCR regulations became effective in 2018, the 
State began to issue permits. Calls were then held on specific 
facilities and technical issues that ADEM sought EPA's input on, such 
as specific corrective action proposed remedies or closure methods. In 
addition, consistent with RCRA section 4005(d), EPA began discussions 
with ADEM on specific facilities and permits to evaluate whether ADEM 
was requiring, as part of its permit process, each CCR unit in the 
State ``to achieve compliance with'' the Federal part 257 standards or 
``other State criteria that the Administrator, after consultation with 
the State, determines to be at least as protective as'' the Federal 
criteria.
    Of particular concern to the Agency were facilities that were 
closing (or had already closed) unlined CCR surface impoundments while 
leaving waste (i.e., CCR) below the water table (WBWT). On March 15, 
2022, EPA shared a list of such facilities in Alabama with ADEM and 
scheduled discussions regarding the closures and groundwater monitoring 
activities at the Greene County Electric Generating Plant and the 
Gadsden Steam Plant. Discussions also focused on the William C. Gorgas 
Electric Generating Plant. ADEM had issued permits at all three of 
these facilities. During these discussions and written communication, 
EPA expressed concern that Alabama's permit program appeared to differ 
from the Federal program, and that these differences appeared to make 
the State's program less protective than the Federal program. The 
Agency specifically identified problems with the State's permit 
requirements covering closure of unlined surface impoundments, 
groundwater monitoring networks, and corrective action. See also Unit 
IV.C of this preamble below and the TSD Volume I for a detailed 
discussion of the deficiencies in ADEM's CCR permits. In addition to 
the concerns raised with respect to Plants Greene, Gorgas, and Gadsden, 
EPA has also raised concerns with respect to the TVA Plant Colbert 
permit. On June 29, 2022, ADEM posted public notice of the draft permit 
for Plant Colbert. Because the proposed permit for Plant Colbert raised 
many of the same issues already being discussed with respect to Plants 
Greene, Gorgas, and Gadsden, EPA submitted a letter to ADEM outlining 
specific concerns with respect to the proposed permit.\8\
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    \8\ Letter from Carolyn Hoskinson, Director, Office of Resource 
Conservation and Recovery, to Mr. Russell A. Kelly, Chief, Permits 
and Services Division, and Mr. Steve Cobb, Chief, Land Division. EPA 
Comments on Proposed Permit, Tennessee Valley Authority Colbert 
Fossil Plant, Alabama Department of Environmental Management, Permit 
No. 17-11. September 15, 2022.
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    As a result of these discussions, on July 7, 2022, EPA informed 
ADEM via telephone that the Agency was putting on hold its completeness 
review of ADEM's CCR permit program Application until Alabama 
demonstrated to EPA that the State was implementing its program 
consistent with the Federal CCR regulations. Further, EPA explained to 
ADEM that it was exploring options for actions to take at the Federal 
level with respect to both the CCR permit program Application, and at 
specific facilities where there are outstanding concerns.
    On October 25, 2022, ADEM proceeded to issue a CCR permit to Plant 
Colbert without revising the proposed permit to address EPA's concerns. 
In a letter dated October 27, 2022, ADEM responded to EPA's letter 
regarding Plant Colbert, presenting an interpretation of the 
requirements applicable to closing CCR impoundments that EPA had 
previously rejected in the discussions about the interpretation of the 
Federal CCR regulations with ADEM described above and in EPA's Part A 
proposed and final decisions. See discussion of Part A proposals in 
Unit IV.C. of this preamble. To date, the State has not taken action to 
revise the permits issued to Plants Colbert, Green, Gorgas, or Gadsden 
to address the deficiencies EPA noted to ADEM.
    On December 9, 2022, ADEM gave EPA notice of its intent to sue EPA 
under section 7002(a)(1)(A) and (1)(B) of RCRA, alleging EPA failed to 
perform a nondiscretionary duty to approve the State's CCR permit 
program.\9\ Among other things, ADEM asserted that EPA failed to comply 
with the statutory requirement to approve the State's CCR permit 
program within 180 days of the State's submittal of the permit program 
Application on December 29, 2021. On February 1, 2023, EPA responded to 
ADEM's Notice of Intent to Sue letter and informed the State that the 
180-day timeframe does not start until EPA determines that a State's 
Application is administratively complete and that, in this case, EPA 
did not start the clock because EPA's concerns with ADEM's 
interpretation of the minimum requirements of the Federal CCR 
regulations had yet to be resolved and EPA was providing an opportunity 
for ADEM to submit further Application information.\10\ EPA further 
stated that the Agency could evaluate the State's program on the 
current record if ADEM decided not to supplement its Application with 
an explanation of how the State's interpretation of its regulations is 
at least as protective as the Federal CCR regulations, but EPA 
expressed concern that the current record would not support a proposal 
to approve the State's partial CCR permit program. Id. On February 17, 
2023, ADEM responded to EPA that it did not intend to supplement the 
record and that EPA should evaluate its program accordingly.\11\ EPA 
thereafter continued to review the Application based on the information 
submitted to date, and this notice reflects EPA's proposed conclusions 
from that review.
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    \9\ Letter from Alabama Attorney General Steve Marshall to EPA 
Administrator Michael Regan, Notice of Endangerment and Intent to 
Sue under Section 7002(a)(1)(A) and (1)(B) of the Resource 
Conservation and Recovery Act. December 9, 2022.
    \10\ Letter from Barry Breen, Acting Assistant Administrator, 
OLEM, to Lance LeFleur, Director, ADEM, February 1, 2023. Email sent 
February 2, 2023.
    \11\ Letter from Lance LeFleur, Director, ADEM, to Barry Breen, 
Acting Assistant Administrator, OLEM, February 17, 2023.
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IV. EPA Analysis of the Alabama Application and Basis for Denial

    As stated above, a State seeking approval of a CCR permit program 
can either adopt the Federal CCR requirements or establish State-
specific criteria that are at least as protective as the Federal CCR 
requirements. See 42 U.S.C. 6945(d)(1)(B). After a State submits a 
complete application, EPA evaluates the State program to determine 
whether it ``requires each

[[Page 55225]]

coal combustion residuals unit located in the state to achieve 
compliance with the applicable [Federal or other equally protective 
State] criteria.'' Id. Specifically, EPA evaluates the terms of the 
permit program or other system of prior approval and conditions and the 
Narrative Statement, to determine whether by its terms the State 
program meets either of these standards for each CCR unit regulated by 
the State. As discussed in more detail below and in the TSD Volume III, 
to make this determination EPA evaluates not only the CCR specific 
requirements but also the State's general authority to issue permits 
and impose conditions in those permits, as well as the State's 
authority for compliance monitoring and enforcement.\12\ Thus, 
collectively, the CCR specific and general permit requirements must 
provide the State with sufficient authority to require compliance from 
all CCR units located within the State. In addition, if the State 
begins issuing CCR permits and overseeing compliance with the permits 
prior to EPA's State program approval decision, the Agency must also 
consider whether the State in fact ``requires each CCR unit located in 
the state to achieve compliance with'' either the Federal criteria in 
part 257 or other State criteria that ``are at least as protective as'' 
the Federal regulations. 42 U.S.C. 6945(d)(1)(B) (emphasis added). See 
Unit IV.A of this preamble (discussing the Agency interpretation of 
RCRA section 4005(d)).
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    \12\ State permit program regulations usually include general 
requirements that apply across multiple permit programs (e.g., 
procedures for issuing permits). When new performance standards are 
issued for a type of facility or unit (for example, CCR 
regulations), states include both general and facility/unit specific 
requirements in the State permit program as necessary to develop a 
program that satisfies the Federal requirements to support approval 
of a State program.
---------------------------------------------------------------------------

    ADEM adopted regulations that largely mirror the Federal CCR 
regulations, but in some places ADEM also added additional or different 
criteria to be consistent with its existing solid waste regulations. 
When a State adopts the language in the Federal CCR regulations, EPA's 
review of the terms of the permit program is generally straightforward, 
and, in this case, EPA's review of the express terms of ADEM's CCR 
permit program demonstrates that the State program includes all 
regulatory provisions required for approval of a partial program.\13\ 
Thus, the terms of the permit program provide ADEM with the authority 
necessary to issue permits that will ensure each CCR unit in the State 
achieves the minimum required level of control (i.e., the State has the 
authority to issue permits that require compliance with standards that 
are at least as protective as those in the Federal CCR regulations).
---------------------------------------------------------------------------

    \13\ EPA conducted a thorough review of the terms of Alabama's 
CCR permit program submittal, consistent with review of submittals 
by states that were granted approval, and that review can be found 
in the Volume III: Technical Support Document for the Proposed 
Notice to Deny Alabama's Coal Combustion Residuals Permit Program, 
EPA Analysis of Alabama CCR Permitting and Technical Regulations. 
U.S. Environmental Protection Agency, Office of Land and Emergency 
Management (5304T), 1200 Pennsylvania Avenue NW, Washington, DC 
20460. August 2023.
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    While the statutes and regulations of the Alabama CCR permit 
program provide the State with sufficient authority to require 
compliance with the Federal requirements or equivalent State 
requirements, EPA is proposing to determine that permits issued by ADEM 
allow CCR units in the State to comply with alternative requirements 
that are less protective than the requirements in the Federal CCR 
regulations with respect to groundwater monitoring, corrective action, 
and closure. For example, as discussed in more detail in subsequent 
sections, ADEM has issued multiple permits allowing CCR in closed units 
to remain saturated by groundwater, without requiring any engineering 
measures to control the groundwater flowing into and out of the closed 
unit. ADEM has also approved groundwater monitoring systems that 
contain an inadequate number of wells, and in incorrect locations, to 
detect groundwater contamination from the CCR units. Finally, ADEM has 
issued multiple permits that effectively allow the permittee to delay 
implementation of effective measures to remediate groundwater 
contamination both on- and off-site of the facility. Overall, EPA's 
review of the permit records demonstrates a consistent pattern of 
deficiencies in the permits and a lack of oversight and independent 
evaluation of facilities' proposed permit terms on the part of ADEM. In 
each case, EPA was unable to locate any evaluation or record of 
decision documenting that ADEM had critically evaluated the materials 
submitted as part of the permit applications, or otherwise documented 
its rationale for adopting those proposed permit terms prior to 
approving the application. As a consequence, EPA cannot conclude that 
the permits are as protective as the Federal CCR regulations.
    As noted above, EPA discussed many of these issues with ADEM and 
the State declined to revise the permits to be consistent with the 
Federal CCR regulations. ADEM also declined to demonstrate that its 
alternative requirements satisfy the requirement in RCRA section 
4005(d)(1)(B). Instead, the Alabama Attorney General, on behalf of 
ADEM, asserted in the Notice of Intent to Sue that EPA does not have 
the authority to consider implementation of the State program when 
determining whether a State program is sufficient, and that the Agency 
may only look to the ``four corners'' of the State program submission 
when evaluating the program for approval. In the Notice of Intent to 
Sue, the ``four corners'' of the application are described as being 
public participation, guidelines for compliance, guidelines for 
enforcement authority, and intervention in civil enforcement 
proceedings. Regarding deficiencies in implementation of a State CCR 
permit program, the State of Alabama's position must, therefore, be 
that EPA first approve a State CCR permit program even if the Agency 
knows the State's implementation is deficient prior to approval, and 
the Agency must then follow the process for withdrawal of the program 
through the program review and withdrawal provisions in RCRA sections 
4005(d)(1)(D) and (E), respectively. Id.
    EPA does not agree with ADEM's interpretation of the Agency's 
authority under RCRA, and the Agency is proposing to deny the program 
under RCRA section 4005(d)(1)(B). Though the statute authorizes EPA to 
approve a State CCR permit program in whole or in part, implementation 
of the groundwater monitoring, corrective action, and closure 
regulations are fundamental to an adequate CCR State permit program. 
EPA does not see any meaningful way for a State to implement a partial 
CCR permit program without the authority to oversee these three major 
elements of the CCR program. Thus, EPA is proposing to deny the entire 
Alabama CCR State permit program that ADEM submitted for approval.
    In Unit IV.A of this preamble, EPA responds to ADEM's position that 
RCRA section 4005(d) prohibits EPA from considering the permits issued 
under the State CCR permit program when determining whether to approve 
the program and that EPA may only address such issues after the State 
program is approved. In Unit IV.B of this preamble, the Agency provides 
a short summary of EPA's conclusions after review of the express terms 
of the ADEM statutes and regulations. In Unit IV.C of this preamble, 
EPA identifies specific permits that the Agency believes are deficient 
and explains the bases for EPA's proposed determination that they are 
inconsistent with the standard for approval in RCRA section 
4005(d)(1)(B).

[[Page 55226]]

A. Legal Authority To Evaluate State CCR Program Submittals

    For the reasons set forth below, EPA does not agree with ADEM's 
assertion that EPA may not consider the State's CCR permit history when 
determining whether to approve its permit program. In short, the Agency 
interprets the statute to require EPA to consider the CCR permits a 
State has issued under its CCR program when determining whether the 
State program can be approved, where such information is available 
prior to approval.
1. The Statute Requires EPA To Consider a State's CCR Permits When 
Determining Whether To Approve the Program if the Information Is 
Available
    Section 4005(d)(1)(B) of RCRA provides in part that the 
Administrator ``shall approve, in whole or in part, a permit program or 
other system of prior approval and conditions submitted under 
subparagraph (A) if the Administrator determines that the program or 
other system requires each coal combustion residuals unit located in 
the State to achieve compliance with'' either: (1) The Federal CCR 
requirements at 40 CFR part 257 (i.e., the Federal CCR regulations); or 
(2) Other State criteria that the Administrator, after consultation 
with the State, determines to be at least as protective as the Federal 
requirements. 42 U.S.C. 6945(d)(1)(B) (emphasis added). The statute 
directs the Administrator to determine whether the State program 
``requires each'' CCR unit in the State ``to achieve compliance'' with 
either the Federal standard or an alternative State standard at least 
as protective as the Federal CCR regulations. This necessarily includes 
Agency consideration of both a State's statute and regulations and what 
the State actually requires individual CCR units to do, such as in 
permits or orders, when such information is available prior to approval 
of the State program. By specifying that EPA is to determine that the 
State program requires each unit ``to achieve compliance,'' rather than 
merely that the State requires compliance or has the authority to 
require compliance, Congress indicated that EPA is not restricted to 
evaluating the letter of the State's regulations. Moreover, the statute 
makes clear that once a permit goes into effect, those are the relevant 
requirements applicable to the CCR unit rather than the regulations. 
See 42 U.S.C. 6945(d)(3) (specifying that the applicable criteria for 
CCR units in an approved State are those contained in the State permit, 
rather than the Federal or State regulations). Whether issued permits 
comply with Federal requirements or a State program that is at least as 
protective is directly relevant to whether the State program ``requires 
each CCR unit in the State to achieve compliance.'' If issued permits 
do not comply, the State program does not require compliance. EPA 
cannot reasonably ignore such information, when available, as it falls 
squarely within the ordinary meaning of what the statute expressly 
directs EPA to consider. This is particularly true, where, as here, the 
Agency knows ADEM is issuing permits to CCR units that do not require 
compliance with the Federal CCR regulations, and the State has not 
demonstrated that its alternative approach is as protective as the 
Federal CCR regulations.
    In this case, ADEM adopted into its State regulations the 
provisions of the Federal CCR regulations. For this reason, ADEM 
believes that EPA must approve the State's CCR program because it in 
large part mirrors to the Federal CCR regulations, thus, according to 
ADEM, the State program satisfies the requirements for an approvable 
program pursuant to RCRA section 4005(d)(1)(B)(i). ADEM is correct that 
EPA may approve a State program under this provision based on the fact 
that the State's regulations are identical to those in the Federal CCR 
regulations, but not where the State interprets the State regulations 
to impose significantly different requirements than the Federal CCR 
regulations, and the State has issued permits authorizing actions that 
the Federal regulations prohibit. Here, despite adopting the language 
in the Federal CCR regulations, ADEM has affirmatively stated that it 
interprets the State regulations differently than the identically 
worded Federal provisions and has issued permits on that basis, even 
though the Agency has informed the State on multiple occasions that its 
interpretation and implementation of the regulations are not consistent 
with the Federal CCR regulations. See Units III.E and IV.C of this 
preamble (discussing Alabama's interpretation of ``infiltration'' under 
Sec.  257.102(d)(1)(i), among other examples). Based on all of the 
information in the record, EPA cannot conclude that Alabama's program 
``requires each'' CCR unit in the State ``to achieve compliance with'' 
the Federal CCR regulations as required by RCRA section 
4005(d)(1)(B)(i).
    Further, because Alabama is interpreting the language in the 
Federal CCR regulations differently than the Agency, Alabama is 
essentially submitting ``other State criteria,'' and in order for EPA 
to approve such a program, Alabama must provide information to support 
a determination that the State criteria are ``at least as protective as 
the [Federal CCR regulations]'' consistent with RCRA section 
4005(d)(1)(B)(ii). EPA has explained its position to Alabama, most 
recently by letter dated February 1, 2023, and Alabama has declined to 
provide any explanation, much less an adequate one, of how its program 
will require each CCR unit to achieve compliance with standards at 
least as protective as the Federal CCR regulations. Accordingly, the 
Agency is proposing to deny Alabama's request for approval of its CCR 
permit program. This proposed denial is based on all the available 
information in the record, and as discussed in Unit IV.C of this 
preamble, it demonstrates that the Alabama CCR permits do not require 
each CCR unit in the State to achieve compliance with requirements at 
least as protective as those contained in the Federal CCR regulations.
2. EPA Is Not Required To Approve a Deficient State Program and Then 
Redress the Deficiencies Through RCRA's Program Review Provisions
    In addition to the express terms of RCRA section 4005(d)(1)(B), as 
explained below, the overall context of RCRA section 4005(d) supports 
consideration of State CCR permits when they have been issued prior to 
approval of the State program. Even were that not the case, it would be 
unreasonable to interpret the statute to require that EPA must approve 
a State program based on the four corners of the submission and then 
use the program review provisions of RCRA section 4005(d)(1)(D) to 
address pre-existing deficiencies in the program. As an initial matter, 
EPA questions how it would be reasonable to ignore directly relevant 
and readily available information in review of a State program that 
will stand in for a Federal program, because once EPA approves a State 
program, the requirements of the State program apply instead of the 
Federal rules. Further, once a State permit is issued, facilities are 
shielded from enforcement of anything other than the provisions of the 
State permit. Compounding the problem is the time it would take to go 
through the statutorily mandated process to withdraw a deficient 
program and the fact that prior noncompliance would be arguably 
sanctioned by approval of a State program that is being implemented 
improperly.
    In this case, all the potential problems that can arise by 
approving a State CCR program based solely on the ``four

[[Page 55227]]

corners'' of the State application are in play. Specifically, the State 
is interpreting the terms of the State program (i.e., the terms of the 
Federal CCR regulations) in a manner that is less protective than the 
Federal CCR regulations, the State is issuing permits based on its 
flawed interpretation, EPA approval of the State program would be the 
equivalent of approving the deficient permits, it would take 
considerable time to withdraw the State program after approval, and, in 
the interim, facilities would be able to operate under permits that are 
less protective than required. Furthermore, the Agency is proposing to 
determine, based on the available information, that Alabama's CCR 
permit program is deficient under two of the bases provided in RCRA 
section 4005(d)(1)(D)(ii), EPA has notified Alabama of the 
deficiencies, and the State has declined to address them. See Unit IV.C 
of this preamble (discussing the deficiencies in Alabama's CCR 
program).
    The statute requires EPA to periodically review approved State 
programs and provides a process by which EPA can address identified 
deficiencies. RCRA sections 4005(d)(1)(D)(i) and 4005(d)(1)(D)(ii), 
respectively. The review provisions in RCRA section 4005(d)(1)(D)(i) 
require review:
     from time to time, as the Administrator determines 
necessary, but not less frequently than once every 12 years;
     not later than 3 years after the date on which the 
Administrator revises the applicable criteria for coal combustion 
residuals units under part 257 of title 40, Code of Federal Regulations 
(or successor regulations promulgated pursuant to sections 6907(a)(3) 
and 6944(a) of this title);
     not later than 1 year after the date of a significant 
release (as defined by the Administrator), that was not authorized at 
the time the release occurred, from a coal combustion residuals unit 
located in the State; and
     on request of any other State that asserts that the soil, 
groundwater, or surface water of the State is or is likely to be 
adversely affected by a release or potential release from a coal 
combustion residuals unit located in the State for which the program or 
other system was approved.
    The statute clearly provides for review of State programs whenever 
``the Administrator determines necessary,'' in addition to the 
situations that mandate EPA review of a State program (e.g., RCRA 
section 4005(d)(1)(D)(i)(I) requiring review periodically and at least 
every 12 years). Under Alabama's reading of the statute, EPA must 
approve a knowingly deficient State program and then undertake a 
program review, either mandatory or discretionary, to address the 
deficiencies in that same program. Under such circumstances, CCR units 
in the State would potentially be allowed to operate in a manner that 
is not consistent with the Federal CCR regulations for many years 
unless EPA were to undertake a voluntary program review immediately 
after approving the program.
    An additional factor that argues against Alabama's interpretation 
is the fact that RCRA section 4005(d)(1)(D)(ii) provides a process that 
EPA must follow to address identified deficiencies in a State CCR 
permit program before EPA may withdraw the program, and, during that 
time, ADEM could continue to issue permits that are not as protective 
as the statute requires. See also 42 U.S.C. 6945(d)(1)(E)(i) (allowing 
withdrawal of a State program only after notice to the State and an 
opportunity for a hearing). Specifically, under RCRA section 
4005(d)(1)(D)(ii), EPA must provide the State with notice of 
deficiencies in the State program and an opportunity for a hearing if 
the Administrator determines that:
     a revision or correction to the permit program or other 
system of prior approval and conditions of the State is necessary to 
ensure that the permit program or other system of prior approval and 
conditions continues to ensure that each coal combustion residuals unit 
located in the State achieves compliance with the criteria described in 
clauses (i) and (ii) of subparagraph (B);
     the State has not implemented an adequate permit program 
or other system of prior approval and conditions that requires each 
coal combustion residuals unit located in the State to achieve 
compliance with the criteria described in subparagraph (B); or
     the State has, at any time, approved or failed to revoke a 
permit for a coal combustion residuals unit, a release from which 
adversely affects or is likely to adversely affect the soil, 
groundwater, or surface water of another State.
    The information currently available to EPA already indicates that 
Alabama's program is deficient under the first two provisions of RCRA 
section 4005(d)(1)(D)(ii). First, a revision to Alabama's CCR permit 
program is necessary to ensure that each CCR unit located in the State 
achieves compliance with State standards that are ``at least as 
protective as'' the Federal CCR regulations because Alabama has never 
adequately explained how its alternative requirements achieve that 
standard. 42 U.S.C. 6945(d)(1)(D)(ii)(I). Second, as explained further 
in Unit IV.C. of this preamble, ADEM has not implemented its permit 
program in a manner that ``ensures each CCR unit located in the State 
achieves compliance with the criteria described in subparagraph (B).'' 
42 U.S.C. 6945(d)(1)(D)(ii)(II). In addition, EPA has notified Alabama 
of these deficiencies on multiple occasions, and the State has not 
provided an adequate justification for the position that its 
interpretation of the Federal CCR regulations should govern over EPA's 
interpretation.
    Given Alabama's continued failure to adequately address EPA's 
concerns with its CCR program, EPA has no reason to believe that 
Alabama will change its interpretation and implementation of its 
program if EPA were to approve Alabama's CCR program and then 
subsequently proceed with the RCRA section 4005(d)(1)(D)(ii) process to 
attempt to resolve the program deficiencies. EPA would then have to go 
through the RCRA section 4005(d)(1)(E) process to withdraw the Alabama 
program. In that case, EPA would then be back at the point where 
Alabama would have to either adopt EPA's interpretation of the Federal 
CCR regulations or explain how its alternative interpretation ensures 
that the State's program is as least as protective as the Federal CCR 
regulations.
    The statutory language is clear, and it does not support Alabama's 
interpretation. In addition, the Agency believes Alabama's 
interpretation could, as in this case, lead to the illogical result 
that EPA must approve a State CCR permit program that it believes it 
likely will eventually have to withdraw. EPA also declines to adopt 
Alabama's suggested approach because the process to withdraw takes 
significant time and in the interim Alabama would likely continue to 
issue permits that allow CCR units in the State to operate under 
conditions that are less protective than those required in the Federal 
CCR regulations. Finally, EPA is aware of several CCR permits that 
allow units to operate less protectively than required by Federal CCR 
regulations and approving Alabama's program would mean that these units 
would no longer be subject to the Federal CCR regulations. Thus, if EPA 
were to approve Alabama's program now (i.e., after the deficient CCR 
permits were issued), the Alabama CCR program, including the facility-
specific permits, would apply in lieu of the Federal CCR

[[Page 55228]]

regulations pursuant to RCRA section 4005(d)(1)(A) and (3).
    For all these reasons, EPA does not believe the statute must be 
interpreted as Alabama suggests and EPA declines to adopt the State's 
interpretation.

B. EPA's Analysis of the Alabama CCR Regulations

    Section 4005(d)(1)(A) of RCRA, 42 U.S.C. 6945(d)(1)(A), requires a 
State seeking CCR permit program approval to submit to EPA, ``in such 
form as the Administrator may establish, evidence of a permit program 
or other system of prior approval and conditions under State law for 
regulation by the State of coal combustion residuals units that are 
located in the State.'' Although the statute directs EPA to establish 
the form of such evidence, the statute does not require EPA to 
promulgate regulations governing the process or standard for 
determining the adequacy of such State programs. EPA, therefore, 
developed the Coal Combustion Residuals State Permit Program Guidance 
Document; Interim Final (82 FR 38685, August 15, 2017) (the ``Guidance 
Document''). The Guidance Document provides recommendations on a 
process and standards that states may choose to use to apply for EPA 
approval of a State CCR permit program, based on the standards in RCRA 
section 4005(d), existing regulations at 40 CFR part 239, and the 
Agency's experience in reviewing and approving State programs.
    As stated above, State permit programs under RCRA generally include 
both sector specific technical regulations (e.g., performance standards 
for CCR units) and general State permitting and enforcement provisions 
that apply to all the different State RCRA permitting programs. In this 
case, Alabama is seeking approval of a partial State CCR permit program 
and it established State regulations that are almost the same as the 
Federal CCR regulations for the portions of the Federal program for 
which the State is seeking approval. To the extent the Federal and 
State provisions are different, the differences do not on their face 
substantively make the State regulations less protective than the 
Federal CCR regulations. EPA reviewed ADEM's CCR regulations and, based 
on that review, EPA proposes to find that the express terms of the 
regulations provide ADEM with sufficient authority to issue permits 
that are at least as protective as those required under the Federal CCR 
regulations. See the TSD Volume III (providing a detailed analysis of 
the regulatory terms of Alabama's CCR regulations). EPA is proposing to 
determine that the terms of the regulations provide the State with 
sufficient authority to implement an adequate CCR permit program 
despite the fact that the Agency is also proposing to deny the 
Application for Alabama CCR permit program based on the State's 
issuance of permits under those same regulations. Therefore, the Agency 
believes the record would support approval of Alabama's program if the 
State either modified its permits to be consistent with the Federal 
requirements or demonstrated that its alternative requirements are at 
least as protective as the Federal CCR regulations.
    EPA briefly discusses its evaluation of the State's regulations 
below. A comprehensive evaluation is included in the TSD Volume III in 
the docket for this proposed action.
1. Adequacy of Technical Criteria
a. Alabama CCR Regulations
    EPA first evaluates the technical criteria that will be included in 
each permit the State issues to determine whether they are the same as 
the Federal criteria, or to the extent they differ, whether the 
modified criteria are ``at least as protective as'' the Federal 
requirements. See 42 U.S.C. 6945(d)(1)(B).
    On April 20, 2018, ADEM, by and through the Alabama Environmental 
Management Commission (EMC), amended ADEM Admin. Code div. 335-13 to: 
(1) Modify Chapters 1, 4, and 5 and (2) Add a new Chapter 15: Standards 
for the Disposal of Coal Combustion Residuals in Landfills and Surface 
Impoundments. These rules became effective on June 8, 2018. In response 
to EPA comments and changes to the Federal CCR regulations, ADEM 
proposed and finalized several amendments to its CCR rules with the 
first revisions becoming effective February 15, 2021. The most recent 
revisions became effective December 13, 2021.
    ADEM's regulations adopt the Federal CCR regulations amended 
through August 28, 2020, and include the corrections EPA made at 
Sec. Sec.  257.102(d)(3)(ii) and 257.103(f)(1)(vi) (85 FR 72506, 
November 12, 2020) (except for certain provisions outlined below).
    EPA has preliminarily determined that the Alabama CCR permit 
program contains all the technical criteria in 40 CFR part 257, subpart 
D, except for the provisions specifically discussed below. EPA's full 
analysis of the terms of the Alabama CCR permit program and how the 
Alabama regulations differ from the Federal requirements can be found 
in the TSD Volume III.
b. Federal Rule Provisions Excluded From Alabama's Request for Approval 
of a Partial Program
    Alabama is requesting approval for a partial State CCR program, 
rather than a full CCR program that includes all the requirements of 
the Federal CCR regulations. ADEM is not seeking approval for the 
following six provisions:
    1. ADEM Administrative Code r. 335-13-15-.01(1)(d); this State 
provision is the analog to the Federal exclusion of inactive surface 
impoundments at inactive facilities, found at Sec.  257.50(e), that was 
vacated in Utility Solid Waste Activities Group v. EPA, 901 F.3d 414 
(per curiam) (USWAG);
    2. ADEM Admin. Code r. 335-13-15-.07(4)(f); this State provision is 
the analog to the Federal requirement for alternative closure 
deadlines, found at 40 CFR 257.103(f);
    3. EPA has revised the Federal regulations to granting 
Participating State Directors authority to issue certifications in lieu 
of requiring a professional engineer (PE) certification. ADEM did not 
adopt these provisions; therefore, an owner or operator of a CCR unit 
must submit certifications from a PE, as appropriate, as required by 
ADEM Admin. Code chapter 335-13-15;
    4. The Federal regulations include a provision that authorizes the 
suspension of groundwater monitoring requirements under certain 
circumstances, found at Sec.  257.90(g), which the State has not 
adopted;
    5. The Federal regulations include a provision for an alternate 
liner demonstration found at Sec.  257.71(d), and the State has not 
adopted this Federal provision; and,
    6. ADEM Admin. Code r. 335-13-15-.06(6)(h)2.: The State has adopted 
the groundwater protection standards for cobalt, lead, lithium, and 
molybdenum found at Sec.  257.95(h)(2) but is not seeking approval 
because the Federal provision has been challenged and is under 
reconsideration.
    More detail on the elements of the partial program and EPA's 
analysis of the program can be found in the TSD Volume III. With the 
exception of specific provisions spelled out in the TSD Volume III, EPA 
has preliminarily determined that the Alabama CCR regulations contain 
all the technical elements of the portions of the Federal CCR 
regulations for which the State is seeking approval.

[[Page 55229]]

2. Review of Generally Applicable Alabama CCR Permit Program Statutes 
and Regulations
    As explained above, supra note 12, Alabama's CCR permit program 
regulations include general requirements that apply across multiple 
permit programs, and its Application for approval of a CCR permit 
program thus includes both general and facility/unit-specific 
requirements in the State CCR permit program. EPA therefore also 
evaluated the Alabama CCR permit program as modified to address CCR 
units using the process discussed in Units II.C and IV.A of this 
preamble. EPA's findings are summarized below and provided in more 
detail in in the TSD Volume III for this notice.
    In evaluating Alabama's CCR permitting requirements, EPA reviewed 
the State's permit requirements for CCR units including applicability, 
duration, application process, denial process, and the process for 
draft and final permit determinations. EPA also reviewed Alabama's 
requirements that apply to modification, suspension, and revocation of 
permits. For permit modifications, EPA specifically looked at major and 
minor modifications to determine which modifications would require 
public participation. After conducting this review, EPA has 
preliminarily determined that the Alabama regulations concerning CCR 
permit applications and approvals is adequate, and that this aspect of 
the Alabama CCR permit program meets the standard for program approval.
    Based on RCRA section 7004, 42 U.S.C. 6974, it is EPA's judgment 
that an adequate State CCR permit program will ensure that: (1) 
Documents for permit determinations are made available for public 
review and comment; (2) Final determinations on permit applications are 
made known to the public; and (3) Public comments on permit 
determinations are considered. Alabama has adopted public participation 
opportunities for the CCR program that can provide an inclusive 
dialogue, allowing interested parties to talk openly and frankly about 
issues within the CCR program and search for mutually agreeable 
solutions to differences. EPA reviewed Alabama's public participation 
requirements, processes, and procedures including public notices, 
public comment periods (including consideration of public comments), 
public hearings, and public availability of final determinations. An 
overview of the Alabama public participation provisions is provided in 
the TSD Volume III. After conducting this review, EPA has preliminarily 
determined that the Alabama approach to public participation 
requirements provides adequate opportunities for public participation 
in the permitting process sufficient to meet the standard for program 
approval.
    EPA also reviewed Alabama's compliance monitoring authority, 
enforcement authority, and the procedures for intervention in civil 
enforcement proceedings. It is EPA's judgment that an adequate permit 
program should provide the State with the authority to gather 
information about compliance, perform inspections, and ensure that 
information it gathers provides an adequate basis for enforcement. 
ADEM's statutory authority for compliance monitoring for its Solid 
Waste Program is set forth in sections 22-27-7, 22-27-9, 22-27-12, 22-
22A-5 and 22-22A-8 of the Code of Alabama, 1975. These portions of the 
statute, as well as ADEM Admin. Code rules 335-13-1-.11(2) and 335-13-
6-.01(2) give the Department authority during an inspection to obtain 
all information necessary to determine whether the owner/operator is in 
compliance with State CCR requirements. This includes authority to 
conduct monitoring and testing when necessary.
    Based on the information Alabama has submitted on the State's 
permitting requirements, EPA has preliminarily determined these aspects 
of the Alabama CCR permit program provide the State with the necessary 
authority to implement an adequate State program. More detail on the 
review and analysis of Alabama's CCR permit program can be found in the 
TSD Volume III.

C. EPA's Analysis of Alabama's Permits Issued Under the State CCR 
Regulations

    EPA conducted a review of Alabama's permitting decisions as part of 
the Agency's evaluation of whether ADEM's CCR permit program requires 
each coal combustion residual unit located in the State to achieve 
compliance with standards at least as protective as the Federal CCR 
regulations. 42 U.S.C. 6945(d)(1)(B). Alabama's permitting decisions 
issued under its CCR regulations are directly relevant to determining 
whether the State's program satisfies this statutory requirement, and 
EPA considers such information to be appropriately part of the record 
for a decision on the permit program when permit issuance begins prior 
to approval of the State program and the Agency has information that 
the State's implementation is not sufficiently protective.
    ADEM submitted its revised State CCR permit program Application on 
December 29, 2021. Less than a month later, on January 11, 2022, EPA 
published several proposed decisions responding to requests from owners 
and operators of CCR units nationwide for extensions of the April 11, 
2021, deadline to cease sending waste to unlined CCR surface 
impoundments (Part A proposals). EPA proposed to deny several of the 
extension requests because facilities were planning to close unlined 
CCR surface impoundments with, among other things, waste remaining in 
groundwater without adopting engineering measures to limit the flow of 
groundwater into and out of the unit. Soon after issuing the Part A 
proposals, several states, utility facilities that own unlined surface 
impoundments, and trade groups contacted EPA to object to the Agency's 
application of the closure requirements to the unlined surface 
impoundments in those proposed decisions. Based on these objections, 
EPA was concerned that Alabama's and other states' CCR permit programs 
were being interpreted and implemented to allow facilities to close 
unlined surface impoundments without complying with all the necessary 
requirements in the Federal regulations.
    Because of these concerns, on March 15, 2022, EPA sent a list to 
ADEM of CCR surface impoundments in Alabama that, based on the 
information available to EPA, appear to be inundated by 
groundwater.\14\ Over the next several months, EPA and ADEM met several 
times to discuss the application of the Federal closure performance 
standards to such impoundments, and to better understand how the State 
interpreted its own requirements.\15\
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    \14\ The CCR surface impoundments with insufficient permits that 
are discussed in this Unit of the preamble are all surface 
impoundments with WBWT. For a list of all the CCR surface 
impoundments EPA identified in Alabama with WBWT, see Email from 
Meredith Anderson to Scott Story. CCR units in AL. March 15, 2022.
    \15\ Interactions between EPA and Alabama about implementation 
of the State program include: April 13, 2022, meeting to discuss the 
Federal closure performance standards; three separate meetings to 
discuss the proposed closure requirements for Plant Gorgas, Plant 
Greene County, and Plant Gadsden; May 10, 2022, meeting to further 
discuss the closure performance standard and specifically how ADEM 
was interpreting and applying the closure and groundwater monitoring 
performance standards at the Ash Pond at Plant Gadsden; and May 28, 
2022, meeting to discuss the status of closure activities at Plant 
Greene County and Plant Gadsden. A list of EPA/Alabama interactions 
is in the Technical Support Document Volume II.
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    EPA also started reviewing permits for unlined surface impoundments 
in Alabama as part of EPA's review of the State CCR permit program. As 
a consequence, in meetings and in correspondence with ADEM, EPA

[[Page 55230]]

expressed concern that Alabama's permit program appeared to differ from 
the Federal program, and that these differences appeared to make the 
State's program less protective than the Federal program. As a result 
of these discussions, on July 7, 2022, EPA informed ADEM via telephone 
that EPA would be unable to approve ADEM's CCR permit program 
Application until Alabama demonstrated to EPA that the State is 
implementing its program to be as protective as the Federal CCR 
regulations.\16\ Further, EPA explained to ADEM that it was exploring 
options for actions to take at the Federal level with respect to both 
the CCR permit program Application and at specific facilities where 
there are outstanding concerns.
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    \16\ July 7, 2022- Telephone call between Carolyn Hoskinson, 
Director of EPA's Office of Resource Conservation and Recovery, and 
Stephen Cobb, Chief of the Land Division at the Alabama Department 
of Environmental Management.
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    Throughout the course of these discussions, and in EPA's nationwide 
Part A determinations, EPA explained the existing requirements under 
the Federal regulations; in response, ADEM offered notably different 
interpretations of some of the obligations under the State's current 
closure requirements. Despite the Agency's concerns, the State 
continues to implement its CCR program in a manner that is less 
protective than the Federal CCR regulations, and Alabama has not 
adequately explained how its alternative State program satisfies the 
statutory requirement to require each CCR unit in the State to achieve 
compliance with either the Federal requirements or with State standards 
that are at least as protective as the Federal requirements.
    As part of the evaluation of Alabama's CCR program submittal, EPA 
reviewed four final State CCR permits issued by ADEM for the following 
facilities: Plants Colbert, Gadsden, Greene County, and Gorgas. EPA's 
review focused specifically on permits issued to unlined surface 
impoundments that have closed or are closing with waste that will 
remain in place below the water table, because these units have the 
greatest potential to cause significant environmental and human health 
effects if mismanaged. EPA limited its review to information in the 
permit record (e.g., the Permit Application or information on ADEM's e-
File site) and to information publicly available on each facility's CCR 
website, even though the permit record alone should contain all the 
information necessary to determine whether the permit is as protective 
as the Federal CCR regulations. EPA also did not attempt to catalog 
every potential inconsistency between the permits and the Federal CCR 
regulations. Instead, EPA concentrated on the permits' consistency with 
fundamental aspects of the closure, groundwater monitoring, and 
corrective action requirements. EPA took this approach because the 
purpose of this review is to determine whether Alabama's program meets 
the statutory standard for approval, not to reach final conclusions 
about an individual facility's compliance with the CCR regulations.
    During its review, EPA identified a consistent pattern of ADEM 
issuing permits to CCR units that fail to demonstrate compliance with 
fundamental requirements in part 257, without requiring the permittees 
to take specific actions to bring the units into compliance. EPA also 
identified a consistent pattern of ADEM approving documents submitted 
by the facilities, such as closure plans, groundwater monitoring plans, 
and assessments of corrective measures, even though the submissions 
lacked critical information or are otherwise deficient. ADEM also did 
not require the permittees to take any action to cure deficiencies in 
the permits even where ADEM previously identified the deficiencies and 
requested further information prior to issuing the final permits. 
Specifically, EPA is proposing to determine that ADEM issued multiple 
permits allowing CCR in closed units to remain saturated by 
groundwater, without requiring engineering measures that will control 
the groundwater flowing into and out of the closed unit. See, 40 CFR 
257.102(d). EPA is also proposing to determine that ADEM approved 
groundwater monitoring systems that contain an inadequate number of 
wells, and in incorrect locations, to monitor all potential contaminant 
pathways and to detect groundwater contamination from the CCR units in 
the uppermost aquifer. See, 40 CFR 257.91. Finally, EPA is proposing to 
determine that ADEM issued multiple permits that effectively allow the 
permittee to delay implementation of effective measures to remediate 
groundwater contamination both on- and off-site of the facility. See, 
40 CFR 257.96-257.97. Overall, EPA's review of the permit records and 
other readily available information documents a consistent pattern of 
deficient permits and a lack of oversight and independent evaluation of 
facilities' proposed permit terms. In each case, EPA was unable to 
locate any evaluation or record of decision documenting that ADEM 
critically evaluated the materials submitted as part of the permit 
application, or otherwise documented its rationale for adopting them. 
For all these reasons, EPA is proposing to conclude that the ADEM 
permits discussed below are not as protective as the Federal CCR 
regulations.
    In the next several sections, EPA discusses specific issues 
identified during the review of ADEM's final permits for Plants 
Colbert, Gadsden, Greene County, and Gorgas.\17\ Based on EPA's review, 
the Agency is proposing to deny Alabama's Application because the 
State's CCR permit program does not require each CCR unit in the State 
to achieve compliance with either the minimum requirements in the 
Federal CCR regulations or with alternative requirements that EPA has 
determined to be at least as protective as the Federal provisions.
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    \17\ On January 31, 2023, EPA Region 4 sent a Notice of 
Potential Violations (NOPV) and Opportunity to Confer to Alabama 
Power Company. The NOPV addressed concerns with compliance of 
Alabama Power Company's Plant Barry Ash Pond. The NOPV addressed the 
following potential violations: failure to meet the criteria for 
conducting the closure of the Plant Barry Ash Pond, failure to 
establish an adequate groundwater monitoring system, and failure to 
address certain site-specific criteria in the Emergency Action Plan. 
Although the permit and record for Plant Barry share many of the 
flaws in the CCR permits for other unlined surface impoundments in 
Alabama, EPA will not address the Plant Barry permit as part of this 
action because the enforcement process with the facility is ongoing.
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1. Colbert Fossil Plant
    TVA owns and operates the Colbert Fossil Plant (Colbert or Colbert 
Plant) located in Colbert County, Alabama, and it submitted a permit 
application for the facility dated December 10, 2021.\18\ The plant 
property is on the south bank of the Tennessee River, approximately 8 
miles west of Tuscumbia, Alabama. The Colbert Fossil Plant was fully 
idled and stopped generating electricity in March 2016. The plant had 
five generating units with a combined generating capacity of 1,204 
megawatts. In accordance with the ADEM Land Division, Solid Waste 
Program, Standards for Disposal of Coal Combustion Residuals in 
Landfills and Surface Impoundments, Chapter 335-13-15-.02, Ash Disposal 
Area 4 (also called Ash Pond 4) is classified as an existing CCR 
surface impoundment. Ash Disposal Area 4 is located on the southern 
portion of the plant property, approximately 3,000 feet south of the 
powerhouse. The CCR surface impoundment is bounded to the west by 
Colbert Steam Plant Road, to the east by Cane Creek, and to the south 
by Lee Highway. EPA reviewed TVA's permit application and draft and 
final permits

[[Page 55231]]

for the Colbert Plant along with associated documents. Issues with 
closure, groundwater monitoring networks, and corrective action at the 
Colbert Plant are discussed below.
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    \18\ Tennessee Valley Authority Colbert Fossil Plant (COF) Ash 
Pond 4 Permit Application. Submitted to ADEM. December 10, 2021.
---------------------------------------------------------------------------

a. TVA Colbert Closure Issues
    The Federal CCR regulations provide two options for closing a CCR 
unit: closure by removal and closure with waste in place. 40 CFR 
257.102(a). Both options establish specific performance standards. 40 
CFR 257.102(c) and (d). TVA closed Ash Pond 4 at Colbert by leaving the 
CCR in the unit in place; but, as explained below, the TVA application 
for Ash Pond 4 did not comply with the Federal closure standards for 
closure with waste in place for unlined surface impoundments and ADEM 
issued the permit without addressing the deficiencies.
    TVA's Permit Application for the Colbert Plant explains that Ash 
Pond 4 was built in 1972 and TVA completed its closure in early 2018, 
prior to its application for a permit under the ADEM CCR rules in 
Chapter 335-13-15.\19\ TVA elected to close Ash Pond 4 by leaving CCR 
in place and constructing a final cover system over the waste, which is 
estimated to be 2.6 million cubic yards (CY) of waste.\20\ Closure of 
Ash Pond 4 was completed in accordance with a closure and post-closure 
care plan dated February 2017, which was approved by ADEM on August 22, 
2017.\21\ Closure activities were deemed complete in March 2018 and a 
certification report dated September 18, 2018, documenting closure of 
Ash Disposal Area 4, was submitted to ADEM.
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    \19\ The terms ``Ash Pond 4'' and ``Ash Pond Area 4'' are both 
used in the Colbert Plant Permit Application to refer to the 
impoundment in question. For purposes of this proposal, EPA is 
referring to the impoundment as Ash Pond 4.
    \20\ The Permit Application states that the ``total capacity of 
Ash Disposal Area 4 is approximately 2.6 million CY, covering 
approximately 52 acres.'' EPA is aware that other reports State that 
the ``approximate volume of CCR material at the time of the 
inspection'' is 3.29 million CY. See, e.g., FY2021 Intermediate 
Inspection of CCR Facilities dated May 6, 2021. For purposes of 
estimating volumes of saturated CCR in this proposal, EPA is taking 
an approach that provides a minimum estimate, relying on the value 
presented in the Permit Application to represent the volume of CCR 
in the impoundment, instead of relying on the larger estimates 
established based on the inspection of the unit.
    \21\ Tennessee Valley Authority. Permit Application for CCR 
Surface Impoundment, TVA Colbert Fossil Plant Ash Disposal Area 4. 
December 10, 2021. Attachment I.
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    ADEM's Final Permit, issued in October 2022, provides the following 
terms and conditions:
    Closure Timeframe and Notifications. The Permittee shall close 
their CCR units as specified in 335-13-15-.07(2), this permit and the 
Application.
    B. Criteria for Closure.
    1. Cover. Closure of a CCR landfill, surface impoundment, or any 
lateral expansion of a CCR unit must be completed by either leaving the 
CCR in place and installing a final cover system or through removal of 
the CCR and decontamination of the CCR unit, as described in 335-13-
15-.07(3)(b) through (j). The minimum and maximum final grade of the 
final cover system may be less than 5 percent and greater than 25 
percent, as specified in the Permit Application, for the Colbert Fossil 
Plant Ash Disposal Area 4. Ash Disposal Area 4 may utilize erosion 
control measures, as specified in the Permit Application, other than 
horizontal terraces. (See Section IX.A. and B.)
    2. Written Closure Plan. The written closure plan, as part of the 
Application, must include, at a minimum, the information specified in 
335-13-15-.07(3)(b)1.(i) through (vi).
    According to ADEM, ``[t]he Department adopted the terms of the 
closure plan as part of the permit as the Department has previously 
approved the plan and determined it meets both State and Federal 
regulations for closure of a CCR unit.'' \22\ Once ADEM approved and 
adopted TVA's Closure Plan into the permit, the Closure Plan, rather 
than the referenced State regulations, became the State requirements 
with which TVA is required to comply. See, 42 U.S.C. 6945(d)(3)(A). As 
discussed in detail in the next section and summarized in Table II, 
between 2019 and 2021, approximately 6 to 13 feet of ash (on average)- 
or 13 to 35 percent of the CCR in the closed Ash Pond remains saturated 
by groundwater.
---------------------------------------------------------------------------

    \22\ Letter from Stephen Cobb to Carolyn Hoskinson, Responding 
to EPA Comments on Proposed Permit for the
    Tennessee Valley Authority Colbert Fossil Plant, October 27, 
2022, Enclosure 1, page 6.
---------------------------------------------------------------------------

i. The CCR in the Closed Ash Pond 4 Remains Saturated by Groundwater
    Neither TVA's Closure Plan, the Permit Application, ADEM's Final 
Permit, or any other document in the permitting record specifically 
discuss how the closure of Ash Pond 4 would meet the closure 
performance standards given the measured groundwater elevations and 
hydrogeology of the site. Accordingly, EPA reviewed information in the 
Permit Application as well as other publicly available information 
available on TVA's CCR website to determine whether groundwater remains 
in contact with the CCR in Ash Pond 4 since closure was completed in 
March 2018. As described below, available groundwater measurements 
recorded between 2018 and 2021 show that, even after closure, 
groundwater levels at Ash Pond 4 continue to be present above the base 
of the unlined impoundment, saturating a portion of the CCR in the 
closed unit. EPA's basis for these findings is described in the 
succeeding paragraphs, which summarize EPA's understanding of the base 
elevation of Ash Pond 4 (e.g., the lowest extent of CCR in the unit), 
the groundwater levels since closure was completed in 2018, and EPA's 
estimate of the volume of CCR that remains saturated with liquid 
(groundwater). More details on EPA's analyses can be found in TSD 
Volume I.\23\
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    \23\ Volume I: Technical Support Document for the Proposed 
Notice to Deny Alabama's Coal Combustion Residuals Permit Program, 
Supplemental Analyses of Technical Issues with ADEM Permits. U.S. 
Environmental Protection Agency, Office of Land and Emergency 
Management (5304T), 1200 Pennsylvania Avenue NW, Washington, DC 
20460. August 2023.
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(1) Base of the Impoundment
    Ash Pond 4 is a 52-acre CCR surface impoundment that was created by 
constructing a single dike around the perimeter of the impoundment and 
two internal divider dikes. EPA was unable to locate information in the 
Permit Application or other publicly available documents that fully 
describes the as-constructed configuration of the bottom of Ash Pond 4 
across its entire footprint prior to the initial receipt of waste. 
However, based on information in the Permit Application and documents 
referenced in the Permit Application, the lowermost documented 
elevations at which CCR occurs within the impoundment varies depending 
on the location, ranging from approximately 413.5 to 427.1 ft above 
mean sea level (MSL). See TSD Volume I, Section II.a.
    EPA also relied on an average elevation to estimate the volume of 
CCR in the impoundment remaining in contact with groundwater, rather 
than trying to account for what may be as much as a 14-foot difference 
across the 52-acre impoundment. Specifically, EPA relied on an average 
bottom elevation of 422 ft above MSL, which is the average of elevation 
measurements taken at 18 locations within the footprint of the 
impoundment based on borings for piezometers and wells. Information on 
these borings is found on construction drawings 10W395-7 through 9 and 
a report from 2010. See TSD Volume I, Section II.a. This average is 
also consistent with several documents in the Permit Application and 
other documents that depict the

[[Page 55232]]

base of the impoundment at 422 ft above MSL. For example, Section A-A 
of construction drawing 10N292R3 shows a bottom elevation of 
approximately 422 ft above MSL in the vicinity of the northern 
perimeter dike where the spillways were constructed. Id. at Volume I, 
Section II.a.i.3. Another example is a slope stability section 
supporting a steady-state seepage analysis that shows a portion of the 
base of the impoundment to be at an elevation of 422 ft above MSL. Id. 
at Section II.a.i.2. Similarly, design drawings from 2010 for a 
temporary rock buttress and sheet pile wall constructed in a portion of 
an internal divider dike show the bottom of the impoundment to be 422 
ft above MSL at this location. Id. at Section II.a.i.3. A final example 
is the liner design demonstration prepared by TVA to comply with Sec.  
257.71 that states ``[f]rom information contained in drawing 10N290, it 
was assumed the base of the pond is at elevation 422 ft.'' Id. at 
Section II.a.iv. However, it is important to note that the use of the 
422 ft elevation mark to represent the base of the unit was an effort 
to represent average conditions. As noted earlier, the preponderance of 
the evidence suggests that base of the impoundment varies depending on 
the location, ranging from approximately 413.5 to 427.1 ft above MSL, 
but an average value of 422 ft above MSL is technically defensible and 
conservatively high. See TSD Volume I, Section II.a. Volumes during 
worst case conditions (i.e., when river stages and water tables are 
higher than reported values) would be greater, and actual saturated CCR 
volumes could be higher than estimated if portions of the unit with 
lower documented waste bottom elevations (less than 422 ft above MSL) 
were considered. The estimates provided by EPA below and in the TSD 
Volume I are reasonable based on the available information provided in 
the Permit Application regarding the waste bottom elevations.
ii. Characterization of Groundwater Elevations
    Information from TVA's Permit Application clearly supports a 
conclusion that at least some portion of the CCR in Ash Pond 4 remains 
saturated by continued infiltration of groundwater. The groundwater 
elevation maps for 2020 and 2021 provided in the Permit Application 
reveal that the lowest measured groundwater elevations range between 
just over 414 to just over 416 ft above MSL.\24\ These levels are found 
in groundwater monitoring wells COF-105 and CA31A, which are screened 
in the residuum/alluvium layer, and consistently measure the lowest 
groundwater elevations of any of the wells immediately surrounding Ash 
Pond 4. In every measurement reported in the Permit Application, the 
groundwater elevations measured in these wells are 0.86 to 2.7 feet 
above the lowest documented elevation of CCR within the unit (413.5 ft 
above MSL). Furthermore, COF-105 is located approximately 150 feet east 
of the unit boundary in the downgradient direction and CA31A is located 
approximately 400 feet northeast of the unit boundary in the 
downgradient direction. As corroborated by monitoring well and 
piezometer data from within the unit, the actual groundwater elevations 
directly beneath the unit are generally higher than these minimum 
recorded values, which are well beyond the unit boundary in 
downgradient directions. This basic information clearly supports a 
conclusion that at least some portion of the waste in Ash Pond 4 is wet 
under typical conditions.
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    \24\ Tennessee Valley Authority. Permit Application for CCR 
Surface Impoundment, TVA Colbert Fossil Plant Ash Disposal Area 4. 
December 10, 2021. Attachment H, Appendix A, Figures A-1 through A-
4.
---------------------------------------------------------------------------

    A closer examination of available data from the Permit Application 
further supports this conclusion. Assuming that the base of the CCR is 
uniformly at 422 ft above MSL, based on the contour intervals depicted 
on the groundwater elevation map for February 27, 2020 (Figure A-1), 
groundwater elevations range from 414.36 to 437.46 ft above MSL, and 
exceed 422 ft above MSL at over fifty percent of the entire Ash Pond 4 
footprint. Similarly, the groundwater elevation contours depicting the 
February 22, 2021 (Figure A-3), groundwater elevation data documents 
water levels ranging from 415.14 to 436.54 ft above MSL, indicating 
that water levels greater than 422 ft above MSL are present at one-
third or more of the area within the impoundment.
    Even though data from summer monitoring events show that summer 
groundwater levels are considerably lower than the data reported for 
February 2020 and 2021, there still appears to be a considerable 
footprint of wet waste under all reported conditions, and conditions 
indicative of groundwater saturation or infiltration into the closed 
unit appear to be sustained without interruption in some regions of the 
unit. On August 10, 2020 (Figure A-2), groundwater levels ranged from 
414.38 to 422.58 ft above MSL and are mapped between 415 and 420 ft 
over most of the unit's footprint, with a small portion in the extreme 
southwest corner of the mapped area showing higher groundwater levels 
of greater than 420 ft. On August 23, 2021 (Figure A-4), groundwater 
elevations ranged from 414.79 to 429.00 ft above MSL and are mapped as 
being greater than 422 ft above MSL beneath a somewhat larger portion 
of the impoundment's surface area in the southwestern corner, with the 
remainder of groundwater elevations in the unit mapped between 415 and 
420 ft above MSL.
    The Permit Application also presents groundwater elevation contour 
maps for the Tuscumbia limestone bedrock aquifer for 2020 and 2021. 
This is appropriate as there is an abundance of information contained 
in the materials presented for the Permit Application, the annual 
groundwater monitoring reports, and the 2019 Comprehensive Groundwater 
Investigation Report that indicates that the Tuscumbia limestone 
aquifer is in direct contact and is in direct hydraulic communication 
with the overlying residuum/alluvium aquifer.\25\ In this respect, EPA 
interprets the Tuscumbia limestone aquifer to be part of the uppermost 
aquifer system for the unit. EPA's analysis in this regard is included 
in Section II.b of the TSD Volume I.
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    \25\ Stantec, Comprehensive Groundwater Investigation Report, 
First Amended Consent Decree # 20-01-2013-900123 Ash Pond 4 and Ash 
Stack 5. TVA Colbert Fossil Plant, Prepared for Tennessee Valley 
Authority Chattanooga, Tennessee. May 17, 2019.
---------------------------------------------------------------------------

    For the Tuscumbia limestone, the Permit Application included four 
contour maps from groundwater elevation measurement events on February 
27, 2020, August 10, 2020, February 22, 2021, and August 23, 2021.\26\ 
These data sets, which are summarized in Table I below, generally 
indicate that water levels in the bedrock aquifer are higher than the 
422-foot base elevation beneath significant regions of the Ash Pond 4 
footprint during most of these four monitoring events, particularly 
during winter conditions. For February 27, 2020 (Figure A-5), 
groundwater elevations in the Tuscumbia limestone ranged from 414.61 to 
437.77 ft above MSL.\27\ TVA's interpretive contours depicting the 
Tuscumbia limestone bedrock groundwater elevations for February 27, 
2020, indicate that the entire

[[Page 55233]]

impoundment is characterized by water levels greater than or equal to 
422 ft above MSL, except for a very small area near monitoring well 
COF-111 near the eastern boundary. For February 22, 2021 (Figure A-7), 
measured groundwater elevation data for the Tuscumbia limestone aquifer 
ranged from 411.11 to 436.70 ft above MSL. TVA's interpretive contour 
map for the same period indicates that groundwater levels at or above 
422 ft above MSL were mapped at approximately half of the unit's 
footprint. Similarly, on August 23, 2021 (Figure A-8), groundwater 
elevation data ranged from 413.47 to 429.07 ft above MSL and 
interpretive contours for same period for the Tuscumbia limestone 
bedrock aquifer again indicate that approximately 50 percent of the 
unit's footprint exhibits groundwater levels at or above 422 ft above 
MSL. Conditions during the August 10, 2020 (Figure A-6), monitoring 
event show lower groundwater levels, with groundwater elevation values 
for the Tuscumbia limestone aquifer ranging from 412.85 to 422.54 ft 
above MSL. TVA's interpretive groundwater elevation contours for the 
same period show groundwater elevations below 422 ft above MSL in all 
areas except for a small portion near the southwestern corner of the 
unit. It should also be noted that surface water levels associated with 
the four monitoring events listed above indicate that surface water 
levels in the Pickwick Reservoir are greater than 413.5 ft above MSL 
(the lowest documented waste bottom elevation) for two of the four 
monitoring events as shown in Table I. It is also worth noting that 
river stage, which fluctuates, was measured as above the lowest 
groundwater elevations measured in the Tuscumbia limestone for three of 
the four time periods presented in the Permit Application.
---------------------------------------------------------------------------

    \26\ Permit Application at Figures A-5 through A-8, 
respectively.
    \27\ The elevation corresponding to wells CA29BR and CA22B on 
Figures A-5 through A-8 were excluded from this range based on TVA's 
footnote indicating these wells are ``poorly connected to site wide 
groundwater flow system.''
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    Together with the documented occurrence of solution features in the 
limestone and associated preferential pathways in groundwater, it is 
reasonable to expect some degree of hydraulic communication between the 
reservoir/river and the underlying limestone aquifer. Depending on the 
magnitude and duration of the occurrence of higher river/reservoir 
levels, some degree of recharge from the river to the underlying 
aquifers may be expected. It is perhaps partly for this reason that the 
CCR in the unit remains wet, at least intermittently, so many years 
after the unit was closed. Despite the disclaimer,\28\ which appears on 
all the Tuscumbia groundwater elevation maps in the Permit Application, 
EPA believes that the interpretive contours provided on these maps 
corroborate the anisotropic groundwater flow conditions to which TVA 
refers. EPA's interpretation of this information confirms the presence 
of northeast striking preferential pathways within the Tuscumbia 
limestone aquifer. In any event, the measured head values in the 
Tuscumbia limestone aquifer within and surrounding the unit are hard 
data points that enable the simplistic analysis regarding position of 
the waste relative to measured water levels. EPA's analysis and 
reasoning on this subject are further detailed in Section II.b of the 
TSD Volume I.
---------------------------------------------------------------------------

    \28\ Permit Application at Note ``1'' on Figures A-5 through A-
8.

    Table I--Maximum and Minimum Reported Groundwater Elevations a for the Tuscumbia Limestone and Associated
     Contempraneous River Stage Elevations for Pickwick Reservoir on Four Monitoring Events During 2020-2021
----------------------------------------------------------------------------------------------------------------
                                                   Feb 27, 2020    Aug 10, 2020    Feb 22, 2021    Aug 23, 2021
----------------------------------------------------------------------------------------------------------------
High Groundwater Elevation......................          437.77          422.54           436.7          429.07
Low Groundwater Elevation.......................          414.61          412.85          411.11          413.47
River Stage \b\.................................          410.95          414.24          412.41          413.79
----------------------------------------------------------------------------------------------------------------
\a\ All data presented in feet above MSL, NGVD 29 datum.
\b\ River stage values obtained from Figures A-5 through A-8 in the Groundwater Plant in the Permit Application.

    The groundwater elevations provided in the Permit Application are 
based primarily on data collected from outside of the unit, without 
consideration of actual groundwater levels directly within and beneath 
the unit. Although data from inside the unit were not provided in the 
Permit Application, data from piezometers and monitoring points within 
Ash Pond 4 are available in the Annual Inspection Reports posted on 
TVA's CCR website. EPA reviewed the water level information reported in 
the Annual Inspection Reports from 2016 through 2022.\29\ These reports 
document the change of water levels within the unit over time since 
closure and provide for a direct, more highly resolved and 
representative analysis of actual groundwater levels and conditions 
directly within and beneath the unit. These data demonstrate that 
significant areas and volumes of CCR below the water table have been 
and remain sustained within the unit as discussed in further detail 
below. These data also enabled EPA to estimate the minimum volumes of 
saturated CCR that remain in the closed unit under various observed 
conditions.
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    \29\ The TVA reports are titled: 2022 Engineering (Annual) 
Inspection of CCR Facilities dated May 9, 2022; FY2021 Intermediate 
Inspection of CCR Facilities dated May 6, 2021; FY2020 Intermediate 
Inspection of CCR Facilities dated July 29, 2020; FY2019 
Intermediate Inspection of CCR Facilities dated August 30, 2019; 
FY2018 Intermediate Inspection of CCR Facilities dated September 4, 
2018; and FY2017 Intermediate Inspection of CCR Facilities dated 
December 15, 2017. Collectively, EPA is referring to one or more of 
these reports as the ``Annual Inspection Reports.''
---------------------------------------------------------------------------

    The most recent Annual Inspection Report from May 2022 states that 
``[t]here are 54 automated vibrating wire piezometers, eight (8) 
automated slope inclinometers, and six (6) manual magnetic 
extensometers installed at Ash Disposal Area 4.'' The Annual Inspection 
Reports categorize the piezometers as ``A'' or ``B'' in the 
alphanumeric identifiers assigned to each individual piezometer. 
Because many of these ``A'' piezometers have recorded ``dry'' 
conditions in later monitoring events, it appears that the ``A'' series 
piezometers generally represent the shallower portions of the 
subsurface beneath the unit, e.g., screened primarily in CCR materials. 
While there seems to be some degree of overlap in the vertical 
dimension, the ``B'' series piezometers appear to be screened into 
generally deeper stratigraphic intervals than the ``A'' series, and 
generally reflect water levels in the deeper portions of the CCR waste 
as well as the underlying native aquifer materials in contact with the 
waste.
    The groundwater elevations measured in ``A'' and ``B'' series 
piezometers for the post-closure period from 2019 through 2021 varied 
over similar ranges. Groundwater elevations measured in the ``A'' 
series ranged from 414.58 to 447.4

[[Page 55234]]

ft above MSL during this post-closure period whereas groundwater 
elevations in the ``B'' series ranged from 414.5 to 445.1 ft above MSL 
during the same period. Average piezometric water levels in the shallow 
``A'' piezometers during this post-closure period were generally at or 
above 430 ft above MSL beneath most of the footprint of the unit, 
except for a lobe of lower groundwater elevations (generally measured 
from 423 to 428 ft above MSL or below) in the east-central portion of 
the unit. The only groundwater elevations measured at or below 422 ft 
above MSL were at locations on the extreme eastern edge of the 
impoundment or further eastward in the vicinity of Cane Creek. At the 
deeper ``B'' piezometers, average groundwater elevations during the 
post-closure period from 2019 to 2021 were observed to be universally 
greater than 425 ft above MSL except for a thin strip along the eastern 
margin of the impoundment containing a small area (approximately 15% or 
less of the unit's footprint area) of somewhat lower groundwater 
elevations (ranging generally from 416 to 424 ft above MSL), which 
projects into the unit in the vicinity of piezometer COF_P4_VWP03_B. 
Lastly, the most recently reported groundwater elevation measurements 
in each piezometer and well (in 2021) continue to show a similar 
pattern, with nearly all groundwater elevation values between 425 to 
440 ft above MSL, except for a thin strip of lower groundwater 
elevations near the extreme eastern margin of the impoundment, again 
with a small lobe-shaped area of lower groundwater elevations (421.5 to 
424.2 ft above MSL) projecting a short distance into the central part 
of the unit from the east-central edge. Again, groundwater exceeding 
the average waste elevation of 422 ft above MSL was measured across 
virtually the entire unit.\30\
---------------------------------------------------------------------------

    \30\ EPA's analysis of post-closure (2019-2021) groundwater 
elevations within the unit evaluated ``A'' and ``B'' series 
piezometers. It should be noted that the ``A'' series also included 
a number of additional piezometers with an ``S'' designation 
indicating shallow screened interval depths. Evaluation of ``A'' 
series data also included shallow alluvium monitoring wells COF-104, 
-105, and -111, and CA-17A. Evaluation of ``B'' series data also 
included alluvium monitoring wells COF-104, -105, and -111. It 
should be noted that these monitoring wells are located along the 
extreme eastern periphery of the unit or downgradient to the east of 
the unit. It is also noted that these few monitoring wells 
consistently recorded some of the lowest groundwater elevations in 
the combined ``A'' and ``B'' data sets. In this this respect, the 
average values for the ``A'' and ``B'' piezometers are somewhat 
lower than they would be if the monitoring well data were excluded. 
This is to say that actual average groundwater elevation conditions 
within the unit proper are likely slightly higher than these 
assessments reflect due to the inclusion of the monitoring well 
data.
---------------------------------------------------------------------------

    EPA also evaluated these data using common commercially available 
software for contouring groundwater data,\31\ creating a series of maps 
that present a series of potentiometric surfaces and groundwater 
elevation measurements based on monitoring well and piezometer data 
from within Ash Pond 4, for various time frames and representative 
values, including pre-closure, during or immediately after closure, and 
post-closure. These groundwater elevation contour maps are available in 
Section II.b of the TSD Volume I.
---------------------------------------------------------------------------

    \31\ EPA used EnviroInsite software to visualize geotechnical 
data (e.g., contouring groundwater elevation data from discrete 
point measurements).
---------------------------------------------------------------------------

    While different software packages could be used to contour 
groundwater data and many different interpolation methods, EPA's 
contouring approach honors the data and other known constraints and is 
a conservate estimation of site conditions on those dates. These 
computer-generated contour maps are useful to illustrate what the 
measured groundwater elevations reveal: that groundwater levels 
decreased immediately after closure, but even several years later 
groundwater levels continue to exceed not only the lowest documented 
waste bottom elevation (413.5 ft above MSL), but also the average waste 
bottom elevation (422 ft above MSL) of the CCR in the unit. The 
computer-generated contours of average groundwater elevations 
representing pre-closure conditions measured at monitoring wells from 
January 1, 2016, through December 31, 2017, indicate pronounced 
groundwater mounding centered on the central and southcentral portions 
of the unit where a broad region of groundwater elevations on the order 
of 450 ft above MSL are outlined. See Section II.b in TSD Volume I. 
Contours of average groundwater elevations over a timeframe that 
includes the initiation of unit closure, measured at monitoring wells 
and piezometers from January 1, 2018, through December 31, 2019, 
indicate a reduction in the groundwater elevations beneath the central 
part of the unit to values on the order of 430 ft above MSL. A 
significant reduction in groundwater elevations as compared to pre-
closure conditions is evident from these data. Id. Further decreases in 
groundwater elevations are indicated from computer-generated contours 
of average groundwater elevations measured at monitoring wells and 
piezometers post-closure from January 1, 2020, through December 31, 
2021. However, the magnitude of groundwater elevation decreases is much 
smaller compared to the period just after closure, with the 
northeastern corner of the unit indicating the greatest relative 
decrease. Id. It is important to note that despite the post-closure 
decreases in groundwater elevations, groundwater levels currently 
remain well above the lowest recorded waste bottom elevation (413.5 ft 
above MSL) of CCR in the unit as well as the average (422-ft above MSL) 
waste bottom elevation of CCR at the preponderance of the impoundment.
    It is important to note, however, that the foregoing analyses are 
somewhat skewed to the high side of the range of groundwater 
fluctuation because the Annual Inspection Reports list the highest 
recorded value for each location over the reported time interval 
(approximately the previous year). It is possible that some portions of 
the unit are above the water table during certain times of year or 
under certain hydrologic conditions. Nevertheless, the available 
reported data strongly suggests that there is a large and measurable 
volume of persistent wet CCR present in the closed unit. With these 
caveats, EPA's overall analysis of groundwater elevation data for Ash 
Pond 4 is as follows.
    Prior to closure, there appears to have been significant 
groundwater mounding beneath Ash Pond 4 that has slowly decreased since 
pond closure. Such mounding resulted in substantially higher 
groundwater levels directly beneath the impoundment that generally 
decrease radially (as indicated by lower levels consistently measured 
in the monitoring wells in the peripheral and downgradient portions of 
the unit). As discussed above, it appears that the ``A'' piezometers 
(assumed shallow) are screened within the CCR materials and are 
measuring piezometric head beneath the impoundment area and the 
(assumed) deeper ``B'' piezometers are sampling groundwater in the 
native geologic materials and/or CCR near the base of CCR waste beneath 
the impoundment. The reported groundwater elevations in both the ``A'' 
(shallow) and the ``B'' (deeper) piezometers indicate that groundwater 
continues to infiltrate into the CCR in many portions of the closed 
unit as noted in the paragraphs above. While the assumed deeper 
piezometers (``B'' series) typically have water levels somewhat closer 
to those observed in the monitoring wells peripheral to the unit, the 
generally higher elevations in the shallow (``A'') piezometers versus 
the deeper (``B'') piezometers indicates that a downward vertical 
gradient likely

[[Page 55235]]

existed between the impoundment and the underlying geologic materials 
prior to closure, that the general potential for downward vertical 
hydraulic gradients has been sustained during and following closure, 
and that it persists currently, many years after closure. A detailed 
analysis of well/piezometer construction information, boring logs and 
other data are needed to further confirm and assess persistence, 
magnitude, and variability of downward vertical hydraulic gradients 
from the unit to the underlying aquifers.
    Upgradient (west) groundwater elevations were consistently above 
waste bottom elevations, whereas downgradient waste bottom elevations 
were consistently near or above groundwater elevations. In a general 
sense, Ash Pond 4 can be described as a quasi-wedge-shaped body with 
higher elevations and generally thicker waste profiles on the west 
side, sloping eastward where generally thinner waste profiles occur at 
lower elevations to the east. While the groundwater table also 
generally slopes from west to east, the groundwater elevation surface 
(i.e., water table) does not fall to the level of the base of the waste 
except in small portions of the eastern half of the unit, at best, and 
at worst only near the extreme eastern margins of the unit. This 
equates to a quasi-wedge-shaped body of saturated waste with generally 
higher elevations and greatest thicknesses to the west, pinching out in 
the eastward direction at the eastern margin of the unit.
    These data and analyses underscore the general concerns that absent 
active engineering measures, which the permit approved by Alabama does 
not require, groundwater will continue to infiltrate into and flow out 
of Ash Pond 4 and the waste will remain wet for the foreseeable future.
iii. Volumes of Saturated CCR Estimates
    Based on the available information concerning the configuration of 
the CCR waste mass, elevation and configuration of the surface defining 
the interface between the CCR waste and underlying native geologic 
materials, and the position of the water table under a variety of 
conditions, EPA made a series of calculations to estimate the volume of 
CCR in Ash Pond 4 that continues to be saturated with groundwater. In 
all the estimates, the volume of saturated waste is generally estimated 
to be the area within the impoundment where groundwater elevations 
exceed the average bottom elevation of 422 ft above MSL, using computer 
contouring software to create modeled contours of the groundwater 
elevation surface within the unit. Under all scenarios considered, 
substantial volumes of CCR remain saturated by continually infiltrating 
groundwater. EPA's analyses and the resulting estimates can be found in 
Section II.c of the TSD Volume I.
    EPA estimates that significant volumes of saturated CCR currently 
remain in the closed unit, ranging from 346,183 to 914,774 CY of CCR. 
EPA further estimates that approximately 13% to 35% of the total volume 
of CCR in the unit remains in the groundwater, and that 75% to 97% of 
the total unit surface area is underlain by saturated CCR. Finally, EPA 
estimates that, on average, approximately 6 to 13 feet of the CCR 
remains saturated with groundwater. See Table II below.
    Under this approach, EPA used a 2-ft contour interval to create 
more granular digital models of the groundwater surface elevation. 
Computer contouring software was further used to calculate the areas 
contained between successive 2-ft contour lines and to calculate the 
average groundwater elevation for that subregion. Saturated waste 
thickness values were then calculated for each sub-area containing 
groundwater elevations greater than 422-ft above MSL. Thickness values 
were then multiplied by the respective areas computed for each sub-area 
to obtain partial volumes of CCR in the aquifer. Total volumes of 
saturated CCR were then computed by adding the partial volumes for each 
sub-area.
    Using this approach, three separate estimates of volumes of 
saturated CCR were calculated from average groundwater elevations 
reported from overburden monitoring wells for the following time 
periods:
     Spring 2019 (January 1, 2019, through May 31, 2019),
     Spring 2020 (January 1, 2020, through May 31, 2020), and
     Spring 2021 (January 1, 2021, through May 31, 2021).
    Table II summarizes the volumes and areas of saturated CCR 
calculated for each of these time intervals.

        Table II--Depth, Surface Area, and Volume Estimates of Saturated CCR at Ash Pond 4 for 2019-2021
----------------------------------------------------------------------------------------------------------------
                   Estimates of saturated CCR                       Spring 2019     Spring 2020     Spring 2021
----------------------------------------------------------------------------------------------------------------
Total Surface Area of Unit (SY) \a\.............................         275,880         275,880         275,880
Total CCR Volume (CY) \b\.......................................       2,600,000       2,600,000       2,600,000
Average Thickness of Saturated CCR (ft).........................              13              13               6
Surface Area of Unit with CCR in Groundwater (SY)...............         263,907         267,657         204,302
Percentage of Unit Area with CCR in Groundwater (%).............              96              97              75
Volume Percentage of Saturated CCR (%)..........................              35              33              13
Volume of Saturated CCR (CY)....................................         914,774         858,445         346,183
----------------------------------------------------------------------------------------------------------------
\a\ Source: AECOM. Closure and Post-Closure Plan. October 12, 2016.
\b\ Source: CTI and Associates. FY2021 Intermediate Inspection of CCR Facilities. May 6, 2021.

    The 2019 and 2020 total estimates of saturated CCR for the unit 
were similar, 914,774 and 858,445 CY, respectively. Total volume 
estimates for 2021 were lower (346,183 CY) owing to lower average 
groundwater elevations over that period as compared to 2019 and 2020. 
It should be noted that daily precipitation amounts from publicly 
available data indicate a greater level of rainfall in the proximity of 
the unit in Spring 2020 as compared to 2021. Additionally, ambient 
groundwater levels in monitoring wells outside of the impoundment were 
generally higher in 2020 as compared to 2021. Lastly, there is a 
greater number of monitoring points with reported water level data for 
2020. It is therefore likely that variations in local precipitation 
exert a strong and variable influence on groundwater elevations beneath 
and in the vicinity of the unit, and therefore the lower levels in 2021 
are not enough to support a conclusion that the unit will eventually 
dry itself out. In any case, the supplemental analysis using the more 
refined contour intervals is consistent with and within the upper and 
lower bounds of previous estimates, further corroborating the overall 
conclusion of sustained and ongoing presence of significant volumes of 
CCR that continues to be infiltrated by groundwater from within the 
unit. The magnitude of the estimates clearly

[[Page 55236]]

varies in response to fluctuations in groundwater levels beneath the 
unit due to variation in annual precipitation and other factors, 
including closure. However, despite some evidence that water levels 
have declined somewhat since closure, the record supports a conclusion 
that substantial volumes of CCR will continue to be perpetually 
inundated by groundwater.
    Based on all these data EPA is proposing to determine that both the 
Closure Plan approved by ADEM and incorporated into the permit, and the 
closure itself (which ADEM also approved) are not consistent with the 
requirements in Sec.  257.102(d). Neither the approved Closure Plan nor 
any other document in the record for the permit accounts for the levels 
of groundwater present in the unit prior to closure or describes any 
engineering measures taken to meet each of the Federal CCR closure-in-
place performance standards in Sec.  257.102(d)(1) and (2) in light of 
the groundwater present in the unit. Nor, based on the post-closure 
groundwater elevation data from piezometer wells from 2019 to the 
present, did the approved closure address the groundwater continuously 
flowing into and out of the CCR, as required by the Federal 
regulations.
    The Federal regulations require that ``prior to installing the 
final cover system . . . [f]ree liquids must be eliminated by removing 
liquid wastes or solidifying the remaining wastes and waste residues.'' 
40 CFR 257.102(d)(2). Free liquids are defined as all ``liquids that 
readily separate from the solid portion of a waste under ambient 
temperature and pressure,'' regardless of whether the source of the 
liquids is from sluiced water or groundwater. 40 CFR 257.53. As EPA has 
previously explained, based on the regulatory terms, the structure, and 
context in which the terms are employed, as well as the dictionary 
definitions of ``liquid,'' and the fact that nothing in the regulatory 
definition limits the source of the liquid, EPA considers groundwater 
to be a liquid under the existing regulation.\32\ Consequently, the 
directive applies to both the freestanding liquid in the impoundment 
and to all separable porewater in the impoundment, whether the 
porewater was derived from sluiced water, stormwater runoff, or 
groundwater that migrates into the impoundment.
---------------------------------------------------------------------------

    \32\ U.S. EPA. Denial of Alternative Closure Deadline for 
General James M. Gavin Plant, Cheshire, Ohio. November 18, 2022. pp 
14-42; 88 FR 31,982, 31,992-31,993 (May 18, 2023).
---------------------------------------------------------------------------

    TVA's Annual Inspection Reports from 2016 through 2018 show that 
groundwater was infiltrating into Ash Pond 4. The average groundwater 
elevations measured at monitoring wells inside Ash Pond 4 from January 
1, 2016 through December 31, 2017 were on the order of 450 feet above 
MSL (i.e., approximately 28 feet above the average elevation of the 
CCR) centered on the central and southcentral portions of the 
unit).\33\ Yet neither the approved Closure Plan nor any other document 
in the record for the permit accounts for the approximately 28 feet of 
groundwater present in the unit prior to closure, or describes any 
engineering measures taken to eliminate the groundwater. The approved 
Closure Plan states only:
---------------------------------------------------------------------------

    \33\ Tennessee Valley Authority. FY2018 Intermediate Inspection 
of CCR Facilities. September 4, 2018; and Tennessee Valley 
Authority. FY2017 Intermediate Inspection of CCR Facilities. 
December 15, 2017.

    Final Closure of the Ash Pond 4 requires following general 
tasks: . . . Begin decanting the Ash Pond 4 using pumps and existing 
siphons. Discharged water will be monitored throughout decanting 
operations to maintain compliance with NPDES [National Pollutant 
---------------------------------------------------------------------------
Discharge Elimination System] permitted limits.

TVA Closure Plan, pp 6-7. As EPA has previously explained, Sec.  
257.102(d)(2)(i) establishes a clear standard to be met: ``free liquids 
must be eliminated.'' \34\ The regulation further specifies how this 
standard is to be met: by ``removing liquid wastes or solidifying the 
remaining wastes and waste residues.'' Id. In situations such as this, 
where the waste in the unit is inundated with groundwater, the 
requirement to eliminate free liquids thus obligates the facility to 
take engineering measures necessary to ensure that the groundwater, 
along with the other free liquids, has been permanently removed from 
the unit prior to installing the final cover system. See, 40 CFR 
257.102(d)(2)(i). Yet neither the Closure Plan that ADEM approved nor 
the permit ADEM issued contained any such requirements.
---------------------------------------------------------------------------

    \34\ See, U.S. EPA. Denial of Alternative Closure Deadline for 
General James M. Gavin Plant, Cheshire, Ohio. November 18, 2022. pp 
14-42.
---------------------------------------------------------------------------

    Moreover, it is clear from the post-closure 2019-2021 Annual 
Inspection Reports that whatever measures were taken as part of closure 
did not actually eliminate free liquids from Ash Pond 4. These reports 
document average groundwater elevations within the Ash Pond that 
significantly exceed 422 above MSL. And the most recently reported 
groundwater elevation measurements in 2021 reported nearly all 
groundwater elevation at values of 425 to 440 ft above MSL, except for 
a thin strip of lower ground water elevations near the extreme eastern 
margin of the impoundment, again with a small lobe-shaped area of lower 
levels (421.5 to 424.2 ft above MSL) projecting a short distance into 
the central part of the unit. All of this information was available 
before ADEM issued the permit in October 2022, yet the permit was 
issued, essentially approving closure with CCR that will remain 
saturated by groundwater, with no engineering measures to limit 
groundwater from continually flowing into and out of the unit.
    A further concern is that, given the groundwater levels that 
continue to be measured in the unit, it is not clear that the remaining 
wastes have been stabilized sufficiently to support the final cover 
system, as required by Sec.  257.102(d)(2)(ii). What is clear, however, 
is that neither the approved Closure Plan nor ADEM's permit provides 
any details on how this performance standard was met, given that 
groundwater continues to flow into and out of the unit from the sides 
and bottom. The approved Closure Plan merely summarizes the Sec.  
257.102(d)(2) performance standards, and contains, for example, no 
description of how, if at all, the groundwater levels would be affected 
by any of the dewatering activities associated with unit closure. 
Consequently, EPA is proposing to determine that the approval of the 
Closure Plan, and subsequently the unit closure itself, in the absence 
of such information, and the failure to include measures in the permit 
requiring TVA to remedy the omission is not consistent with Sec.  
257.102(d)(2)(ii).
    EPA was also unable to find any description in the ADEM approved 
Closure Plan or any other permit document of engineering measures that 
TVA took to ``control, minimize, or eliminate, to maximum extent 
feasible'' either the post-closure infiltration of the groundwater into 
the waste or the post-closure releases of CCR or leachate to the 
groundwater, as a consequence of the groundwater that continues to 
infiltrate into and be released from the impoundment from the sides and 
bottom of the unit. 40 CFR 257.102(d)(1)(i). Based on the data and 
analyses described above, groundwater continues to infiltrate into the 
unit and yet the only measures described in the Closure Plan and the 
permit are those taken to facilitate consolidation and cap 
construction. In essence, this means the Ash Pond will continue 
releasing CCR contaminants indefinitely past the waste boundary unless 
TVA takes additional actions that are not required by or explained in 
the permit. Given that

[[Page 55237]]

reasonably available engineering measures exist that can prevent, or at 
least control, the flow of groundwater into the Ash Pond (and 
consequently the releases out of the Ash Pond), such as physical 
barriers or hydraulic containment systems, EPA cannot conclude that 
TVA's Closure Plan adequately describes how the closure work will meet 
the requirement to ``control, minimize or eliminate, to the maximum 
extent feasible'' post-closure infiltration into the unit and post-
closure releases of CCR or leachate to the groundwater. EPA is 
proposing to determine that the permit's exclusive reliance on 
engineering measures related to the consolidation and cap construction 
is inconsistent with Sec.  257.102(d)(1)(i).
    In addition, EPA was unable to identify any description in the 
Closure Plan narrative of how TVA will ``preclude the probability of 
future impoundment of water, sediment, or slurry.'' 40 CFR 
257.102(d)(1)(ii). The continued presence of groundwater in the unit 
constitutes the impoundment of water, and in the absence of any 
engineering measures, such as a slurry wall, there are no intrinsically 
obvious facts to demonstrate that this performance standard has been 
met. Finally, the Closure Plan contains no discussion of how the 
closure activities will minimize the need for additional maintenance of 
the Ash Pond beyond a brief discussion of the final cover system. 40 
CFR 257.102(d)(1)(iv).
    EPA raised these issues to ADEM in comments on the draft Colbert 
permit. In response, ADEM did not dispute EPA's conclusion that CCR in 
Ash Pond 4 remains saturated by groundwater. Instead ADEM stated that 
EPA's comments were based on a misinterpretation of the Federal 
regulations, raising three specific interpretations of the regulations 
that EPA has previously rejected. First, ADEM stated that ``the Federal 
CCR regulations do not require that the closure account for groundwater 
levels either before or after closure.'' Rather they claim the only 
requirements relevant to groundwater are the location restrictions 
applicable to new or operating units in Sec.  257.60 for an operating 
unit.\35\ To support this point ADEM argues that Sec.  257.102(d)(1)(i) 
does not refer to groundwater. Second, ADEM argues that the Federal 
standards have been met because Colbert has installed a cover system 
that meets the standard in Sec.  257.102(d)(3), and the facility has 
complied with all of the requirements in the general performance 
standard relating to ``infiltration.'' The State supports this claim by 
pointing to the absence of specific requirements for an infiltration 
layer or barrier along the sides or bottom of a CCR unit, and by 
defining ``infiltration'' to refer exclusively to vertical infiltration 
from the surface, e.g., as rainwater entering through the cover system. 
Finally, ADEM states that ``In the event that it is determined that the 
closure activities conducted at Ash Disposal Area 4, as described 
above, are insufficient to prevent further groundwater contamination, 
additional controls or methods will be considered and addressed through 
the ongoing Assessment of Corrective Measures (ACM) and selection of a 
final remedy,'' that is, as part of corrective action.
---------------------------------------------------------------------------

    \35\ Letter from Stephen Cobb to Carolyn Hoskinson, Responding 
to EPA Comments on Proposed Permit for the Tennessee Valley 
Authority Colbert Fossil Plant. October 27, 2022. Enclosure 1, page 
6.
---------------------------------------------------------------------------

    EPA has explained, at length, that a closed, unlined impoundment, 
where the CCR remains in groundwater several feet deep because the 
facility failed to take any reasonably available engineering measures 
to prevent, or at least control, the flow of groundwater into the unit 
(and consequently the releases out of the unit), does not meet the 
requirements of Sec.  257.102(d).\36\ Specifically, in the final 
decision denying an extension under Part A for Gavin Generating 
Station, EPA expressly rejected the various interpretations of the 
regulatory text that ADEM offers in its October 27 letter. 
Specifically, EPA rejected the claim that the Federal closure 
regulations do not require a facility to address groundwater in the 
impoundment as part of closure. As noted above, based on the regulatory 
terms, the structure, and context in which the terms are employed, as 
well as the dictionary definitions of ``liquid,'' and the fact that 
nothing in the regulatory definition limits the source of the liquid, 
EPA considers groundwater to be a ``liquid'' under the existing 
regulation. See, Gavin Final Denial, p, 34; Response to Comments (RTC) 
on Gavin Proposed Denial, pp. 42-43, 53-58, 76.\37\ Moreover, the 
source of the liquid is not important with respect to its basic and 
fundamental designation as a liquid. It therefore does not matter 
whether the liquid in the surface impoundment comes from the rain, 
waters the facility deliberately places in the unit, floodwaters from 
an adjacent river, or from groundwater--all are liquids, and once 
present in the unit, they have the same potential to create leachate 
(another type of liquid), as well as to contribute to hydraulic head 
and drive flows driven by hydraulic gradients, and potentially 
destabilize the cover system.
---------------------------------------------------------------------------

    \36\ U.S. EPA. Denial of Alternative Closure Deadline for 
General James M. Gavin Plant, Cheshire, Ohio. November 18, 2022. pp 
14-42.
    \37\ U.S. EPA. Denial of Alternative Closure Deadline for 
General James M. Gavin Plant (Cheshire, Ohio) Response to Comments 
on Proposed Denial (Docket ID No. EPA-HQ-OLEM-2021-0590). November 
2022.
---------------------------------------------------------------------------

    EPA also explained its decision to rely on the plain language 
meaning of ``infiltration,'' explicitly rejecting the interpretation 
that the term refers only to the vertical migration of liquid through 
the cover system. See, Gavin Final Denial, pp 34-38; RTC pp. 38-47. 
Finally, EPA rejected the interpretation that under part 257 risks from 
a CCR unit submerged in groundwater are properly addressed exclusively 
as part of corrective action. Gavin Final Denial, pp. 41, RTC, pp 65-
68, 102. Accordingly, EPA is proposing to determine that ADEM's permit 
approved a closure of Ash Pond 4 that is not consistent with Sec.  
257.102(d).
    Because Alabama interprets its regulations to impose different 
requirements than the Federal regulations in part 257, EPA must 
determine that the State's requirements are ``at least as protective 
as'' the Federal requirements in order to approve the program. 42 
U.S.C. 6945(d)(1)(B)(ii). All the information available to EPA supports 
a conclusion that the closure approved in the Colbert permit is 
significantly less protective than a closure that meets the 
requirements under the Federal CCR regulations. Simply put, this is 
because allowing groundwater to continue flowing through the waste 
indefinitely will not protect human health and the environment. As 
discussed at length in 88 FR 32008-32012 (May 18, 2023), there are 
several ways in which the failure to remove CCR from the water table as 
part of closure can result in significantly higher risks than a 
comparable closure where waste no longer remains in contact with the 
water table.
    The Electric Power Research Institute (EPRI), a coal industry 
analytical group, reached similar conclusions in a report issued in 
2006, finding that ``[c]aps are not effective when CCP is filled below 
the water table, because groundwater flowing through the CCP will 
generate leachate even in the absence of vertical infiltration through 
the CCP.'' 38 39

[[Page 55238]]

Similarly, an earlier EPRI study examined the dewatering of three 
sites, two with ash situated above the water table and one with ash in 
contact with groundwater. The study concluded: ``[T]he existence of 
saturated ash will greatly reduce the effectiveness of any cap design 
when the facility is underlain by geologic materials with high 
hydraulic conductivity, because groundwater will continue to leach ash 
constituents.'' \40\ The fact that coal ash is in contact with 
groundwater can reduce the effectiveness of dewatering as well: 
``[W]hen ash remains below the water table, dewatering may be less 
effective because groundwater continues to leach constituents from the 
saturated ash, particularly if the impoundment is underlain by geologic 
media with relatively high rates of groundwater flow. In the case of 
[the studied site], concentrations increased because groundwater 
contact time with the saturated ash increased when the hydraulic 
gradient of the pond was removed.''
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    \38\ CCP means ``coal combustion product,'' another term for 
CCR.
    \39\ Electric Power Research Institute. Groundwater Remediation 
of Inorganic Constituents at Coal Combustion Product Management 
Sites, Overview of Technologies, Focusing on Permeable Reactive 
Barriers. Technical Report. 2006. 3-6.
    \40\ Electric Power Research Institute. Evaluation and Modeling 
of Cap Alternatives at Three Unlined Coal Ash Impoundments. 
Technical Report. 2001.1005165.
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    Finally, EPA is proposing to determine that the record fails to 
support a finding that ADEM's alternative approach of relying on 
corrective action to impose additional controls through the ongoing ACM 
and selection of a final remedy will be as protective as the Federal 
requirements. As discussed previously, data that was available at the 
time of permit issuance documents that groundwater elevations remain 
within the Ash Pond over three years after closure was completed, yet 
the permit that ADEM issued is silent on the need to address this as 
part of the corrective action process. Moreover, as discussed in the 
next section, EPA has serious concerns about the protectiveness of the 
corrective action at Colbert that ADEM is overseeing; for example, it 
has been three years since TVA posted its initial ACM, and the facility 
has still not selected a remedy. EPA is aware of no information to 
support a conclusion that continuing to allow saturated CCR to remain 
in Ash Pond 4 while TVA delays corrective action will protect human 
health or the environment, and ADEM has offered no explanation to 
support a conclusion that it is.
    Accordingly, EPA is proposing to determine that the permit for the 
Colbert Plant does not require TVA to achieve compliance with either 
Sec.  257.102(d) or with alternative State standards that EPA has 
determined to be at least as protective.
b. Groundwater Monitoring and Corrective Action Issues
i. Summary of Federal Requirements
    The objective of a groundwater monitoring system is to characterize 
groundwater to determine whether it has been contaminated by the CCR 
unit being monitored. This begins in detection monitoring, by 
conducting statistical comparisons between (1) The background level of 
a constituent measured in one or more upgradient wells, and (2) The 
level of that same constituent in a downgradient well. If the 
concentration of the constituent in the downgradient well is higher 
than the background concentration by a statistically significant 
amount, (i.e., a statistically significant increase (SSI) over 
background has been detected), this provides evidence of a potential 
release from the unit. After an SSI, assessment monitoring is required 
for additional constituents, and the concentrations of each of those 
constituents at downgradient wells are compared to a groundwater 
protection standard established for each constituent (either background 
level or a regulatory limit). Prompt contaminant detection is important 
in order for corrective measures to be developed to stop migration of 
contaminants as soon as possible.
    To ensure detection of a release, the regulations establish a 
general performance standard that all groundwater monitoring systems 
must meet: all groundwater monitoring systems must consist of a 
sufficient number of appropriately located wells that will yield 
groundwater samples in the uppermost aquifer that represent the quality 
of the background groundwater and the quality of groundwater passing 
the downgradient waste boundary, monitoring all potential contaminant 
pathways. 40 CFR 257.91(a)(1) and (2). Because hydrogeologic conditions 
vary so widely from one site to another, the regulations do not 
prescribe the exact number, location, and depth of monitoring wells 
needed to achieve the general performance standard. Rather the 
regulation requires installation of a minimum of one upgradient and 
three downgradient wells, as well as any additional monitoring wells 
necessary to achieve the general performance standard of accurately 
representing the quality of the background groundwater and the 
groundwater passing the downgradient waste boundary, monitoring all 
potential contaminant pathways. 40 CFR 257.91(c)(1) and (2). The 
number, spacing, and depths of the monitoring wells must be determined 
based on a thorough characterization of the site, including a number of 
specifically identified factors relating to the hydrogeology of the 
site (e.g., aquifer thickness, groundwater flow rates and direction). 
40 CFR 257.91(b). Groundwater elevation measurements must be obtained 
around the unit(s) at sampling events over time to characterize 
groundwater flow direction and identify seasonal and temporal 
fluctuations. 40 CFR 257.91(b). Further, any facility that determines 
that the regulatory minimum number of wells is adequate to meet the 
performance standard must document the factual basis supporting that 
determination. 40 CFR 257.91(f). In essence, the regulation establishes 
a presumption that the minimum of one upgradient and three downgradient 
wells is not sufficient, and it requires the facility to rebut the 
presumption in order to install only this minimum. See, 80 FR 21399. 
The number and placement of the monitoring wells is critical to proper 
characterization of the groundwater.
    The Federal CCR regulations establish a phased approach to 
monitoring. The first phase is detection monitoring where ``indicator'' 
constituents are monitored to determine whether groundwater is 
potentially being contaminated. In selecting the parameters for 
detection monitoring, EPA chose constituents that are present in CCR 
and would rapidly move through the subsurface, and thus provide an 
early indication of other contaminants that may be migrating from the 
CCR units. See, 80 FR 21397. The constituents that are monitored in 
detection monitoring are listed in Appendix III to 40 CFR part 257.
    After groundwater samples are collected during each monitoring 
event, the samples are sent to a laboratory for analysis to determine 
constituent concentrations. Once the facility has the analytical 
results, it must conduct statistical analyses to determine the 
background level of each constituent in upgradient groundwater for 
comparison with data from downgradient compliance wells. This stage is 
also critical, as even a sufficient number of properly placed wells 
will not provide adequate characterization if the sampling and analysis 
of data are not properly conducted. In order for upgradient groundwater 
quality to be accurately characterized, the statistical approach must 
be appropriate for site conditions and the data sets obtained. To this 
end, the regulations require an owner or operator to select a 
statistical approach and meet the performance

[[Page 55239]]

standards applicable to that approach when analyzing the data. 40 CFR 
257.93(f)-(g).
    If a facility determines that there is an SSI over background 
levels for one or more of the constituents in Appendix III at a 
monitoring well at the downgradient waste boundary, there is an 
opportunity to complete an alternate source demonstration (ASD) showing 
that a source other than the unit (i.e., an alternate source) was the 
cause of the SSI. 40 CFR 257.94(e)(2). A successful ASD must be 
sufficient to rebut the presumption that the CCR unit is the source of 
the SSI in a downgradient well of a properly designed groundwater 
monitoring network by demonstrating that a source other than the CCR 
unit is responsible for the SSI. An ASD requires conclusions that are 
supported by site-specific facts and analytical data in order to rebut 
the site-specific monitoring data and analysis that resulted in an SSI. 
Speculative or theoretical bases for the conclusions are insufficient. 
If a successful ASD for an SSI is not completed within 90 days, an 
assessment monitoring program must be initiated. Id.
    In assessment monitoring, facilities are required to monitor for 
additional constituents of concern, which are listed in appendix IV to 
part 257. Whenever assessment monitoring results indicate a 
statistically significant level (SSL) exceeding the groundwater 
protection standard has been detected at a downgradient well for any of 
the Appendix IV constituents, the facility must start the process for 
cleaning up the contamination by characterizing the nature and extent 
of the release and of site conditions that may affect the cleanup, and 
by initiating an assessment of corrective measures.
    As discussed in Unit III.B of this preamble and TSD Volume III, 
Alabama adopted regulations that mirror the Federal CCR regulations.
ii. TVA Colbert Groundwater Monitoring Issues
    ADEM approved the Groundwater Monitoring Plan (GWMP) dated December 
10, 2021, and incorporated the approved plan into the Final Permit.\41\ 
Once ADEM approved and adopted TVA's GWMP into the permit, the GWMP, 
rather than the referenced State regulations, became the State 
requirements with which TVA is required to comply. After reviewing the 
GWMP and all the materials in the permit record, EPA is proposing to 
determine that the groundwater monitoring network that ADEM approved is 
less protective than the Federal regulations in several regards. As 
discussed below and in the technical support document, EPA identified a 
number of deficiencies in the approved monitoring network.
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    \41\ Alabama Department of Environmental Management. Colbert 
Fossil Plant Coal Combustion Residual Permit. Permit No. 17-11, 
October 25, 2022. Section V.A., specifying that ``The Permittee 
shall install and/or maintain a groundwater monitoring system, 
identified in Table 1, as specified in 335-13-15-. 06(2) and the 
approved groundwater monitoring plan.''
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    First, EPA is proposing to determine that the approved monitoring 
system inappropriately includes numerous monitoring wells located 
beyond the waste boundary, as well as an insufficient number of 
monitoring wells at necessary locations and vertical depths to ensure 
that all potential contaminant pathways have been monitored. In 
addition, EPA has identified critical deficiencies in the construction 
of a significant number of the bedrock monitoring wells that call into 
question the accuracy of the monitoring data. As a consequence, EPA is 
proposing to determine that ADEM's Final Permit fails to require TVA to 
``install a groundwater monitoring system that. . .accurately 
represent[s] the quality of the groundwater passing the waste boundary 
of the CCR unit, [and to monitor] all potential contaminant pathways.'' 
40 CFR 257.91(a)(2).
(1) ADEM Issued a Final Permit That Approved the Bedrock Wells To Not 
Be Installed at the Waste Boundary in Accordance With Sec.  257.91(a)
    The Federal CCR regulations require that a downgradient monitoring 
system ``be installed at the waste boundary that ensures detection of 
groundwater contamination in the uppermost aquifer,'' and define the 
uppermost aquifer as ``the geologic formation nearest the natural 
ground surface that is an aquifer, as well as lower aquifers that are 
hydraulically interconnected with this aquifer within the facility's 
property boundary.'' 40 CFR 257.53, 257.91(a)(2). The cross sections 
and boring logs that were included as attachments to the Permit 
Application confirm that the unconsolidated and underlying limestone 
aquifers are hydraulically interconnected and communication via 
vertical migration can occur. The hydraulic connection between the 
Tuscumbia limestone aquifer, and the Tennessee River/Pickwick Reservoir 
and Cane Creek, as well as the hydrogeologic continuum between the 
Tuscumbia limestone and the overlying epikarst, residuum, and alluvial 
units of the upper aquifer system, all indicate that the Tuscumbia is 
an integral part of the composite uppermost aquifer system. 
Accordingly, the entire horizontal length along the CCR unit must be 
monitored in all hydrogeologic units present, alluvium, residiuum, 
epikarst, and bedrock in accordance with Sec.  257.91.
    The approved GWMP includes bedrock monitoring wells COF-111BR, COF-
112BR, COF-113BR, COF-114BR, CA17B, CA30B, MC1, MC5C, and COF-108BR 
(future installation), CA6 (background), and COF-116BR (background) as 
part of the groundwater monitoring system. However, none of these 
bedrock wells are located at the downgradient waste boundary as 
expressly required by Sec.  257.91(a)(2). Instead, they are located 
hundreds of feet away from this boundary. Among the wells that monitor 
bedrock, only COF-111BR is located adjacent to the downgradient (east) 
side of the unit and the other downgradient open-borehole bedrock wells 
are located hundreds of feet to the east, and in many cases on the 
other side of Cane Creek.
    Another systemic issue is that the bedrock wells were installed as 
open-borehole completions with long permanently grouted surface 
casings, and as a consequence have significant potential to 
systemically exclude zones that have been ``cased off'' from the 
monitoring well network. Permanent steel casing installations range 
from 14.6 to 76.0 feet in length for in-program wells. These cased off 
intervals represent potential data gaps, depending on the circumstances 
and geology local to that specific region of the unit. As a highly 
relevant example, well COF-111 is screened from 9-19 feet below ground 
surface (bgs). The open interval for the adjacent well pair, COF-111 
BR, is 76-126 ft bgs. This results in a 57-foot vertical gap at a 
critical location adjacent to the unit's downgradient boundary, where 
the groundwater quality is entirely unmonitored. This is significant 
because the failure to monitor in the variable and significant zone of 
transition from uppermost alluvium to residuum, epi-karst, and finally 
to ``unweathered'' limestone would be a significant and systemic data 
gap in potential contaminant pathways. Accordingly, EPA is proposing to 
determine that ADEM has approved a monitoring plan with an insufficient 
number of monitoring wells at necessary locations and vertical depths 
to ensure that all potential contaminant pathways have been monitored.

[[Page 55240]]

(2) ADEM Approved Wells That Were Not Constructed in Accordance With 
Sec.  257.91(e), and as a Consequence the Monitoring System Does Not 
Accurately Represent the Quality of Groundwater Flowing From Ash Pond 4
    The Federal regulations provide that ``monitoring wells must be 
cased in a manner that maintains the integrity of the monitoring well 
borehole.'' 40 CFR 257.91(e). Integrity of the monitoring well borehole 
includes all elements of the well within and including the borehole 
itself. Such elements include the surface casing, generally intended to 
isolate deeper geologic materials (commonly consolidated materials, 
i.e., bedrock) from overlying unconsolidated materials and associated 
groundwater, but also the filter pack, bentonite and grout seals, 
screened intervals, riser pipe, and other constructed monitoring well 
elements internal to the borehole used to isolate and ensure the 
integrity of the sampling interval (e.g., screened interval). The 
integrity of these elements individually and as an integrated system is 
essential to meeting the performance standards in Sec.  257.91(a), (b), 
and (e).
    As noted in ADEM's October 27, 2022 letter, these installations 
included installation of a permanently grouted surface casing. ADEM 
further indicated Rotosonic drilling methods were used to identify the 
first three-to five-foot zone of unweathered material, and that a 
casing was installed from this depth to the ground surface. It should 
be noted that Rotosonic drilling can be a disruptive process that may 
not result in full recovery of undisturbed samples of soil or bedrock. 
For this reason, absent any additional information, the use of the 
Rotosonic method as a tool for discriminating between weathered, 
partially weathered, and unweathered bedrock, must be used with care, 
particularly if sample materials are altered, pulverized, or otherwise 
destroyed or obfuscated by the process of drilling as indicated by a 
``no recovery'' zone or interval.\42\ In a variable zone of transition 
from weathered material (residuum) to unweathered bedrock (in this case 
limestone), recovered samples from each type of material would likely 
be affected by the drilling process to some degree, and most competent 
intervals are often preserved to a greater degree than decomposed or 
partially decomposed intervals. In such a context, absent documentation 
demonstrating a continuous core sample from the interval in question, 
with full recovery, which penetrates and unequivocally identifies the 
interface between weathered and unweathered material, it would not be 
possible to confirm that any missing sample intervals did not simply 
represent voids or other potentially permeable zones. The potential to 
mischaracterize three-to five-foot zones as ``competent and 
unweathered'' on the basis of an incomplete sequence of samples 
therefore appears to be substantial. It should therefore be noted that 
in this context a three-to-five-foot penetration into ``unweathered'' 
bedrock would generally not be considered a ``conservative'' approach, 
absent additional information validating the integrity of the casing 
seal and its effectiveness in isolating the ``unweathered'' bedrock 
interval from the overlying materials. In such a scenario, at best, the 
penetration of just a 3- to 5-foot interval of ``unweathered'' bedrock 
with variably weathered materials just above introduces uncertainty 
with respect to the integrity and effectiveness of the casing in 
isolating the open interval from groundwater in the overlying residuum 
and epikarst. Based on information provided, it is not clear how the 
approach (as described) can be demonstrated to have achieved the 
performance criteria outlined in Sec.  257.91(e).
---------------------------------------------------------------------------

    \42\ See Section II.d of TSD Volume I.
---------------------------------------------------------------------------

    In addition, the boring and well construction logs that were 
included in the Permit Application indicate that nearly one-half of the 
groundwater wells surrounding Ash Pond 4 were constructed as open 
boreholes in bedrock, with open hole intervals ranging from 45 feet up 
to as much as 100 feet in length. If EPA's analysis is accurate, nearly 
one half of the groundwater monitoring wells surrounding Ash Pond 4 
appear to not meet the casing requirements of Sec.  257.91(e).
    One limitation of open-borehole bedrock wells of this kind is that 
the entire bedrock interval serves as the monitoring zone. In effect, 
the long open interval serves as a reservoir within which inputs from 
various fractures intersected by the borehole are blended, resulting in 
an average composition of some kind. In this situation, it is very 
difficult or even impossible to monitor a specific zone because the 
contaminants being monitored could be diluted to the extent of being 
non-detectable. On this subject, ADEM's October 27, 2022, letter 
states:

    An Interstate Technology and Regulatory Council guidance 
document entitled Characterization and Remediation of Fractured Rock 
discusses construction and design considerations for monitoring 
wells installed in karst aquifers. Section 7.3.3 states ``Where the 
bedrock has adequate strength and competency, monitoring wells may 
be constructed as an open borehole.'' Because of the proven 
competent nature of the Tuscumbia Limestone, there is substantial 
confidence that the integrity of the monitoring well borehole will 
be maintained.

    To justify their approval of long open borehole intervals, ADEM 
states:

    As described above, the karst aquifer present at this site 
consists of a rock matrix with distinct fractures that create 
preferential pathways for groundwater flow. Studies comparing 
hydraulic properties measured within different karst aquifers 
indicate that conduits typically account for more than 95 percent of 
the permeability of an aquifer (Rosenberry et al., 2008). Thus, 
because the majority of water within the monitoring well column will 
be provided by discrete fractures of the bedrock unit, the potential 
for dilution in the open hole borings would be limited.

    While EPA agrees that fractured intervals in the karst limestone 
aquifer are highly relevant as contaminant migration pathways as 
compared to the (unfractured) rock matrix, treating all discrete 
fractures that may contribute groundwater and/or contaminants to a 
borehole equally would fail to ``accurately represent the quality of 
the groundwater passing the downgradient waste boundary.'' 40 CFR 
257.91(a)(2). The implied logical extension--that is, `the majority of 
water in a large open borehole may be sampled to provide accurate and 
representative groundwater samples--is simplynot correct. The technical 
literature provides a many detailed examples that illustrate the 
opposite conclusion. See Section II.d of TSD Volume I. A more likely 
scenario is that specific fractures serve as contaminant migration 
conduits and a long borehole may cross connect these fractures with 
fractures containing clean and/or less contaminated groundwater. In 
such a case, the water in the borehole represents in effect a blended 
average of the individual contributions from the specific fractures 
which it cross connects. As no information has been provided which 
indicate the means or methods by which specific fractures may have been 
isolated and more precisely monitored, EPA is proposing to determine 
that the long-screened interval open-borehole monitoring wells yield 
blended or otherwise unrepresentative samples, and thus do not comply 
with the performance standards in Sec.  257.91(a)(1) and (2) and (e). 
Many options are available to redevelop and reconfigure these existing 
open boreholes to fully comply with the regulations, including 
installing standard monitoring wells (e.g., with discrete screened 
intervals) within the open boreholes with discrete

[[Page 55241]]

screened intervals targeted to the most important discrete fracture 
zones, or a variety of specialized technologies and methods developed 
to address fracture-specific sampling in fractured bedrock 
environments. ADEM chose to approve the GWMP without requiring any of 
them.
(3) ADEM's Permit Authorizes Intrawell Data Comparisons That Are Not 
Consistent With Federal CCR Requirements
    The approach to intrawell data comparisons described in the 
approved GWMP does not require TVA to achieve compliance with the 
requirement in Sec.  257.91(a)(1) to establish background groundwater 
quality in an upgradient well unless the criteria in Sec.  
257.91(a)(1)(i) or (ii) are met. The approved GWMP contains procedures 
that would allow TVA to update the background data set used in 
intrawell comparisons, which would mean including data in the 
background characterization that is potentially impacted by a release 
from the CCR unit.\43\ See, 40 CFR 257.91(a)(1).
---------------------------------------------------------------------------

    \43\ Tennessee Valley Authority. Colbert Fossil Plant Ash Pond 4 
Permit Application, December 10, 2021. Appendix C Section 2.3, p. 4 
of 9 (PDF p. 469 of 603).
---------------------------------------------------------------------------

    Intrawell comparisons are not simply a statistical method; in the 
CCR regulations, they are an approach to background characterization. 
Intrawell data comparisons use samples taken at different times from 
the same well to characterize both background groundwater quality and 
downgradient compliance groundwater quality. This means downgradient 
compliance wells also serve as background wells. Alternatively, 
interwell data comparisons use samples taken from different wells--
upgradient or sidegradient wells characterize background groundwater 
quality and downgradient wells to characterize downgradient groundwater 
quality.
    The Federal CCR regulations do not mention interwell or intrawell 
comparisons specifically; instead, they establish requirements for 
characterizing background. Background groundwater quality is required 
to be established in an upgradient well, unless a groundwater flow 
gradient does not exist or it can be shown that groundwater samples 
from a well that is not upgradient of the CCR unit would characterize 
background groundwater quality as accurately or more accurately than 
samples from an upgradient well. 40 CFR 257.91(a)(1)(i),(ii). It also 
must be demonstrated that the data were gathered when the well was 
known to be uncontaminated by the CCR unit. This generally means that 
background data used in intrawell comparisons must be obtained prior to 
placement of CCR in the unit. This also indicates a strong preference 
for interwell comparison, which would necessarily be used when 
background is established in any well other than a downgradient 
compliance well (i.e., an upgradient or side gradient well).
    The approach to intrawell data comparisons described in the 
approved GWMP includes procedures to periodically update intrawell 
background data sets. Updating background data sets may be appropriate 
in interwell monitoring, where background groundwater quality may 
change over time due to migration of contaminants toward a CCR unit 
from upgradient sources. However, in intrawell monitoring, background 
data were obtained at compliance wells at the downgradient boundary of 
a monitored CCR unit, prior to placement of CCR in the unit. After a 
CCR unit begins operation, sampling data obtained from these 
downgradient wells cannot be known to be unimpacted by leakage from the 
unit.
    Samples from downgradient monitoring wells are intended to 
determine whether a release could have occurred. If concentrations of 
constituents monitored at the downgradient wells change, this would not 
represent a change in background groundwater quality, it would 
represent a release from the CCR unit. Mischaracterizing any increase 
in constituent concentration at these wells over time as a change in 
``background'' would result in elevating background levels and could 
mask releases by preventing detection of SSLs of constituents, which 
trigger corrective action requirements.
    Because the procedures for updating background levels used in 
intrawell data comparisons are approved in the Final Permit, this 
permit does not require Colbert to achieve compliance with either the 
Federal requirements at Sec.  257.91(a)(1) or an alternative State 
requirement that is equally protective.
c. TVA Colbert Permit Corrective Action Issues
    In 2018 TVA detected SSLs for cobalt and arsenic.\44\ TVA first 
completed an ACM to comply with the requirements of the Federal CCR 
regulations in July 2019 (``2019 ACM''). An ACM was completed in 2021 
to comply with a 2018 Consent Decree issued by ADEM (``2021 CD 
ACM'').\45\ The 2021 CD ACM included State requirements applicable to 
units not regulated by the Federal program, as well as requirements 
applicable to CCR units regulated by the Federal program.
---------------------------------------------------------------------------

    \44\ Tennessee Valley Authority. 2019 Annual Groundwater 
Monitoring and Corrective Action Report, TVA Colbert. January 2020. 
p. 3.
    \45\ Notice Of Electronic Filing in the Circuit Court of Colbert 
County, Alabama. Alabama Department of Environmental Management v. 
Tennessee Valley Aut 20-Cv-2013-900123.00. C001 Alabama Department 
of Environmental Management Joint Motion for Entry of First Amended 
Consent. Decree. August 15, 2018.
---------------------------------------------------------------------------

    On October 25, 2022, ADEM issued the Final Permit to TVA for Ash 
Disposal Area 4 (also identified as Ash Pond 4 in the 2021 CD ACM). The 
Final Permit contained only the following terms and conditions for 
corrective action:

    C. Assessment of Corrective Measures. The Permittee must 
initiate an assessment of corrective measures as specified in 335-
13-15-.06(7) if any constituent listed in Appendix IV of 335-13-15 
has been detected at a statistically significant level exceeding the 
groundwater protection standard, or immediately upon detection of a 
release from the CCR unit.
    1. The permittee must continue to monitor groundwater in 
accordance with the assessment monitoring program while assessing 
corrective measures.
    2. Selection of Remedy. Based on the results of the corrective 
measures assessment, the Permittee must select a remedy as specified 
in 335-13-15-.06(8).
    3. Implementation of the Corrective Action Program. Within 90 
days of selecting a remedy, the Permittee must initiate remedial 
activities as specified in 335-13-15-.06(9), and shall be required 
to modify the permit in accordance with Section II.E.9.

    In its Colbert Permit RTC, ADEM explains that:

    TVA submitted to the Department an initial Assessment of 
Corrective Measures (ACM) in July of 2019. A revised ACM was 
submitted by TVA in April 2021 and is still undergoing a detailed 
review to ensure that the proposed final remedy selected by TVA 
conforms to the requirements of ADEM Admin. Code r. 335-13-15-.06(7) 
and (8). The proposed corrective measures will use monitored natural 
attenuation (MNA) and institutional controls, interim responses, and 
adaptive management. Should additional revisions be required, the 
Department will review them to ensure compliance with the 
requirements of ADEM Admin. Code r. 335-13-15-.06(7) and (8).
    Because an ACM has not been finalized and a final remedy has not 
been selected, the permit does not include provisions for the 
remediation of the groundwater at this time. However, once a final 
remedy is determined complete by the Department, the permit will be 
revised to include such provisions. The permit revision to include 
the final remedy will include public participation.

    The Final Permit issued by ADEM merely reiterates the Alabama

[[Page 55242]]

regulations, which are the same as the Federal corrective action 
requirements. However, incorporating the regulations verbatim in the 
permit does not require TVA to achieve compliance with those 
requirements. This is because ADEM did not take into account relevant 
facts about the status of corrective action at Colbert, such as whether 
the 2019 ACM complied with the regulatory requirements, or whether the 
2021 CD ACM complied with either the Consent Decree or the regulations 
or both.\46\ Most importantly, ADEM did not adjudicate what actions are 
still necessary in light of those facts to achieve compliance with the 
regulations and include those actions as requirements in the Final 
Permit. As a consequence, EPA is proposing to determine that the permit 
in essence authorizes TVA to continue to delay selection of a remedy 
well beyond the required deadline, in order to pursue assessment of a 
remedy that does not appear to meet the criteria in Sec.  257.97(b).
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    \46\ The Federal CCR regulations State that an ACM is complete 
when it is placed in the facility operating record. 40 CFR 
257.96(d). The regulations require posting of this information to 
the publicly accessible website within 30 days 40 CFR 257.107(d), 
(h)(8). The 2021 Revised ACM was not posted to the TVA Colbert CCR 
website at the time of EPA's review.
---------------------------------------------------------------------------

    In the Colbert Permit RTC, ADEM states that it is still reviewing 
the 2021 CD ACM and has not determined whether the ACM and TVA's 
preferred remedy (MNA with institutional controls but no source control 
measures beyond the existing closure with waste remaining in place) 
complies with the regulations. It is not clear whether ADEM provided 
comments on the 2019 ACM or whether it believes that the ACM satisfies 
the requirements in Sec. Sec.  257.95 and 257.96, which remain 
applicable to Ash Pond 4. ADEM also states in the Colbert Permit RTC 
that an ACM has not been finalized and a final remedy has not been 
selected, so the permit does not include provisions for the remediation 
of the groundwater. Whether or not the 2021 CD ACM meets the 
requirements of the regulations is precisely the type of adjudication 
required in a permitting action. What the permittee is required to do 
in order to achieve compliance with the regulations must be determined 
prior to final permit issuance, because the permit must contain these 
requirements. This is the role of a permitting authority (i.e., ADEM).
    Under the Federal regulations, an assessment of corrective measures 
that will ``prevent further releases, remediate any releases, and 
restore affected areas to original conditions'' is required once 
corrective action is triggered. 40 CFR 257.96. Section 257.96(c) 
requires an analysis of the effectiveness of potential corrective 
measures in meeting all requirements and objectives of the remedy 
required by Sec.  257.97, and mandates that the analysis address at 
least the criteria listed in Sec.  257.96(c)(1) through (3). Based on 
the results of an ACM conducted in accordance with Sec.  257.96, a 
remedy that meets the requirements of Sec.  257.97(b) must be selected 
``as soon as feasible.'' 40 CFR 257.97(a).
    The full extent of corrective action requirements applicable to 
Colbert are not yet known due to numerous concerns about the adequacy 
of the detection and assessment groundwater monitoring system and its 
ability to identify all SSLs. However, based on review of the Final 
Permit, the Colbert Permit RTC, the 2019 ACM, the 2021 CD ACM, and the 
January 13, 2023, Progress Report, EPA has identified a number of areas 
in which it appears that neither the ACMs nor the proposed remedies are 
consistent with or as protective as the Federal requirements.\47\ At a 
minimum, EPA would have expected the permit to have clearly established 
a deadline for submission of a final ACM and to have identified 
specific corrections that must be made to address the specific 
deficiencies discussed in the paragraphs below.
---------------------------------------------------------------------------

    \47\ Tennessee Valley Authority. TVA Seventh Semi-Annual Report 
on the Progress of Remedy Selection at Ash Disposal Area 4. January 
13, 2023.
---------------------------------------------------------------------------

i. The Colbert Permit Does Not Require TVA To Complete an ACM That 
Includes an Assessment of Source Control Measures in Accordance With 40 
CFR 257.96
    40 CFR 257.97(b)(3) requires that all remedies control the source 
of releases in order to reduce or eliminate, to the maximum extent 
feasible, further releases of contaminants into the environment. 
Neither the 2019 ACM nor the 2021 CD ACM contains any assessment of 
measures to achieve this requirement (i.e., source control). Section 
4.2. of the 2019 ACM states, ``Since closure of the Ash Disposal Area 4 
CCR Unit serves as a source control measure, the remedial technologies 
considered in the following sections are focused on addressing the area 
of groundwater exhibiting arsenic and cobalt at concentrations above 
the GWPS.'' The 2021 CD ACM also does not evaluate any source control 
measures, focusing exclusively on three groundwater remediation 
alternatives involving MNA.\48\ However, the assessment required by 
Sec.  257.96 must include more than one source control measure, and 
must actually assess how the various measures would perform according 
to the criteria in Sec.  257.96(c). Here there is no assessment of the 
one source control measure identified in the ACMs--the closure of Ash 
Pond 4, which left a significant amount of CCR in contact with 
groundwater--and how it would perform according to the criteria in 
Sec.  257.96(c) compared to other source control alternatives, such as 
clean closure or the imposition of engineering measures to control or 
eliminate the groundwater that continues to flow in and out of the 
impoundment.
---------------------------------------------------------------------------

    \48\ MNA refers to reliance on natural attenuation processes to 
achieve corrective action objectives within a time frame that is 
reasonable compared to that offered by other, more active methods. 
The ``natural attenuation processes'' at work in such a remediation 
approach generally include a variety of physical, chemical, or 
biological processes that, under favorable conditions, act without 
human intervention to reduce the mass, toxicity, mobility, volume, 
or concentration of contaminants in soil or groundwater.
---------------------------------------------------------------------------

    ADEM's failure to require submission of an ACM that actually 
evaluates whether the closure of the Ash Pond meets the source control 
requirements in Sec.  257.97(b)(3) also undercuts their claim that they 
will use the corrective action process to address any remaining 
concerns with respect to the closure of the Ash Pond. In its October 
27, 2022, letter to EPA regarding compliance at TVA Colbert, ADEM 
states on page 7,

    In the event that it is determined that the closure activities 
conducted at Ash Disposal Area 4 . . . are insufficient to prevent 
further groundwater contamination, additional controls or methods 
will be considered and addressed through the on-going Assessment of 
Corrective Measures (ACM) and selection of a final remedy . . .

    Ash Disposal Area 4 completed closure in 2018, and groundwater 
monitoring in 2022 revealed SSLs of additional constituents at wells 
without prior SSLs, which indicates that the closure activities were 
insufficient to prevent further groundwater contamination. Yet the 
permit issued by ADEM does not require TVA to take any action to remedy 
this deficiency.
ii. The Colbert Permit Does Not Require Collection of Data Needed To 
Characterize Site Conditions That May Affect a Remedy To Support the 
Assessments in the ACMs
    40 CFR 257.95(g)(1) requires a facility to characterize the nature 
and extent of the release and any relevant site conditions that may 
affect the remedy ultimately selected. The

[[Page 55243]]

characterization must be sufficient to support a complete and accurate 
assessment of the corrective measures necessary to effectively clean up 
all releases from the CCR unit pursuant to Sec.  257.96. The 2019 ACM 
and 2021 CD ACM do contain information about the delineation of the 
identified releases. Although, given the concerns discussed previously 
about the adequacy of the downgradient wells in the groundwater 
monitoring well network, EPA is concerned that additional plume 
delineations may be needed, because potential contaminant pathways are 
unmonitored and additional releases may have occurred.
    But critically, the reports do not include any information 
collected about site conditions that would affect the efficacy of any 
remedies analyzed in the 2019 and 2021 CD ACMs. Site data needed to 
assess remedies vary depending on the remedy being assessed, but could 
include: speciated results of constituent concentrations in groundwater 
and soil, in dissolved and suspended phases; concentrations of 
constituents, if present, which are necessary to complete reactions 
that result in immobilization of contaminants (e.g. iron or sulfur); 
and data to confirm the presence of attenuated and immobilized 
contaminants in the subsurface, to demonstrate attenuation is occurring 
naturally. As discussed in subsequent sections, the absence of such 
data is particularly critical with respect to MNA, which is the only 
remedy identified in the 2021 CD ACM. But neither ACM contains any of 
these data, which would be needed to accurately assess any of the 
remedies identified in the 2019 and 2021 ACMs. Yet the Final Permit 
does not include terms to address these deficiencies, such as a 
requirement to collect data to characterize site conditions that would 
affect the corrective measures considered in either ACM, or a deadline 
to submit a revised ACM that contains such data.
iii. Colbert's Permit Does Not Require an ACM That Accurately Assesses 
Alternatives According to the Criteria in 40 CFR 257.96(c)
    40 CFR 257.96(c)(1) requires an assessment of how well alternative 
remedies will control exposure to residual contamination. Instead, the 
2019 ACM assesses potential risks from any exposure to residual 
contamination that may occur. This is inconsistent with the Federal 
regulations and is, in any event, a less useful metric to evaluate 
control measure technologies relative to one another, particularly when 
more than one alternative leaves contaminants in the environment. This 
is because this alternative criterion serves as an assessment of harm 
from the contaminants themselves if they are not removed from the 
environment, rather than an assessment of each technology's 
effectiveness at removing them. For example, in Table 6-1 in the 2019 
ACM--MNA is assessed as low risk with respect to this alternative 
criterion, but it would have assessed poorly according to the criterion 
of how well alternative remedies will control exposure to residual 
contamination. This is less an assessment of MNA's effectiveness at 
meeting the requirements of Sec.  257.97(b) and more an assessment of 
whether those requirements must be met, which is not the purpose of the 
ACM. Moreover, this conclusion of low risk is unsupported by data or 
analysis.
    The 2019 ACM also fails to consider safety impacts and cross-media 
impacts. See, 40 CFR 257.96(c)(1). The 2021 CD ACM does not correct 
this deficiency as it entirely fails to assess alternative remedies 
with respect to this criterion at all. The Final Permit issued by ADEM 
does not require any actions, by a deadline, to remedy these 
deficiencies in the ACMs.
iv. The Final Permit Allows TVA To Continue To Pursue a Remedy (MNA) 
That Has Not Been Demonstrated To Meet All of the Requirements in Sec.  
257.97(b)
    The 2019 ACM for Colbert identified MNA as one of several potential 
corrective measures to address groundwater contamination (i.e., 
hydraulic control and treatment; in-situ treatment). However, the 2021 
CD ACM considers only MNA as a primary remedy, which suggests that TVA 
is now largely pursuing a remedy that relies exclusively on MNA.
    MNA refers to reliance on natural attenuation processes to achieve 
corrective action objectives within a time frame that is reasonable 
compared to that offered by other, more active methods. The ``natural 
attenuation processes'' at work in such a remediation approach could 
generally include a variety of physical, chemical, or biological 
processes that, under favorable conditions, act without human 
intervention to reduce the mass, toxicity, mobility, volume, or 
concentration of contaminants in soil or groundwater. However, mass 
reduction through degradation generally is not a viable process for 
most inorganic contaminants (i.e., the constituents in Appendix IV to 
40 CFR part 257) in groundwater, except for radioactive decay. These 
constituents are atoms, and atoms do not break down or degrade through 
any naturally occurring process unless they are radioactive.
    Thus, while MNA can reduce the concentration or mobility of 
inorganic contaminants in groundwater if immobilization occurs through 
adsorption or absorption to subsurface soils, it does not remove the 
contaminants from the environment. MNA, therefore, would not perform 
well with respect to the requirement in Sec.  257.97(b)(4), which 
requires that remedies ``remove from the environment as much of the 
contaminated material that was released from the CCR unit as is 
feasible.'' This is particularly true in this circumstance, where, as 
discussed in the next sections, TVA has failed to collect the site data 
needed to identify whether any naturally occurring attenuation may be 
occurring on-site, as well as the mechanism by which it occurs, and to 
assess whether site characteristics that control and sustain this 
naturally occurring attenuation are sufficient to immobilize the entire 
release. Assessments in an ACM are relative in that the expected 
performance of the different technologies are compared with one another 
according to how well each alternative meets each regulatory criterion. 
Given both the absence of any evidence of any attenuation mechanisms 
occurring at the Ash Disposal Area 4, and the conclusion in the 2020 
ACM that the other alternatives such as pump and treat are feasible, 
there would appear to be no basis for assessing MNA more favorably than 
an alternative that unquestionably removes contaminants from the 
environment. The Final Permit nevertheless allows TVA to continue to 
attempt to validate MNA as a technology instead of accurately assessing 
alternatives based on-site conditions and selecting a remedy that meets 
the requirements in Sec.  257.97(b).
v. ADEM Issued a Final Permit That Impermissibly Allows a Remedy (MNA) 
That Is Based on Unsupported Assessments
    The 2019 and 2021 ACMs assessed the performance of MNA favorably 
without any supporting data that characterize site conditions that may 
ultimately affect a remedy, as required by Sec.  257.95(g)(1). In order 
to legitimately consider MNA as required by Sec.  257.96(c), site data 
are needed to identify any naturally occurring attenuation that may be 
occurring, and to assess whether site characteristics that control and 
sustain this naturally occurring attenuation are sufficient to

[[Page 55244]]

immobilize the entire release. ``It is necessary to know what specific 
mechanism (e.g., what type of sorption or reduction and oxidation 
reaction) is responsible for the attenuation of inorganics so that the 
stability of the mechanism can be evaluated. [. . .] Changes in a 
contaminant's concentration, pH, oxidation and reduction potential 
(ORP), and chemical speciation may reduce a contaminant's stability at 
a site and release it into the environment.'' \49\ Determining the 
existence, and demonstrating the irreversibility, of MNA mechanisms is 
necessary to assess the performance, reliability, ease of 
implementation, and the time required to begin and complete the remedy. 
40 CFR 257.96(c)(1) and (2). This information would ultimately be 
necessary to assess how well MNA meets the requirements of Sec.  
257.97(b).
---------------------------------------------------------------------------

    \49\ Use of Monitored Natural Attenuation at Superfund, RCRA 
Corrective Action, and Underground Storage Tank Sites, EPA OSWER 
Directive 9200.4-17P. April 21, 1999. p. 8.
---------------------------------------------------------------------------

    MNA of inorganic contaminants would be assessed most favorably at 
sites where immobilization is demonstrated to be in effect and the 
process/mechanism is irreversible. Immobilization that is not permanent 
would require ongoing monitoring in accordance with Sec.  257.98(a)(1) 
as long as immobilized constituents remain in the aquifer matrix.
(1) The ACMs Do Not Include Data That Characterize Site Conditions or 
Identify Any Attenuation Mechanisms Occurring at the Ash Disposal Area 
4
    The site data that were collected focus only on contaminant 
concentrations and trend analyses regarding the presence of 
contaminants. The 2019 ACM and 2021 CD ACM do not discuss how 
attenuation may be naturally occurring through any particular MNA 
mechanisms (e.g., adsorption, precipitation, dispersion). EPA was not 
able to find any indication in the Final Permit or supporting 
documentation to confirm that the Permittee has identified the 
mechanism by which MNA would occur at the site. Nor is there any 
condition in the Final Permit requiring the development and submission 
of such information. The Final Permit should have required collection 
of groundwater data (e.g., pH or oxidation potential, speciated 
concentrations of constituents of concern) as well as samples to 
identify the presence of immobilized constituent in subsurface soils. 
The Final Permit also should have required an amended ACM which 
considered this information in the assessment of all alternatives, 
including assessment of the performance of identified naturally-
occurring attenuation mechanisms (i.e., MNA).
    Determining the existence and demonstrating the irreversibility of 
MNA mechanisms is necessary to evaluate the performance, reliability, 
ease of implementation, and the time required to begin and complete the 
remedy. See, 40 CFR 257.96(c)(1) and (2). This information would 
ultimately be necessary to show that MNA meets the requirements of 
Sec.  257.97(b) and would need to be supported with site-specific 
characterization data and analysis. Yet the Final Permit contained no 
terms or conditions requiring TVA to remedy these deficiencies.
(2) MNA Is Not a Viable Remedy Without Source Control
    From a scientific point of view, source control is necessary in 
order for any MNA remedy to be effective at a particular site.\50\ In 
order to properly assess MNA, first the attenuation mechanisms (for 
inorganic metals, these include both chemical and physical reactions) 
by which the specific constituents released may be immobilized at a 
specific site must be identified. As discussed above, no mechanism was 
identified in either the 2019 or 2021 ACM. After attenuation mechanisms 
are identified, it is necessary to determine whether the aquifer has 
the capacity (i.e., the presence of these reactants available in 
sufficient amounts) to provide those reactions to attenuate the release 
that has occurred. If site data are obtained verifying the localized 
presence and availability of reactants, appropriate types of soil, and 
other factors needed to immobilize the constituents, it must be 
determined whether they are available in sufficient quantities to react 
with the quantity of constituents released. This can be done using the 
estimated mass of the release that was calculated in accordance with 
Sec.  257.95(g)(1)(ii), as well as site data collected to determine the 
presence and concentrations of the chemical and physical materials 
required to complete the immobilization reactions. If there are enough 
available reactants to immobilize the entire release, and the site 
conditions are right for those reactions to occur, then MNA may be 
effective at immobilizing a release. However, if the source of a 
release has not been controlled (i.e., the CCR remains in contact with 
groundwater and releases are ongoing), then it is impossible to know if 
an aquifer has the capacity to attenuate the release, even if 
attenuation mechanisms have been identified and site conditions are 
favorable for those reactions to occur. That is because the amounts of 
contaminants being released will continue over time, and releases of 
new constituents could occur. Therefore, it is impossible to determine 
whether the aquifer has sufficient chemical and physical materials 
required to complete the immobilization reactions because the total 
amount of the release is not yet known.
---------------------------------------------------------------------------

    \50\ Id.
---------------------------------------------------------------------------

    At TVA Colbert, source control has not been achieved. As discussed 
above, the closure of Ash Pond 4 has resulted in continuing releases 
from the closed unit, i.e., a continual source of groundwater 
contamination from the unit. Therefore, based on the current record, 
MNA is not a viable remedy for Ash Pond 4. This should have been 
addressed prior to permit issuance during the permit application review 
stage or by some other means, such as a schedule of compliance in the 
final permit, e.g., by requiring TVA to submit a revised ACM that 
accurately assesses MNA and includes a corrective measure which 
achieves source control in each alternative assessed.
(3) The Assessment of Cross-Media Impacts in the ACMs Is Inaccurate and 
Not Supported by Data
    The table in the 2019 ACM, which summarizes TVA's assessment of 
groundwater corrective measures, states that MNA poses a low risk of 
cross-media impacts. The reason given is that ``all work activities 
occur in-situ.'' This conclusion is only accurate if natural 
attenuation through immobilization is occurring on-site, but no such 
showing has been made. In fact, in the absence of any information to 
the contrary, it is more likely that MNA through dilution and 
dispersion would occur, that is, by mixing with clean groundwater as it 
migrates from the unit, ultimately transferring the contamination from 
groundwater to surface water. But the transfer of contamination from 
groundwater to surface water is a cross-media impact and it only occurs 
in-situ until the groundwater reaches the surface water. The assessment 
of low risk of cross-media impacts is therefore not supported by facts 
and site data. See, 40 CFR 257.95(g)(1).
    A similar table (6-1) in the 2021 CD ACM assesses ``potential 
adverse impacts'' as low. Its assessment of the first alternative, MNA 
with no institutional controls or adaptive management, is favorable 
even though it is noted that there would be no protection of surface 
water in the short term. In fact, because all three

[[Page 55245]]

alternatives rely on MNA and do not include active remediation or 
containment, none of them would protect surface water in the short 
term. It is unclear why this concern is not noted in all the 
alternatives. There is also no discussion of long-term impacts to 
surface water. Accordingly, EPA is proposing to determine that the 
assessment of these potential remedies as low risk is not supported by 
any evidence, and that the assessment of the third alternative does not 
meet the requirements of Sec.  257.96(c)(1) because it does not 
consider impacts to surface water (i.e., cross-media impacts).
    The lack of data to support the assessments in both ACMs means they 
may not accurately reflect MNA's ``effectiveness of potential 
corrective measures in meeting all of the requirements and objectives'' 
in Sec.  257.97(b). 40 CFR 257.96(c) Conclusions without a supporting 
assessment or data do not constitute ``an analysis of the effectiveness 
of potential corrective measures.'' 40 CFR 257.96(c) (emphasis added). 
In addition, inaccurate assessments in an ACM can ultimately result in 
selection of a remedy that will not meet the requirements of Sec.  
257.97(b). The Final Permit issued by ADEM in October 2022 does not 
require TVA to take any actions to remedy the deficiencies in either 
the earlier 2019 ACM or subsequent 2021 CD ACM.
(4) The 2021 CD ACM Is More Deficient Than the 2019 ACM
    Even though the 2021 CD ACM was developed in response to comments 
from ADEM, it not only fails to remedy the deficiencies in the 2019 
ACM, but also contains provisions that raise additional concerns. 
First, the remedial objectives in section 1.3 of the 2021 CD ACM do not 
address the requirements in Sec.  257.97(b)(3) or (4) relating to 
source control or the removal of the release from the environment--
rather, they only consider off-site impacts of groundwater 
contamination.
    It is unclear whether the 2021 ACM was intended to replace or to 
supplement the 2019 ACM. But assessed on its own merits, the 2021 CD 
ACM failed to assess two remedies included in the 2019 ACM: hydraulic 
control and treatment and enhanced in-situ treatment as primary 
corrective measures. Only three alternatives are considered in the 2021 
CD ACM, which all rely on MNA as the primary corrective measure. The 
only consideration of active corrective measures is in alternative 
three, as part of an adaptive management strategy if MNA does not meet 
the remedial objectives on its own. Therefore, EPA is proposing to 
determine that the 2021 CD ACM does not meet the requirement in Sec.  
257.96(a) to assess corrective measures ``to prevent further releases, 
to remediate any releases and to restore affected area to original 
conditions,'' because the alternatives, limited to MNA without 
additional source control, would not meet any of these requirements at 
the Colbert Plant.
(5) The Ongoing Data Collection and Model Development Are Not Necessary 
To Select a Remedy
    According to the January 13, 2023 Progress Report, the facility has 
delayed selection of a remedy by, among other tasks, continuing to 
monitor the migration of the release and developing a computer model to 
predict groundwater behavior. It is not necessary to delay completion 
of an ACM or selection of a remedy until a model can be developed and 
refined; the Federal regulations do not require development of a 
groundwater model to complete an ACM or to select a remedy. Since 
actual site monitoring data-- rather than an estimate from a model-- is 
required to characterize the release sufficiently to assess corrective 
measures-- the primary use of a model in this stage of CCR corrective 
action would be to estimate the amount of time needed to complete a 
remedy. But this estimate may be accomplished through other methods 
(e.g., calculation of the mass of the release, groundwater flow 
velocity, hydraulic conductivity, and the attenuation capacity of the 
downgradient subsurface where MNA mechanisms have been identified and 
can be quantified). Nor is such delay consistent with the requirements 
of Sec.  257.95(g), which only requires characterization ``sufficient 
to support a complete and accurate assessment of the corrective 
measures necessary to effectively clean up all releases from the CCR 
unit pursuant to Sec.  257.96.'' In order to support the assessment in 
the ACM, this characterization must be complete prior to the deadline 
to complete the ACM.
    Based on all of the above, EPA is proposing to determine that the 
permit fails to require the Permittee to select its remedy ``as soon as 
feasible,'' as required by Sec.  257.97(a). Section 5.C.2 of the 
permit, entitled ``Selection of Remedy,'' only reiterates the 
regulatory requirement that the Permittee must select a remedy as soon 
as feasible. It has been three years since the 2019 ACM for the Ash 
Pond was placed in the facility's operating record, and it is not clear 
why the facility has not selected a remedy.\51\ The 2021 CD ACM does 
not reflect progress toward selection of a remedy, as it does not 
address any of the deficiencies in the 2019 ACM. For example, even 
though the 2021 CD ACM focuses exclusively on MNA, it still fails to 
identify any attenuation mechanism, or to include any of the supporting 
data that characterize site conditions that may ultimately affect a 
remedy, as required by Sec.  257.95(g)(1). For all the reasons 
discussed above, EPA is proposing to determine that neither the 2019 
ACM, the 2021 CD ACM, or the two ACMs taken together meet the 
requirements of Sec.  257.96 or Sec.  257.97 or support selection of a 
compliant remedy. By failing to require TVA to obtain the necessary 
data and submit a revised ACM by a date certain, the Final Permit 
appears to authorize the permittee to continue to indefinitely delay 
selecting a remedy, while the permittee continues to conduct the same 
sampling it has conducted since 2019, that is likely to be insufficient 
to support the selection of that alternative as a remedy. Accordingly, 
EPA is proposing to determine that the permit does not require 
compliance with the Federal requirements and, because it allows the 
facility to continue to delay corrective action, the alternative State 
requirement is less protective.
---------------------------------------------------------------------------

    \51\ Tenessee Valley Authority. 2019 Assessment of Corrective 
Measures Report for the Ash Pond TVA Colbert Fossil Plant, 
Tuscumbia, Alabama. July 15, 2019.
---------------------------------------------------------------------------

2. Plant Gadsden
    EPA reviewed the Final Determination Initial Permit And Variance 
for the Alabama Power Company, Gadsden Steam Plant (Plant Gadsden 
Permit), issued by ADEM under Permit No. 28-09 on December 18, 
2020.\52\ The permit summary on Page 1 says:
---------------------------------------------------------------------------

    \52\ Alabama Department of Environmental Management. Final 
Determination Initial Permit And Variance for the Alabama Power 
Company, Gadsden Steam Plant, issued under Permit No. 28-09. 
December 18, 2020.

[t]he Plant Gadsden Ash Pond is a CCR surface impoundment located in 
Section 2, Township 12 South, Range 6 East in Etowah County, Alabama 
consisting of approximately 130.22 acres with a disposal area that 
consists of approximately 58.73 acres. The permit requires the 
Permittee to manage CCR in accordance with the conditions of the 
permit, ADEM Admin. Code r. 335-13-15, . . . and the approved permit 
application.
. . .
The Permittee must comply with all conditions of the permit except 
to the extent and for the duration such noncompliance is authorized 
by a variance granted by ADEM. The first variance requests to 
exclude boron as an Appendix IV assessment monitoring

[[Page 55246]]

constituent. The second variance requests groundwater protection 
standards of 6 micrograms per liter ([micro]g/L) for cobalt; 15 
[micro]g/L for lead; 40 [micro]g/L for lithium; and 100 [micro]g/L 
for molybdenum. The third variance requests the final grade of the 
cover system be less than 5 percent and greater than 25 percent. The 
fourth variance being requested is from 335-13-15-.03(6) requiring a 
100 foot buffer from the perimeter of the facility boundary.
a. Plant Gadsden Closure Issues
    Section VII.B.1 of Plant Gadsden Permit contains the following 
terms and conditions:

    A. Closure Timeframe and Notifications. The Permittee shall 
close their CCR units as specified in 335-13-15-07(2), this permit 
and the Application.
    B. Criteria for Closure.
    1. Cover. Closure of a CCR landfill, surface impoundment, or any 
lateral expansion of a CCR unit must be completed by either leaving 
the CCR in place and installing a final cover system or through 
removal of the CCR and decontamination of the CCR unit, as described 
in 335-13-15-.07(3)(b) through (j). The minimum and maximum final 
grade of the final cover system may be less than 5 percent and 
greater than 25 percent, as specified in the Permit Application. 
(See Section IX.C.)
    2. Written Closure Plan. The written closure plan, as part of 
the Application, must include, at a minimum, the information 
specified in 335-13-15-.07(3)(b) 1.(i) through (vi).

    The Ash Pond was closed by removing CCR from the southern portion 
of the Lower Pond (the area of the western expansions in the 1970s) and 
consolidating the ash in the Lower Pond to about 30 acres in the 
northern portion of the Lower Pond. The CCR in the Upper Pond (original 
ash pond prior to expansions) was regraded to achieve a minimum 3% 
slope, and a cover system was constructed over the re-graded Upper Pond 
and consolidated ash in the Lower Pond.\53\
---------------------------------------------------------------------------

    \53\ Alabama Power. Revised Closure Permit Application for the 
Plant Gadsden Ash Pond. April 30, 2020. Appendix 6.
---------------------------------------------------------------------------

    Closure construction activities for the Ash Pond were certified as 
completed in October 2018, and a certification of completion of closure 
activities was later submitted in April 2020, and approved by ADEM on 
June 9, 2022.54 55
---------------------------------------------------------------------------

    \54\ Alabama Power. Plant Gadsden 2020 Notice of Closure 
Completion Plant Gadsden Ash Pond Alabama Power Company.
    \55\ Alabama Power. Plant Gadsden 2022 Closure Inspection 
Gadsden Steam Plant Permit No. 28-09.
---------------------------------------------------------------------------

i. Base of the Impoundment
    Plant Gadsden is located in Gadsden, Alabama, south of the Coosa 
River. The Ash Pond is located on the north side of and adjacent to the 
Coosa River. The Permit Application states that the Ash Pond was 
initially constructed in 1949 and subsequently expanded to the west in 
1976 and 1978.\56\ The Permit Application states that the fully 
constructed Ash Pond was 75 acres. Id. at Appendix 8. Alabama Power 
closed the Ash Pond by consolidating CCR to a smaller area within the 
impoundment footprint. Id. at Appendix 6. As a result, the consolidated 
closed footprint of Ash Pond 4 decreased to approximately 59 acres. Id. 
at Appendix 2.
---------------------------------------------------------------------------

    \56\ Alabama Power. Revised Closure Permit Application for the 
Plant Gadsden Ash Pond. April 30, 2020. Appendix 3.
---------------------------------------------------------------------------

    EPA was unable to locate information in the Permit Application or 
other publicly available documents that characterizes the bottom 
elevation of the Ash Pond across its entire footprint. Nonetheless, 
similar to the review for the permit for Plant Colbert, EPA estimates 
the average bottom elevation of the impoundment for purposes of 
calculating the volume of CCR that remains saturated by groundwater. 
EPA is estimating that the average bottom elevation of the closed Ash 
Pond is 510 ft above MSL.\57\ This estimate is based on consideration 
of the information available in the Permit Application. Specifically, 
EPA considered the following information: (1) the original ground 
surface contours shown on construction drawings for areas that were 
closed by leaving CCR in place; (2) information showing that the bottom 
of the impoundment was lower than the original ground surface contours 
at some locations while the unit was in operation; and (3) closure-
related drawings portraying an estimated waste bottom.
---------------------------------------------------------------------------

    \57\ USEPA. Volume I: Technical Support Document for the 
Proposed Notice to Deny Alabama's Coal Combustion Residuals Permit 
Program, Supplemental Analyses of Technical Issues with ADEM 
Permits. August 2023. Section III.a.
---------------------------------------------------------------------------

    EPA's estimate recognizes that the original ground surface contours 
for most of the impoundment footprint (both the initial footprint and 
western expansions) range between 505 to 515 ft above MSL, or an 
average elevation of 510 ft above MSL. In addition, certain closure 
drawings show that current surface elevations in the upper northern 
part of the unit are actually lower in 2016 than the original ground 
surface elevations depicted on the 1978 expansion drawing. This means 
that the original ground surface elevations shown on the 1949, 1976, 
and 1978 drawings do not necessarily reflect the bottom of the 
impoundment at closure at all locations within the unit footprint. The 
2016 drawing shows the bottom elevation at this upper northern part of 
the unit to be no higher than 505 to 510 ft above MSL, which is lower 
than the original ground contours at this location that ranged from 510 
to 515 ft above MSL. Finally, the four cross-sections provided in the 
Gadsden Permit Application depict the impoundment bottom appearing to 
range between 495 to 510 ft above MSL, but these cross-sections are 
annotated with a note that the bottom elevations have not been 
verified. Based on the available information, EPA's estimated average 
bottom elevation of 510 ft above MSL is a reasonable reconciliation of 
the available information.
ii. Characterization of Groundwater Elevations
    The CCR program groundwater monitoring network installed at the 
unit consists of fifteen downgradient monitoring wells (GSD-AP-MW-1 
through MW-12 and GSD-AP-PZ-1, PZ-5, and PZ-6). The following 
evaluation of groundwater elevation data for the unit focuses on the 
twelve monitoring wells that are immediately adjacent to the waste 
boundary (i.e., MW-1 through MW-12). Monitoring wells PZ-1, PZ-5 and 
PZ-6 are located hundreds of feet from the waste boundary and thus were 
not considered. Also, three ``upgradient'' monitoring wells (MW-14, -
16, and -17) are located to the southeast on the other side of the 
Coosa River and are not considered with respect to groundwater 
elevations within the unit. Based on the single groundwater flow map 
included in the Permit Application,\58\ based on August 19, 2019, data, 
groundwater elevations in monitoring wells surrounding the unit ranged 
from a high of 512.03 ft above MSL along the northeastern boundary of 
the unit (GSD-AP-MW-3) to 506.95 ft above MSL along the western 
boundary (GSD-AP-MW-7). The potentiometric surface contour map 
presented for August 19, 2019, reveals a somewhat radial flow pattern, 
with highest groundwater elevation values recorded along the 
northeastern boundary of the facility. Between monitoring wells GSD-AP-
MW-1 and GSD-AP-MW-4 along the northeastern boundary of the unit, 
groundwater elevation values are similar, approximately 512 ft above 
MSL, resulting in a northwest to southeast trending ridge-like region 
of relatively high groundwater elevations.
---------------------------------------------------------------------------

    \58\ Alabama Power. Revised Closure Permit Application for the 
Plant Gadsden Ash Pond. April 30, 2020, Appendix 7, Plant Gadsden 
Ash Pond Groundwater Monitoring Plan, Figure 6.
---------------------------------------------------------------------------

    Groundwater elevations drop to the north, northeast, northwest, 
west and to

[[Page 55247]]

the south and southwest from this central axis which is mapped as a 
groundwater divide just east of the unit boundary on the August 19, 
2019, map. There are no data in the Permit Application that can enable 
a determination of groundwater flow directions to the east and 
southeast of the unit, thus the possibility of unmonitored flow in 
these directions has not been ruled out. These uncertainties 
notwithstanding (see Unit IV.C.2.b of this preamble for additional 
assessment of uncertainties associated with the groundwater monitoring 
network), the available information indicates that groundwater from the 
Ash Pond generally flows toward the surface water features represented 
by the main stem of the Coosa River as well as toward the tributary 
stream segments to the north and northwest of the unit. Groundwater 
elevations within the unit appear to be primarily controlled by the 
consistently higher elevations along the northeastern boundary of the 
unit as well as the lower elevations associated with the Coosa River to 
the northwest, west, and southwest. On August 19, 2019, the elevation 
of the Coosa River was reported to be approximately 508 ft above 
MSL.\59\
---------------------------------------------------------------------------

    \59\ Volume I: Technical Support Document for the Proposed 
Notice to Deny Alabama's Coal Combustion Residuals Permit Program, 
EPA Analysis of Alabama CCR Permits. U.S. Environmental Protection 
Agency, Office of Land and Emergency Management (5304T), 1200 
Pennsylvania Avenue NW, Washington, DC 20460. August 2023. Section 
III.b.i.
---------------------------------------------------------------------------

    It is important to note that the groundwater elevations reported on 
August 19, 2019, represent a relatively low condition, on balance, and 
groundwater elevation values measured at the unit are observed to 
oscillate over several feet on average in response to seasonal rainfall 
or other variations, with individual wells immediately adjacent to the 
Ash Pond (i.e., GSD-AP-MW-1 through MW-12) varying over a range of 
approximately 3.9 to 8.5 feet between 2018 and 2022,\60\ which covers 
the period after closure construction activities for the Ash Pond were 
certified as completed in October 2018. Similarly, the Coosa River 
levels show considerable variation, ranging from 503.3 to 512.6 ft 
above MSL between 2018 and 2022 as monitored by a gauge located 
approximately 900 feet upstream of GSD-AP-MW-11. Given these 
fluctuations, EPA considered additional groundwater elevation data from 
documents included on Alabama Power's CCR website. Groundwater 
elevation data from measurement events since August 19, 2019, were 
initially evaluated to illustrate the range of groundwater elevation 
fluctuations at the site, as summarized in Table III. The recorded 
elevations of the Coosa River on the corresponding dates are also 
included on the table.
---------------------------------------------------------------------------

    \60\ Id at Section III.c.iii.

    Table III--Groundwater Elevation Fluctuations at the Ash Pond and Corresponding Coosa River Elevations a
----------------------------------------------------------------------------------------------------------------
                                                           Groundwater elevation  (ft     Coosa River elevation
                                                                   above MSL)               (ft above MSL) \b\
                          Date                          --------------------------------------------------------
                                                                                            Range Over 24-Hour
                                                             Maximum         Minimum              Period
----------------------------------------------------------------------------------------------------------------
8/19/2019..............................................          512.03          506.95              507.6-507.8
4/13/2020..............................................          517.91          508.71              507.9-510.3
8/24/2020..............................................          512.57          507.64                507.8-508
3/15/2021..............................................          516.98          507.18                507-507.4
10/4/2021..............................................          513.76          508.03              507.9-508.1
1/11/2022..............................................          515.65          508.01              507.8-508.2
5/5/2022...............................................          516.18          507.97              507.6-508.1
10/24/2022.............................................          510.86          506.64         \c\ 507.5-507.7
----------------------------------------------------------------------------------------------------------------
\a\ Measured at groundwater monitoring wells GSD-AP-MW-1 through GSD-AP-MW-12.
\b\ Source: U.S. Geological Survey (USGS). See Section III.b.i of TSD Volume I for further details.
\c\ These data are provisional and may be revised by the USGS.

    As shown here, groundwater levels are variable, and are generally 
higher during spring monitoring events (March, April) as compared to 
late summer/fall events (August, October). In consideration of the 15 
groundwater elevation monitoring events from October 4, 2018, through 
October 24, 2022, EPA calculated average minimum, average maximum, and 
overall average groundwater elevations within the unit over the four-
year period, as follows:

Groundwater Elevation (overall average): 511 ft above MSL
Groundwater Elevation (average maximum): 514.6 ft above MSL
Groundwater Elevation (average minimum): 508.6 ft above MSL

    The average range of fluctuation between maximum and minimum values 
at a particular monitoring well location over this same period of 
interest was 5.9 feet.
    These values were used in conjunction with the estimates for the 
bottom-of-waste elevation to calculate estimated volumes of saturated 
waste, as presented in the following section.
iii. Volumes of Saturated Ash Estimates
    Based on available information and the averages discussed above, 
EPA estimated the volume of CCR in the Ash Pond that, on average, would 
continue to be saturated with approximately 1 to 4.6 feet of 
groundwater.\61\ Because both the base elevation of the waste and the 
groundwater elevations vary, those estimates both overstate and 
underestimate the degree of saturation. For example, at its lowest 
point, the base of the impoundment measures 505 ft above MSL, and the 
highest elevation of groundwater was measured at 519.26 ft above MSL 
(GSD-AP-MW-1 on February 25, 2019). However, the data show that even 
during the periodically dry conditions in summer when the groundwater 
elevations can decline to values approaching Coosa River surface 
levels, significant volumes of saturated waste may still be present 
because of uncertainties with the waste bottom elevation. If areas of 
waste are present below the elevation of the Coosa River, as some 
information suggests, these areas of waste are expected to remain 
saturated because, absent any information to the contrary, it is 
presumed that a hydraulic connection between the uppermost aquifer and 
the river exists due to the close proximity of the Ash Pond to the 
river. In any case,

[[Page 55248]]

the regular and significant oscillation in waters levels in the CCR 
indicate that significant volumes of saturated CCR persist routinely 
despite closure efforts to date. Moreover, evaluation of water level 
elevations over time show that water levels are higher than the bottom 
of the impoundment under most conditions, and there is no indication 
from available information that this situation will change absent 
additional engineering controls.
---------------------------------------------------------------------------

    \61\ Id at Section III.c.iv.
---------------------------------------------------------------------------

    EPA's analysis shows that substantial volumes of saturated CCR 
currently remain in the closed impoundment under conditions where 
groundwater elevations were at the overall average or maximum average 
levels, ranging from approximately 95,000 to 436,000 CY, respectively. 
Furthermore, these saturated volume estimates equate to approximately 
8% to 36% of the total volume of CCR in the Ash Pond with an average 
thickness of CCR over the entire footprint between approximately 1 to 
4.6 feet of statured CCR within the unit. These estimates are further 
explained in Section III.c of the TSD Volume I. Table IV summarizes the 
volumes and areas of saturated CCR calculated under both conditions.

     Table IV--Estimates of Saturated CCR at Plant Gadsden Ash Pond
------------------------------------------------------------------------
                                              Overall         Maximum
     Groundwater elevation condition          average         average
------------------------------------------------------------------------
Groundwater elevation (ft above MSL)....             511           514.6
Average waste bottom (ft above MSL).....             510             510
Saturated CCR thickness (feet)..........               1             4.6
Total CCR in Ash Pond (cubic yards).....       1,200,000       1,200,000
Area of Ash Pond (acres)................           58.73           58.73
Area of Ash Pond (square yards).........         284,253         284,253
Volume of saturated CCR (cubic yards)...          94,751         435,855
Fraction of total CCR saturated (%).....             7.9            36.3
------------------------------------------------------------------------

    Based on EPA's estimates, the closure of the Plant Gadsden Ash 
Pond, authorized and approved by ADEM, does not meet the requirements 
of Sec.  257.102(d). Overall, the closure of the Gadsden Ash Pond 
presents the same issues as the closure of the Colbert Ash Pond 4 
discussed in the previous section. The post-closure groundwater 
monitoring data from 2019 through 2021 show that groundwater is still 
infiltrating into the Ash Pond. The average groundwater elevations 
measured at monitoring wells surrounding the Ash Pond from 2018 through 
2022 were on the order of 514 ft MSL (i.e., approximately 4 feet above 
the average bottom elevation of the CCR). Yet neither the approved 
Closure Plan nor any other document in the record for the permit 
accounts for the levels of groundwater present in the unit prior to 
closure or describe any engineering measures taken to meet each of the 
Federal CCR closure-in-place performance standards in Sec.  
257.102(d)(1) and (2) in light of the groundwater present in the unit. 
Nor based on the post-closure groundwater elevation data from 
piezometer wells from 2019-2021, did the approved closure address the 
groundwater that continues to saturate the CCR in the closed unit. EPA 
is therefore proposing to determine that the permit for Plant Gadsden 
does not require Alabama Power to achieve compliance with either Sec.  
257.102(d) or with alternative State standards that EPA has determined 
to be at least as protective. EPA is therefore, proposing to determine 
that Alabama's CCR permit program does not satisfy the statutory 
requirement in RCRA section 4005(d)(1)(A) or (B).
    As previously explained, in situations such as this, where the 
waste in the unit is continually saturated with groundwater, the 
requirement to eliminate free liquids obligates the facility to take 
engineering measures to ensure that the groundwater, along with the 
other free liquids, has been permanently removed from the unit prior to 
installing the final cover system. See, 40 CFR 257.102(d)(2)(i). Yet 
neither the Closure Plan that ADEM-approved nor the permit ADEM issued 
contained any such requirements.
    While the approved Closure Plans for the Ash Pond at Plant Gadsden 
discuss dewatering techniques employed before and during closure, it 
appears the facility at most eliminated only the ``free water'' ponded 
above the CCR, and only dewatered the CCR and sediment ``to the extent 
necessary to provide a stable working surface for earthwork equipment'' 
as provided in the closure and post-closure for the Ash Pond:

2.2 DEWATERING FOR CLOSURE
    Free water in the clear pool will be removed through pumping, 
maintaining compliance with the NPDES discharge limits. The saturated 
ash will be dewatered to the extent necessary to allow a stable working 
surface for earthwork equipment. Interstitial water '' removal. All 
water will be sent to an onsite water treatment system prior to 
discharge to ensure compliance with the NPDES discharge limits.\62\
---------------------------------------------------------------------------

    \62\ Alabama Power. Revised Closure Permit Application for the 
Plant Gadsden Ash Pond. April 30, 2020. Appendix 8, p 2.
---------------------------------------------------------------------------

    The ``free water'' referenced above is only a subset of the ``free 
liquids'' that must be eliminated; and that standard (``eliminated'') 
applies equally to the pore water intermingled with the CCR. See, 40 
CFR 257.102(d)(2)(i). The Closure Plans do not acknowledge the 
groundwater within the consolidated footprint that continues to 
routinely flow into the base of the impoundment and saturate the CCR or 
describe any engineering measures to eliminate those free liquids, 
despite the continued saturation. Moreover, it is clear from the post-
closure 2019-2022 monitoring data that the measures that were taken 
during closure did not actually eliminate the free liquids from Ash 
Pond.
    A further concern is that, given the failure to eliminate the free 
liquids from the saturated CCR underlying the consolidated unit, it is 
not at all clear that the remaining wastes have been stabilized 
sufficiently to support the final cover system, as required by Sec.  
257.102(d)(2)(ii). Creating a stable working surface for earthwork 
equipment while the cover system is being installed is not the same as 
ensuring that the unit has been sufficiently dewatered prior to 
installation of the cover system and that over the long term there will 
be no differential settlement of the CCR in the closed unit that would 
disrupt the integrity of the cover system and allow

[[Page 55249]]

liquids to infiltrate into the closed unit. Neither the approved 
Closure Plan nor ADEM's permit provides any details of engineering 
measures that were taken to address the groundwater that continues to 
flow into and out of the unit from the sides and bottom. In the absence 
of such measures, EPA has no basis for concluding that the standard in 
Sec.  257.102(d)(2) has been met.
    EPA was also unable to find any description in the ADEM approved 
Closure Plan or any other permit document of engineering measures that 
Alabama Power took to ``control, minimize, or eliminate, to maximum 
extent feasible'' either the post-closure infiltration of the 
groundwater into the waste or the post-closure releases of CCR or 
leachate to the groundwater, resulting from the groundwater that 
continues to infiltrate into the impoundment from the sides and bottom 
of the unit. 40 CFR 257.102(d)(1)(i). Based on the data and analyses 
described above, groundwater continues to infiltrate into the unit and 
yet the only measures described in the Closure Plan and the permit are 
those taken to facilitate consolidation and cap construction.\63\ In 
essence, this means the Ash Pond will continue releasing CCR 
contaminants indefinitely unless Alabama Power is taking additional 
actions that are not required by or explained in the permit.
---------------------------------------------------------------------------

    \63\ Id at Appendix B (Infiltration Equivalency Demonstration) 
in Appendix 8.
---------------------------------------------------------------------------

    The absence of such measures from the closure approved by ADEM is 
consistent with the State's interpretation of its closure requirements, 
but as discussed above, it is neither consistent with, nor as 
protective as, the Federal regulations. As with the TVA Colbert Plant 
Permit, EPA is proposing to determine that the record does not support 
a finding that ADEM's alternative approach of relying on the existing 
corrective action process will be as protective as the Federal 
requirements. As discussed in a subsequent section, EPA has serious 
concerns about the protectiveness of the corrective action at Gadsden 
that ADEM is overseeing.
    All of this information was available before ADEM issued the permit 
in December 2020, and again when ADEM approved the completion of 
closure on June 9, 2022. Yet the permit continues to authorize the 
closure of the unit with no engineering measures to limit the 
groundwater from continually flowing into and out of the CCR in the 
unit, and with no permit terms on the need to address this as part of 
the corrective action process.
    Accordingly, EPA is proposing to determine that the permit for 
Plant Gadsden does not require Alabama Power to achieve compliance with 
either Sec.  257.102(d) or with alternative State standards that EPA 
has determined to be at least as protective.
b. Plant Gadsden Groundwater Monitoring Issues
    The Plant Gadsden Permit says on page 1,
    Groundwater monitoring and corrective action requirements in the 
permit establish a groundwater monitoring system of wells that provides 
an accurate representation of the groundwater quality underlying the 
unit and a groundwater monitoring plan to establish appropriate 
sampling and analysis of the system to detect the presence of CCR 
constituents.
    In addition, Section V of the Plant Gadsden Permit incorporates the 
GWMP submitted with the Permit Application, and directed Alabama Power 
to comply with the State regulations and the approved plan:

Section V. Groundwater Monitoring and Corrective Action Requirements.
A. Groundwater Monitoring System. The Permittee shall install and/or 
maintain a groundwater monitoring system, identified in Table 1, as 
specified in 335- 13- 15-. 06(2) and the approved groundwater 
monitoring plan.
Once ADEM approved and adopted the GWMP into the permit, the GWMP, 
rather than the referenced State regulations, became the State 
requirements with which the facility is required to comply.
    Based on EPA's review of the approved groundwater monitoring plan, 
EPA is proposing to determine that the groundwater monitoring well 
network ADEM approved does not meet the performance standards in Sec.  
257.91(a) or (b). As discussed in more detail below, EPA is proposing 
to determine that the approved groundwater monitoring system is not 
based on a thorough characterization of the elements listed in Sec.  
257.91(b). EPA is also proposing to determine that the groundwater 
monitoring system does not ``yield groundwater samples from the 
uppermost aquifer,'' but has been screened instead in only a portion of 
the aquifer. 40 CFR 257.91(a). Further, it appears that the background 
wells were not installed in locations hydraulically upgradient of the 
Ash Pond, and EPA was unable to locate sufficient information in the 
permitting record demonstrating that the standard for such wells in 
Sec.  257.91(a)(1)(i) or (ii) was met. In addition, based on the 
documentation provided in the Permit Application, it appears that the 
downgradient compliance wells are spaced too far apart and/or are 
screened too deeply and/or shallow to accurately represent the quality 
of groundwater passing the waste boundary and to monitor all potential 
contaminant pathways in the uppermost aquifer. See, 40 CFR 
257.91(a)(2). Therefore, EPA is proposing to determine that ADEM's 
Final Permit fails to require Alabama Power to achieve compliance with 
either the Federal regulations or with an equally protective State 
requirement.
i. Failure To Delineate the ``Uppermost Aquifer'' and To Base the 
System on Thorough Characterization of Site Data
    The Federal CCR regulations require that a groundwater monitoring 
system sample ``the uppermost aquifer,'' which is defined as ``the 
geologic formation nearest the natural ground surface that is an 
aquifer, as well as lower aquifers that are hydraulically 
interconnected with this aquifer within the facility's property 
boundary.'' 40 CFR 257.53, 257.91(a). The design of the monitoring 
systems must be based on a thorough characterization of, among other 
things, the ``aquifer thickness, groundwater flow rate, groundwater 
flow direction including seasonal and temporal fluctuations in 
groundwater flow; and saturated and unsaturated geologic units and fill 
materials overlying the uppermost aquifer, materials comprising the 
uppermost aquifer, and materials comprising the confining unit defining 
the lower boundary of the uppermost aquifer.'' 40 CFR 257.91(b)(1) and 
(2). EPA is proposing to determine that ADEM approved a groundwater 
monitoring plan that does not meet these requirements.
    Based on the limited information in the permit record, it appears 
the facility failed to fully define the limits of the uppermost 
aquifer, particularly its lower boundary. The GWMP provided in the 
Permit Application provides only limited characterization of the 
geologic units beneath the Ash Pond. In addition, the technical 
information provided in the Permit Application is insufficient to 
support a determination of the lateral and vertical limits of the 
entire uppermost aquifer; for example, EPA found only limited data on 
the ``saturated and unsaturated geologic units and fill materials 
overlying the uppermost aquifer and materials comprising the uppermost 
aquifer.'' 40 CFR 257.91(b)(2). And EPA was unable to find adequate 
information about the ``materials comprising the confining unit 
defining the lower boundary of the uppermost aquifer.'' Because the 
information in the Permit Application

[[Page 55250]]

was inadequate, EPA also consulted information available on Alabama 
Power's CCR website to understand the hydrogeology of the site. EPA is 
proposing to determine that neither the information in the Permit 
Application nor the additional information available on Alabama Power's 
CCR website constitutes ``a thorough characterization of . . . aquifer 
thickness, groundwater flow rate, groundwater flow direction including 
seasonal and temporal fluctuations in groundwater flow; and saturated 
and unsaturated geologic units and fill materials overlying the 
uppermost aquifer, materials comprising the uppermost aquifer, and 
materials comprising the confining unit defining the lower boundary of 
the uppermost aquifer.'' 40 CFR 257.91(b)(1) and (2).
    A generalized visual representation of the various lithologies 
composing the uppermost aquifer beneath the Ash Pond can be found in 
the cross sections in Figures 5A and 5B (included on pages 142 and 143) 
in the Permit Application and in other places, such as Figures 4A, 4B, 
9, and 10 from the 2021 Semi-Annual Groundwater Monitoring and 
Corrective Action (GWMCA) Report for Plant Gadsden.\64\ Based on EPA's 
assessment of the available information, the uppermost aquifer, which 
has not yet been fully identified and characterized, is a composite 
layered system consisting of unconsolidated deposits of alluvial origin 
on top of a predominantly mudstone bedrock. The unconsolidated alluvial 
deposits consist of interlayered deposits of silt, sand, gravel, and 
clay material. These unconsolidated alluvial deposits unconformably 
overlay a variably fractured and weathered bedrock material, 
predominantly mudstones of the Conasauga formation. The three-
dimensional surface represented by the contact between the uppermost 
portion of the (consolidated) bedrock and the overlying alluvium 
(unconsolidated), which can also be described as the top-of-rock 
surface, is a distinct hydraulically relevant zone of interest. These 
points are illustrated (in part) in the geologic cross-sections on 
Figures 5A and 5B (included on pages 142 and 143) in the Permit 
Application, which show the uppermost aquifer consisting of layers of 
sand, silt, gravel, as well as the underlying Conasauga bedrock 
formation. The elevation of this contact zone changes laterally across 
the unit, depending on location, and these differences in elevation are 
important with respect to the siting of appropriate monitoring well 
location and depths.
---------------------------------------------------------------------------

    \64\ Southern Company Services. 2022 Semi-Annual Groundwater 
Monitoring and Corrective Action Report, Alabama Power Company Plant 
Gadsden Ash Pond. Prepared for Alabama Power Company. January 31, 
2022.
---------------------------------------------------------------------------

    Immediately located beneath the unconsolidated alluvial materials 
is a zone of degraded bedrock (typically referred to as ``weathered 
bedrock'') in the uppermost portion of the Conasauga bedrock. This 
weathered bedrock material consists primarily of variably weathered 
mudstones which have been degraded by naturally occuring processes. The 
weathered rock zones vary in thickness laterally and vertically. This 
interface between the unconsolidated alluvial materials and the 
underlying bedrock constitutes an irregular geologic contact, which 
varies spatially in terms of the thickness and degree of the weathered 
bedrock material, that is sandwiched between alluvial deposits above, 
and lightly weathered or unweathered bedrock below. The contact can be 
thick and gradational in some areas, and abrupt and thin in other 
areas. This variability demands additional characterization as it 
creates the potential for preferential pathways which may exploit the 
weathered interval. While limited information has been collected from 
this interval, a few monitoring wells are partially screened across the 
bedrock/overburden contact, and thus monitor the weathered bedrock 
interval to some degree at those locations. However, the variable 
nature of the bedrock/overburden contact was not sufficiently 
characterized to meet the performance standards in Sec.  257.91(a) or 
(b), as discussed in more detail below.
    Beneath the uppermost veneer of weathered bedrock are rocks of the 
Conasauga group, which consists of varying amounts of limestone, 
dolomite, and shale, with chert and siltstone horizons present locally. 
The 2021 Semi-Annual GWMCA Report states, ``The Limited core logs from 
the Site indicate the Conasauga [beneath the Ash Pond] to be a medium 
to dark gray mudstone or shale with noticeable calcite veining.'' \65\ 
While the Report goes on to State, ``The Conasauga Formation is not 
considered to be a water-bearing aquifer at the Site,'' this statement 
conflicts with boring logs and other information which indicate that 
the mudstones of the Conasauga Formation are locally fractured, 
weathered and hydraulically connected to the alluvium and weathered 
bedrock deposits lying above. The lower limits of the hydraulically 
connected portions of the bedrock, however, have not yet been 
established, and reporting is not consistent on this. Both the Permit 
Application and the 2021 Semi-Annual GWMCA Report generally describe 
the aquifer similarly. For example, the 2021 Semi-Annual GWMCA Report 
\66\ states,
---------------------------------------------------------------------------

    \65\ Id.
    \66\ Id.

The uppermost aquifer beneath the Site corresponds to a coarse and more 
permeable fraction of alluvial overburden soils and weathered or 
fractured rock near the soil-rock interface. The uppermost aquifer is 
typically located at depths between 15 and 50 feet below ground surface 
(BGS). Soils are generally poorly graded sands with layers of clay and 
well-graded gravels that overlay a mudstone or shale bedrock,''
See also Permit Application at section 3 of the GWMP. As shown on 
Figures 5A and 5B in the Permit Application, bedrock intervals are not 
included in the represented monitoring wells and little 
characterization appears to have penetrated the bedrock beyond the 
uppermost intervals.
    But elsewhere the 2021 Semi-Annual GWMCA Report states that,

Vertical delineation wells targeted more permeable/fractured water-
bearing zones within the Conasauga formation in the upper 50 feet of 
bedrock.
    A further inconsistency appears on the geologic cross sections 
included in the 2021 Semi-Annual GWMCA Report (see Figures 4A, 4B, 9, 
and 10), which indicate the connection of the alluvial and bedrock 
zones to depths of over 100 feet into the mudstone bedrock. These cross 
sections and the associated boring logs, some of which were included in 
the Permit Application and some of which were included in the 2021 
Semi-Annual GWMCA Report, confirm that this group of geologic layers 
and formations are hydraulically interconnected to depths of over 100 
feet into the bedrock. The totality of this information forces the 
conclusions that the lower limits of the uppermost aquifer have not 
been determined and the uppermost aquifer and hydraulically connected 
underlying intervals extends at least 100 feet into the bedrock.
    In other words, based on the available information, the uppermost 
aquifer consists of the alluvial aquifer nearest the ground surface and 
at least the uppermost 100 feet of the hydraulically connected bedrock 
beneath it. See, 40 CFR 257.53 (definition of uppermost aquifer). As 
such the materials presented in the Permit Application do not present a 
complete or accurate representation of the uppermost aquifer and 
hydraulically connected aquifer zones beneath it.
    In addition, the top-of-bedrock surface has not been adequately 
resolved in all

[[Page 55251]]

areas of the site because some boring logs lack reliable confirmatory 
data. According to the boring logs that were included in the Permit 
Application, there are multiple missing intervals of ``no recovery'' 
from numerous borings advanced into bedrock, which indicate a large 
potential for hydraulically significant zones that are currently 
insufficiently characterized. As a consequence, EPA is proposing to 
determine that the thickness, variability, nature, and hydrogeologic 
significance of the transitional zone of weathering in the uppermost 
part of bedrock has not been established, as required by Sec.  
257.91(b).
    Furthermore, a hydraulic divide, generally located along the 
northeastern boundary of the unit, indicates the groundwater hydraulics 
are more complex than the current coarse monitoring network can 
adequately evaluate. Additional monitoring points are needed laterally 
(and vertically) in this area to provide the ``thorough 
characterization of groundwater flow rate [and] groundwater flow 
directions, including seasonal and temporal fluctuations in groundwater 
flow'' required to support the design of the groundwater monitoring 
system pursuant to Sec.  257.91(b)(1). There are also insufficient data 
to allow for the determination of groundwater flow directions at the 
eastern limits of the Ash Pond. While GSD-AP-MW-12 is downgradient of 
GSD-AP-MW-1, there are no wells or piezometers that would serve as 
hydraulic control points to the east of the Ash Pond to fully 
characterize the groundwater flow directions at the eastern waste 
boundary. Furthermore, GSD-AP-MW-1 consistently has one of the highest 
groundwater elevations, and the possibility of eastward flow beyond the 
eastern boundary cannot be ruled out without additional data. 
Additional groundwater monitoring wells are needed to the northeast, 
east, and southeast of the easternmost boundary of the Ash Pond. In 
summary, EPA is proposing to determine that significant numbers of 
additional characterization borings and monitoring wells are needed to 
effectively characterize the alluvial aquifer nearest the ground 
surface and hydraulically connected zones within the weathered bedrock 
and upper portion of the bedrock intervals. See, 40 CFR 257.91(b).
ii. ADEM Issued a Final Permit With Background Wells That Do Not Meet 
the Sec.  257.91(a)(1) Performance Standard
    The Federal CCR regulations require that a groundwater monitoring 
system consist of a sufficient number of wells at appropriate locations 
and depths to yield samples from the uppermost aquifer that accurately 
represent the quality of the background groundwater that has not been 
affected by leakage from a CCR unit. 40 CFR 257.91(a)(1). The 
regulations also specify that background wells must normally be 
hydraulically upgradient of the CCR unit, unless specific showings have 
been made. See, Id. EPA is proposing to determine that the approved 
GWMP fails to document either that the background wells are upgradient 
of the CCR unit or that the wells meet the performance standards in 
Sec.  257.91(a)(1)(i) or (ii). EPA is also proposing to determine that 
the background wells in the approved groundwater monitoring system do 
not ``accurately represent the quality of the background groundwater'' 
because of differences in the lithology between the background wells 
and the majority of the wells in the downgradient groundwater 
monitoring network, which is discussed in detail below.
    At the time of permit issuance, the approved groundwater monitoring 
network installed at the unit consisted of three ``background'' 
monitoring wells (GSD-AP-MW-14, -16, and -17). According to the single 
groundwater flow map included in the Permit Application,\67\ 
groundwater predominantly flows toward the main stem of the Coosa River 
from both the southern and northern sides of the river. The Coosa River 
acts as a hydraulic divide between the Ash Pond and the region to the 
south of the river where the background wells are located. 
Consequently, the Plant Gadsden background wells, which are all located 
on the southern side of the river, are hydraulically disconnected from 
the Ash Pond, rather than ``upgradient'' of the Ash Pond. In addition, 
they are in a different flow system and therefore cannot accurately 
represent the quality of the background groundwater at the Ash Pond.
---------------------------------------------------------------------------

    \67\ Alabama Power. Revised Closure Permit Application for the 
Plant Gadsden Ash Pond. April 30, 2020. Appendix 7, Plant Gadsden 
Ash Pond Groundwater Monitoring Plan, Figure 6.
---------------------------------------------------------------------------

    The Federal regulations specify that wells that are not 
hydraulically upgradient of the CCR unit can only serve as background 
wells if one of two showings have been made: (1) that hydrogeologic 
conditions do not allow the owner or operator to determine whether 
wells are hydraulically upgradient; or (2) sampling at other wells will 
be as representative or more representative of background groundwater 
quality than that provided by the upgradient wells. 40 CFR 
257.91(a)(1)(i), (ii).
    EPA found nothing in the Permit Application or on the facility's 
CCR website to indicate that site conditions made it infeasible to 
determine whether background wells could be installed at locations that 
are hydraulically upgradient on the same side of the river. For 
example, while on-site access may be limited due to conditions near the 
Ash Pond, there is no discussion about other access points offsite to 
the north, northeast, or east of the unit that may provide adequate 
background samples. In addition, there are site-specific geologic 
conditions identified in the Permit Application that indicate that 
sampling at the current background wells will not ``accurately 
represent the quality background groundwater'' quality at the Ash Pond. 
40 CFR 257.91(a)(1). For example, based on the boring logs presented in 
the Permit Application, background monitoring well GSD-AP-MW-17 is 
screened in limestone but nearly all of the bedrock groundwater 
monitoring wells surrounding the Ash Pond are screened in a different 
rock type (i.e., mudstone). In addition, background monitoring well 
GSD-AP-MW-16 is screened in sand and gravel alluvial materials and 
based on a note included within the boring log, it is partially 
screened into approximately four feet of limestone bedrock, whereas 
numerous wells in the shallow downgradient compliance monitoring 
network surrounding the Ash Pond are screened just above or across the 
interface between mudstone and overlying overburden materials. 
Limestone and mudstone are different rock types and, based on the 
boring logs presented in the Permit Application, limestone substrates 
do not appear to have been penetrated by monitoring wells installed for 
the unit's downgradient compliance monitoring network on the northern 
side of the river.
    Due to fundamental differences between limestone and mudstone 
mineralogy and chemical composition, it is not clear that ambient 
geochemical conditions in the limestone-hosted aquifer would be 
representative of an environment where mudstone predominates, and site-
specific comparative analysis of both the geology and geochemistry for 
the two distinct geochemical environments and flow systems is necessary 
to determine whether the wells across the river are in fact 
sufficiently representative of conditions within the uppermost aquifer 
to serve as representative background wells. Although the Groundwater 
Monitoring Plan included a limited

[[Page 55252]]

narrative at Section 4.2.2, entitled ``Groundwater Geochemistry,'' the 
narrative did not address any known differences in geology, lithology, 
or mineralogy between the two aquifers that are located on opposite 
sides of the river. ADEM nevertheless approved the plan without 
requiring the facility to resolve these issues.
iii. The Gadsden Final Permit Allows Insufficient Locations and Depths 
of Downgradient Compliance Wells To Monitor the Uppermost Aquifer
    As previously discussed, the Federal regulations specify that a 
groundwater monitoring system must ``consist[ ] of a sufficient number 
of wells, installed at appropriate locations and depths, that . . . 
accurately represent the quality of the groundwater passing the waste 
boundary of the CCR unit.'' 40 CFR 257.91(a)(2). The regulations 
further specify that ``[a]ll potential contaminant pathways must be 
monitored.'' Id. But as discussed in more detail below, EPA is 
proposing to determine that ADEM approved a GWMP with an insufficient 
number of wells laterally along the downgradient perimeter of the unit 
to monitor all potential contaminant pathways. EPA is also proposing to 
determine that monitoring wells in the approved plan were not installed 
at appropriate depths to ensure that all potential contaminant pathways 
were monitored. Finally, EPA is proposing to determine that the 
approved groundwater monitoring system fails to account for 
preferential pathways beneath the Ash Pond.
(1) Insufficient Lateral Spacing of Compliance Wells To Monitor All 
Potential Contaminant Pathways
    At the time of permit issuance, the approved groundwater monitoring 
network installed at the unit consisted of only fifteen compliance 
monitoring wells (GSD-AP-MW-1 through GSD-AP-MW-12 and GSD-AP-PZ-1, 
GSD-AP-PZ-5 and GSD-AP-PZ-6), at an impoundment with a perimeter of 
approximately 7,500 feet.
    Most of the groundwater monitoring wells that parallel the river 
for the Plant Gadsden Ash Pond unit are spaced approximately 400 to 900 
feet apart, and lateral distribution of wells is somewhat uniform with 
downgradient monitoring wells surrounding the waste boundary at an 
average lateral spacing of 630 feet.\68\ These large lateral well 
spacings are particularly problematic to the north, northwest, west, 
and to the southwest where groundwater discharges to the Coosa River. 
Given the propensity for groundwater to flow within the preferential 
pathways that exist at the site and the close proximity of the Coosa 
River to the unit, one would expect to see a detailed rationale 
explaining why these well locations at large lateral distances were 
sufficient to monitor all potential contaminant pathways. However, 
EPA's review of the approved GWMP did not identify any such 
explanation. Therefore, given the proximity to the Coosa River, the 
large well spacings make it likely that all potential contaminant 
pathways--such as the gravel and other coarse material in the alluvium 
and fractures, or the dissolution features at or below the weathered 
bedrock surface that may be causing groundwater to surface water 
discharges immediately adjacent to the Ash Pond--are not currently 
monitored.
---------------------------------------------------------------------------

    \68\ Southern Company Services 2022 Annual Groundwater 
Monitoring and Corrective Action Report, Alabama Power Company Plant 
Gorgas Ash Pond. Prepared for Alabama Power Company. February 1, 
2023.
---------------------------------------------------------------------------

(2) Insufficient Number of Downgradient Compliance Wells Installed at 
Appropriate Depths To Monitor the Entire Aquifer (Inadequate Vertical 
Spacing)
    EPA is also proposing to determine that ADEM approved a GWMP that 
lacked ``a sufficient number of wells, installed at appropriate 
locations and depths'' to ensure that all potential contaminant 
pathways in the entire uppermost aquifer are monitored. As stated 
previously, the uppermost aquifer is a composite layered system 
consisting of unconsolidated deposits of alluvial origin on top of 
mudstone bedrock. The unconsolidated alluvial deposits consist of 
interlayered deposits of silt, sand, gravel, and clay material. These 
unconsolidated alluvial deposits overlay a variably fractured and 
weathered bedrock material, predominantly mudstones of the Conasauga 
formation. The contact between the uppermost portion of the 
(consolidated) bedrock and the overlying (unconsolidated) alluvium, 
which can also be described as the top-of-rock surface, is a distinct 
hydraulically relevant zone of interest, and many ``downgradient'' 
compliance monitoring wells in the approved network are screened across 
this interface, as is appropriate. However, although the lower limits 
of the hydraulically connected portions of the bedrock have not yet 
been established, as previously discussed, the available information 
supports the conclusion that this group of geologic layers and 
formations are hydraulically interconnected to depths of 100 feet or 
more into the bedrock. Consequently, EPA is proposing to determine that 
the entire group of geologic layers and formations should have been 
more comprehensively monitored. See, 40 CFR 257.53 (definition of 
uppermost aquifer).
    The downgradient well network ADEM approved is focused on a narrow 
subset of the uppermost geologic layers associated with river 
deposition. These unconsolidated materials occur in terrace deposits at 
low elevations near the current Coosa River channel as well as at 
higher topographic levels. These alluvial deposits are reported to 
range from approximately 20 to 30 feet in thickness. Most of the 
downgradient compliance monitoring wells in the approved network are 
screened in these shallow materials, and most of the wells are screened 
only in the gravel.\69\ Additional compliance wells are needed both at 
the upper and lower bounds of the uppermost aquifer system, including 
within alluvial deposits and hydraulically connected weathered bedrock 
and bedrock zones, to ensure all potential contaminant pathways will be 
monitored in all relevant flow zones.
---------------------------------------------------------------------------

    \69\ The Plant Gadsden Permit Application at page 111 includes a 
statement that ``[m]onitoring wells target the uppermost aquifer 
with wells screened in coarse fractions of the alluvial materials or 
more weathered, fractured upper bedrock beneath the Site.''
---------------------------------------------------------------------------

    A few wells are screened near the top of the Conasauga bedrock 
formation, and a few wells are cross screened across the interface 
between the alluvium (the gravel) and the underlying bedrock. As 
depicted on the cross-section in Figure 5A in the Permit Application, 
no wells appear to have been screened in either the sand or silt layers 
that are situated above the gravel; and a single well on the cross-
section in Figure 5B in the Permit Application appears to be partially 
screened in the silt. But additional compliance wells should have been 
installed in those upper zones given that the sand and silt layers are 
saturated with groundwater. Even when the gravel layers were not 
present, the well screens were set at the bottom of the alluvium or at 
the top of bedrock, and not in the silts. Wells in each of the 
saturated units are needed in order to monitor all potential 
contaminant pathways.
    In addition, as previously discussed, key interfaces, such as the 
interface between alluvium and weathered bedrock have apparently not 
been fully characterized; as this portion of the bedrock system is 
hydraulically connected to the overlying alluvium, additional 
compliance wells are needed in the upper part of the bedrock in most 
areas of the Ash Pond unit to ensure that all potential contaminant 
pathways are monitored. Additional wells also

[[Page 55253]]

need to be installed in deeper intervals of the underlying Conasauga 
mudstones which are hydraulically connected the uppermost zone of 
weathered bedrock. The relevant zone of interest in the upper part of 
the Conasauga group is at least 100 feet in thickness, as discussed 
previously, but the true thickness of the uppermost aquifer has not 
been determined. As such additional monitoring wells may need to be 
screened more deeply to ensure all potential contaminant pathways are 
monitored.
(3) Preferential Pathways Are Not Monitored
    Preferential pathways have been documented in the uppermost aquifer 
under the Ash Pond. Yet under the approved GWMP, these significant 
potential contaminant pathways do not appear to be adequately 
monitored, despite the express requirement in Sec.  257.91(a)(2).
    Based on the boring logs and cross-sections in the Permit 
Application and the 2021 Semi-Annual GWMCA Report, several types of 
preferential pathways are present at the site. These include, among 
others, continuous lenses or channel-like bodies of coarse sand and 
gravel in overburden, low-lying areas along the overburden/bedrock 
interface, laterally continuous zones of weathered bedrock in the 
uppermost part of the bedrock section, and zones of fracturing and/or 
weathering and/or dissolution within deeper levels of the bedrock. The 
current monitoring network only incompletely monitors some of these.
    While some monitoring wells are installed in sand and gravel bodies 
in the alluvium, it appears that the monitoring network does not target 
all such zones that may be serving as preferential pathways. As just 
one example, consider the southwestern unit boundary that borders the 
Coosa River; as indicated on Figures 5B and 6 of the approved GWMP, 
while the wells installed along this boundary (GSD-AP-MW-8 thru GSD-AP-
MW-12) are screened along a zone where groundwater flow is likely 
occurring along preferential pathways, they are spaced over 500 feet 
apart. Considering the unique geologic conditions at the site that 
could result in the presence of more localized preferential pathways, 
it is not known whether the gravel materials screened by GSD-AP-MW-11 
are present elsewhere along this boundary. In short, there could be 
sand and gravel alluvial zones or highly fractured zones in bedrock 
near the bedrock/alluvium interface that have not been identified and 
are unmonitored. EPA is proposing to determine that additional borings 
(and possibly monitoring wells) should have been installed along this 
boundary, and it appears that this level of detailed investigation to 
identify preferential pathways was not performed elsewhere along the 
unit.
    It is clear that preferential pathways in the bedrock exist based 
on the characterization and monitoring Alabama Power conducted as part 
of the continuing corrective action at the site. However, there is 
little to no discussion in the Permit Application regarding how these 
pathways were identified and how the lateral/vertical dimensions of the 
pathways were delineated to ensure that compliance wells were installed 
correctly to monitor these pathways. As illustrated on Figures 9 and 10 
of the 2021 Semi-Annual GWMCA Report, assessment monitoring has 
identified plumes emanating from the unit to the northeast in 
overburden and bedrock. After installing additional monitoring wells to 
delineate the contaminant plume, Alabama Power identified that 
contamination was present deeper in the Conasauga bedrock formation 
than any of the compliance wells previously installed as part of the 
groundwater monitoring system. For example, Figures 5 and 10 of the 
2021 Semi-Annual GWMCA Report indicate that pathway in bedrock has 
influenced migration of a lithium plume beyond the unit boundary at 
least hundreds of feet to the northeast to depths of at least 130 feet 
into the bedrock. It is reasonable to expect that similar pathways may 
exist also along the same regional northeast to southwest geologic 
strike to the southwest of the unit, exploiting these same inherent 
zones of fracturing in the bedrock, yet the southwestern waste 
boundary, along the Coosa River, generally lacks any monitoring points 
in deeper bedrock.
    In summary, after reviewing the GWMP and all the materials in the 
permit record, EPA is proposing to determine that the monitoring 
network that ADEM approved is not likely to detect all groundwater 
contamination in the uppermost aquifer and is therefore less protective 
than the Federal regulations.
c. Plant Gadsden Corrective Action Issues
    In January 2020, the first SSLs above groundwater protection 
standards were reported for arsenic and lithium. An ACM was prepared in 
July 2020. On December 18, 2020, ADEM issued the Final Permit to 
Alabama Power for Gadsden Ash Pond. EPA is proposing to determine that 
the Final Permit issued to the Gadsden Ash Pond, as with the other 
permits discussed in this notice, fails to require Alabama Power to 
achieve compliance with the Federal corrective action requirements.
    The Gadsden Final Permit states that the Permittee is required ``. 
. . to manage CCR in accordance with the conditions of the permit, ADEM 
Admin. Code r. 335- 13- 15, `Standards for the Disposal of Coal 
Combustion Residuals in Landfills and Surface Impoundments,' and the 
approved permit application.'' \70\ The permit also contains the same 
recitation of the corrective action regulations as the Colbert Final 
Permit did.
---------------------------------------------------------------------------

    \70\ Alabama Department of Environmental Management. Initial 
Permit and Variance, Gadsden Steam Plant, Permit No. 28-09. December 
18, 2020. PDF p. 2.
---------------------------------------------------------------------------

Corrective Action
    1. Assessment of Corrective Measures. The Permittee must initiate 
an assessment of corrective measures as specified in 335-13-15-. 06(7) 
if any constituent listed in Appendix IV of 335- 13- 15 has been 
detected at a statistically significant level exceeding the groundwater 
protection standard, or immediately upon detection of a release from 
the CCR unit.
    a. The permittee must continue to monitor groundwater in accordance 
with the assessment monitoring program while assessing corrective 
measures.
    2. Selection of Remedy. Based on the results of the corrective 
measures assessment, the Permittee must select a remedy as specified in 
335-13-15-. 06(8).
    3. Implementation of the Corrective Action Program. Within 90 days 
of selecting a remedy, the Permittee must initiate remedial activities 
as specified in 335-13-15-. 06(9), and shall be required to modify the 
permit in accordance with Section II. E. 9.
    In the RTC for the Gadsden Final Permit, ADEM states that, ``The 
ACM is currently under review. Once the final review is complete, the 
Department will provide comments to Alabama Power related to the 
submitted ACM and proposed final remedy.'' The preferred remedy in the 
ACM was MNA with adaptive site management and ``remediation system 
enhancement.'' \71\ Any comments provided by ADEM to

[[Page 55254]]

Alabama Power on the 2020 ACM were not available for review.
---------------------------------------------------------------------------

    \71\ It is not clear what is meant by ``remediation system 
enhancement'' with respect to MNA, because MNA relies upon naturally 
occurring processes for remediation. The only systems installed are 
for performance monitoring. Any ``enhancement'' would require action 
on the part of Alabama Power to remediate the releases and would be, 
by definition, a different remedy.
---------------------------------------------------------------------------

    As with Colbert, incorporating the regulations verbatim in the 
permit does not require Gadsden to achieve compliance with those 
requirements. This is because ADEM did not take into account relevant 
facts about the status of corrective action at Gadsden, such as whether 
the 2020 ACM, which was completed more than 2 years prior to issuance 
of the permit, complied with the regulatory requirements. Most 
importantly, ADEM did not adjudicate what actions are still necessary 
in light of those facts to achieve compliance with the regulations and 
include those actions as requirements in the Final Permit.
    Whether the 2020 ACM meets the requirements of the regulations and 
what actions Alabama Power must take to remediate groundwater in 
compliance with Sec.  257.97 are precisely the types of adjudication 
required in a permit. What the permittee is required to do in order to 
achieve compliance with the regulations must be determined prior to 
final permit issuance, because the permit must contain these 
requirements. This is the role of a permitting authority (i.e., ADEM). 
Delaying this decision effectively allows Alabama Power to continue 
operating out of compliance with the regulations, while operating in 
compliance with the permit. In this case, that means Alabama Power can 
continue to pursue a remedy that does not appear to meet the 
requirements of Sec.  257.97, and consequently, delay or avoid the 
cleanup. This results in a permit program that is less protective than 
the Federal regulations.
    In sum, EPA is proposing to determine that, by failing to determine 
the adequacy of the revised ACM or the permittee's proposed remedy, the 
permit in essence authorizes Alabama Power to continue to pursue a 
remedy that does not appear to meet the requirements in Sec.  257.97(b) 
and is based on the results of a deficient ACM. Accordingly, EPA is 
proposing to determine that this permit does not require compliance 
with the Federal requirements and, because it allows the facility to 
continue to delay initiating corrective action that would address the 
continuing groundwater contamination, the State requirement is less 
protective than the Federal regulations.
i. Gadsden Final Permit Does Not Require an ACM That Includes an 
Assessment of Source Control Measures in Accordance With 40 CFR 257.96
    40 CFR 257.97(b)(3) requires that all remedies control the source 
of releases in order to reduce or eliminate, to the maximum extent 
feasible, further releases of contaminants into the environment. The 
ACM for Gadsden contains no assessment of control measures to achieve 
this requirement (i.e., source control). Instead, section 2.5 describes 
the closure of the unit, which has already occurred, and states, ``Site 
closure appears to have already been effective in controlling the 
source and reducing infiltration into the underlying aquifer.'' 
However, the ACM must include more than one source control measure and 
must actually analyze how effectively each of the potential measures 
would meet the criteria in Sec.  257.96(c). See, 40 CFR 257.96(a), (c). 
Here, as was the case with Plant Colbert, there is no assessment of the 
one source control measure identified in the ACM--the closure of the 
Ash Pond, which left a significant amount of CCR in contact with 
groundwater--and how effectively it would achieve the criteria in Sec.  
257.96(c) compared to other source control alternatives, such as clean 
closure or the imposition of engineering measures to control or 
eliminate the groundwater that continues to flow in and out of the 
impoundment. Yet the permit issued by ADEM does not require any actions 
to remedy these readily apparent deficiencies.
    ADEM's failure to require Alabama Power to submit an ACM that 
actually evaluates whether the closure of the Ash Pond meets the source 
control requirements in Sec.  257.97(b)(3) also undercuts their claim 
that they will use the corrective action process to address any 
remaining concerns with respect to the closure of the Ash Pond. As 
discussed above, closure construction activities for the Ash Pond were 
certified as completed in October 2018, and a certification of the 
completion of closure activities was submitted in April 2020. As 
discussed above, in the two years between the time closure was 
completed and the permit was issued in December 2020, groundwater 
elevations were measured between 2 and 7 feet above the average base 
elevation of the closed unit. Yet ADEM issued the permit without 
evaluating the ACM. Nor did the State take any further action when they 
approved the closure of the Ash Pond in 2022.
ii. The Gadsden Permit Does Not Require Alabama Power To Collect Site 
Data Needed To Characterize Site Conditions That May Affect a Remedy To 
Support Assessments in the ACM
    As discussed above, Sec.  257.95(g)(1) requires a facility to 
characterize the nature and extent of the release and any relevant site 
conditions that may affect the remedy ultimately selected. The 
characterization must be sufficient to support a complete and accurate 
assessment of the corrective measures necessary to effectively clean up 
all releases from the CCR unit pursuant to Sec.  257.96. The 2020 ACM 
delineates releases but does not characterize any site conditions that 
would affect its preferred remedy of in-situ immobilization through 
treatment or MNA (e.g., testing for the presence of released 
constituents in soils to demonstrate they are being removed from the 
groundwater and immobilized on-site). As discussed in subsequent 
sections, these data are necessary to accurately assess any of the 
remedies identified in the ACM, particularly MNA. The Final Permit 
issued by ADEM does not require collection of these data or any 
revisions to the ACM to remedy this deficiency.
iii. The Assessment of In-situ Geochemical Treatment and MNA in the 
ACMs Is More Favorable Than Can Be Supported by the Available Data
    The 2020 ACM for Gadsden identified in-situ geochemical treatment 
and MNA as corrective measures to address groundwater contamination, in 
addition to hydraulic control and treatment. As discussed previously, 
MNA relies on natural processes to treat releases; in-situ geochemical 
treatment adds chemicals to the subsurface to create conditions for 
this immobilization to occur. For arsenic and lithium, in-situ 
geochemical treatment and MNA can reduce mobility through sorption to 
soils, but they do not remove the contaminants from the environment. 
Therefore, MNA and geochemical in-situ treatment generally would not 
perform well with respect to the requirement in Sec.  257.97(b)(4) that 
remedies ``remove from the environment as much of the contaminated 
material that was released from the CCR unit as is feasible,'' since 
the constituents remain in the subsurface soils, albeit immobilized.
    In order for immobilization through MNA or in-situ treatment to be 
assessed favorably with respect to reliability, the chemical reactions 
and processes involved in this immobilization must be demonstrated to 
be irreversible. Immobilization that is not permanent could be 
reversed, causing contaminants to be released back into groundwater, 
where they can migrate off-site. Immobilization that is not permanent 
would also require ongoing monitoring in accordance with Sec.  
257.98(a)(1) as long as immobilized constituents remain in the 
subsurface. Determining the viability and demonstrating the 
irreversibility of immobilization

[[Page 55255]]

mechanisms is necessary to assess the performance, reliability, ease of 
implementation, and the time required to begin and complete the remedy. 
40 CFR 257.96(c)(1) and (2). These assessments would need to be 
supported with site-specific characterization data and analysis. This 
information would ultimately be necessary to show that MNA and 
geochemical in-situ treatment meet all the requirements of Sec.  
257.97(b), but the permit record does not include such information.
(1) The 2020 ACM Does Not Include Data That Characterize Site 
Conditions or Identify Any Attenuation Mechanisms Occurring at the Ash 
Pond
    The 2020 ACM assessed the performance of MNA favorably without any 
supporting data to characterize site conditions that may ultimately 
affect a remedy, as required by Sec.  257.95(g)(1). For example, site-
specific groundwater data (e.g., pH or oxidation potential, speciated 
concentrations of constituents of concern) were not considered in the 
assessment narrative, and analytical results of soil samples to 
identify the presence of immobilized constituents in the subsurface 
were not provided. The site data that were collected focus only on 
contaminant concentrations and trend analyses regarding the presence of 
contaminants. The ACM also does not discuss how attenuation may be 
naturally occurring through any particular MNA mechanisms (e.g., 
adsorption, precipitation, dispersion). EPA was not able to find any 
indication in the permit or supporting documentation to confirm that 
the Permittee has identified the mechanisms by which MNA would occur at 
the site for both arsenic and lithium. Nor is there any condition in 
the permit requiring the development and submission of such 
information.
(2) MNA Is Not a Viable Remedy Without Source Control
    As discussed previously for Plant Colbert, MNA is not viable 
without source control, because the total amount of contaminants in the 
groundwater will continue to increase as the releases from the unit 
continue and potential releases of new constituents will occur. 
Therefore, it is impossible to determine whether the aquifer has 
sufficient chemical and physical materials required to complete any 
identified immobilization reactions because the total amount of the 
release is not yet known.
    Source control has not been achieved here, as releases from the Ash 
Pond are ongoing. The closure of the Ash Pond with waste remaining in 
place in the aquifer has resulted in a continual source of groundwater 
contamination from the unit. Therefore, MNA is not a viable remedy for 
the Ash Pond and should not be included in the 2020 ACM unless the ACM 
is revised to include an alternative that achieves source control.
(3) Plant Gadsden's Permit Does Not Require an ACM That Accurately 
Assesses Groundwater Remediation Alternatives According to the Criteria 
in 40 CFR 257.96(c)
    The 2020 ACM also fails to meet the requirements at Sec.  
257.96(c)(3) to consider safety impacts, cross-media impacts, and 
control of exposure to any residual contamination in its assessment of 
MNA. Neither the narrative nor Table 5 in the 2020 ACM consider these 
impacts for MNA. Table 5 in the 2020 ACM, in the column labeled 
``potential impacts of remedy'' assesses the potential impacts from MNA 
as ``none.'' This conclusion is not only unsupported by data or 
analysis but is also inconsistent with other information in the ACM. 
The Ash Pond is next to a river and groundwater flow is depicted toward 
the river in Figure 3 in the 2020 ACM. Because no site data were 
collected that would demonstrate immobilization of constituents is 
occurring, the only MNA that is known to occur is dilution and 
dispersion (i.e., the normal transport associated with groundwater 
releases). This means that contaminants are migrating out of the Ash 
Pond in groundwater toward the river. Migration of contamination from 
groundwater to surface water is a cross-media impact. Thus, the 
assessment of potential impacts from the remedy for MNA in Table 5, 
which includes these cross-media impacts, should be ``high.''
    The lack of data to support the assessments in the ACMs means they 
may not accurately reflect MNA's ``effectiveness in meeting all of the 
requirements and objectives'' in Sec.  257.97(b). Conclusions without a 
supporting assessment or data do not constitute ``an analysis of the 
effectiveness of potential control measures.'' 40 CFR 257.96(c) 
(emphasis added). Inaccurate assessments in an ACM can ultimately 
result in selection of a remedy that will not meet the requirements of 
Sec.  257.97(b). Yet the Final Permit issued by ADEM does not require 
any actions to remedy this deficiency.
3. Plant Gorgas
    EPA reviewed the Initial Permit and Variance (Final Permit) for the 
Alabama Power Company, William C. Gorgas Electric Generating Plant 
(Plant Gorgas), issued by ADEM under Permit No. 64-12 on February 28, 
2022.\72\ Plant Gorgas is located near Parrish, Alabama. The units 
covered by the Final Permit include the Plant Gorgas Ash Pond, Plant 
Gorgas Gypsum Pond, Plant Gorgas Bottom Ash Landfill, and Plant Gorgas 
CCR and Gypsum Landfill. The Plant Gorgas CCR and Gypsum Landfill is 
still in operation while the other three CCR units are in the process 
of closing or closed. For this proposal, of the CCR units at Plant 
Gorgas, EPA only evaluated the Final Permit for the Plant Gorgas Ash 
Pond (Ash Pond) because it is directly comparable to the other State 
CCR permits evaluated in this proposal, and because, based on the 
characteristics of the unit and the surrounding hydrogeology, it has 
the greatest potential for significant environmental and human health 
effects if mismanaged.
---------------------------------------------------------------------------

    \72\ Alabama Department of Environmental Management. Initial 
Permit and Variance William C. Gorgas Electric Generating Plant 
Permit Number 64-12. February 28, 2022.
---------------------------------------------------------------------------

    The Plant Gorgas Ash Pond is a ``CCR surface impoundment located in 
Sections 20, 21, 28 and 29, Township 16 South, Range 6 West in Walker 
County, Alabama . . . with a disposal area that consists of 
approximately 423.32 acres.'' Final Permit at pg. 2. The Ash Pond is 
located southeast of Plant Gorgas on the opposite side of the Mulberry 
Fork of the Black Warrior River. The Permit Application describes that 
the Ash Pond was originally formed by a cross-valley dam in 1953, with 
the original dam located on the northern boundary of the impoundment 
adjacent to Mulberry Fork.\73\ The original dam was raised to increase 
the capacity of the impoundment in the mid-1970's, and then raised once 
again in 2007. Id. at Appendix 4. When the Ash Pond was in operation, 
the impoundment covered an approximate area of 420 acres containing 25 
million CY of waste.
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    \73\ Alabama Power Company. Revised Closure Permit Application 
for the Plant Gorgas Ash Pond. April 30, 2020.
---------------------------------------------------------------------------

    EPA has identified issues with closure, groundwater monitoring 
networks, and corrective action at Plant Gorgas, and we discuss those 
issues below.
a. Plant Gorgas Closure Issues
    As noted, the closure at Plant Gorgas is not yet complete. To 
evaluate the closures at Plants Colbert and Gadsden, EPA reviewed the 
measured post-closure groundwater elevations to determine whether the 
Sec.  257.102(d) performance standards were met. But since the closure 
of the Gorgas Ash

[[Page 55256]]

Pond is not yet complete, that same information (``measured post-
closure groundwater elevations'') is not available. As discussed below, 
however, it is clear that CCR in the Ash Pond is currently saturated by 
groundwater. Despite the saturated CCR currently in the unit, it may be 
possible for the Ash Pond to close with waste in place if engineering 
measures are implemented to meet the performance standards in Sec.  
257.102(d). Although some engineering measures are described in the 
Closure Plan, EPA was unable to locate the information in the permit 
record to support a definitive conclusion that the proposed closure 
will meet the performance standards in Sec.  257.102(d). For example, 
EPA was unable to locate any evaluation of the expected impact of the 
proposed engineering measures on groundwater elevations conducted by 
either the permittee or ADEM. EPA's inability to reliably estimate 
post-closure conditions is a consequence of the complexity of the site, 
the absence of critical information in the Closure Plan, and the 
inadequacy of the groundwater monitoring system at the site (which is 
discussed in the next section). Nevertheless, as described below, based 
on the available information there are several reasons to determine 
that it is unlikely that the proposed closure of the Ash Pond will meet 
the performance standards in Sec.  257.102(d). EPA is therefore 
proposing to determine that the approved Closure Plan fails to 
demonstrate that the closure will meet the performance standards in 
Sec.  257.102(d), as required by Sec.  257.102(b)(1)(i). Based on 
ADEM's failure to require the permittee to provide this information, or 
to otherwise resolve the issues presented below before approving the 
Closure Plan, EPA is proposing to determine that the Final Permit fails 
to require the Gorgas Ash Pond to achieve compliance with either Sec.  
257.102(d), or with an equally protective State alternative. See 42 
U.S.C. 6945(d)(1)(B).
i. CCR in the Ash Pond Is Currently Saturated by Groundwater and Is 
Likely To Remain so Once Closure Is Complete
    Given the complexity of the site and the absence of detailed 
information in the Permit Application, EPA lacks the data to reliably 
estimate the amount of CCR that will remain saturated after closure 
activities are complete. These deficiencies are significant enough that 
ADEM's approval of a Closure Plan with these deficiencies, and in the 
absence of any evaluation, leads to the conclusion that the State CCR 
permit program does not meet the standard in 42 U.S.C. 6945(d)(1). 
However, based on the available information in the Permit Application, 
there are many reasons to determine that the proposed closure of the 
Ash Pond will not meet the performance standards in Sec.  257.102(d). 
Based on the limited data available, EPA estimates that groundwater 
will continue to saturate a substantial amount of CCR, even after the 
activities described in the approved Closure Plan have been completed. 
As described below, available groundwater measurements recorded between 
2021 and 2022 show that groundwater levels at the Ash Pond continue to 
be present above the base of the unlined impoundment, saturating 
substantial amounts of CCR in the closing unit. Moreover, comparison of 
groundwater elevation data from 2021 and 2022 to elevation data in the 
same wells for prior years does not yet indicate any statistically 
significant or sustained declines, further supporting EPA's conclusions 
about future persistence of saturated CCR waste.
    As shown on the center line cross section B-B' on construction 
drawing G-204 in the Permit Application, the base of the Ash Pond 
varies substantially. In view of this information, EPA conducted an 
analysis using existing monitoring wells near the waste boundary and 
south of the planned closure buttress. Few monitoring wells are located 
directly adjacent to the CCR; most are located hundreds of feet away 
from the waste boundary, with many at distances of over 1,000 feet 
away. Faced with these significant limitations, EPA based estimates of 
saturated waste presence and thickness on the limited available pairs 
of wells which are in close proximity to the waste material and are 
located on opposite sides of the main waste body or larger fingers of 
CCR waste. Using this approach allowed for limited direct comparison of 
recent water levels data collected in 2021 and 2022 to the top and 
bottom elevations of the CCR in that area of the unit. EPA considered 
transects between the following well pair or pairs of clustered wells:

 [GS-AP-MW-16S/GS-AP-MW-16D/GS-AP-PZ-16] to [GP-AP-MW-19]
 [GS-AP-MW-21/GS-AP-MW-21V] to [GS-AP-MW-1/GS-AP-MW-1R/GS-AP-
MW-46]
 [GS-AP-MW-12/GS-AP-MW-12V] to [GS-AP-MW-1/GS-AP-MW-1R/GS-AP-
MW-46]

    Lastly, it is also important to note that EPA's assessment of water 
levels in this action focused primarily on those monitoring wells which 
were screened nearest the CCR in the unit at those specific locations. 
These included wells screened in a variety of different levels within 
the uppermost aquifer system. It must be recognized that this exercise 
suffered from the limitations of the well network as screened interval 
elevations varied somewhat from transect to transect. Regardless of 
these complexities, water levels in most screened intervals were 
consistently above the base of the impoundment.
    This assessment suggests the sustained presence of significant 
thickness of saturated waste in all of the areas EPA investigated. For 
the [GS-AP-MW-16S/GS-AP-MW-16D/GS-AP-PZ-16] to [GP-AP-MW-19] transect 
near the southern end of the Ash Pond, reported groundwater elevation 
measurements from monitoring wells GS-AP-MW-16S and GS-AP-MW-19 range 
from roughly 381 to 407 ft above MSL. In this area near the center of 
the unit, the bottom of the CCR unit is located at approximately 335 
feet above MSL and the top of the waste at closure is planned to be 
roughly 450 feet above MSL. Based on these data EPA estimates that at 
the deepest point of this transect a layer of CCR between 46 and 72 ft 
in thickness is saturated. As stated above, EPA's estimates were 
complicated by Alabama Power's failure to install many of the 
monitoring wells at the waste boundary which is inconsistent with the 
requirement in Sec.  257.91(a)(2)). In this case, EPA used data from 
GS-AP-MW-16S and GS-AP-MW-19 because, based on the materials in the 
Permit Application, they are a well pair that are located along 
opposite sides of the unit from each other, or in other words, the two 
wells span across a large portion of the unit. Nevertheless, the 
lateral distance between GS-AP-MW-16S and GS-AP-MW-19 is still roughly 
2,000 feet, and the bottom unit elevation is highly variable over that 
distance given the incised valley setting in which the unit sits.
    EPA also evaluated the most recent groundwater elevation data from 
the Plant Gorgas 2022 Annual Groundwater Monitoring and Corrective 
Action Report to determine if any recent closure activity at the site 
has influenced groundwater elevations.\74\ Regarding the impact of 
closure activity on groundwater elevations, the report itself is 
contradictory. On page 20, the report indicates that no significant 
changes in groundwater elevations or flow have been noted at the site 
as ash

[[Page 55257]]

pond dewatering activities have not been initiated. However, on pages 
21 and 22, the report states that dewatering operations began in 2022 
and may be contributing to the groundwater elevations observed. 
Further, on page 56 of the report, there is an acknowledgment that 
``[t]he lack of obvious or significant trends [or changes in 
groundwater quality] is likely in part due to (1) dewatering operations 
not starting until the first week of July 2022, (2) the low 
permeability nature of the subsurface flow systems, and (3) the number 
of wells that have been recently installed or replaced (too few data 
points for trend analyses).'' In any event, EPA's evaluation indicated 
that groundwater elevation data collected in July 2022 is mostly 
comparable to historical data, suggesting little influence thus far 
from dewatering efforts. For example, most decreases in groundwater 
elevations were observed to be less than a few feet. Some larger 
decreases (greater than 10 feet) were observed at the southern portion 
of the Ash Pond, but the report indicated that these decreases may be 
the result of resumed mining activity south or southwest of the Ash 
Pond, rather than closure activity related to the Ash Pond. Therefore, 
while some uncertainty remains as to just how much CCR is currently 
saturated, the available site data indicates that considerable areas, 
thicknesses, and volumes of saturated CCR remain in the impoundment.
---------------------------------------------------------------------------

    \74\ Southern Company Services 2022 Annual Groundwater 
Monitoring and Corrective Action Report, Alabama Power Company Plant 
Gorgas Ash Pond. Prepared for Alabama Power Company. January 31, 
2023.
---------------------------------------------------------------------------

    Similarly, along the [GS-AP-MW-21/GS-AP-MW-21V] to [GS-AP-MW-1/GS-
AP-MW-1R/GS-AP-MW-46] transect through Finger 1 of the Ash Pond, water 
levels reported in 2021 and 2022 for GS-AP-MW-21 and GS-AP-MW-46 ranged 
from 335 to 367 feet above MSL. The elevation of the bottom of the CCR 
is roughly 322 feet above MSL and the top of the CCR unit is planned to 
be approximately 428 feet above MSL in that part of the unit. Based on 
these data EPA estimates that at the deepest point of this transect a 
layer of CCR between 13 and 45 ft in thickness is saturated.
    EPA also considered groundwater and waste elevations along the [GS-
AP-MW-12/GS-AP-MW-12V] to [GS-AP-MW-1/GS-AP-MW-1R/GS-AP-MW-46] transect 
near the center main valley of the Ash Pond and extending eastward 
along the northern side of Finger 1. Water levels from 2021 and 2022 
from GS-AP-MW-12 and GS-AP-MW-46 ranged from 360 to 380 feet above MSL. 
Given that the bottom of and top of the CCR are approximately 270 feet 
and 390 ft above MSL respectively in the center of the impoundment, EPA 
estimates that between 90 to 110 feet of saturated waste are present. 
Similarly, for Finger 1 of the unit, EPA estimates that between 35 and 
55 feet of saturated waste are present, based on bottom and top of the 
CCR being at 325 feet and 430 ft above MSL, respectively. Based on 
these limited available data, significant thicknesses of saturated CCR 
are present in these areas.
    Lastly, EPA evaluated groundwater elevations along a north to south 
transect, south of the planned closure buttress, along the west side of 
the main valley containing CCR. From north to south, this included 
monitoring wells, GS-AP-MW-12, -13, -14, -47, -15, -16, and -18. This 
transect is approximately 6,150 feet in length, or over a mile. Over 
this distance the available monitoring wells were located from 
approximately 25 to 1,100 feet away from the edge of the CCR waste and 
from 50 to 1,500 feet from the central part of the valley filled with 
CCR. EPA used engineering drawings available in the Permit Application 
to estimate CCR top and bottom elevations adjacent to each groundwater 
monitoring point (e.g., construction drawings G-204, C-200 to C-205). 
CCR thickness values varied from 65 to 149 feet along the transect. In 
some locations more than one estimate was made due to the complexity of 
the subsurface. EPA then subtracted the CCR waste bottom elevation from 
the most recent water levels for each location (primarily July 18, 
2022), to determine the thickness of saturated CCR, which varied from 
zero (no saturated waste) to approximately 115 feet of saturated CCR. 
This analysis supported the overall conclusion that saturated CCR is 
present in all of these locations and is therefore likely present at 
all locations south of the planned closure buttress. Even at those 
locations where pinpoint estimates of waste bottom elevations exceeded 
the groundwater elevation values, there were also immediately adjacent 
measurements indicating lower elevations of CCR that were below 
groundwater elevation values. For example, in the GS-AP-MW-15 area, 
estimates of waste bottom elevations varied by over 52 feet: at the 
lower end of the range in Finger 6, EPA estimates there are 13 feet of 
saturated CCR, compared with over 65 feet of saturated waste in the 
adjacent main valley of the unit (i.e., station 70+00 on section B-B' 
on construction drawing G-204). The only area arguably without any 
saturated CCR is the extreme southern tip of the unit; on July 18, 
2022, groundwater elevation values at GS-AP-MW-18 indicate that the 
waste is above the water table. However, groundwater elevation values 
measured at the closely adjacent well, GS-AP-MW-18R, which is also 
screened in the Pratt strata, but more shallowly at elevations 
comparable to the waste, on the same day, indicate approximately 63 
feet of saturated waste.
    According to the Closure Plan, it appears that dewatering may have 
commenced relatively recently in 2022, so the measured groundwater 
elevations described above from 2022 may not reflect early stage 
decreases in hydraulic head within the unit from any initial dewatering 
efforts. But as discussed below, the Closure Plan contains neither 
meaningful details nor supporting analysis to demonstrate that the 
saturated CCR in the consolidated southern portion of the unit will 
ever be dewatered sufficiently to meet the performance standards in 
Sec.  257.102(d)(2). Moreover, as discussed below, in the absence of 
any engineering measures that would effectively prevent the continued 
migration of groundwater into the closed unit, there is no information 
in the Permit Application that suggests any meaningful decline is 
likely in the groundwater elevations proximal to and within the CCR 
unit. Significant thickness of saturated waste is therefore expected to 
persist in the areas south of the closure buttress where CCR is still 
present at elevations at or above the basal excavation level for the 
consolidation effort (i.e., > 270 ft above MSL).
(1) In Order To Close the Ash Pond With Waste in Place Effective 
Engineering Measures Must Be Implemented
    The fact that prior to closure the base of the Ash Pond intersects 
with groundwater does not mean that the unit may not ultimately be able 
to meet the performance standards in Sec.  257.102(d) for closure with 
waste in place. Depending on the site conditions a facility may be able 
to meet these performance standards by demonstrating that a combination 
of engineering measures and site-specific circumstances will ensure 
that, after closure of the unit has been completed, the groundwater is 
no longer in contact with the waste in the closed unit. In this case 
EPA is proposing to determine that the approved Closure Plan fails to 
demonstrate that either performance standard in Sec.  257.102(d) will 
be met. In addition, neither the approved Closure Plan nor the Permit 
requires any engineering measures, such as the slurry wall proposed for 
Plant Greene, described in Unit IV.C.4 of this preamble, or a 
groundwater extraction system (e.g., pumping wells) to control

[[Page 55258]]

or prevent the continued infiltration of liquids (groundwater) into the 
CCR from the sides and beneath. Nor does the approved Closure Plan or 
the Permit require any engineering measure that will effectively 
control releases of leachate to the groundwater. Based on these facts, 
and as discussed in more detail below, EPA is proposing to determine 
that the approved Closure Plan fails to demonstrate that the closure at 
Plant Gorgas will meet the Federal performance standards in Sec.  
257.102(d) or an equally protective alternative State standard.
ii. Consistency With 40 CFR 257.102(d)(2)
    As discussed previously, the Federal CCR regulations applicable to 
surface impoundments closing with waste in place require that ``[f]ree 
liquids must be eliminated by removing liquid wastes or solidifying the 
remaining waste and waste residues, [and] remaining wastes must be 
stabilized sufficient to support final cover system.'' 40 CFR 
257.102(d)(2). But due to the lack of meaningful details and supporting 
analysis in the Closure Plan, EPA is proposing to determine that the 
Closure Plan approved by ADEM does not demonstrate that the proposed 
closure at Plant Gorgas will meet either standard.
    According to the approved Closure Plan, various dewatering 
techniques will be employed before and during closure; however, the 
Closure Plan appears to largely limit the use of these techniques to 
the CCR in the northern portion of the unit that will be excavated and 
transported to the consolidated area, and to the areas under the new 
Closure Buttress.\75\ For example, in the sections specifically 
discussing dewatering, the Closure Plan states:
---------------------------------------------------------------------------

    \75\ Alabama Power Company. Revised Closure Permit Application 
for the Plant Gorgas Ash Pond. April 30, 2020. Revised Closure Plan 
for the Plant Gorgas Ash Pond. Appendix 11, pp 7-8 (Emphasis added).

4.3 Procedures During Closure
4.3.1 Dewatering
This conceptual dewatering plan was developed to provide a summary 
of the removal of free water, interstitial water, contact water, and 
surface water as defined below.
 Free water--water contained in the CCR unit above the 
surface of CCR material
 Interstitial water--water within the pore space of CCR 
material
 Contact water--surface or ground water that comes in 
contact with CCR material
 Surface water--non-contact surface water at the site that 
requires management
. . .
The free water in the northern portion of the pond will be decanted 
by pumping to a water treatment facility prior to discharge off-
site. The management of the free water levels in the pond are 
important for site water management controls including coordination 
with the proposed dredging and other construction processes. 
Interstitial water levels will be monitored in critical areas to 
allow for safe excavation and working on ash as needed to facilitate 
construction activities.
The main pond free water management pumps will deliver water to the 
water treatment plant for treatment and discharge up to a treatment 
rate of 12,000 gpm. The pumping system will be equipped with a 
floating intake, including a sediment curtain around the intake.

Removal of contact water will be completed within the limits of the 
Ash Pond using both in-situ (in place prior to excavation/handling) 
and ex-situ (after initial handling/excavation) techniques. 
Dewatering of ash during closure activities includes removing water 
using a variety of methods, including but not limited to passive, 
gravity-based methods (e.g. trench drains, rim ditching, wick 
points) and/or active dewatering methods (e.g. use of the ash 
thickening plant, and in-situ pumps or well points) as needed to 
allow for CCR removal and transportation. Ex-situ dewatering 
techniques consist of but are not limited to the following: gravity 
dewatering (settling basins and/or lateral trenching), racking and 
windrowing, mechanical thickening, and absorbent desiccation.

EPA expects that Alabama Power intends to dewater the entire unit to 
some extent, if only to ensure that the consolidated unit can support 
the weight of the earthmoving equipment needed to grade the surface and 
to install the cover system. But EPA was unable to find any discussion 
of the methods that will be used to dewater the significant volumes of 
saturated CCR in the southern portion of the impoundment in sufficient 
detail to evaluate whether the free liquids (and not simply the ``free 
water'' defined above) will be eliminated as required by Sec.  
257.102(d)(2)(i). For example, on page three, the Closure Plan states 
only that ``During closure, the ash pond will be progressively 
dewatered as required to facilitate closure.'' And on page 5, the Plan 
states

Initial stages of construction and dewatering will include lowering 
of the pond levels through pumping and treatment at the onsite water 
treatment facility to optimize dredge performance. Once the desired 
initial free water depth is achieved in the pond, further dewatering 
will occur incrementally in response to storm events in order to 
maintain the free water at a relatively constant depth that will 
lower as ash removal from the designated areas progresses.

    Moreover, the narrative in the Closure Plan does not explain how 
the liquids within the consolidated southern portion of the unit will 
be eliminated in light of the groundwater that, as described above, is 
expected to continue to saturate the remaining CCR. None of the 
proposed engineering measures mentioned in the Closure Plan are 
discussed in sufficient detail to support a determination that the 
proposed measures could effectively remove these liquids. For example, 
the approved plan mentions that a leachate collection system will be 
installed at the downgradient limit of the Closure Buttress but fails 
to explain which liquids the proposed drain system will capture and how 
well or extensively it will do so.
    However, based on the limited information available, the leachate 
collection system that ADEM has approved appears to likely have only a 
minimal impact on the level of liquids in the closed unit, as it is 
designed to capture only a limited amount of leachate. According to the 
construction drawings submitted with the Permit Application, it appears 
the drain will only extend approximately 1,200 feet laterally beneath a 
portion of the 274-acre impoundment and appears to rely exclusively on 
gravity to direct any residual pore water or other free liquids to the 
drains. In essence, the leachate collection system appears to be 
designed to only collect leachate along its 1,200 foot design length, 
and to only address residual leachate produced from limited pore water 
within the CCR, which was perhaps expected to drain over a shorter 
limited time frame, during the so-called ``dewatering phase.'' But 
since not all groundwater leaving the unit will flow to the drain 
system, any collection of free liquids from saturated CCR farther south 
in the unit or along the eastern fingers would be purely coincidental, 
even without considering the likely ongoing inputs of ``new'' 
groundwater (``contact water'') into the system south of the 
Buttress.\76\
---------------------------------------------------------------------------

    \76\ ADEM confirmed these details during conversations with EPA 
in July 2022.
---------------------------------------------------------------------------

    In addition, to be effective the leachate treatment system would 
need to address not only leachate generated from short-term 
``dewatering'' activities, but also the significantly greater long-term 
volumes of leachate emanating from the continuously saturated CCR 
resulting from ongoing groundwater inputs into the unit from the sides 
and bottom. More critically, the system was not designed to handle the 
volumes of ``new'' leachate that will continue to be generated from the 
continued groundwater flow into the unit. The Closure Plan therefore 
appears to have grossly underestimated the amount of

[[Page 55259]]

free liquids that will continue to flow through the saturated waste to 
the face drain and associated leachate collection system.
    To illustrate this concern, EPA performed a rough estimate of 
potential recharge to the groundwater system within the 1,300-acre 
watershed area which contains the unit. After subtracting the 274 acres 
representing the closed, capped and consolidated unit, and assuming all 
precipitation directly contacting the cap will be effectively managed 
by the drainage system and other engineering controls, one is left with 
1,026 acres available for potential recharge to the groundwater system. 
Conservatively assuming 1-ft of effective recharge to groundwater in 
one year over the 1,026-acre catchment area results in approximately 
334 million gallons of effective recharge. Assuming this total 
effective recharge is evenly distributed over time and remains in the 
catchment area that contains the unit, and all flows into the unit, 
this would result in a value on the order of 636 gallons per minute of 
groundwater flow focused to the subsurface CCR waste beneath the capped 
unit. In other words, additional engineering controls capable of 
managing (and treating as necessary) this additional ongoing input of 
groundwater into the unit would be a minimum necessity for a successful 
Closure Plan.
    Based on all of the above, it appears that further engineering 
measures would be necessary to ensure that all free liquids are 
eliminated prior to installing the final cover system, as required by 
Sec.  257.102(d)(2)(i).
    Additional data are necessary to demonstrate that saturated CCR 
will not be present in the base of the closed unit prior to the 
installation of the final cover system. Absent such data, the permit 
record does not support a finding that the remaining wastes will be 
stabilized sufficiently to support the final cover system, as required 
by Sec.  257.102(d)(2)(ii). If the CCR in the unit is not sufficiently 
stabilized, e.g., if it has not been completely drained, differential 
settlement of the CCR after installation of the cover system is 
possible, especially given the substantial added load from the 
consolidation of CCR from the northern portion of the Ash Pond. If the 
settlement is great enough, it could cause a disruption in the 
continuity, and potentially failure of, the final cover system. 
Additional information is needed to determine that the permit meets 
Federal requirements. This could have been accomplished either by 
requiring submission of the information prior to the issuance of the 
permit or by including a permit term requiring submission of the 
information, along with a clause allowing for further permit conditions 
if necessary.
iii. Consistency With 40 CFR 257.102(d)(1)(i)
    The available information indicates groundwater is likely to 
continue to infiltrate into the unit and yet the only measures 
described in the Closure Plan and the Permit to address this continued 
infiltration are those taken to facilitate consolidation and cap 
construction. As explained in previous sections, the exclusive reliance 
on a cover system in this circumstance would not ``control, minimize, 
or eliminate, to maximum extent feasible'' the post-closure 
infiltration of the groundwater into the waste. 40 CFR 
257.102(d)(1)(i).
    The approved Closure Plan does not adequately account for the 
hydrogeology of the site, which includes complex topography, 
stratigraphy, hydrology, and other complex site characteristics such as 
preferential pathways (faults, mines, etc.) that make it likely that 
groundwater elevations will be higher than the bottom elevation of the 
surface impoundment, even after the cover system is installed. The 
cover system will only prevent liquids (precipitation) from entering 
directly into the unit from the surface/top of the unit. But as shown 
on the construction drawings in the Closure Plan (e.g., drawing C-100), 
precipitation will continue to fall onto the surrounding higher ground 
surfaces in the catchment area beyond the lateral extent of cover 
system and then percolate down below the ground surface, the underlying 
aquifer will recharge and groundwater levels will continue to 
infiltrate into the CCR from beneath the unit, as well as from the 
sides.
    There are commonly used engineering measures that can prevent, or 
at least control, the post-closure flow of groundwater into the unit; 
for example, physical barriers such as slurry walls or liner systems or 
by other means such as hydraulic containment systems (e.g., groundwater 
extraction wells), additional backfilling to create a buffer between 
the bottom of the unit and groundwater, CCR relocation, etc. EPA is 
therefore proposing to determine that ADEM's approval of a Closure Plan 
that relies exclusively on consolidation and cap construction to 
control infiltration into the Ash Pond is inconsistent with Sec.  
257.102(d)(1)(i).
    EPA is also proposing to determine that the approved Closure Plan 
fails to demonstrate that post-closure releases of CCR or leachate to 
the groundwater will be controlled ``to the maximum extent feasible.'' 
40 CFR 257.102(d)(2)(i). While a leachate collection system is proposed 
in the Closure Plan, EPA was unable to find either analysis or evidence 
demonstrating the extent to which the proposed leachate collection 
system will control ``post-closure releases of CCR or leachate to the 
groundwater to the maximum extent feasible.'' 40 CFR 257.102(d)(2)(i). 
Moreover, the available information does not support a determination 
that the proposed system will meet this performance standard. As 
previously discussed, the leachate collection system is not designed to 
control the volume of leachate that is likely to be created from the 
continued infiltration of groundwater, nor does it extend underneath 
the entire unit.
    In addition, there is substantial evidence that the hydrogeologic 
pathways that will allow unimpeded migration of groundwater into the 
unit from the bottom and sides of the unit will also allow leachate to 
migrate laterally and vertically out of the unit at particular 
locations. The absence of natural or engineered hydraulic barriers 
along the base and sides of the unit, which allows for both 
infiltration and exfiltration of liquids, will likely result in 
additional releases of contaminated groundwater (i.e., ``plumes'') out 
of the unit via the bottom or sides. For example, preferential 
pathways, such as geologic faults and mine shafts from former mining 
operations, are present beneath the unit that would be expected to draw 
contamination from any uncaptured leachate down into the aquifer. The 
existence of preferential pathways was clearly acknowledged in the GWMP 
that was included in the Permit Application as Appendix C.\77\
---------------------------------------------------------------------------

    \77\ Alabama Power Company. Revised Closure Permit Application 
for the Plant Gorgas Ash Pond. April 30, 2020. Response to Comments, 
Approved Groundwater Monitoring Plan included in the October 20, 
2021. For example, the following statements were made within the RTC 
for the GWMP:
    [i]n-conjunction [with statements made earlier in the letter], 
the geology at Plant Gorgas dictates preferential flow through coal 
seams and vertical to subvertical joints, fractures, and faults. 
Targeting such features for monitoring, even if stepped back from 
the waste boundary, is technically justified. This because 
preferential flow paths concentrate groundwater migration through 
enhanced fracture interconnectivity within otherwise impermeable 
rock strata. Therefore, given the travel-times described [earlier in 
the letter], and the age of the facility--it was appropriate to 
target these features for determining potential impacts to 
groundwater.
---------------------------------------------------------------------------

    The approved Closure Plan does not account for these pathways or 
otherwise evaluate how well the proposed drain system will capture 
liquids. To meet the performance standard in Sec.  257.102(d)(1)(i), 
the approved Closure Plan would have to show that the

[[Page 55260]]

leachate will be channeled to the leachate collection system rather 
than to the preferential pathways, EPA was unable to find anything in 
the Permit Application or permit record to show that either Alabama 
Power or ADEM made any such showing. As discussed previously, the 
available information indicates that the face drain and under-designed 
leachate collection system would likely be ineffective in preventing 
such releases, given the under-designed leachate collection system.
b. Plant Gorgas Groundwater Monitoring Issues
    The Final Permit incorporated the GWMP submitted with the Permit 
Application, and directed Alabama Power to comply with the State 
regulations and the approved plan:

A. Groundwater Monitoring System. The Permittee shall install and/or 
maintain a groundwater monitoring system, identified in Table 1, as 
specified in 335-13-15-.06(2) and the approved groundwater 
monitoring plan.

Once ADEM approved and adopted the GWMP into the permit, the GWMP, 
rather than the referenced State regulations, became the State 
requirements with which the facility is required to comply.
    Based on EPA's review of the approved GWMP, EPA is proposing to 
determine that the groundwater monitoring well network approved by ADEM 
does not meet the performance standards in Sec.  257.91(a) or (b). As 
discussed in more detail below, EPA is proposing to determine that the 
groundwater monitoring system does not ``yield groundwater samples from 
the uppermost aquifer,'' but has been screened instead in only a 
portion of the aquifer. 40 CFR 257.91(a). EPA is also proposing to 
determine that approved groundwater monitoring system is not based on a 
thorough characterization of any of the elements listed in Sec.  
257.91(b). Further, EPA is proposing to determine that the approved 
monitoring system inappropriately includes numerous downgradient 
monitoring wells that are not located at the waste boundary. See 40 CFR 
257.91(a)(2). In addition, based on the documentation provided in the 
Permit Application, it appears that there are an insufficient number of 
monitoring wells at necessary locations and depths to meet the Federal 
performance standards for either the background wells or the compliance 
wells. See, 40 CFR 257.91(a)(1)-(2). Therefore, EPA is proposing to 
determine that ADEM's Final Permit fails to require Alabama Power to 
achieve compliance with either the Federal regulations or with an 
equally protective State requirement.
i. Failure To Delineate the ``Uppermost Aquifer''
    The Federal regulations require that a groundwater monitoring 
system sample ``the uppermost aquifer,'' which is defined as ``the 
geologic formation nearest the natural ground surface that is an 
aquifer, as well as lower aquifers that are hydraulically 
interconnected with this aquifer within the facility's property 
boundary.'' 40 CFR 257.53, 257.91(a). The design of the monitoring 
systems must be based on a thorough characterization of, among other 
things, the ``aquifer thickness, groundwater flow rate, groundwater 
flow direction including seasonal and temporal fluctuations in 
groundwater flow; and saturated and unsaturated geologic units and fill 
materials overlying the uppermost aquifer, materials comprising the 
uppermost aquifer, and materials comprising the confining unit defining 
the lower boundary of the uppermost aquifer.'' 40 CFR 257.91(b)(2). EPA 
is proposing to determine that ADEM approved a groundwater monitoring 
plan that does not meet these requirements.
    Based on the limited information in the permit record, it appears 
the facility failed to define both the upper and lower limits of the 
uppermost aquifer. The GWMP provided in the Permit Application provides 
only limited characterization of the geologic units beneath the Ash 
Pond. In addition, the technical information provided in the Permit 
Application and available on Alabama Power's CCR website is 
insufficient to support a determination of the lateral and vertical 
limits of the entire uppermost aquifer; for example, EPA found only 
limited data on the ``saturated and unsaturated geologic units and fill 
materials overlying the uppermost aquifer and materials comprising the 
uppermost aquifer.'' 40 CFR 257.91(b)(2). And EPA was only able to find 
limited and conflicting information about the ``materials comprising 
the confining unit defining the lower boundary of the uppermost 
aquifer.'' Id. In the absence of such key information it is impossible 
to determine that the monitoring system adequately covers the entire 
uppermost aquifer, which includes all ``lower aquifers that are 
hydraulically interconnected'' with the aquifer nearest the ground 
surface. 40 CFR 257.53 (definition of ``uppermost aquifer''). 
Nevertheless, ADEM approved Alabama Power's GWMP unconditionally.
    A representation of the various aquifers beneath the Ash Pond can 
be obtained by examining the cross sections found in the 2021 Remedy 
Selection Report.\78\ The uppermost aquifer may be described in its 
most basic expression as a ``layer cake'' with interbedded layers of 
sub-horizontal sedimentary rocks. As depicted in these cross sections, 
for example Figure 9B of Appendix B of this report, for instance the 
aquifer nearest the ground surface is shown as the Cobb Group. A 
portion of the Cobb Group is present in higher elevations of the site, 
overlying the Pratt Group. Both the Cobb and Pratt Groups are part of 
the regionally significant Pottsville Formation. Coal beds known to be 
present regionally in the Cobb Group were not identified near the unit 
and Cobb Group rocks near the unit consist of sandstones, mudstones, 
and shales. Some individual sandstone beds are depicted as having 
thicknesses of over 50 feet as well as significant lateral extent, on 
the order of thousands of feet. The Cobb Group also contains thick 
laterally extensive mudstones, and the mudstones are interbedded with 
thinner sand layers in the northern part of the unit. The aggregate 
thickness of the Cobb Group is on the order of 200 to 250 feet or more 
at the unit. As the stratigraphically highest rock layer, the Cobb 
Group thickness varies across the unit due to differences of the 
uppermost surface elevation of the Cobb Group resulting from 
differential erosion. Alluvial materials and/or fill deposits rest 
unconformably and discontinuously on top of the Cobb Group's upper 
erosional surface in many areas of the unit, particularly to the south. 
These Cobb Group stratigraphic intervals are poorly characterized in 
comparison to the underlying Pratt Group, with few monitoring wells 
installed in the Cobb Group rocks.
---------------------------------------------------------------------------

    \78\ Southern Company Services. 2021 Groundwater Remedy 
Selection Report, Alabama Power Company Plant Gorgas Ash Pond. 
Prepared for Alabama Power Company. December 2021.
---------------------------------------------------------------------------

    The upper part of the Pratt Group includes interbedded sandstones, 
siltstones, mudstones, as well as several distinct coal beds. The 
uppermost of these named coal beds is the Pratt Coal Seam and 
associated layers, but additional named coal seams are present at 
successively deeper levels, as described in Section 3 of the approved 
GWMP: ``The Pratt Coal Group generally contains three named coal seams 
each separated by 10 to 30 feet of intraburden. In descending order, 
they are, the Pratt, Nickel Plate, and American coal seams.''
    Beneath the upper part of the Pratt Group and its named coal seams, 
a significant thickness of interbedded

[[Page 55261]]

sandstones and mudstones on the order of 50 feet or more is present. 
These intervals are described as the Lower Pratt Group, which has 
received comparatively little characterization and few monitoring 
wells. The Pratt Group, including both the lower and upper portions, is 
depicted as having an aggregate thickness of approximately 200 feet 
beneath the unit. Differential erosion, particularly within the main 
channel-like finger of the Ash Pond, has locally resulted in alluvial 
materials and/or fill deposits resting unconformably on top of the 
Pratt Group's upper erosional surface, particularly in the central part 
of the unit.
    In the southern portion of the unit, the Gillespy Group, also of 
the Pottsville Formation, is shown on cross sections as underlying the 
Pratt Group at great depths, but characterization of this interval is 
extremely limited. The cross sections in the 2022 Semi-Annual 
Groundwater Monitoring and Corrective Action Report show that the 
Gillespy Group also has an aggregate thickness on the order of 200 
feet, yet the upper and lower contacts between the Gillespy and 
underlying and overlying layers is poorly characterized, particularly 
with respect to the lower contact, and the thus the variability and 
full vertical extent (i.e., thickness) of the Gillespy Group under the 
Ash Pond has not been precisely determined. On cross section F-F' 
(Figure 4F), the Gillespy Group is depicted as just over 200 feet in 
thickness. The cross section also depicts the contact with the 
underlying Mary Lee Group mudstones at a depth of several hundred feet 
below the unit at a corresponding elevation just above MSL. However, it 
is not clear what data informs this interpretation as no borings are 
known to have penetrated the full thickness of the Gillespy Group near 
the unit based on the cross sections and monitoring well installation 
details. As such the true thickness of the uppermost aquifer and 
hydraulically connected aquifers is not known, nor has it been 
established whether the Gillespy Group constitutes an effective lower 
confining unit to the uppermost or aquifer system. See 40 CFR 
257.91(b). It is also notable that the elevation of the top of the 
Gillespy Group is relatively high near the northern part of the unit, 
and differential erosion has resulted in deposits of overburden, 
alluvium and/or fill, including fill/dam materials resting 
unconformably on top of the upper part of the Gillespy Group in the 
northern part of the unit, as shown of cross section F-F'.
    The additional relevant geologic aspects of the aggregate layering 
which constitutes the uppermost aquifer system includes faulting and 
folding of the layering. Following the ``layer cake'' analogy, the 
layers of rocks have been disrupted locally on several steep fault 
lines that predominantly strike north-northwest in the vicinity of the 
unit, as such the ``layer cake'' package of rocks has been disrupted 
and contains many distinct ``slices'' separated by these faults. The 
faults indicate significant vertical offset on cross sectional 
representations, and the rock layers are locally bent or ``folded'' 
near these fault structures, resulting in steeper dips. The entire 
package has been slightly tilted regionally to the south as if the 
northern end of the ``layer cake's serving platter'' had been lifted 
slightly.
    The final element, following the ``layer cake'' analogy, is the 
``icing on the cake.'' Like drizzled icing, unconsolidated fill and 
alluvial materials irregularly cover the tilted, faulted, and eroded 
surface of the ``layer cake'' of rock layers. It is expected that 
overburden including alluvial materials (e.g., sands and gravels) 
originally present as stream deposits in the incised erosional stream 
valleys were covered by the introduced CCR materials. These buried 
alluvial materials therefore represent the uppermost veneer of the 
uppermost aquifer system. Since there are few wells screened in these 
former stream valleys, this element of the uppermost aquifer system is 
significantly underrepresented in the monitoring network.
(1) Uppermost Aquifer
    Within this complex ``layer cake'' geology of variable sedimentary 
layering, Alabama Power screened most of its monitoring wells in the 
Upper Pottsville Aquifer system, which is described in Section 3.2.2 of 
the 2022 Semi-Annual Groundwater Monitoring and Corrective Action 
Report as follows:

Groundwater occurs in the Pratt Coal Group of the Upper Pottsville 
Formation at the site. The primary occurrences of groundwater in the 
uppermost aquifer are: (1) coal seams, (2) rock fractures or zones 
of fracture enhanced permeability, and to a lesser extent (3) 
bedding planes. Fractured intervals are sparse across the site as 
defined by caliper logging and tend to occur with greater density in 
the upper 100 feet of rock.
Groundwater yield at the site is considered low and typical of the 
Pottsville aquifer system in areas without major geologic 
structures. Wells were generally screened in the Pratt coal seam or 
across groundwater yielding fractures. Depth to groundwater 
producing zones were highly variable at the site and typically 
ranged from 30 to 240 feet BGS.

It is further noted in Section 3.2.3 of the 2022 Semi-Annual GWMCA 
Report that,

Groundwater flow is accomplished primarily by means of fracture 
flow, where groundwater flows along more conductive secondary 
discontinuities in the rock mass such as joints or cleat fabric in 
coal seams. Fracture flow in complex geologic media such as the 
heterogenous Pottsville Formation can be complex. Groundwater in the 
Pottsville aquifer is most commonly regarded as confined due to 
large permeability contrasts within the aquifer (Stricklin, 1989). 
The Pottsville at the Site is probably better described as a series 
of discrete, confined to semi-confined, groundwater yielding zones 
where groundwater elevations can vary significantly laterally and 
vertically and are governed by the heterogeneity of the lithology 
and degree of fracture network interconnectivity . . . .
    At higher stratigraphic intervals (water-table flow system), 
groundwater flows towards the Ash Pond or other surface water 
bodies. This flow system is driven by gravity and mimics the 
topography of the site. Within deeper rock strata such as coals of 
the Pratt Group (Pratt Coal Group or deep bedrock flow system), 
groundwater flows radially away from the site.

Most of the characterization and monitoring is concentrated in the 
named coal seams of the Pratt Coal Group, and three primary flow 
systems (i.e., aquifers) have been identified, as follows:

    At the Site, the groundwater flow regime is now grouped into 
three general flow systems: (1) shallow water-table flow system, (2) 
Pratt Coal flow system, and (3) American Coal flow system.

    In this system of nomenclature, the Nickel Plate Coal Seam is 
generally included within the Pratt Coal System. EPA also noted that 
the Pratt Coal System and the American Coal Systems are mapped together 
and separately in different groundwater monitoring reports. For 
example, the approved GWMP (Figure 6B) has them mapped together and the 
2020 Annual GWMCA Report \79\ has them mapped separately (Figures 6B 
and 6C). Accordingly, subsequent references to aquifers in the coal 
seams, below, if not specifically described as the ``Pratt'' or 
``American'' aquifers, describe the three coal seam flow systems of the 
Pratt Coal Group jointly as an aggregate combined system.
---------------------------------------------------------------------------

    \79\ Southern Company Services. 2020 Annual Groundwater 
Monitoring and Corrective Action Report, Alabama Power Company Plant 
Gorgas Ash Pond. Prepared for Alabama Power Company. January 31, 
2021.
---------------------------------------------------------------------------

    In addition to the three systems designated above (shallow water 
table, Pratt, and American), lower intervals of the stratigraphic 
section have been designated \80\ as another (fourth) system, which is 
primarily localized to the northern part of the unit in the vicinity

[[Page 55262]]

of the Ash Pond dam and northward.\81\ In this area, the geologic units 
located at depths corresponding to the transition zone from the lower 
Pratt Group to rocks of the underlying Gillespy Group are mapped 
together as the ``Base of Pratt to Gillespy Transition'' aquifer zone. 
This interval is at much higher elevations in the northern part of the 
site than in the southern portion. In any case, based on these aquifer 
designations various interpretive representations of groundwater flow 
have been constructed and were provided in the Permit Application and 
annual monitoring reports. Based on these interpretations, in the Cobb 
Group, above the Pratt Coal Group, groundwater is within an unconfined 
aquifer and flows toward the unit. Within the Pratt Coal Group, 
groundwater flow is interpreted to be mainly within the American and 
Pratt Aquifers and flows radially away from the unit. However, these 
interpretations are informed by insufficient data considering the large 
geographic area represented by the Ash Pond as well as the topographic 
and hydrogeologic complexity. The Ash Pond is approximately 500 acres 
and sits within a watershed of roughly 1,300 acres with hundreds of 
feet of topographic relief. The small number of wells installed in each 
of the respective aquifer layers simply does not allow for a sufficient 
level of resolution regarding the true configuration of the 
potentiometric surface and related groundwater flow directions. As 
such, the interpretations represented by the various potentiometric 
surface contour maps included in the 2022 Semi-Annual GWMCA Report 
contain a large degree of uncertainty.\82\ For example, there are just 
a few wells screened in the unconfined materials above the coal seams. 
Figure 6A of the 2022 Semi-Annual GWMCA Report, entitled Potentiometric 
Surface Contour Map (Upper) Water Table Aquifer, February 7, 2022, 
Plant Gorgas Ash Pond, is based on just 10 water level monitoring 
points over an area hundreds of acres in size. Figure 6B of the same 
report Potentiometric Surface Contour Map, Pratt Aquifer, February 7, 
2022, is based on just 31 water level monitoring points over the same 
area. Figure 6C of the same report is entitled Potentiometric Surface 
Contour Map, American Aquifer, February 7, 2022. This interpretation is 
based on just 21 water level monitoring points over the same immense 
area. Lastly, there are a limited number of water level monitoring 
points (13) that intersect the Gillespy; nearly all of the these are 
screened across the interface between the Gillespy and the lower part 
of the Pottsville Formation (see inset map on Figure 6B) entitled, 
Generalized Potentiometric Surface Contour Map--Base of Pratt to 
Gillespy Transition (North of Dam). In summary, given the large size of 
the Ash Pond and the surrounding area, interpretations of the flow 
systems are highly generalized because of the limited number of 
monitoring points in each hydrostratigraphic units.
---------------------------------------------------------------------------

    \80\ Id.
    \81\ Southern Company Services. 2022 Semi-Annual Groundwater 
Monitoring and Corrective Action Report, Alabama Power Company Plant 
Gorgas Ash Pond. Prepared for Alabama Power Company. July 31, 2022. 
See inset map entitled, ``Generalized Potentiometric Surface Contour 
Map--Base of Pratt to Gillespy Transition zone (North of Dam)'' 
included on Figure 6B.
    \82\ Id.
---------------------------------------------------------------------------

    Additionally, the nature of the lower boundary of the aggregate 
``uppermost aquifer'' system has not been sufficiently characterized or 
monitored due to the limited number of wells installed into this zone, 
and the documented importance of fracturing, where present, such as in 
the subsurface beneath the unit, and its association with increased 
permeability values. This issue is discussed below. A key consideration 
with respect to the base of the Pratt to Gillespy transition is whether 
this transitional formation contact represents the boundary between the 
materials comprising the ``uppermost aquifer,'' and materials 
comprising the ``confining unit defining the lower boundary of the 
uppermost aquifer.'' 40 CFR 257.91(b)(2). It is asserted in the 2022 
Semi-Annual GWMCA Report that,

Except for the far northern portion of the Ash Pond, conceptually, 
there is likely to be little hydraulic communication with strata 
deeper than the sandstone unit immediately underlying the American 
Coal Seam (American Coal Flow System). Below this interval, a low 
permeability mudstone to interbedded mudstone-sandstone unit likely 
forms a barrier to vertical migration of groundwater as hydraulic 
conductivity values in the 10-\7\ centimeter per second 
(cm/s) range are reported for shales at the site as derived from 
packer testing. This interval reflects the transition to Gillespy 
Coal Group.

    Additional information presented in the same report presents 
contradictory information regarding the confining potential of the 
basal portion of the Gillespy Coal Group:

However, to the north and underlying the Ash Pond dam, strong 
hydraulic gradients likely force groundwater along vertical 
fractures and bedding planes through the upper part of the Gillespy 
Coal Group. Geophysical and hydrophysical logs obtained in well 
locations north of the dam suggest that three to four discrete 
bedding planes occurring between 30 and 90 ft BGS transmit 
groundwater. The most prominent typically occurring at a depth of 49 
to 56 ft BGS (likely Gillespy equivalent; approximately 100 feet 
below American Coal Seam).

    The potential for vertical flow, within the Gillespy is further 
described as follows:

Strong upward vertical gradients are observed in paired well 
locations (see groundwater elevations in MW-6S/6D and MW-41HS/HD 
pairs) installed north of the ash pond dam. Potentiometric data 
suggests upward vertical flows along with northerly lateral flow.

Lastly, the same report discusses permeability test results, which 
again present an inconsistent picture of the Gillespy formation's 
potential to act as a ``confining unit defining the lower boundary of 
the uppermost aquifer,'' as follows:

Forty-three packer tests were conducted resulting in a range of 
hydraulic conductivity (k) values from an estimated low of 7 x 
10-\7\ cm/sec to a high of 4 x 10-\3\ cm/sec, 
with most tests (31) in the moderate range (10-\5\ cm/sec 
to 10-\4\ cm/sec), two test results in the more permeable 
range (10-\3\ to 10-\2\ cm/sec), and ten test 
results in the less permeable range (10-\6\ cm/sec). 
There is a general trend of decreasing estimated hydraulic 
conductivity with depth. Packer test results vary over 4 orders of 
magnitude. Test intervals at the high end of the data range are 
associated with weathered discontinuities (fractures/joints). 
Moderate values are associated with minor fractures or bedding 
planes. The lowest values are associated with more shale intervals 
without substantial fractures. Test intervals with coal seams are in 
the moderate to high end of the data range.

    EPA disagrees that this information supports a determination that 
the lower part of the Gillespy formation constitutes a ``confining unit 
defining the lower boundary of the uppermost aquifer.'' The totality of 
the information instead supports the opposite conclusion. Since 
vertical flow is clearly a recognized phenomenon within the Gillespy 
within the northern part of the unit, and this flow is described as 
being associated with fractures,\83\ it is logical to expect similar 
vertical flow and enhanced permeability in other areas where fractures 
are present. Given the prevalence of steeply dipping north-northwest 
striking fracturing in the area, as well as the likelihood that the 
linear valley that underlies the unit, which also strikes north 
northwest, is also controlled by underlying fractures of this 
orientation, it is reasonable to expect enhanced flow potential along

[[Page 55263]]

and in the vicinity of these fractures where they may exist. Since the 
subsurface directly beneath the unit is likely the locus of such 
fracturing (see Unit IV.C.3.b.i.(4)(c) of this preamble for more 
information on the existence of preferential pathways), it is logical 
to determine that vertical permeability is high beneath the unit where 
it matters most. In other words, this situation suggests that rather 
than a ``confining unit defining the lower boundary of the uppermost 
aquifer,'' the near vertical fracturing which penetrates all units (see 
cross sections), including the Gillespy, creates the opposite condition 
in the uppermost aquifer system, directly beneath the unit. It is 
therefore unlikely that the uppermost aquifer beneath the Ash Pond has 
been adequately characterized, and its full thickness in the vertical 
dimension remains unknown based on the information in the permit 
record. As was noted above, the lowest measured permeability values are 
associated with shale intervals without substantial fractures. Although 
conditions are not sufficiently documented directly beneath the unit, 
the likely presence of fractures here would be expected to invalidate 
the presence of ``shale intervals without substantial fractures,'' and 
hence the ``lowest measured permeability values,'' while present in 
other areas around the unit, would likely not be present directly 
beneath the unit.
---------------------------------------------------------------------------

    \83\ Southern Company Services. 2022 Annual Groundwater 
Monitoring and Corrective Action Report, Alabama Power Company Plant 
Gorgas Ash Pond. Prepared for Alabama Power Company. January 31, 
2023. Section 3.2.3.
---------------------------------------------------------------------------

    In sum, the uppermost aquifer system- that is, the aquifer nearest 
the ground surface and the underlying aquifers that are hydraulically 
connected to it--has not been fully assessed. EPA's assessment of the 
available information is that there are at least four flow systems that 
are appropriately considered the ``uppermost aquifer'' at the Ash Pond: 
(1) the upper unconfined water table (locally includes unconfined Cobb 
Group); (2) the Pratt Coal seam; (3) the American Coal seam; and (4) 
the Lower Pratt/Gillespy Transition zone.
    The geologic units above and beneath the coal seams are sandstones 
and interbedded sandstones with mudstone or shale, and both are capable 
of storing and transmitting groundwater, and therefore should have been 
more fully characterized and included in the monitoring network. In 
particular, the depth of the lower confining unit has not been 
established, and as such, the full extent of the uppermost aquifer 
system has not yet been established in the vertical (depth) dimension. 
At several locations, the geologic units immediately below detected 
groundwater contamination are entirely uncharacterized and unmonitored. 
This situation hobbles the monitoring network's ability to identify and 
evaluate potential migration of contaminated groundwater out of the 
unit at the lower levels, which is discussed further in Unit 
IV.C.3.b.i.(4)(b) of this preamble.
(2) Background Wells Do Not Meet the 40 CFR 257.91(a)(1) Performance 
Standard
    The Federal CCR regulations require that a groundwater monitoring 
system consist of a sufficient number of wells at appropriate locations 
and depths to yield samples from the uppermost aquifer that accurately 
represent the quality of the background groundwater that has not been 
affected by leakage from a CCR unit. 40 CFR 257.91(a)(1). The 
regulations also specify that background wells must normally be 
hydraulically upgradient of the CCR unit unless specific showings have 
been made. See, Id. EPA is proposing to determine that the approved 
GWMP fails to document either that the background wells are upgradient 
of the CCR unit or that the wells meet the performance standards in 
Sec.  257.91(a)(1)(i) or (ii). EPA is also proposing to determine that 
the background wells in the approved groundwater monitoring system do 
not ``accurately represent the quality of the background groundwater'' 
because no background wells were installed in the lower flow systems of 
the uppermost aquifer: i.e., the Pratt Coal seam; the American coal 
seam, and the Lower Pratt/Gillespy Transition Zone.
    Four groundwater monitoring wells have been used at various times 
to characterize background water quality (GS-AP-MW-8, GS-AP-MW-13, GS-
AP-MW-16S, and GS-AP-MW-17V). One of the wells, GS-AP-MW-13 was 
installed in 2016 and later abandoned in 2019. The three remaining 
monitoring wells (GS-AP-MW-8, GS-AP-MW-16S, and GS-AP-MW-17V) were 
installed exclusively in the upper flow system (i.e., in the upper 
water table aquifer/unconfined Cobb Group formation), where Alabama 
Power has concluded that groundwater flows toward the Ash Pond. No 
background wells were ever installed in the three lower flow systems of 
the uppermost aquifer, which is where contamination is currently 
present.
    According to the 2021 Plant Gorgas Annual GWMCA Report, to the 
north and underlying the Ash Pond dam, strong hydraulic gradients force 
groundwater along vertical fractures and bedding planes through the 
upper part of the Gillespy Coal Group toward the Ash Pond.\84\ The 
approved GWMP also provides details regarding vertical gradients and 
the potential for using monitoring wells in the shallow flow system as 
background wells. For example, page 10 states:
---------------------------------------------------------------------------

    \84\ Southern Company Services. 2021 Annual Groundwater 
Monitoring and Corrective Action Report Alabama Power Company Plant 
Gorgas Ash Pond. Prepared for Alabama Power Company. January 31, 
2022.

It is because vertical flow is the dominant mechanism for movement 
through these flow systems and that is a function of the Pottsville 
operating as a series of discrete, confined to semi-confined 
groundwater yielding zones. Upgradient well locations monitor 
younger, recharging waters that will eventually migrate vertically 
---------------------------------------------------------------------------
downward into groundwater yielding zones of the Pratt Coal Group.

    Based on the limited data available it appears that groundwater in 
the upper water table (or un-confined Cobb) aquifer may migrate 
downward into the lower flow systems due to vertical hydraulic 
gradients. However, as discussed at length above, these interpretations 
contain a large degree of uncertainty because they are informed by very 
little data, given the size of the Ash Pond as well as the topographic 
and hydrogeologic complexity of the site. The complexity of the site is 
of particular concern here; in addition to the compositional 
variability of the layers, differential fracturing also creates 
variable hydraulic conditions which needed to be carefully considered 
in selecting upgradient background well locations. Lastly, the wells 
currently selected for background monitoring ignore horizontal flow in 
the lower flow systems where groundwater contamination is present and 
migrating laterally. EPA is proposing to determine there is 
insufficient data to conclude that the approved background wells meet 
the performance standards in Sec.  257.91(a)(1).\85\
---------------------------------------------------------------------------

    \85\ Because Alabama Power believes the background wells to be 
hydraulically upgradient, the Permit Application did not include a 
demonstration that the background wells will be ``as representative 
or more representative'' as hydraulically up gradient wells. 40 CFR 
257.91(a)(1)(ii).
---------------------------------------------------------------------------

    EPA is also proposing to determine that there are insufficient 
number of background wells in the approved groundwater monitoring 
system. As discussed in the preceding section, there are at least four 
flow systems that would each require background wells focused on the 
specific hydrogeologic conditions in each of these zones: (1) The upper 
water table aquifer; (2) The Pratt Coal seam; (3) The American Coal 
seam; and (4) The Lower Pratt/Gillespy Transition zone. In addition to 
these

[[Page 55264]]

four, it remains unclear whether other flow systems should have been 
included in the monitoring program, which would require the 
installation of appropriate zone-specific background wells. For 
example, the Cobb Group appears to contain multiple permeable sandstone 
units, as do portions of the Pratt Group both above and below the named 
coal seam aquifers. It would appear that background wells should have 
been installed in one or both of these geological formations to capture 
this geologic variability. As noted above, in addition to the 
compositional variability of the layers, differential fracturing also 
creates variable hydraulic conditions that needed to be more carefully 
considered in selecting background well locations.
    The Federal regulations require a monitoring well system that 
accurately represents the quality of background groundwater. 40 CFR 
257.91(a)(1). Background concentrations need to be determined for the 
entire uppermost aquifer system and must be supported by an explanation 
of the hydraulic and geologic factors that validate the selection of 
particular locations as representative background conditions. If the 
uppermost aquifer varies laterally and vertically in terms of geology 
and chemical composition, it is necessary for the background monitoring 
wells installed to adequately reflect this same range of variability 
(i.e., representative conditions in these same layers absent CCR-
related impacts). This requires enough monitoring wells to capture the 
variability represented by the natural system in appropriate 
dimensions, such as lateral and/or vertical variability. Consequently, 
in cases of multiple flow systems comprised of variable geology, as a 
first order requirement, background wells in each hydrostratigraphic 
unit of interest would be technically necessary.
    The specific conditions at Plant Gorgas further illustrate this; 
the geochemistry of the groundwater within the shallow water table 
aquifer (consisting of younger groundwater within sandstone and shales) 
would not represent the geochemistry of deeper flow systems (consisting 
of older groundwater within interbedded sandstones with coal seams). It 
is also uncertain how unique conditions in the lower flow systems, such 
as the presence of coal seams and current and historical mining 
operations could affect background water quality in the lower flow 
systems.
    In summary, the uncontaminated ``flavors'' (i.e., representative 
conditions) of each relevant aquifer zone need to be established to 
provide a representative direct comparison relative to CCR impacts in 
these same zones on an ``apples to apples'' basis. However, the 
approved background monitoring system is insufficient in terms of 
general numbers of background monitoring wells as well as a general 
failure to include background monitoring in key sub-elements of the 
layered hydrogeologic system representing the uppermost aquifer. It 
therefore does not appear to accurately represent the full range of 
``background'' conditions in the uppermost aquifer.
(3) Compliance Wells Are Not Installed at the Downgradient Waste 
Boundary
    40 CFR 257.92(a)(2) requires that downgradient compliance wells 
``be installed at the waste boundary that ensures detection of 
groundwater contamination in the uppermost aquifer.'' The waste 
boundary is ``a vertical surface located at the hydraulically 
downgradient limit of the CCR unit. The vertical surface extends down 
into the uppermost aquifer.'' 40 CFR 257.53. Notwithstanding this clear 
direction, most wells in the monitoring network installed at Plant 
Gorgas were located far from the waste boundary. Yet ADEM approved the 
system without condition or revision.
    For example, EPA evaluated well placement along a north to south 
transect, south of the buttress, along the west side of the main valley 
containing CCR. From north to south, this included, GS-AP-MW-9, -10, -
11, 12, -13, -14, -47, -15, -16, and -18. This transect is 
approximately 8,400 feet in length, or over a mile and a half. Over 
this distance the monitoring wells were located from 55 feet to 510 
feet away from the waste boundary, with and average distance from the 
waste boundary near 295 feet. On average, over the entire unit, 
monitoring wells here were located approximately 740 feet from the 
waste boundary.
ii. Insufficient Locations and Depths of Downgradient Compliance Wells 
To Monitor the Uppermost Aquifer
    As previously discussed, the Federal regulations specify that a 
groundwater monitoring system must ``consist[ ] of a sufficient number 
of wells, installed at appropriate locations and depths, that . . . 
accurately represent the quality of the groundwater passing the waste 
boundary of the CCR unit.'' 40 CFR 257.91(a)(2). The regulations 
further specify that ``[a]ll potential contaminant pathways must be 
monitored.'' Id. But the groundwater monitoring system that ADEM 
approved meets none of these requirements. As discussed in more detail 
below, EPA is proposing to determine that ADEM approved a GWMP with an 
insufficient number of wells laterally along the downgradient perimeter 
of the unit to monitor all potential contaminant pathways. EPA is also 
proposing to determine that monitoring wells in the approved plan were 
not installed at appropriate depths to ensure that all potential 
contaminant pathways were monitored. Finally, EPA is proposing to 
determine that the approved groundwater monitoring system fails to 
account for preferential pathways beneath the Ash Pond.
(1) Insufficient Lateral Spacing of Compliance Wells To Monitor All 
Potential Contaminant Pathways
    The majority of the compliance wells along the perimeter of the 
Plant Gorgas Ash Pond are spaced hundreds and sometimes thousands of 
feet apart. For example, only a single detection monitoring well (GS-
AP-MW-2) was installed near the waste boundary to monitor groundwater 
over a large area flowing from the Plant Gorgas Ash Pond along the 
northeastern boundary. The lateral distances from GS-AP-MW-2 to the 
adjacent compliance wells to the north and south, GS-AP-MW-3, and GS-
AP-MW-1R, respectively, both approach 2,000 feet (as the crow flies). 
Furthermore, the waste boundary between the two compliance wells GS-AP-
MW-2 and GS-AP-MW-1R is approximately two miles. This unmonitored two-
mile portion of the waste boundary runs along three sides of an 
adjacent offsite 16-acre parcel that appears to include residential 
structures. In effect, this leaves a two-mile stretch without any 
compliance wells to detect contamination before it migrates off-
site.\86\ See Figure 5A in the 2021 Plant Gorgas Annual GWMCA 
Report.\87\
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    \86\ Two wells (GS-AP-MW-43H and GS-AP-MW-44HO) are also 
situated in the vicinity of the adjacent offsite 16-acre parcel, but 
these wells are designed to horizontally delineate the plume of 
contamination that has already migrated beyond the unit boundary.
    \87\ According to a representative from the Copeland Ferry--
Pumpkin Center Water Authority Publicly Owned Treatment Works, they 
serve public drinking water to residents in the vicinity of the Ash 
Pond. EPA is also working to confirm whether nearby households are 
on public or private water supply.
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    This is not an anomaly, and extremely large lateral well spacings 
and large lateral gaps in monitoring well coverage are not an isolated 
occurrence. Prior to closure, the perimeter of the unit was roughly 
14.7 miles in length, and following closure, the perimeter of the 
consolidated CCR will be approximately 7.8 miles in lateral extent.\88\ 
Because

[[Page 55265]]

ADEM approved the groundwater monitoring system in its current form, 
and it appears that the monitoring network will change little during 
the ongoing closure activities, it is reasonable to evaluate the 
lateral well spacing in terms of the current (pre-closure) perimeter, 
i.e., 14.7 miles. Over this 14.7-mile unit boundary there are presently 
only 30 downgradient compliance wells, indicating an average spacing of 
approximately 2,600 feet, or roughly half a mile between monitoring 
wells. Prior to 2021, there were only 20 downgradient compliance wells, 
indicating an average lateral spacing of downgradient compliance wells 
in the lateral dimension was on the order of 3,900 feet apart, or 
almost three quarters of a mile.
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    \88\ This approach is further supported in view of the fact that 
the original footprint, although reconfigured, is still integral to 
the overall closure strategy. Further, SSLs have been detected in 
the reconfigured northern region, which will require monitoring and/
or corrective action into the future.
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    Because wells installed to characterize the release in accordance 
with Sec.  257.95(g)(1)(i) are not located on the downgradient waste 
boundary and are monitored for different constituents at different 
frequencies, these wells are not properly included in an evaluation of 
adequacy of the detection and assessment wells installed to comply with 
requirements in Sec.  257.91(a). And even if EPA were to consider the 
delineation wells as part of the detection and assessment monitoring 
systems, that would only bring the total number of monitoring wells to 
68, which would equate to one well per every 1,150 feet of boundary.
    However, by any reasonable standard, lateral well spacings on the 
order of thousands of feet would be excessive. While appropriate 
lateral well spacing is site-specific, and varies from site to site, 
lateral well spacing appropriate for a site such as the Ash Pond at 
Plant Gorgas may be determined by several factors. These include, but 
are not limited to, the character, the degree of homogeneity, and 
dimensions of the emplaced waste body itself; the nature, variability, 
and complexity of the subsurface geology; as well as the dynamics, 
complexities, and boundary conditions of the hydraulic flow system into 
which the CCR has been emplaced. A greater degree of complexity and 
variability concerning these elements would translate to a greater 
number of compliance wells in the lateral dimension, i.e., a smaller 
inter-well spacing, for the well network to adequately monitor such a 
system. Conversely, a well characterized system, based on geological, 
hydrogeological, and geotechnical investigations at the site, which has 
been demonstrated to be simple, stable, and uniform would allow for a 
fewer number of compliance wells to capture the limited inherent 
variability. In addition, factors related to resolution and uncertainty 
also affect the lateral well spacing appropriate to a given site. In 
this regard it should be noted that the Federal regulations indicate 
clear expectations regarding expected levels of resolution, which are 
generally described as that necessary to ensure that all potential 
contaminant pathways in the entire uppermost aquifer are monitored, 
including preferential pathways. Uncertainties and data gaps also 
equate to the need for greater levels of monitoring than would 
otherwise be required to compensate for these deficiencies. In other 
words, if characterization data are not available to support a larger 
minimum lateral well spacing, a default to a more rigid general 
standard is needed, requiring more wells. At the Ash Pond at Plant 
Gorgas, a much smaller lateral well spacing is needed to meet the 
requirements. This is due to (1) The complexity of the buried CCR; (2) 
The low resolution and extreme uncertainties in the characterization of 
the groundwater flow system which encompasses the unit; (3) The 
demonstrated complexity of the geologic layering in the vertical 
dimension; and (4) The presence of significant localized fracturing and 
numerous mapped faults which cut through the unit and surrounding 
areas. In a general sense, therefore, instead of thousands of feet 
apart, monitoring well spacings should have been on the order of 
hundreds of feet, except where known features such as narrow buried 
erosional stream valleys or fracture zones dictate even tighter lateral 
spacing. For example, the lateral spacings between wells MW-9, -10, -
11, and -12 ranges from roughly 700-1,200 feet apart, yet none of these 
monitoring wells were located sufficiently close together to intersect 
the mapped fracture which cuts through this area of the site. A tighter 
well spacing is needed to adequately characterize the site. As another 
example, many wells are screened in zones which intersect underground 
coal mines. These mine tunnels represent potential preferential 
pathways which should have been more intensively monitored. The lateral 
and vertical dimensions of these types of underground workings are 
knowable and should be factored into decisions concerning appropriate 
monitoring well spacings to effectively ensure these preferential 
pathways are monitored. Much smaller lateral and vertical wells 
spacings are necessary to meet the requirements in this scenario, 
instead of wells that are thousands of feet apart.
(2) Insufficient Number of Downgradient Compliance Wells Installed at 
Appropriate Depths To Monitor the Entire Aquifer (Inadequate Vertical 
Spacing)
    EPA is also proposing to determine that ADEM approved a GWMP that 
lacked ``a sufficient number of wells, installed at appropriate 
locations and depths'' to ensure that all potential contaminant 
pathways in the entire uppermost aquifer are monitored. As discussed 
above, the uppermost aquifer contains at least four flow systems: (1) 
the upper water table; (2) the Pratt Coal seam; (3) the American Coal 
seam; and (4) the Lower Pratt/Gillespy Transition zone. A system of 
compliance wells that meet the performance standards of Sec.  
257.91(a)(2) must be installed in each of them. But none of the four 
flow systems contain sufficient numbers of wells to meet these 
standards.
    Nearly all the compliance wells installed in the three lower flow 
systems were screened across the shallow coal seams located between 
approximately 250 and 350 ft-MSL, i.e., in the Pratt Coal seam and the 
American Coal seam. Of the eight cross sections reviewed,\89\ it 
appears that only two downgradient compliance wells were screened below 
the coal seams in the Lower Pratt/Gillespy Transition zone (GS-AP-MW-6S 
and -6D). These wells are downgradient due to the unit's radial flow at 
this depth, and two wells are insufficient to comprehensively monitor 
this portion of the uppermost aquifer. First, all the monitoring wells 
installed below the coal seams are focused along the western and 
northern section of the unit, leaving the northeastern, southwestern, 
southern, and eastern sections with little to no data in the aquifer 
below the coal seams. Conservatively, this means the lower flow systems 
within the Lower Pratt/Gillespy Transition for over half of the pre-
closure extent of the unit (at least 237 acres) are not being 
monitored.
---------------------------------------------------------------------------

    \89\ Anchor QEA. Prepared for Alabama Power Company. Plant 
Gorgas Groundwater Remedy Selection Report. December 2021. Figures 
5A and 5B in the revised GWMP and Figures 9A thru 16 in the
---------------------------------------------------------------------------

    This is further corroborated by the cross-sections in Figures 11A, 
14A, 15, and 16 of the Groundwater Remedy Selection Report, which 
document the large portions of the uppermost aquifer below the coal 
seams where no data

[[Page 55266]]

have been obtained.\90\ According to Figure 14A, there appears to be 
only one well cluster (GS-AP-MW-6S/6V/6D) installed below the coal 
seams, approximately 900 feet from the edge of the ash pond immediately 
downgradient of the current dam. Given the unit's pre-closure size of 
474 acres and a vast downgradient waste boundary exceeding fourteen 
miles in length, this single well cluster would certainly not monitor 
all potential contaminant pathways in this lower flow system.
---------------------------------------------------------------------------

    \90\ Id at pp 81, 83 of the revised Groundwater Monitoring Plan 
and Figures 9A thru 16.
---------------------------------------------------------------------------

    There are also only 10 wells screened in the upper water table 
(i.e., in the unconfined materials above the coal seams in the Cobb 
Group). As shown in Figure 6A of the 2022 Semi-Annual GWMCA Report, 
entitled Potentiometric Surface Contour Map (Upper) Water Table 
Aquifer, February 7, 2022, Plant Gorgas Ash Pond, these 10 water level 
monitoring points are installed over hundreds of acres, only 7 of these 
are designated as compliance wells, and there is conflicting 
information between the Permit Application and the most recent Annual 
GWMCA Report from 2022 regarding the stratigraphic layers in which 
these compliance wells are screened. For example, the 2022 Annual GWMCA 
Report only indicates that two of these 7 wells are screened across the 
``shallow water table.'' EPA therefore is proposing to determine that 
the compliance monitoring with respect to the shallow unconfined water 
table aquifer zone is not adequate to comply with the regulations.
    Similarly, based on the 2022 Semi-Annual GWMCA Report, 52 wells 
were installed in the Pratt Group as a whole across the entire 274-acre 
Ash Pond.\91\ Of these, based on the interpretation of the flow system 
provided in the 2022 Semi-Annual GWMCA Report, water levels were 
measured at 31 wells installed in Pratt Coal seam,\92\ and water levels 
were measured at 21 wells screened in the American Coal seam.\93\ 
However, the compliance well network listed in Table 1A in the Permit 
Application indicates only 15 compliance wells screened in the Pratt 
coal seam zone, and only 11 compliance wells screened in the American 
Coal seam.
---------------------------------------------------------------------------

    \91\ Monitoring wells screened in the Nickel Plate coal seam are 
included in the Pratt Coal seam category for this discussion.
    \92\ Southern Company Services. 2022 Semi-Annual Groundwater 
Monitoring and Corrective Action Report, Alabama Power Company, 
Plant Gorgas Ash Pond. Prepared for Alabama Power Company. July 31, 
2022. Figure 6B, Potentiometric Surface Contour Map, Pratt Aquifer, 
February 7, 2022.
    \93\ Id at Figure 6C of the same report is entitled 
Potentiometric Surface Contour Map, American Aquifer,
---------------------------------------------------------------------------

    Lastly, based on the interpretation of the flow system provided in 
the 2022 Semi-Annual GWMCA Report, water levels were measured and 
plotted for 15 wells to inform a representation of potentiometric 
contours for the Base of the Pratt--Gillespy transition zone.\94\ 
However, these 15 wells do not appear to be screened in equivalent 
levels of the transition zone and only 13 of these are listed on Tables 
1A (3 Wells), 1B (8 Wells), and 1C (2 wells) in the 2022 Semi-Annual 
GWMCA Report. Moreover, not all of 13 wells were included/depicted on 
Figure 6B \95\ and only 3 ``Pottsville Fm--Gillespy zone transition'' 
wells are listed as compliance wells on Table 1A in the Permit 
Application. This lack of clarity concerning the characterization and 
monitoring of the transition zone between the lower Pratt Group and 
Gillespy Group, supports EPA's basic conclusion above, that the base of 
the uppermost aquifer has not been determined or sufficiently 
characterized vertically (or laterally).
---------------------------------------------------------------------------

    \94\ Id at inset map on Figure 6B entitled, Generalized 
Potentiometric Surface Contour Map--Base of Pratt to Gillespy 
Transition (North of Dam).
    \95\ Id.
---------------------------------------------------------------------------

    In summary, installing so few compliance monitoring wells over such 
great lateral distances and over such significant vertical intervals 
cannot possibly monitor all the potential contaminant pathways at Plant 
Gorgas, given the size of the Ash Pond as well as the topographic and 
hydrogeologic complexity of the site.
(3) Preferential Pathways Are Not Monitored
    Numerous preferential pathways have been documented in the 
uppermost aquifer under the Ash Pond. Yet under the approved GWMP, none 
of these significant potential contaminant pathways appear to be 
adequately monitored, despite the express requirement in Sec.  
257.91(a)(2).
    The approved GWMP states that, ``Locally, Pratt Coal Group strata 
gently dip (0.5[deg] to 1.0[deg]) to the south and south-southwest. 
Figure 5A Geologic Cross-Section A-A' and Figure 5B Geologic Cross-
Section B-B' illustrate the geologic layering beneath the site.'' It is 
immediately apparent from these cross sections that a simple, nearly 
flat series of geologic layers is an overly simplistic representation 
of the site. As has been noted in many reports from Alabama Power in 
the permit record, the geologic layering is disrupted in many locations 
by mappable faults which indicate significant displacement and have 
steepened dips resulting in folding in some areas of the subsurface.
    Nevertheless, the monitoring network does not include monitoring 
wells with screens deliberately targeted to these mapped faults and 
associated fractures. Given the presence of these significant fault 
zones, some of which have been mapped and delineated within the 
aquifer, additional monitoring wells should have been installed to 
detect whether CCR contaminants are migrating beyond the unit 
boundaries in pathways that follow these fracture lines. As an 
illustrative example, as shown on Figures 7A, 7B, 8A and 8B of the 2022 
Semi-Annual GWMCA Report, a series of north-northwest striking 
fractures with steep dips to the west cut through the unit. One such 
fracture is mapped from the region of MW-10R north-northwestward 3600 
feet (over half a mile) to the Mulberry Fork and beyond, further to the 
north-northwest. Monitoring wells MW-12 and 12V are located hundreds of 
feet to the east of the fault and therefore did not intersect it. 
Similarly, MW-11 is too far away from the feature and too shallow, so 
it also failed to intersect the feature. Ultimately it does not appear 
that any monitoring wells effectively monitor this significant 
potential contaminant pathway, which is particularly problematic as the 
fault appears to intersect the river in the general downgradient 
direction and thus has the (unassessed) potential to directly discharge 
CCR-related contaminants to the river system. This natural fracture-
controlled ``pipeline'' represents a likely conduit for preferential 
groundwater flow which follows the strike of the fracture and thus 
represents a significant, unmonitored, potential contaminant pathway. 
It is notable that none of these identified fractures are included on 
Figure 5, Monitoring Well Location Map Plant Gorgas Ash Pond, of the 
same report.
    Additional preferential pathways are associated with underground 
mine workings which impinge on parts of the unit. Coal mining 
operations, including underground workings, are also well documented in 
the vicinity of the site, and coal beds have been generally targeted 
for most of the monitoring well installations. But while some 
monitoring points appear to be screened at the same horizon as these 
underground mine workings, their lateral extent in the subsurface 
remains unknown, and as such the potential for preferential pathways 
which exploit these zones represents a clear data gap. For example, the 
geologic cross sections included in the 2021 Plant Gorgas

[[Page 55267]]

Annual GWMCA Report indicate the presence of former mine shafts that 
could significantly impact groundwater flow, and therefore warranted 
additional characterization and focused monitoring. These pathways were 
also documented in the December 2021 Remedy Selection Report, which 
ADEM received 3 months prior to its issuance of the Plant Gorgas permit 
in February 2022. In addition, according to the cross section in Figure 
5A in the revised GWMP and Figure 12A in the Groundwater Remedy 
Selection Report, at least one fault that could serve as a potential 
preferential pathway for groundwater has been mapped immediately 
adjacent to the Ash Pond and penetrates below the coal seams. It is 
therefore another significant failure of the approved groundwater 
monitoring system that it does not include wells to monitor the 
targeted and delineated contaminant pathways that follow coal seams, 
underground workings, or other natural and/or man-made features that 
can act as preferential pathways for groundwater and contaminant 
migration. See 40 CFR 257.91(a)(2). The significance of ADEM's failure 
to address this deficiency is illustrated by the numerous and 
documented SSIs and SSLs detected in the monitoring wells which are 
screened within the coal layers.
    In summary EPA is proposing to determine that the groundwater 
monitoring network ADEM approved for the Ash Pond at Plant Gorgas falls 
far short of the performance standards in Sec.  257.91(a) and (b). The 
uppermost aquifer has not been sufficiently characterized or monitored. 
In particular, the lower limits of the uppermost aquifer and 
hydraulically connected aquifers beneath it have not been defined. 
Compliance monitoring wells have not been located at the waste boundary 
in most locations. There are an insufficient number of monitoring wells 
along the perimeter of the downgradient waste boundary, and at 
insufficient depths, to monitor all potential contaminant pathways in 
the entire uppermost aquifer, given the potential for radial flow in 
deeper aquifer zones. Finally, numerous preferential pathways have not 
been monitored.
    ADEM's permit does include a permit condition that states:

The Permittee shall install and maintain additional groundwater 
monitoring wells as necessary to assess changes in the rate and 
extent of any plume of contamination or as otherwise deemed 
necessary to maintain compliance with [ADEM Admin. Code] 335-13-15-. 
06. A plan in the form of a permit modification request should be 
submitted to the Department as required by Section V.D.

However, this condition does not actually require any action that will 
bring the groundwater monitoring system into compliance; for example, 
by requiring the facility to fully characterize the uppermost aquifer 
system or install additional monitoring wells at the waste boundary. 
Or, more broadly, it does nothing to compel the facility to meet the 
requirements in 40 CFR 257.91(a) and (b).
c. Plant Gorgas Corrective Action Issues
    In November 2018, the first SSLs above a groundwater protection 
standard were detected at the Gorgas Plant. SSLs were reported for 
lithium, arsenic, and molybdenum. The Ash Pond reported SSLs of all 
three constituents; the Gypsum Pond, CCR Landfill, and Gypsum Landfills 
reported SSLs of lithium only; and the Bottom Ash Landfill reported 
SSLs of arsenic. One ACM was developed for all the units at the 
facility in June 2019 and revised in February 2020 (``revised 
ACM'').\96\ On February 28, 2022, ADEM issued a Final Permit to Alabama 
Power for Plant Gorgas Ash Pond, Gypsum Pond, and Bottom Ash Landfill.
---------------------------------------------------------------------------

    \96\ Anchor QEA. Assessment of Corrective Measures, Plant 
Gorgas. Prepared for Alabama Power Company. June 2019 (Revised: 
February 2020).
---------------------------------------------------------------------------

    In the RTC for the Gorgas Final Permit,\97\ ADEM states:
---------------------------------------------------------------------------

    \97\ Alabama Department of Environmental Management. Initial 
Permit and Variance, William C. Gorgas Electric Generating Plant, 
Permit No. 64-12, Public Commenters. February 28, 2022.

In November of 2019, the Department provided extensive comments to 
Alabama Power related to the submitted ACM and proposed final 
remedy. The Department's comments addressed many of the concerns 
raised by commenters, including the selection of monitored natural 
attenuation (MNA) as the final remedy despite providing limited data 
to its efficiency as a remedy. To date, Alabama Power has not 
submitted a revised ACM, as the facility has been collecting 
---------------------------------------------------------------------------
additional data to support a final remedy proposal.

    It appears the permit record (Final Permit and RTC) may not reflect 
all the relevant information about the status of corrective actions at 
Plant Gorgas that was available to ADEM when the permit was issued. 
According to Alabama Power ``[a] Groundwater Remedy Selection Report 
was prepared and submitted on December 17, 2021, to meet the 
requirements of 40 CFR 257.97, ADEM Admin. Code r. 335-13-15-.06(8), 
and Part C of ADEM Administrative Order AO 18-096-GW . . .''.\98\ The 
remedy the facility selected for the Ash Pond, Gypsum Pond, and Bottom 
Ash Landfill consists of closure with waste in place and capping, 
permeation grouting at the Ash Pond, and MNA. Additionally, any 
comments that may have been provided by ADEM to Alabama Power on the 
2020 ACM were not available for review.
---------------------------------------------------------------------------

    \98\ Southern Company Services 2022 Annual Groundwater 
Monitoring and Corrective Action Report, Alabama Power Company Plant 
Gorgas Ash Pond. Prepared for Alabama Power Company. February 1, 
2023. p 2.
---------------------------------------------------------------------------

    The Plant Gorgas Final Permit contained the same recitation of the 
corrective action regulations as the other permits issued by ADEM. As 
with the others, incorporating the regulations verbatim in the permit 
does not require Alabama Power to achieve compliance with those 
requirements at Plant Gorgas. Here as well, it appears that ADEM did 
not take into account relevant facts about the status of corrective 
action at Plant Gorgas, such as whether the 2020 revised ACM or the 
selected remedy submitted to ADEM in December 2021 complied with the 
regulatory requirements. Most importantly, ADEM did not determine what 
actions are still necessary in light of those facts to achieve 
compliance with the regulations and include those actions as 
requirements in the Final Permit. Instead, two months later, ADEM 
issued a Final Permit that was silent on the adequacy of the revised 
ACM and the applicant's selected remedy. Over a year later, it does not 
appear that ADEM has evaluated the adequacy of the revised ACM and the 
applicant's selected remedy. As a consequence, EPA is proposing to 
determine that, by remaining silent, the permit in essence authorized 
Alabama Power to continue to pursue a remedy based on the results of an 
ACM that does not meet the requirements of Sec.  257.96, even though 
the selected remedy does not appear to meet the requirements in Sec.  
257.97(b), and the ACM identified other measures that would meet those 
requirements.
    Delaying a decision on the adequacy of the facility's selected 
remedy until some unspecified point after permit issuance \99\ 
effectively allows Alabama Power to continue operating out of 
compliance with the regulations, while operating in compliance with the 
permit. Releases continue to migrate off-site during this delay, and in 
this case, it appears the contamination may have already migrated off-
site to residential

[[Page 55268]]

property.100 101 The sanctioned delay in implementing an 
effective remedy with no schedule for compliance results in a permit 
program that is less protective than the Federal regulations.
---------------------------------------------------------------------------

    \99\ It appears that ADEM has still not evaluated either the 
revised 2020 ACM or Alabama Power's selected remedy.
    \100\ Alabama Power. Letter to Mr. Taylor. Alabama Power Plant 
Gorgas Ash Pond Closure and Groundwater Investigations. July 6, 
2020.
    \101\ Alabama Power. Letter to Mrs. Salter. Alabama Power Plant 
Gorgas Ash Pond Closure and Groundwater Investigations. October 30, 
2020.
---------------------------------------------------------------------------

    EPA is proposing to determine that the Final Permit contains many 
of the same issues discussed with respect to the other permits. The 
Final Permit does not contain a deadline for correction and resubmittal 
of the ACM to address any of the deficiencies ADEM identified in its 
2019 comments, or any response to Alabama Power's selected remedy. EPA 
has also identified deficiencies in the revised ACM beyond those ADEM 
discussed in the RTC.
i. The Plant Gorgas Final Permit Does Not Require Collection of Site 
Data Needed To Support Assessments in the ACM
    As discussed previously, Sec.  257.95(g)(1) requires a facility to 
characterize the nature and extent of the release and any relevant site 
conditions that may affect the remedy ultimately selected. The 
characterization must be sufficient to support a complete and accurate 
assessment of the corrective measures necessary to effectively clean up 
all releases from the CCR unit pursuant to Sec.  257.96.
    The revised ACM identified MNA as a corrective measure to address 
groundwater contamination, in addition to other corrective measures 
(e.g., hydraulic control and treatment; in-situ treatment). The revised 
ACM delineates releases of lithium, arsenic, and molybdenum but does 
not characterize the site conditions that would affect Alabama Power's 
selected remedy of MNA. Although the ACM identifies a number of 
potential attenuation mechanisms that might be effective for arsenic, 
lithium, and molybdenum, the ACM does not demonstrate that any of these 
mechanisms occur on site. EPA was unable to locate any data confirming 
that any of those potential attenuation mechanisms are occurring at 
Plant Gorgas. For example, this could include testing for the presence 
and quantity of lithium detected in the aquifer matrix solids to 
demonstrate that the constituent is being removed from the groundwater 
and immobilized on-site. But no site data were discussed in the ACM.
    The subsequent Remedy Selection Report also fails to contain the 
necessary site data. Although the Report, like the ACM, identifies a 
number of potential attenuation mechanisms that might be occurring on-
site for arsenic, lithium, and molybdenum, the Report does not conclude 
that any of these mechanisms occur on-site. Some site data that were 
not available in the ACM are discussed in Section 5.3 of the Remedy 
Selection Report, but they do not demonstrate that any significant 
amount of lithium, molybdenum, or arsenic is being immobilized in the 
``solids'' samples,\102\ (e.g., aquifer matrix) or otherwise confirm 
the presence of attenuated constituents in the aquatic matrix. The 
Report identifies only dispersion and dilution as an MNA mechanism that 
currently occurs at Plant Gorgas. Ultimately none of the data presented 
support selection of MNA as a primary remedy.
---------------------------------------------------------------------------

    \102\ Anchor QEA. Prepared for Alabama Power Company. Plant 
Gorgas Groundwater Remedy Selection Report. December 2021. Tables 6 
and 12 in Appendix D.
---------------------------------------------------------------------------

    Site data would also be needed to support any assessment of the 
performance, reliability, ease of implementation, and the time required 
to begin and complete the remedy must also be assessed and supported 
with site characterization data and analysis. 40 CFR 257.96(c)(1) and 
(2). But the Final Permit issued by ADEM requires neither the 
collection of data, or any revisions to the ACM, or any change in the 
facility's selected remedy to address these deficiencies.
ii. The Final Permit Does Not Require Submission of a Revised ACM That 
Accurately Assesses MNA
    In the revised ACM, Alabama Power acknowledges that, ``USEPA (2015) 
discourages using dilution and dispersion as primary MNA mechanisms, as 
these mechanisms disperse contaminant mass rather than immobilize it.'' 
\103\ ADEM also raised this as a concern in its 2019 comments on the 
original ACM.\104\ However, as noted neither the revised ACM or the 
Remedy Selection Report identifies any natural attenuation mechanisms 
other than dilution and dispersion that have been demonstrated to be 
occurring on-site: ``The performance of MNA requires further 
investigation, especially related to the identification of an 
attenuating mechanisms, capacity of the Pottsville Formation for 
attenuation, and time to achieve GWPS.'' \105\ This investigation was 
not completed prior to completion of the ACM. Regardless, Alabama Power 
assessed the performance of MNA as ``medium'' based on the dilution and 
dispersion (i.e., releases of contaminants) occurring on-site and the 
identification of potential attenuation mechanisms.
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    \103\ Anchor QEA. Assessment of Corrective Measures, Plant 
Gorgas. Prepared for Alabama Power Company. June 2019 (Revised: 
February 2020). p. 14.
    \104\ Alabama Department of Environmental Management. Response 
to CCR Documents Submitted to the Department. Alabama Power Company. 
November 14, 2019.
    \105\ Anchor QEA. Assessment of Corrective Measures, Plant 
Gorgas. Prepared for Alabama Power Company. June 2019 (Revised: 
February 2020). p. 17.
---------------------------------------------------------------------------

    Such a favorable assessment of MNA is contrary to the requirement 
in Sec.  257.97(b)(4) that ``[r]emedies must . . . [r]emove from the 
environment as much of the contaminated material that was released from 
the CCR unit as is feasible.'' As previously discussed, while MNA can 
reduce the concentration or mobility of inorganic contaminants in 
groundwater if immobilization occurs through adsorption or absorption 
to subsurface soils, it does not remove the contaminants from the 
environment. MNA, therefore, would not perform well with respect to the 
requirement in 40 CFR 257.97(b)(4). This is particularly true in this 
circumstance, where Alabama Power has failed to collect the site data 
needed to identify whether any naturally occurring attenuation may be 
occurring on-site, as well as the mechanism by which it occurs, and to 
assess whether site characteristics that control and sustain this 
naturally occurring attenuation are sufficient to immobilize the entire 
release. Because the revised ACM presents no information that MNA would 
meet these requirements, the ACM should have assessed MNA's performance 
and reliability as ``low.''
    Similarly, in order for MNA through immobilization to be assessed 
favorably with respect to its reliability at meeting the other 
requirements in Sec.  257.97(b), such as the requirement in Sec.  
257.97(b)(2) to attain groundwater protection standards, the chemical 
reactions and processes involved that achieve immobilization must be 
demonstrated to be present on site and be permanent. Immobilization 
that is not permanent could be reversed, causing contaminants to be 
released back into groundwater and to migrate off-site. Yet despite the 
absence of any data demonstrating immobilization mechanisms to be 
present, let alone permanent, the revised ACM assessed the reliability 
of MNA through immobilization as ``high.'' This conclusion is 
unsupported; since no immobilization mechanisms were

[[Page 55269]]

demonstrated to be present, they could not be known to be reliable.
    The revised ACM also fails to consider safety impacts, cross-media 
impacts, and control of exposure to any residual contamination in its 
assessment of MNA. See 40 CFR 257.96(c)(3). Neither the narrative nor 
Table 5 in the 2020 ACM discuss these impacts for MNA. Yet Table 5 in 
the 2020 ACM, in the column labeled ``potential impacts of remedy'' 
nevertheless concludes that the potential impacts from MNA are 
``none.'' This conclusion is unsupported by data or analysis. This 
conclusion is also inconsistent with other information in the revised 
ACM. The Ash Pond and Bottom Ash Landfill are both adjacent to a river. 
In the revised ACM in Figure 3, groundwater flow is depicted from the 
Ash Pond toward the river. The Bottom Ash Landfill is also near and 
upgradient from an adjacent river. As noted, the only MNA that is known 
to occur at the site is dilution and dispersion (i.e., the normal 
transport associated with groundwater releases.) This means that 
contaminants are migrating in groundwater from the Ash Pond to the 
river. Migration of contamination from groundwater to surface water is 
a cross-media impact. Therefore, the assessment of potential impacts 
from the remedy for MNA in Table 5, which includes these cross-media 
impacts, should be ``high.''
    Conclusions without a supporting assessment or data do not 
constitute ``an analysis of the effectiveness of potential control 
measures.'' 40 CFR 257.96(c) (emphasis added). In addition, the lack of 
data to support the assessments in the revised ACM means it may not 
accurately reflect MNA's ``effectiveness in meeting all of the 
requirements and objectives'' in Sec.  257.97(b). Inaccurate 
assessments in an ACM can ultimately result in selection of a remedy 
that will not meet the requirements of Sec.  257.97(b), which is what 
appears to be occurring here.
    In an ACM, technologies' expected performances are compared with 
one another according to how well each alternative meets each 
regulatory criterion. The Revised ACM identified MNA as one of several 
potential corrective measures to address groundwater contamination 
(i.e., hydraulic control and treatment; in-situ treatment). Given both 
the absence of any evidence of any attenuation mechanisms occurring at 
the Ash Pond, and the conclusion in the revised ACM that the other 
alternatives, such as pump and treat, are feasible, there would appear 
to be no basis for assessing MNA more favorably than an alternative 
that unquestionably removes contaminants from the environment. For the 
same reasons, there is no apparent basis for ultimately selecting MNA 
as the remedy.
    ADEM's Final Permit contains no measures to remedy this, even 
though in their 2019 comments on the original ACM, ADEM raised many of 
the same issues discussed above. For example, ADEM requested that 
Alabama Power update the ACMs to include detailed information for each 
requirement. In particular, the comments noted that:

    Furthermore, ADEM Admin. Code r. 335-13-15-.06(8)(b)3. and (b)4. 
require that the remedy must (1)'' control the source(s) of releases 
so as to reduce or eliminate, to the maximum extent feasible, 
further releases of constituents in Appendix IV into the 
environment'' and (2) '' remove from the environment as much of the 
contaminated material that was released from the CCR unit as 
feasible . . .''.The ACMs evaluate a number of options, with source 
control (by consolidating and capping the CCR units) and monitored 
natural attenuation (MNA) proposed as the most effective remedy. The 
Department requests a more detailed justification for the proposed 
remedies given that source control will not be achieved for an 
average of 10 years and that no other mechanism is proposed to 
reduce the potential for further releases to the'' maximum extent 
feasible'.

    EPA was unable to find any evidence that a revised ACM or a more 
detailed justification was submitted in response to ADEM's concerns. By 
failing to require Alabama Power to take any concrete action to address 
these deficiencies, the Final Permit effectively authorizes the 
permittee to continue to indefinitely pursue a remedy that ADEM 
previously determined had not been demonstrated to meet the 
requirements in Sec.  257.97(b). Accordingly, EPA is proposing to 
determine that the permit does not require Alabama Power to achieve 
compliance with the Federal requirements; and because it allows the 
facility to continue to delay implementing a remedy that would meet the 
requirements of Sec.  257.97, the alternate State requirement is less 
protective.
4. Plant Greene County
    EPA reviewed the Final Determination Initial Permit and Variance 
for the Alabama Power Company, Greene County Electric Generating Plant 
(Plant Greene County Permit), issued by ADEM under Permit No. 32-03 on 
December 18, 2020.\106\ The permit summary on Page 1 says,
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    \106\ Alabama Department of Environmental Management. Final 
Determination Initial Permit and Variance for the Alabama Power 
Company, Greene County Electric Generating Plant, issued under 
Permit No. 32-03. December 18, 2020.

[t]he Plant Greene County Ash Pond is a CCR surface impoundment 
located in Sections 21 and 28, Township 19 North, Range 3 East in 
Greene County, Alabama consisting of approximately 559.41 acres with 
a disposal area that consists of approximately 477.24 acres. The 
permit requires the Permittee to manage CCR in accordance with the 
conditions of the permit, ADEM Admin. Code r. 335-13-15, '' 
Standards for the Disposal of Coal Combustion Residuals in Landfills 
and Surface Impoundments,'' and the approved permit application.
. . .
The Permittee must comply with all conditions of the permit except 
to the extent and for the duration such noncompliance is authorized 
by a variance granted by ADEM. The first variance requests to 
exclude boron as an Appendix IV assessment monitoring constituent. 
The second variance requests groundwater protection standards of 6 
micrograms per liter ([micro]g/L) for cobalt; 15 [micro]g/L for 
lead; 40 [micro]g/L for lithium; and 100 [micro]g/L for molybdenum. 
The third variance requests the final grade of the cover system be 
less than 5 percent and greater than 25 percent. The fourth variance 
being requested is from 335-13-15-.03(6) requiring a 100 foot buffer 
from the perimeter of the facility boundary.

    As with the other permits evaluated in this proposal, EPA has 
identified issues with ADEM's approval of the closure, groundwater 
monitoring network, and corrective action at Plant Greene County, which 
are discussed below. As previously discussed, EPA focused on only a 
subset of the potential issues associated with the permit and limited 
its review to information in the permit record (e.g., the Permit 
Application) and information publicly available on Alabama Power's CCR 
website. This is because the purpose of this review is to determine 
whether Alabama's program meets the statutory standard for approval, 
not to reach final conclusions about an individual facility's 
compliance with the CCR regulations.
a. Plant Greene County Closure Issues
    Plant Greene County had not completed closure of the Ash Pond when 
ADEM issued the Final Permit in December 2020. But the final permit 
ADEM issued looks largely the same as the permits issued to the other 
facilities. ADEM incorporated the Alabama CCR regulations by reference 
into the Final Permit for Plant Greene County, and it approved and 
incorporated the Closure Plan submitted as part of the application into 
the Final Permit without modification.\107\ The Final Permit provides:
---------------------------------------------------------------------------

    \107\ Although the Permit terms are ambiguous, it appears from 
the Response to Public Comment that ADEM approved the Closure Plan 
submitted as part of the Permit Application.


[[Page 55270]]


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SECTION VII. CLOSURE AND POST-CLOSURE REQUIREMENTS.
A. Closure Timeframe and Notifications. The Permittee shall close 
their CCR units as specified in 335-13-15-07(2), this permit and the 
Application.
B. Criteria for Closure.
1. Cover. Closure of a CCR landfill, surface impoundment, or any 
lateral expansion of a CCR unit must be completed by either leaving 
the CCR in place and installing a final cover system or through 
removal of the CCR and decontamination of the CCR unit, as described 
in 335-13-15-.07(3)(b) through (j). The minimum and maximum final 
grade of the final cover system may be less than 5 percent and 
greater than 25 percent, as specified in the Permit Application. 
(See Section IX.C.)
2. Written Closure Plan. The written closure plan, as part of the 
Application, must include, at a minimum, the information specified 
in 335-13-15-.07(3)(b)1.(i) through (vi).
3. Initiation of Closure Activities. Except as provided for in 335-
13-15-.07(3)(e)4 and 335-13-15-.07(4), the owner or operator of a 
CCR unit must commence closure of the CCR unit no later than the 
applicable timeframes specified in either 335-13-15-.07(3)(e)l or 2.
4. Completion of closure activities. Except as provided for in 335-
13-15-.07(3)(f)2, the owner or operator must complete closure of the 
CCR unit subject to the requirements in 335-13-15-.07(3)(f)l.(i) 
through (ii).

    According to the Closure Plan submitted with the Permit 
Application, Alabama Power intends to remove CCR from the southern 
portion of the Ash Pond and consolidate it within the northern portion 
of the existing ash pond.\108\ After the excavation and consolidation 
have been completed, the footprint of the remaining waste will occupy 
approximately 221 acres. The Plan calls for the 221 acres of 
consolidated waste to be closed in place, with a final cover system 
consisting of an engineered synthetic turf and geomembrane to be 
installed on the consolidated unit. In addition, according to the Plan, 
a barrier wall keyed into the low permeability Demopolis Chalk will be 
installed around the perimeter of the consolidated CCR material to 
create a hydraulic barrier that ``limits the movement of interstitial 
water through the constructed interior dike and existing northern 
dike.'' \109\ This hydraulic barrier will be connected to the 
geomembrane of the final cover system.\110\ According to the Closure 
Plan:
---------------------------------------------------------------------------

    \108\ Alabama Power Company. Revised Closure Permit Application 
for the Plant Greene County Ash Pond. April 30, 2020. Appendix 9, p 
3, 18-19.
    \109\ Id. p.16.
    \110\ Additional details regarding the barrier wall system are 
provided in the Permit Application in Appendix 6 and Appendix 7, 
entitled ``Draft--Construction Quality Assurance Plan.'' Although 
the drawings are marked with statements such as ``60 Percent Design 
Package'' or ``Issued for 60% Client Review,'' and the Construction 
Quality Assurance Plan is marked ``Draft,'' it appears that ADEM 
approved these materials with the permit condition directing the 
Permittee to close their CCR units ``as specified in the 
Application.''

These actions will effectively control the source of CCR 
constituents to groundwater by removing free water and some 
interstitial water from the ash, reducing the footprint area of the 
ash and preventing further infiltration of surface water resulting 
from rainfall through the ash. Removal of the free liquid will 
reduce the volume of water available to flow from the Ash Pond 
during and after closure, while also minimizing the hydraulic head 
driving water through the subsurface.\111\
---------------------------------------------------------------------------

    \111\ Alabama Power Company. Revised Closure Permit Application 
for the Plant Greene County Ash Pond. April 30, 2020. Appendix 9, p 
19.

    In many respects, the outlines of the closure presented in the Plan 
could be implemented to be consistent with the Federal requirements; 
however, ADEM approved the Plan without requiring Alabama Power to 
provide the information necessary to confirm that several critical 
closure requirements--which were not addressed or were insufficiently 
described--would be met. Specifically, neither the Closure Plan nor 
other materials in the Permit Application addressed how the performance 
standards in Sec.  257.102(d)(2) will be met with respect to the 
saturated CCR that it appears will remain in the base of the 
consolidated unit. The Permit could either have specified what the 
facility needs to do to meet the requirements, or ADEM could have 
required the facility to submit a revised Closure Plan. ADEM did 
neither, and as a consequence, there is no binding and enforceable 
provision for the facility to comply with these performance standards. 
In essence, ADEM has issued a permit that allows the facility to decide 
whether to comply with Sec.  257.102(b) and (d)(2), rather than 
``requiring each CCR unit to achieve compliance with'' those 
provisions. 42 U.S.C. 6945(d)(1).
    While it was in operation, the base of the Ash Pond was in 
continuous contact with the groundwater beneath the unit. Even now 
groundwater continues to saturate the CCR in the unit.\112\ EPA 
estimated the amount of saturated CCR remaining in the Ash Pond using 
the same methodologies described above for Plants Colbert and Gadsden. 
The average groundwater elevation from groundwater monitoring wells in 
the vicinity of the Ash Pond between September 2019 and August 2021 is 
84.8 ft above MSL. While the base elevation for the unit varies, by 
relying on an average base elevation of 83 feet, EPA estimates that, on 
average, just under 2 feet in depth of CCR across the entire footprint 
of the impoundment is currently in contact with groundwater. This 
equates to roughly 640,000 CY of saturated waste. Dewatering and pool 
drawdown continue at the site, and when combined with the installation 
of the slurry wall, groundwater elevations would be expected to 
decrease over time. However, the extent to which the CCR will remain 
saturated once closure activities are completed cannot be estimated due 
to the lack of information in the relevant documents.
---------------------------------------------------------------------------

    \112\ Alabama Power Company. Revised Closure Permit Application 
for the Plant Greene County Ash Pond. April 30, 2020. GWMP pp 220-
221.
---------------------------------------------------------------------------

    As discussed previously, the Federal regulations applicable to 
surface impoundments closing with waste in place require that ``[f]ree 
liquids must be eliminated by removing liquid wastes or solidifying the 
remaining waste and waste residues, [and that] remaining wastes must be 
stabilized sufficient to support final cover system.'' 40 CFR 
257.102(d)(2). But due to the deficiencies in the Closure Plan, it is 
not clear that the closure approved by ADEM will meet either standard.
    According to the approved Closure Plan, various dewatering 
techniques will be employed before and during closure; however, the 
Closure Plan appears to limit the use of these techniques to the CCR in 
the southern portion of the unit that will be excavated and transported 
to the consolidated area, and to the areas under the new dike.\113\ For 
example, in the sections specifically discussing dewatering, the 
Closure Plan states:
---------------------------------------------------------------------------

    \113\ Alabama Power Company. Revised Closure Permit Application 
for the Plant Greene County Ash Pond. April 30, 2020. Appendix 9, pp 
5,7, and 9.

i. Dewatering
Dewatering of the CCR Ponds consists of two phases: decanting of 
free water and dewatering of interstitial water within the CCR 
material. Dewatering will be required prior to ash excavation and 
throughout construction. . . .
Interstitial dewatering refers to the removal of subsurface water 
within the saturated CCR material. This dewatering requires lowering 
phreatic water levels to improve material handling for excavation 
and transport. Removal of interstitial water will likely require 
both passive and active methods of drainage.
* * * * *
The CCR material within the subgrade of the proposed interior dike 
will be over excavated and a stable, temporary slope formed to the 
interior to allow the dike and barrier wall to be constructed. 
During this time, the subgrade beneath the new dike will be 
dewatered (discussed in a following section).
* * * * *

[[Page 55271]]

As dewatering continues, CCR material will be excavated from the 
closure by removal areas and placed and compacted in horizontal 
lifts on top of the existing CCR material within the consolidation 
area.
As discussed previously, the CCR material will be dewatered in a 
systematic fashion prior to and during excavation activities, to 
maintain the phreatic surface below the working elevation of removal 
operations. For construction of the closed ash pond, it is expected 
that the CCR material will be handled multiple times prior to final 
placement and closure of the pond. CCR material will be stacked and 
dewatered to the proper moisture content prior to placement in the 
consolidation area.

(emphasis added).\114\ The Closure Plan lacks the required description 
of how--or even whether--Alabama Power intends to dewater the entire 
unit. For example, there are inconsistent statements in the Closure 
Plan about the scope of the dewatering activities Alabama Power intends 
to conduct. In one section, there is a reference to ``dewatering of 
wetter ash across the site, especially in the southern end of the 
pond.'' But the remainder of the discussion focuses on a technique that 
is unlikely to be used on CCR that is not intended to be excavated and 
transferred, which suggests that Alabama Power does not intend to fully 
dewater all of the CCR in the unit. Specifically, the Closure Plan 
states that:
---------------------------------------------------------------------------

    \114\ Alabama Power Company. Revised Closure Permit Application 
for the Plant Greene County Ash Pond. April 30, 2020. Appendix 9, pp 
7-8.

Utilization of stacking & casting methods is anticipated. With this 
approach, ash with higher moister[sic] content will be excavated and 
stacked in piles to allow for gravity drainage. A similar technique 
of windrowing may be used throughout the site. This technique 
involves spreading the wet ash in thin lifts and rowing/tilling the 
ash to allow the moisture to evaporate from the surface.
To expedite interstitial water dewatering and construction 
stormwater management, a capillary break drainage system may also be 
considered for the ash excavation/placement around the interior 
dike. The drainage system will help relieve pore water pressure in 
the underlying ash as the weight of earthwork filling is applied.

This is compounded by the Closure Plan's repeated references to the 
removal of ``free water,'' rather than the ``free liquids'' the Federal 
regulations specify must be eliminated.\115\ For example, on pages 18-
19, under the heading ``f. Achievement of Closure Performance 
Standards,'' the Closure Plan states:
---------------------------------------------------------------------------

    \115\ Alabama Power Company. Revised Closure Permit Application 
for the Plant Greene County Ash Pond. April 30, 2020. Appendix 9, pp 
5, 7-8, 19.

Free water will be removed, and interstitial water will be lowered 
to accomplish the CCR removal from the closure by removal areas and 
to close in a consolidated footprint.
* * * * *
These actions will effectively control the source of CCR 
constituents to groundwater by removing free water and some 
interstitial water from the ash, reducing the footprint area of the 
ash and preventing further infiltration of surface water resulting 
from rainfall through the ash.

(emphasis added). Alabama Power has defined the term ``free water'' in 
other Closure Plans as ``water contained in the CCR unit above the 
surface of CCR material.'' \116\ Compare, 40 CFR 257.53 (definition of 
``free liquids'').
---------------------------------------------------------------------------

    \116\ See, e.g., Alabama Power Company. Revised Closure Plan for 
the Plant Gorgas Ash Pond. Appendix 11, p 7.
---------------------------------------------------------------------------

    Moreover, the Closure Plan never refers to the groundwater within 
the northern portion of the unit or describes any engineering measures 
that will be implemented to remove these liquids. Based on the 
information provided, further engineering measures would be necessary 
to effectively eliminate these free liquids from the unit prior to 
installing the final cover system, required by Sec.  257.102(d)(2)(i). 
Absent further data demonstrating that saturated CCR will not be 
present in the base of the closed unit prior to the installation of the 
final cover system, the permit record does not support a finding that 
the remaining wastes will be stabilized sufficiently to support the 
final cover system, as required by Sec.  257.102(d)(2)(ii). If the CCR 
in the unit is not sufficiently stabilized, e.g., if it has not been 
completely drained prior to the installation of the final cover system, 
differential settlement of the CCR after installation of the cover 
system is possible, especially given the substantial added load from 
the consolidation of CCR from the southern portion of the Ash Pond. If 
the settlement is great enough it could cause a disruption in the 
continuity, and potentially failure, of the final cover system. 
Additional information is needed to determine that the permit meets 
Federal requirements. This could have been accomplished either by 
requiring submission of the information prior to the issuance of the 
permit or by including a permit term requiring submission of the 
information, along with a clause allowing for further permit conditions 
if necessary.
    Based on all of the above, EPA is proposing to determine that, by 
failing to resolve these issues, ADEM's permit does not require the 
Plant Greene County Ash Pond to achieve compliance with the Federal 
requirements for closure, or with alternative closure requirements that 
are at least as protective as the Federal requirements.
b. Plant Greene County Groundwater Monitoring Issues
    Based on EPA's review of the approved groundwater monitoring well 
network, EPA is proposing to determine that ADEM approved a groundwater 
monitoring system that fails to meet the Federal requirements. As 
previously discussed, the Federal regulations specify that a 
groundwater monitoring system must be installed that ``consists of a 
sufficient number of wells, installed at appropriate locations and 
depths, to yield groundwater samples from the uppermost aquifer that 
accurately represents the quality of the groundwater passing the waste 
boundary of the CCR unit.'' 40 CFR 257.91(a)(2). The regulations 
further specify that ``[a]ll potential contaminant pathways must be 
monitored.'' Id. But as discussed in more detail below, EPA is 
proposing to determine that ADEM approved a groundwater monitoring plan 
with an insufficient number of wells laterally along the perimeter of 
the unit to monitor all contaminant pathways. EPA is also proposing to 
determine that monitoring wells in the approved plan were not installed 
at appropriate depths to ensure that all contaminant pathways in the 
entire uppermost aquifer were monitored. These are essentially the same 
issues previously discussed with respect to Plants Gadsden and Gorgas.
i. Insufficient Number of Downgradient Compliance Wells Installed at 
Appropriate Depths To Monitor the Entire Aquifer (Inadequate Vertical 
Spacing)
    The downgradient well network approved by ADEM was focused 
primarily on a narrow subset of the uppermost geologic layers within 
what is referred to in the Permit Application as Unit 2: Poorly Graded 
Sands With Gravel Lenses. Other interconnected portions of the 
uppermost aquifer are not being monitored as discussed below. When 
evaluating whether monitoring wells are installed at appropriate depths 
(i.e., the adequacy of vertical monitoring well coverage), it is 
important to look at cross-sectional views of the entire uppermost 
aquifer in the vertical dimension to understand interrelationships of 
groundwater monitoring wells, screen depths, and lithological 
variations. These points are illustrated (in part) in the geologic 
cross-sections on Figures 5A and 5B included on pages 208 and 209 of 
the Permit Application, which show that the uppermost aquifer consists 
of layers of

[[Page 55272]]

poorly graded sands with gravel lenses (identified as Unit 2), as well 
layers of lean clay to sandy clay (identified as Unit 1). These cross 
sections and the boring logs that were included in the Permit 
Application confirm that the two geologic formations are hydraulically 
interconnected and both are therefore the ``uppermost aquifer.'' See, 
40 CFR 257.53 (defining uppermost aquifer to include lower 
hydraulically connected aquifers). Accordingly, monitoring wells must 
be installed in the two formations.
    Nearly all of the compliance wells at the waste boundary of the 
unit are screened in Unit 2, well below (in some cases over 20 feet 
below) the top of the uppermost aquifer; as a consequence there are an 
insufficient number of wells across nearly all of Unit 1. More 
precisely, EPA found that the groundwater monitoring well network for 
the Ash Pond unit has an insufficient number of wells screened in Unit 
1 (i.e., a vertical data gap) along at least three sides, as follows: 
(1) a 1500-foot section of Unit 1 parallel to the Barge Canal, as shown 
on Figure 4A, entitled ``Geologic Cross Section A-A' Plant Greene 
County Ash Pond''; (2) a 6000-foot section of Unit 1 along the western 
side of the unit, as shown on Figure 4B, entitled ``Geologic Cross 
Section B-B' Plant Greene County Ash Pond''; and (3) an approximately 
2000-foot section of Unit 1, along the northern side of the unit 
between groundwater monitoring wells GC-AP-MW-59-HO and GC-AP-MW-1 as 
shown on Figure 4C, entitled ``Geologic Cross Section C-C' Plant Greene 
County Ash Pond.'' These figures are found in the 2021 Plant Greene 
County Annual GWMCA Report.\117\ EPA was unable to determine if a 
similar gap currently exists along the southern side of the Plant 
Greene County Ash Pond, because no cross-section extending along the 
southern waste boundary of the unit was included in either the 2021 
Plant Greene County Annual GWMCA Report or the Permit Application. The 
omission of a cross-section in the Permit Application that extends 
along the southern side of the Ash Pond is significant because, given 
the proximity to the Black Warrior River, which is located immediately 
adjacent to the south and southeast of the Ash Pond, additional 
potential contaminant pathways that would need to be monitored would 
normally be expected to be present.
---------------------------------------------------------------------------

    \117\ Alabama Power. Plant Greene 2021 Annual Groundwater 
Monitoring and Corrective Action Report. January 31, 2022. Two 
similar geologic cross sections are found in the Groundwater 
Monitoring Plan included in the Permit Application. The two geologic 
cross sections were included as Figures 4A, for A-A1, and 4B, for B-
B1; however, no geologic cross section for C--C1 was included in the 
Permit Application.
---------------------------------------------------------------------------

ii. Insufficient Lateral Spacing of Compliance Wells To Monitor All 
Potential Contaminant Pathways
    EPA is also proposing to determine that ADEM approved lateral 
spacing between wells along the perimeter of the Ash Pond that is 
insufficient to meet the performance standards in Sec.  257.91(b). 
Monitoring wells used for the detection and assessment monitoring 
program are spaced approximately one thousand feet apart with few 
exceptions. Large lateral well spacings are particularly problematic to 
the east, south and west of the waste boundary of the unit where 
groundwater is expected to discharge to surface water. Given the 
proximity to the various surface water features, such as the Black 
Warrior River and the Barge Canal, the large well spacings make it 
likely that potential contaminant pathways from groundwater discharging 
to surface water located immediately adjacent to the Ash Pond are not 
being monitored. This groundwater to surface water pathway was 
acknowledged in the Permit Application with a statement that reads, as 
follows: ``Groundwater that migrates downward into the surficial 
aquifer will migrate vertically through the Unit 1 clay and then, 
primarily laterally (horizontal) and to a lesser extent vertically 
along more coarse fractions of the Unit 2 aquifer toward the Black 
Warrior River and barge canal.'' \118\
---------------------------------------------------------------------------

    \118\ Alabama Power Company. Revised Closure Permit Application 
for the Plant Greene County Ash Pond. April 30, 2020. PDF pp. 192.
---------------------------------------------------------------------------

    Based on the concerns discussed above, EPA is proposing to 
determine that by approving the deficient downgradient groundwater 
monitoring well network in the Permit Application, ADEM's final permit 
does not require Alabama Power to achieve compliance with the 
performance standards in Sec.  257.91(a)(2), or with an equally 
protective alternative.
c. Plant Greene County Corrective Action Issues
In November 2018, SSLs above the groundwater protection standards at 
Plant Greene County were reported for arsenic and lithium. An ACM was 
prepared in June 2019 (``2019 ACM''). On December 18, 2020, ADEM issued 
a final permit to Alabama Power for the Plant Greene County Ash Pond. 
In the RTC for the Final Permit, ADEM states:

In November of 2019, the Department provided extensive comments to 
Alabama Power related to the submitted ACM and proposed final 
remedy. The Department's comments addressed many of the concerns 
raised by commenters, including the selection of monitored natural 
attenuation (MNA) as the final remedy despite providing limited data 
to its efficiency as a remedy. To date, Alabama Power has not 
submitted a revised ACM, as the facility has been collecting 
additional data to support a final remedy proposal.

    The Plant Greene County Final Permit only contained a recitation of 
the corrective action regulations, but did not require Alabama Power to 
achieve compliance with those requirements. This is because the Final 
Permit does not require Alabama Power to take specific actions to 
correct the deficiencies in the 2019 ACM, even though, as discussed in 
its RTC on the permit, ADEM identified them a year before issuing the 
Final Permit. Significantly, ADEM did not determine what actions are 
still necessary in light of those facts for Alabama Power to achieve 
compliance with the regulations and include those actions as 
requirements in the Final Permit. For example, the Final Permit does 
not require the permittee to take any particular actions to address 
ADEM's comments on the 2019 ACM or with respect to Alabama Power's 
proposed remedy, such as specifying the additional data needed to 
support the permittee's preferred remedy under a set timetable. As a 
consequence, EPA is proposing to determine that the permit authorized 
Alabama Power to continue to indefinitely pursue a remedy that appears 
not to meet the requirements of Sec.  257.97(b), and that is based on 
the results of an ACM that does not meet the requirements of Sec.  
257.96.
    Whether the 2019 ACM meets the requirements of the regulations, and 
what actions Alabama Power must take to remediate groundwater in 
compliance with Sec.  257.97 are precisely the types of issues that 
must be determined before the permit is issued. This is because, once 
the permit is issued, the requirements in the permit become the State 
requirements with which the Permittee must comply. 42 U.S.C. 
6945(d)(3)(A). And if the permittee is not in compliance with the 
regulations, the permit must specify what the permittee is required to 
do in order to achieve compliance with those regulations. This is the 
role of a permitting authority (i.e., ADEM). Delaying this decision 
until after permit issuance effectively allows Alabama Power to 
continue operating out of compliance with the regulations, while 
operating in compliance with the permit. This results in a permit 
program

[[Page 55273]]

that is less protective than the Federal regulations.
    As discussed below, EPA is proposing to determine that the Final 
Permit fails to require Alabama Power to achieve compliance with 
several of the Federal corrective action requirements.
    These are many of the same deficiencies that ADEM identified in its 
comments on the 2019 ACM, but declined to remedy in the permit issued a 
year and a half later.\119\
---------------------------------------------------------------------------

    \119\ Alabama Department of Environmental Management. Response 
to CCR Comments Submitted to the Department, Alabama Power Company. 
November 14, 2019. pp 6-7.
---------------------------------------------------------------------------

i. The Final Permit Does Not Require Collection of the Data Needed To 
Support Assessments in the ACM
    As discussed previously, Sec.  257.95(g)(1) requires a facility to 
characterize the nature and extent of the release and any relevant site 
conditions that may affect the remedy ultimately selected. The 
characterization must be sufficient to support a complete and accurate 
assessment of the corrective measures necessary to effectively clean up 
all releases from the CCR unit pursuant to Sec.  257.96. The 2019 ACM 
delineates releases of arsenic, cobalt, and lithium but does not 
characterize site conditions that would affect any of the potential 
remedies identified in the ACM (e.g., testing for the presence and 
quantity of arsenic and lithium detected in soils to demonstrate they 
are being removed from the groundwater and immobilized on-site.)
    The 2019 ACM identified MNA as a potential corrective measure to 
address groundwater contamination, in addition to other corrective 
measures (e.g., hydraulic control and treatment; in-situ treatment). 
However, Alabama Power failed to collect the site data needed to 
identify whether natural attenuation may be occurring on-site, as well 
as the mechanism by which it occurs, and to assess whether site 
characteristics that control and sustain this naturally occurring 
attenuation are sufficient to immobilize the entire release. For 
example, in order to accurately assess MNA, site data are needed to 
determine whether immobilization occurs on-site through adsorption or 
absorption to subsurface soils. In addition, data would be needed to 
determine whether the chemical reactions and processes involved that 
achieve immobilization are permanent. Immobilization that is not 
permanent could be reversed, causing contaminants to be released back 
into groundwater and to migrate off-site.
    Although the Remedy Selection Report contained some data regarding 
the presence of released constituents in soils,\120\ the relative 
performance, reliability, ease of implementation, and the time required 
to begin and complete the remedy must also be assessed for each 
alternative, including MNA. 40 CFR 257.96(c)(1) and (2). These 
assessments must be supported with site characterization data and 
analysis, but no data were provided in the ACM to support an assessment 
of MNA against these criteria, relative to other alternatives, to 
support its selection. The Remedy Selection Report discusses site data 
in the context of these criteria for MNA only, with no side-by-side 
assessments of alternatives based on site data provided. Additionally, 
the data discussed in Section 4.3.2 of the Remedy Selection Report do 
not demonstrate that any significant amount of lithium or cobalt is 
being immobilized in the solids samples.\121\
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    \120\ Alabama Power Company. Plant Greene County Groundwater 
Remedy Selection Report, September 2021. Appendix D, Tables 6, 9 and 
19.
    \121\ Id at Appendix D, Tables 6 and 12.
---------------------------------------------------------------------------

ii. The Final Permit Does Not Require Submission of a Revised ACM That 
Accurately Assesses MNA According to the Criteria in 40 CFR 257.96(c)
    No naturally occurring attenuation mechanisms other than dilution 
and dispersion were identified at Plant Greene County in the ACM. 
Alabama Power acknowledges in the ACM that, ``USEPA (2015) discourages 
using dilution and dispersion as primary MNA mechanisms, as these 
mechanisms disperse contaminant mass rather than immobilize it.'' \122\ 
Regardless, Alabama Power assessed the performance of MNA as ``medium'' 
based on the fact that the aquifer is sandy and dilution and dispersion 
(i.e., releases of contaminants) are occurring.
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    \122\ Alabama Power Company. Assessment of Corrective Measures 
Greene County Ash Pond. June 2019, p. 12
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    This favorable assessment of MNA is inconsistent with Sec.  
257.97(b)(4), which specifies that ``[r]emedies must . . . remove from 
the environment as much of the contaminated material that was released 
from the CCR unit as is feasible.'' Neither dilution nor dispersion 
removes the contaminants from the environment. Therefore, at this site 
MNA would not meet this requirement, since the constituents would 
remain in the environment, albeit in a different environment (i.e., the 
river rather than the aquifer). Absent information to support a 
conclusion that MNA can meet these requirements at this site, MNA 
performance and reliability should have been assessed as ``does not 
meet.''
    Further, in order for MNA through immobilization to be assessed 
favorably with respect to its reliability at meeting the other 
requirements in Sec.  257.97(b), such as the requirement in Sec.  
257.97(b)(2) to attain groundwater protection standards, the chemical 
reactions and processes involved that achieve immobilization must be 
demonstrated to be permanent. Immobilization that is not permanent 
could be reversed, causing contaminants to be released back into 
groundwater and to migrate off-site. Assessing the reliability of MNA 
through immobilization as ``high'' in the ACM was not supported by 
data, since no immobilization mechanisms were identified, they could 
not be known to be reliable. Although Section 4.3.2 of the Remedy 
Selection Report contained some data regarding the presence of released 
constituents in soils, the data do not demonstrate that any significant 
amount of lithium or cobalt are being immobilized in the solid 
samples,\123\ and therefore these data do not actually support 
selection of MNA as a primary remedy for these contaminants.\124\
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    \123\ Alabama Power Company. Plant Greene County Groundwater 
Remedy Selection Report, September 2021. Appendix D, Tables 6 and 
12.
    \124\ Some data were provided in the Remedy Selection Report to 
indicate arsenic may be immobilized on-site.
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    In another section of the ACM, MNA was assessed as easy to 
implement because no design or construction would be required. If MNA 
occurs through immobilization of constituents in the subsurface that is 
not permanent, this would generally require ongoing monitoring as long 
as contaminants remain in the soil--indefinitely--in accordance with 
Sec.  257.98(a)(1). Since the goal of the remedy would be for 
immobilized constituents to remain in the subsurface indefinitely, 
monitoring would be needed to demonstrate whether this goal is 
achieved. This is a much longer compliance monitoring timeframe than 
any other alternative, except possibly in-situ geochemical 
manipulation, which means that implementation is not significantly 
easier than alternatives that can be completed sooner, such as 
hydraulic control and treatment.
    EPA is also proposing to determine that the ACM fails to meet the 
requirements to consider safety impacts, cross-media impacts, and 
control of exposure to any residual contamination in its assessment of 
MNA in either the narrative or Table 6. See 40 CFR 257.96(c)(3). Table 
6, in the column labeled ``potential impacts of remedy'' assesses the 
potential impacts from MNA as ``none.'' This conclusion is

[[Page 55274]]

unsupported by data or analysis. This conclusion is also inconsistent 
with information in the ACM. The Ash Pond is bounded on three sides by 
adjacent surface water features. In the ACM in Figure 3, groundwater 
flow is depicted from the Ash Pond toward surface water features. 
Further, as noted Section 4.2.1 of the Groundwater Monitoring Plan, 
entitled ``Groundwater Elevations and Flow,'' ``[g]roundwater 
elevations in monitoring wells located adjacent or close to the barge 
canal and the river appear to demonstrate a temporary reversal of flow 
to the groundwater system associated with recent storm events.'' This 
temporary reversal of flow indicates a connection between surface water 
and groundwater in the vicinity of the Ash Pond.
    Because no site data were presented to demonstrate that 
immobilization of lithium or cobalt is occurring at Plant Greene, the 
only MNA that is known to occur for these two constituents is dilution 
and dispersion (i.e., the normal transport associated with groundwater 
releases). This means that these contaminants are migrating in 
groundwater from the Ash Pond to the river. Migration of contamination 
from groundwater to surface water is a cross-media impact. Therefore, 
the assessment of potential impacts from the remedy for MNA in Table 6, 
which includes these cross-media impacts, should be ``high.''
    Conclusions without a supporting assessment or data do not 
constitute ``an analysis of the effectiveness of potential control 
measures.'' 40 CFR 257.96(c) (emphasis added). In addition, the lack of 
data means the ACM does not sufficiently establish MNA's 
``effectiveness in meeting all of the requirements and objectives'' in 
Sec.  257.97(b). Inaccurate assessments in an ACM can ultimately result 
in selection of a remedy that will not meet the requirements of Sec.  
257.97(b).
    ADEM identified many of these same issues in their comments on the 
2019 ACM. For example, on page 6, ADEM states:

ADEM Admin. Code r. 335-13-15-.06(8) contains substantial 
requirements that must be evaluated when selecting a remedy, such as 
the long- and short-term effectiveness and protectiveness of the 
potential remedy, the effectiveness of the remedy in controlling the 
source to reduce further releases, among many others. The ACMs 
submitted by APCO do not match the level of detail required in the 
regulations. Please update the ACMs to include detailed information 
for each requirement of this section. Furthermore, ADEM Admin. Code 
r. 335-13-15-.06(8)(b)3. and (b)4. require that the remedy must (1) 
``control the source(s) of releases so as to reduce or eliminate, to 
the maximum extent feasible, further releases of constituents in 
Appendix IV into the environment'' and (2) ``remove from the 
environment as much of the contaminated material that was released 
from the CCR unit as feasible. . .''.
* * * * *
The Department requests a more detailed evaluation of the 
effectiveness of MNA, or any other proposed remedy, based on site 
specific conditions.

Yet ADEM's Final Permit does not require Alabama Power to take any 
actions to remedy any of the deficiencies they identified.
iii. The Permit Does Not Require an Assessment of Source Control 
Measures
    The permit record contains no assessment of source control 
measures. Section 2.5 of the 2019 ACM describes the approved closure 
with waste remaining in the Ash Pond but contains no assessment of how 
well the closure would control releases. Nor can that information be 
found in the Remedy Selection Report, or the Closure Plan.
    Moreover, the ACM neither identifies nor assesses any alternative 
measures. 40 CFR 257.96 requires that various alternatives for source 
control be compared in accordance with the criteria in Sec.  257.96(c).
    ADEM raised similar concerns in their comments, which state:

The ACMs evaluate a number of options, with source control (by 
consolidating and capping the CCR units) and monitored natural 
attenuation (MNA) proposed as the most effective remedy. The 
Department requests a more detailed justification for the proposed 
remedies given that source control will not be achieved for an 
average of 10 years and that no other mechanism is proposed to 
reduce the potential for further releases to the ``maximum extent 
feasible''.

Yet the permit ADEM subsequently issued does not require any actions to 
remedy this deficiency.
5. EPA Conclusion About Alabama's Implementation of the CCR Regulations
    Given the systemic problems noted above in ADEM's CCR permits 
related to the groundwater monitoring, corrective action and closure 
requirements, EPA is proposing to determine that ADEM's implementation 
of its permit program is resulting in a State program that is notably 
less protective than the Federal CCR regulations. First, ADEM's permits 
allow closure with waste in place in unlined surface impoundments, 
without requiring any, or sufficient, controls to prevent groundwater 
from flowing in and out of CCR in the units indefinitely. In such 
circumstances, the permit will allow ongoing contamination of 
groundwater from CCR impoundments. Second, ADEM's permits do not 
require Permittees to achieve compliance with the groundwater 
monitoring regulations. The State-issued permits discussed in this 
notice approve groundwater monitoring networks that are insufficient to 
accurately determine if a unit is leaking. Finally, ADEM's permits are 
inadequate related to the implementation of the corrective action 
requirements because they allow facilities to delay effective responses 
to contaminant releases that may pose a risk to human health and the 
environment. Compounding this problem is the fact that the groundwater 
monitoring networks are insufficient and that means there may be 
additional unmonitored releases are occurring.
    Ultimately, Alabama's CCR permit program Application would not 
``require each coal combustion residuals unit located in the State to 
achieve compliance with the applicable [Federal or other equally 
protective State] criteria.'' 42 U.S.C. 6945(d)(1)(B). Therefore, EPA 
is proposing this denial of Alabama's CCR permit program Application.

V. Proposed Action

    EPA has preliminarily determined that the Alabama CCR permit 
program does not meet the statutory standard for approval. Therefore, 
in accordance with 42 U.S.C. 6945(d), EPA is proposing to deny the 
Alabama CCR permit program.

Michael S. Regan,
Administrator.
[FR Doc. 2023-17023 Filed 8-11-23; 8:45 am]
BILLING CODE 6560-50-P