[Federal Register Volume 59, Number 127 (Tuesday, July 5, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-16220]


[[Page Unknown]]

[Federal Register: July 5, 1994]


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Part II





Environmental Protection Agency





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Sole Source Aquifer Designation of the Vashon-Maury Island Aquifer 
System, King County, Washington; Notice
ENVIRONMENTAL PROTECTION AGENCY

[FRL-5006-8]

 
Sole Source Aquifer Designation of the Vashon-Maury Island 
Aquifer System, King County, Washington

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final determination.

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SUMMARY: The Region 10 Administrator of the Environmental Protection 
Agency (EPA) has determined that the Vashon-Maury Island Aquifer System 
is a sole or principal source of drinking water, and if contaminated, 
would create a significant hazard to public health. This action was 
taken under the authority of section 1424(e) of the Safe Drinking Water 
Act in response to a petition submitted to EPA by the Seattle-King 
County Department of Public Health on April 2, 1992. As a result of 
this determination, all federal financially assisted projects proposed 
in the designated area will be subject to EPA review to ensure that 
they do not create a significant hazard to public health.

EFFECTIVE DATE: This determination shall be promulgated for purposes of 
judicial review at 1:00 p.m. Eastern time on July 19, 1994.

ADDRESSES: The information upon which this determination is based is 
available to the public and may be inspected during normal business 
hours at the EPA Library, 10th Floor, Park Place Building, 1200 Sixth 
Avenue, Seattle, Washington 98101.

FOR FURTHER INFORMATION CONTACT: Scott E. Downey, Environmental 
Protection Specialist, Ground Water Section, WD-133, U.S. Environmental 
Protection Agency, Region 10, 1200 Sixth Avenue, Seattle, Washington 
98101, 206-553-0682.

SUPPLEMENTARY INFORMATION: This action is being taken under the 
authority of section 1424(e) of the Safe Drinking Water Act (42 United 
States Code, 300f, 300h-3(e), Public Law 93-523). The information upon 
which EPA is issuing this final determination has been summarized in 
the ``Support Document for Sole Source Aquifer Designation of the 
Vashon-Maury Island Aquifer System'', EPA 910/K-94-002.

I. Background

    Section 1424(e) of the Safe Drinking Water Act states:

    If the Administrator determines, on his own initiative or upon 
petition, that an area has an aquifer which is the sole or principal 
drinking water source for the area and which, if contaminated, would 
create a significant hazard to public health, he shall publish 
notice of that determination in the Federal Register. After the 
publication of any such notice, no commitment for federal financial 
assistance (through a grant, contract, loan guarantee, or otherwise) 
may be entered into for any project which the Administrator 
determines may contaminate such aquifer through a recharge zone so 
as to create a significant hazard to public health, but a commitment 
for federal assistance may, if authorized under another provision of 
law, be entered into to plan or design the project to assure that it 
will not so contaminate the aquifer.

    Although EPA has the authority to initiate ``sole source aquifer'' 
designations, the Agency has a policy of acting only in response to 
petitions. Petitions may be submitted to EPA by any individual or 
organization and must address procedures and criteria outlined in EPA's 
``Sole Source Aquifer Designation Petitioner Guidance'', EPA 440/6-87-
003.
    On April 2, 1992, EPA Region 10 received a petition from the 
Seattle-King County Department of Public Health requesting that EPA 
designate Vashon-Maury Island as a sole source aquifer. The petition 
was developed in cooperation with the Vashon-Maury Island Ground Water 
Advisory Committee and the Vashon-Maury Island Water Utilities 
Coordinating Committee. Recognizing the value of the aquifer as a 
present and future source of drinking water, the petition was submitted 
as an additional way to protect the Island's ground water resources.
    EPA's initial review of the petition led to a request for 
additional hydrogeologic and water usage information. This information 
was subsequently submitted to EPA by the petitioner. On October 21, 
1992, the petition was considered complete enough to undergo a more 
detailed technical review. The technical review was completed in April 
of 1994 and EPA's findings and basis for the proposed designation were 
documented in EPA's Support Document.

II. Basis for Determination

    The Region 10 Administrator has determined that the Vashon-Maury 
Island Aquifer System meets all applicable sole source aquifer 
designation criteria established through Federal statute and EPA 
guidance documents, as follows:
    (1) Sole or Principal Source of Drinking Water: Sole source 
aquifers must supply at least 50 percent of the drinking water to 
persons living in the area overlying the aquifer and in areas supplied 
by the aquifer. The Vashon-Maury Island Aquifer System supplies 
approximately 71 percent of the drinking water to persons living on the 
Island.
    (2) Potential Public Health Hazard: Contamination of the sole 
source aquifer must create a significant hazard to public health. As 
the principal drinking water source for the area, contamination of the 
Vashon-Maury Island Aquifer System would create a significant hazard to 
public health.
    (3) Definable Aquifer Boundaries: EPA guidance allows designations 
to be made for entire aquifers, hydrogeologically connected aquifers 
(aquifer systems), or part of an aquifer if that portion is 
hydrogeologically separated from the rest of the aquifer. The Vashon-
Maury Aquifer System boundary is based on hydrogeological principles 
and EPA's interpretation of available data. The Island's hydrogeology 
is representative of an aquifer system, as data indicate that water 
from shallow aquifers infiltrates to underlying deeper aquifers. The 
sole source aquifer boundary is coincident with the shoreline of the 
Island, and at depth includes all geologic units that can supply 
significant quantities of drinking water to wells. This boundary is 
assumed because stratigraphic data are not available to fully map the 
vertical extent of the aquifer materials.
    (4) No Alternative Source of Drinking Water: There can be no 
physical, legal, or economically feasible alternative source(s) of 
drinking water of sufficient volume that could replace the sole source 
aquifer, should it become contaminated. EPA has determined that there 
are no reasonably available alternative source(s) of drinking water 
that could replace the aquifer.

III. Description of the Vashon-Maury Island Aquifer System

    Note: Information in this section represents an unfootnoted 
summary from EPA's Support Document, EPA 910/K-94-002.

    Vashon-Maury Island is located near the southern end of Puget Sound 
in the southwestern corner of King County, Washington. The Island 
covers an area of 36.7 square miles and its population has been 
estimated at approximately 7,800 persons. Recorded data indicates an 
average rainfall of 46.53 inches.
    The aquifer system is composed of both interbedded glacial and non-
glacial deposits. In general, the water table elevation reflects the 
surface topography and the ground water moves radially outward from the 
interior to the shorelines of the Island.
    The uppermost and most recent deposits (Quaternary Vashon unit) are 
mainly stratified sand and gravel overlying glacial till and sandy 
gravel interbedded with medium and fine-grained sand. The Vashon unit 
contains a surficial aquifer comprised primarily of glacial till which 
has poor water-bearing characteristics, and the uppermost fresh water 
aquifer (Principal Aquifer) comprised of outwash sand and gravel beds. 
The Principal Aquifer is found at an elevation of between 0 and 400 
feet above mean sea level. Recharge of the Principal Aquifer is 
probably highest along a north-south corridor of west-central Vashon 
Island, and is estimated to be approximately 9 million gallons per day. 
The Principal Aquifer supplies ninety-five percent of the wells located 
on the Island.
    Underlying the Vashon unit are non-glacial deposits (Quaternary 
Olympia beds) generally consisting of thin-bedded sand and silt with 
local layers of gravel, massive silt and clayey silt. The Olympia beds 
serve as a leaky aquitard between the upper Principal Aquifer and the 
lower Deep Aquifer. The Deep Aquifer underlies the Olympia beds and 
consists of a variety of interbedded glacial tills, sand and gravel 
units and laminated silts and clays. The Deep Aquifer is located at an 
elevation of between about 100 to 300 feet below mean sea level. 
Recharge to the Deep Aquifer is estimated at between 1.73 and 3.46 
million gallons per day.
    Ground water quality data was sampled from 72 wells in the aquifer 
area. In general, deeper wells exhibited higher specific conductance 
values. Elevated chloride concentrations were found in near-shore wells 
on the northern and eastern edges of the Island. Ground water quality 
trend data is limited, but combined water system and spring data 
indicate that source water nitrate concentrations show a generally 
increasing trend.
    The sand interbeds within the surficial glacial till deposits allow 
easy infiltration, and although discontinuous, make much of the 
Principal Aquifer vulnerable to contamination. The Deep Aquifer is also 
vulnerable to contamination from activities occurring on the land 
surface, as evidence suggests that it receives recharge from the 
Principal Aquifer.
    Potential sources of contamination include landfill leachate, on-
site sewage disposal systems, leaky sewer lines, underground storage 
tanks, agricultural chemicals, small hazardous waste generators, 
accidental spills, seawater intrusion, and improper household, forestry 
and farm practices.
    The Island has one publicly-owned water well (the largest water 
system on the Island), at least six large private water systems, and 
more than 100 smaller water systems. Some purveyors use both surface 
water and ground water to supply their distribution system. In 
addition, private wells provide water to a considerable number of 
houses and businesses across the Island. It is estimated that 71% of 
the water supplied to households on the Island is from ground water and 
29% is from surface water sources. There are no alternative sources of 
drinking water for the Island that can be physically, legally, and 
economically supplied.

IV. Project Reviews

    Designation of a sole source aquifer authorizes EPA to review 
federal financially-assisted projects proposed within the designated 
area. The principal mechanism used by EPA Region 10 to identify 
projects for review are Memorandums of Understanding (MOUs) with 
federal funding agencies. These MOUs outline procedures for screening 
and referring projects to EPA in order to ensure that only projects 
which may have a significant impact to ground water quality are 
reviewed.
    Most projects referred to EPA for review meet all federal, state, 
and local ground water protection standards and are approved without 
any additional conditions being imposed. Occasionally, site or project-
specific concerns for ground water quality protection lead to specific 
recommendations or additional pollution prevention requirements as a 
condition of funding. In rare cases, federal funding has been denied 
when the applicant has been either unwilling or unable to modify the 
project.
    Whenever feasible, EPA coordinates the review of proposed projects 
with other offices within EPA and with various federal, state, or local 
agencies that have a responsibility for ground water quality 
protection. Relevant information from these sources is given full 
consideration in the sole source aquifer review process. Such 
coordination can complement, support, and strengthen existing ground 
water protection mechanisms.

V. Public Comments

    EPA issued a news release (April 12, 1994) and a public notice 
(April 14, 1994) to request comments and announce the proposed 
designation. Both stated that a public hearing would be held if 
sufficient interest were expressed to EPA in advance. No requests for a 
formal hearing were received and it was subsequently cancelled.
    Five written comments were received prior to the expiration of the 
public comment period on June 1, 1994. Three letters were from Vashon 
Island residents and expressed support for the proposed designation. 
One letter was from the King County Department of Public Works, Roads 
and Engineering Division, and requested information and coordination of 
future federal financially-assisted road projects on the Island. 
Another letter was from the Bureau of Reclamation and stated there were 
no ongoing or proposed federal financially-assisted projects within the 
area. No controversial issues were raised as a result of this proposed 
action.

VI. Summary

    This determination affects only the Vashon-Maury Island Aquifer 
System located in King County, Washington. As a result of this 
determination, all federal financially-assisted projects proposed in 
the designated area will be subject to EPA review to ensure that they 
do not create a significant hazard to public health.

    Dated: June 17, 1994.
Chuck Clarke,
Regional Administrator, U.S. Environmental Protection Agency, Region 
10.
[FR Doc. 94-16220 Filed 7-1-94; 8:45 am]
BILLING CODE 6560-50-P