[Federal Register Volume 63, Number 41 (Tuesday, March 3, 1998)]
[Notices]
[Pages 10367-10368]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-5422]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF ENERGY


Floodplain and Wetlands Involvement Notification for the A-01 
Outfall Constructed Wetlands Project at the Savannah River Site (SRS)

AGENCY: Department of Energy (DOE).

ACTION: Notice of floodplain and wetlands involvement.

-----------------------------------------------------------------------

SUMMARY: DOE proposes to construct and operate an artificial wetlands 
to treat effluent from the A-01 outfall located on SRS. The A-01 
effluent has consistently not met proposed outfall limits which will 
become effective on October 1, 1999. DOE needs to reduce the copper and 
chronic toxicity levels in the effluent to ensure compliance when these 
proposed outfall limits go into effect. It has been determined that a 
subsurface flow wetlands and an associated detention basin would 
adequately treat the effluent to meet the new discharge limits. As part 
of the proposed project activities, a new outfall structure would be 
constructed within the 100-year floodplain and wetlands associated with 
Tim's Branch, the headwaters stream into which the treated effluent 
would be discharged. These activities would necessitate temporary 
construction access, construction of the new outfall structure, and 
placement of riprap material in this drainage corridor. In accordance 
with title 10 CFR part 1022, DOE will prepare a floodplain and wetlands 
assessment and will perform this proposed action in a manner so as to 
avoid or minimize potential harm to or within the affected floodplain 
or wetlands.

DATES: Comments on the proposed action due on or before March 18, 1998.

ADDRESSES: Comments regarding this assessment should be addressed to 
Andrew R. Grainger, National Environmental Policy Act (NEPA) Compliance 
Officer, Savannah River Operations Office, Building 773-42A, Room 212, 
Aiken, South Carolina 29808. The fax/phone number is (800) 881-7292. 
The e-mail address is [email protected].

FOR FURTHER INFORMATION ON GENERAL FLOODPLAIN/WETLANDS ENVIRONMENTAL 
REVIEW REQUIREMENTS, CONTACT: Ms. Carol M. Borgstrom, Director, Office 
of NEPA Policy and Assistance (EH-42), U. S. Department of Energy, 1000 
Independence Avenue, SW., Washington, DC 20585. Telephone (202) 586-
4600 or (800) 472-2756.
    A location map showing the project sites and further information 
can be obtained from the Savannah River

[[Page 10368]]

Operations Office (see ADDRESSES above).

SUPPLEMENTARY INFORMATION: The recent issuance of the revised National 
Pollutant Discharge Elimination System (NPDES) permit for SRS by the 
South Carolina Department of Health and Environmental Control (SCDHEC) 
established new outfall limits for copper, lead, mercury, and chronic 
toxicity which will become effective on October 1, 1999. Subsequent to 
SCDHEC issuing the revised permit, samples taken at the A-01 outfall 
have resulted in the effluent consistently not meeting the new 1999 
outfall limits for copper and chronic toxicity. DOE needs to implement 
actions to reduce these concentrations prior to that time when the new 
outfall limits are scheduled to go into effect. Extensive research has 
indicated that a constructed subsurface flow wetlands with an 
associated detention basin would treat these constituents and reduce 
the concentrations below the new permit limits before the effluent 
reaches the NPDES compliance sampling point.
    The proposed action entails the construction, and operation of the 
following: (1) A system of pipes to collect the process and storm water 
effluent from the local outfalls (i.e., A-01, A-03, A-04, A-05, and A-
06), (2) a subsurface flow wetlands/detention basin complex to treat 
the effluent from these outfalls, and (3) an outfall system to 
discharge the treated effluent into Tim's Branch, the previously-
established onsite receiving stream for the subject outfalls. The A-01 
sampling point monitored by both SRS and SCDHEC would be relocated from 
the current location to the new outfall structure prior to the effluent 
flow entering the waters of the State.
    Construction of the collection pipeline and subsurface flow 
wetlands/detention basin complex would involve the siting and 
implementation of these project components in upland areas above the 
floodplain and wetlands areas associated with Tim's Branch. These 
upland sites are currently occupied by either planted pine forest or 
previously-developed area (e.g., graveled parking lots). The pine 
forest, dominated by a mature overstory of longleaf pine (Pinus 
palustris), has been managed by the U.S. Forest Service over the past 
four decades for timber production purposes only. Best management 
practices (e.g., placement of silt fences) would be employed during 
construction activities associated with this portion of the proposed 
action to ensure there is no deposition of erosional material or 
sediment into the downslope wetland areas.
    Construction of the new outfall discharging into Tim's Branch would 
entail placement of an outflow pipe from the wetlands/basin complex, 
construction of an outfall structure on the margin of the stream 
channel, and placement of riprap within the streambed itself to prevent 
erosion and scouring by the discharged effluent. The location of the 
proposed new outfall would be on the south side of the Tim's Branch 
stream corridor. The width of wetland area within that portion of the 
stream corridor is approximately two to four meters. The stream channel 
is deeply cut into the bottomland and the streambed is situated 
approximately one to two meters below the grade of the surrounding 
forest floor. These wetlands are characterized by a headwaters drainage 
habitat dominated by an overstory of sweetgum (Liquidambar 
styraciflua), water oak (Quercus nigra), and hickory (Carya spp.). 
Hydrology is provided through effluent from the local NPDES outfalls 
and storm water runoff from the surrounding higher elevation lands. The 
soils within the stream channel appear to be largely erosional sediment 
in composition. The project activities to be located immediately on the 
south side of Tim's Branch and within the streambed itself are also 
located within the 100-year floodplain. Proceeding with this proposed 
action will require authorization by the U.S. Army Corps of Engineers 
under a Clean Water Act Section 404 nationwide permit.
    A number of mitigation activities would be implemented to minimize 
potential impacts to the floodplain and wetlands. Operation of 
construction equipment in the wetland and floodplain areas would be 
minimized. Silt fences and other erosion control structures as needed 
would be installed to ensure there is no deposition in the downslope 
wetland areas. Minimal wetland acreage (i.e., less than 0.3 acres) 
would be impacted as a result of fill associated with the 
aforementioned outfall structure and placement of riprap material in 
the streambed.
    Additionally, an erosion control plan would be developed so that 
the proposed action complies with applicable State and local floodplain 
protection standards and further to ensure that no additional impacts 
to wetlands will occur due to erosion and sedimentation. Best 
management practices would be employed during construction and 
maintenance activities associated with this proposed action.
    In accordance with DOE regulations for compliance with floodplain 
and wetland environmental review requirements (title 10 CFR Part 1022), 
DOE will prepare a floodplain and wetlands assessment for this proposed 
DOE action. The assessment will be included in the environmental 
assessment (EA) being prepared for the proposed action in accordance 
with the requirements of NEPA. A floodplain statement of findings will 
be included in any finding of no significant impact that is issued 
following the completion of the EA or may be issued separately.

    Issued in Aiken, SC, on February 19, 1998.
Lowell E. Tripp,
Director, Engineering and Analysis Division, Savannah River Operations 
Office.
[FR Doc. 98-5422 Filed 3-2-98; 8:45 am]
BILLING CODE 6450-15-P