Notice of Wetland Involvement for Interim Measures for the Mixed Waste Management Facility (MWMF) Groundwater at the Burial Ground Complex (BGC), Savannah River Site, Aiken, South Carolina

DEPARTMENT OF ENERGY

Notice of Wetland Involvement for Interim Measures for the Mixed

Waste Management Facility (MWMF) Groundwater at the Burial Ground

Complex (BGC), Savannah River Site, Aiken, South Carolina

AGENCY: Savannah River Operations Office (SR), Department of Energy

(DOE).

ACTION: Notice of wetland involvement.

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SUMMARY: DOE-SR proposes to install a small metal sheet pile wall dam

which would be positioned to impound about 0.49 hectares (1.2 acres) of

water around and over the BGC southwest groundwater seepline. This

action would be taken in cooperation with the South Carolina Department

of Health and Environmental Control (SCDHEC) to reduce the amount of

tritium contaminated water seeping to the surface from the BGC

southwest plume and eventually discharging to Fourmile Branch, an

onsite stream. This interim measure is intended to control the movement

and discharge of contaminated groundwater until the final, more

permanent corrective measure is taken. In accordance with 10 CFR 1022,

DOE will prepare a wetland assessment and will perform this proposed

action in a manner so as to avoid or minimize potential harm to or

within the affected wetland.

DATES: Comments on the proposed action due on or before August 4, 1999.

ADDRESSES: For further information, including a site map and/or copy of

the wetland assessment, or to submit comments regarding this notice,

contact A. R. Grainger, National Environmental Policy Act (NEPA)

Compliance Officer, Savannah River Operations Office, Building 742-A,

Room 185, 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.

SUPPLEMENTARY INFORMATION: A groundwater contaminant plume has been

detected and is emanating from the Old Radioactive Waste Burial Ground

(ORWBG) which is located at the southwest corner of the BGC at SRS.

Tritium-contaminated water from this southwest plume is seeping to the

surface at areas along the Old F-Area Effluent Ditch (OFED). Currently,

groundwater that emanates from this seep combines with surface drainage

from the immediate area to form a small stream in the southern portion

of the OFED. Eventually, this stream mixes with F-Area discharge water

which then flows into Fourmile Branch, an onsite stream.

DOE-SR proposes to install a small metal sheet pile wall dam

[approximately 1.5 to 2.1 meters (5 to 7 feet) high and 100.6 meters

(330 feet) long] which would be positioned to impound about 0.49

hectares (1.2 acres) of water around and over the BGC southwest

groundwater seepline. The impounded 0.49 hectares (1.2 acres) has been

determined to be jurisdictional wetlands. The proposed action is not

within the 100-year or baseline floodplain.

This action would be taken in cooperation with SCDHEC to reduce the

amount of tritium-contaminated water seeping to the surface and

eventually discharging to Fourmile Branch. The impoundment would retard

surface water flow to Fourmile Branch by increasing travel time,

thereby mitigating the discharge of tritium-contaminated water. In

addition, a drip irrigation system is being evaluated to enhance the

effectiveness of the interim measure. This feature would further

minimize discharges to Fourmile Branch by pumping impounded water

behind the dam during peak flow conditions to upstream locations.

The interim measure will also address the remediation of volatile

organic compounds (VOCs) from ``hotspot'' regions associated with the

southwest plume area. Airlift recirculation wells will be installed in

``hotspot'' regions where concentrations of VOCs have routinely

exceeded drinking water standards. Airlift recirculation wells provide

a means for removing VOCs from contaminated groundwater, through a

combination of in place air stripping and airlift pumping processes.

This interim measure is intended to control the movement and

discharge of contaminated groundwater until the final, more permanent

corrective measure is taken.

Undertaking the proposed action will not affect DOE's ability to

fully evaluate reasonable alternatives for the final action. An

Environmental Assessment (EA) will also evaluate several alternatives

to the proposed action.

In accordance with DOE regulations for compliance with wetland

environmental review requirements (10 CFR 1022), DOE-SR will prepare a

wetland assessment for this proposed DOE action. The assessment will be

included in the EA (DOE/EA-1302) that is being prepared for the

proposed action in accordance with the requirements of NEPA.

Issued in Aiken, SC, on July 7, 1999.

Lowell E. Tripp,

Director, Engineering and Analysis Division, Savannah River Operations

Office.

[FR Doc. 99-18432 Filed 7-19-99; 8:45 am]

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