Notice of Floodplain and Wetlands Involvement for Hydrogeological Characterization Studies at the Pantex Plant, Amarillo, TX

DEPARTMENT OF ENERGY

Notice of Floodplain and Wetlands Involvement for Hydrogeological

Characterization Studies at the Pantex Plant, Amarillo, TX

AGENCY: Department of Energy (DOE).

ACTION: Notice of floodplain and wetlands involvement.

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SUMMARY: DOE proposes to conduct hydrogeological characterization

studies, some of which would be within floodplains and wetlands within

the borders of or surrounding the Pantex Plant in Carson County, 17

miles northeast of Amarillo, Texas. In accordance with 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 and wetlands.

DATES: Comments on the proposed action must be received by June 30,

1994.

ADDRESSES: Comments concerning this Notice should be addressed to:

Floodplain and Wetlands Comments, Tom Walton, Public Affairs Office,

U.S. Department of Energy, Amarillo Area Office, P.O. Box 30020,

Amarillo, Texas 79177, (806) 477-3120, (806) 477-3185 (Fax).

Information on this proposed action, including a map of proposed

sampling locations, is also available.

FOR FURTHER INFORMATION CONTACT: Information on general DOE floodplain

and wetlands environmental review requirements is available from: Carol

M. Borgstrom, Director, Office of NEPA Oversight, U.S. Department of

Energy, 1000 Independence Avenue SW., Washington, DC 20585, (202) 586-

4600, (800) 472-2756.

SUPPLEMENTARY INFORMATION: DOE proposes to conduct a hydrogeological

characterization study within floodplains and wetlands on and

surrounding the Pantex Plant. The characterization studies would be

conducted in support of the Permit for Industrial Solid Waste

Management Site issued by the Texas Water Commission (now known as the

Texas Natural Resources Conservation Commission) as part of DOE's

effort to determine the nature and extent of any environmental

contamination resulting from Pantex operations. On-site activities

would occur within Solid Waste Management Units (SWMU) 6 (Playa Basin

1), SWMU 7 (Playa Basin 2), SWMU 8 (Playa Basin 3), SWMU 9 (Playa Basin

4), and SWMU 10 (Pantex Lake). Off-site activities would occur at Playa

5, located 2 miles southwest, and the Playa owned by the Texas

Department of Criminal Justice, located 4.5 miles northeast of the

Pantex Plant. On- and off-site activities would be conducted by the

State of Texas under an Agreement in Principle with the DOE. The

characterization studies occurring near or in the floodplain and

wetlands would include:

1. Drilling boreholes for the purpose of collecting core samples

from the playa basins.

2. Routine sampling, downloading, and maintenance of installed

instrumentation.

3. Conducting soil gas surveys in and near the floodplain and

wetlands.

4. Seismic survey activities to define playa basin geologic

structure.

5. Trenching in or near the floodplain and wetlands for the

installation of soil moisture instrumentation such as: thermocouple

psychrometers, tensiometers, and Time Domain Reflectometers (TDR).

6. Trenching in and near the floodplain and wetlands to perform

chemical (food coloring) tracer tests.

7. Surveying activities to define playa basin topography.

A more specific description of the seven activities listed above

follows:

1. Borehole drilling would involve driving a drilling rig and a

portable core sample laboratory to the site, drilling the boreholes,

and collecting the core samples as the drilling progresses. The

boreholes would be either closed by back-filling with the cuttings, or

completed as soil solution sampling wells or neutron probe access

tubes. The core sample borings will not exceed 120 feet in depth and

the soil solution sampling wells and neutron probe access tubes would

not exceed a maximum depth of 80 feet. Because the playa basin is

ephemeral, drilling activities would only occur during the dry cycle of

the playa.

2. The routine sampling, downloading, and maintenance of installed

instrumentation would involve driving a utility vehicle to the site.

Some instrumentation would be installed in the wetland and would

involve entering the playa during the wet season to take samples and

download data. Personnel entering wet areas of the playa would enter on

foot to avoid undue impact to the floodplain and wetlands.

3. Soil gas surveys would be conducted during both dry and wet

seasons in the playas and would involve driving a utility vehicle near

the playa floor to download soil gas to a portable gas chromatograph.

Personnel entering wet areas of the playa would enter on foot to avoid

undue impact to the floodplain and wetlands.

4. Seismic survey activities would involve driving two utility

vehicles and a tailer mounted weight-drop unit, used as an energy

source, into the playa basin. This activity involves driving across the

playa floor and can only be accomplished when the playa is completely

dry, to minimize undue impact to the floodplain and wetlands.

5,6. Trenching in or near the floodplain and wetlands would involve

driving a truck (larger than ton) and trailer mounted backhoe into the

wetland areas to excavate the trenches. The trenches for the tracer

tests would not exceed 3 meters in depth and would be the appropriate

length and width to satisfy OSHA requirements. The trenches would

remain open as long as the tracer tests are ongoing, and then would be

backfilled and leveled. The trenches for the installation of the soil

moisture instrumentation would not exceed 4.5 feet in depth and would

involve installing TDR and psychrometer probes into the sidewall and

endwall of the trench. These instrument trenches would be backfilled

immediately after the probes are installed. Clean Water Act Section 404

permit authorization has been received for the trenching in these

areas.

7. Surveying activities would involve driving a utility vehicle

carrying equipment into the playa basin. The surveying would be done by

personnel on foot to minimize any potential impact to the floodplain

and wetlands.

In accordance with DOE regulations for compliance with floodplain

and wetlands environmental review requirements (10 CFR part 1022), DOE

will prepare a floodplains and wetlands assessment for this proposed

DOE action which may be incorporated into the appropriate National

Environmental Policy Act documentation. After DOE issues the

assessment, a floodplain statement of findings will be published in the

Federal Register.

Ralph G. Lightner,

Director, Office of Southwestern Area Programs, Environmental

Restoration.

[FR Doc. 94-14552 Filed 6-10-94; 2:00 pm]

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