National Nuclear Security Administration Office of Los Alamos Site Operations; Floodplain Statement of Findings for the Proposed Access Control and Traffic Improvements at Los Alamos National Laboratory, Los Alamos, NM

AGENCY:

National Nuclear Security Administration, Office of Los Alamos Site Operations, Department of Energy.

ACTION:

Floodplain Statement of Findings.

SUMMARY:

This Floodplain Statement of Findings is for the construction and operation of proposed access control and traffic improvements at Los Alamos National Laboratory (LANL). Construction actions could occur near and over the floodplains of Mortandad and Los Alamos Canyons; there would be no action within established wetland areas (see Figure 1). In accordance with 10 CFR Part 1022, the Department of Energy (DOE), National Nuclear Security Administration (NNSA) Office of Los Alamos Site Operations has prepared a floodplain/wetland assessment and will perform this proposed action in a manner so as to avoid or minimize potential harm to or within the affected floodplains.

FOR FURTHER INFORMATION CONTACT:

Elizabeth Withers, U.S. Department of Energy, National Nuclear Security Administration, Office of Los Alamos Site Operations, 528 35th Street, Los Alamos, NM 87544. Telephone (505) 667-8690; facsimile (505) 667-9998; or electronic address: ewithers@doeal.gov. For Further Information on General DOE Floodplain Environmental Review Requirements, contact: Carol M. Borgstrom, Director, Office of NEPA Policy and Compliance, EH-42, Department of Energy, 100 Independence Avenue, SW., Washington DC 20585-0119. Telephone (202) 586-4600 or (800) 472-2756, facsimile (202) 586-7031.

SUPPLEMENTARY INFORMATION:

In accordance with DOE regulations for compliance with floodplain and wetlands environmental review requirements (10 CFR part 1022), NNSA prepared a floodplain/wetland assessment for this action. The NNSA included the floodplain/wetland assessment document as part of an Environmental Assessment issued on July 23, 2002 by the NNSA. No comments were received on the proposed floodplain action.

Project Description: NNSA considered a proposal for the construction of various access control and traffic improvements to be installed at Los Alamos National Laboratory (LANL). One of the elements of the proposed action would be the construction of a short road around the east side of Technical Area 3 at LANL along the mesa tops. Bridges would be constructed from either side of the road to span over floodplains located at the heads of Mortandad and Sandia Canyons. No actions would be taken directly in the floodplains nearby. This project is estimated to occur over the next three years from 2003 through 2005.

Alternatives: The No Action Alternative was considered. Under the No Action Alternative access control into LANL would continue to be provided by the implementation of temporary measures as needed. No safety improvements of the intersections would be undertaken.

Floodplain Impacts: The proposed action would have the potential for minimal impacts on the floodplains. Should a rain event occur during construction activities, there may be some sediment movement down canyon because of the loosened condition of the soil from the clearing and construction activities.

Floodplain Mitigation: Placement of Best Management Practices (such as silt fences, straw bales or wattles, or wooden or rock structures to slow down water runoff and run-on at cleared sites) at the construction areas and post-construction reseeding and re-vegetation of the construction sites will minimize soil disturbance and reduce or prevent the potential for soil erosion. Upon completion of the construction activities the downstream flow and function of the floodplain will not be impeded. No debris will be left at the work site. No vehicle maintenance or fueling within 100 feet of the floodplain would occur. Any sediment movement from the sites would be short term and temporary.