NNSA NEWS RELEASE
The Department of Energy National Nuclear Security Administration’s (NNSA) Los Alamos Field Office has issued a Floodplain Statement of Findings for proposed installation of a three-strand smooth wire fence intended to create an operational boundary between the public and direct access to the High Explosive (HE) Transfer Facility. The proposed fencing would be installed from a former spur of Anchor Ranch Road to the existing chain link fence north of X-Ray Road. The fence would cross approximately 60 feet of the Pajarito Canyon 100-year floodplain.
The fence would be installed in a radius of 1250 feet minimum distance from the HE Transfer Facility. NNSA’s is proposing to transport fence materials including t-posts and wire to the area outside the floodplain by wheeled all-terrain vehicles. Existing two-track roads and trails would be used wherever possible. Materials would be transported into the floodplain by hand. T-posts would be installed by hand with a fence post driver. LANL civil engineering standards require that T-post type metal fence posts would be driven into the ground at intervals of no more than 16 feet and to a depth of no less than 36 inches. The project estimates the posts would be set at approximately 10 feet intervals. The Pajarito Canyon 100-year floodplain is approximately 60 feet wide at the location where the fence crosses the floodplain. Therefore, there should be no more that five to six posts installed in the floodplain. Posts would be installed outside of the stream channel.
NNSA has reevaluated the proposed action and found that there are no alternatives that would locate the proposed action outside a floodplain and identified mitigation measures that would avoid or minimize impacts to the floodplain.
NNSA did not receive any public comments during the 15-day Floodplain Assessment public review and comment period. Upon completion of the proposed action the floodplain will retain the same values and functions as present prior to the fence installation. The Statement of Findings can be accessed online at https://www.energy.gov/nepa/articles/los-alamos-national-laboratory-floodplain-statement-findings-high-explosive-transfer.