Annual Long-term Monitoring Status Report for the Los Alamos County Airport Landfill Cover System Replacement

LOCATION: Los Alamos National Laboratory, NM

CLIENT: Newport Nuclear News BWXT – Los Alamos (N3B)

The Evapotranspiration (ET) Landfill Cover located at the Los Alamos County Airport was completed in 2016 and is currently in the fifth year of an initial five (5)-year performance monitoring period. In accordance with “Long Term Monitoring Plan (LTM Plan), Los Alamos County Airport Landfill Cover Replacement, Solid Waste Management Units 73-001(a,d), Technical Area 73”, dated March 2017, inspections of the landfill cover are performed in various time frames to assess the general condition of the closure system and to identify any maintenance or repair issues. The results of these inspections are documented in an annual report that is submitted to the New Mexico Environment Department in accordance with the Resource Conservation and Recovery Act.

BGI has been tasked to prepare the annual reports for 2019-2020 and 2020-2021. The Year 4 annual inspection report has been submitted and the Year 5 report is being prepared. The BGI Team is utilizing data and quarterly inspection reports provided by N3B. Inspections included water balance and methane monitoring, surface water control features, erosion controls, and site access control. The cover systems are currently in good condition and working as designed. There was some minor rill erosion noted at the base of the eastern side slope of the landfill at the end of Year 4. Measures taken including the installation of multiple rows of wattles have worked to mitigate further rill and gully erosion in the area.