LANL News:

This floodplain assessment has been prepared for two projects by two separate proponents in Los Alamos County.

Portions of the project are located on Department of Energy property. One project is the construction and operation of a new water supply line within the right-of-way of New Mexico Highway 4 (N.M. 4) by Los Alamos County’s Department of Public Utilities. The other project is the installation of a fiber optic conduit and cable within the right-of-way of N.M. 4 and New Mexico Highway 502 (N.M. 502) by Pueblo de San Ildefonso.

The two project proponents are working together to install the waterline and the fiber optic cable in the same trench along N.M. 4 in order to minimize ground disturbance and to take advantage of the opportunity to streamline permitting and construction. The segment of the Pueblo’s fiber optic cable planned for installation along N.M. 502 would start just east of the Pueblo’s eastern boundary, where it would connect to existing fiber optic infrastructure, and proceed west to the north side of the interchange with N.M. 4, where it will then cross under N.M. 502 and go into the County’s waterline trench.

The project activities within the 100-year floodplain include:

• 1) excavation of a trench;
• 2) installation of 12-inch and 16-inch PVC-coated ductile iron pipe and associated fittings;
• 3) partial backfilling and compaction;
• 4) placement of a PVC fiber optic conduit above and to the side of the new pipeline; and
• 5) final backfilling, compaction, and surface grading of the trench. They also include horizontal drilling beneath some segments of the 100-year floodplain.

DOE/NNSA has published this Floodplain Assessment for a 15-day public review and comment period. The document is available here.

Please provide comments on this Floodplain Assessment to Kristen Dors at:

• Email: kristen.dors@nnsa.doe.gov
  Mail: U.S. Department of Energy
  Los Alamos Field Office
  ATTN: Kristen Dors
  3747 West Jemez Road Los Alamos, NM 87544
• After the close of the public comment period and prior to issuing a floodplain statement of findings, DOE/NNSA will reevaluate the practicability of alternatives to the proposed floodplain action, mitigating measures, and take into account all substantive comments received during the public comment period. DOE/NNSA will endeavor to allow 15 days of public review prior to implementation of the proposed action.