Groundwater Monitoring Well R-76 Well Pad Construction, Well Drilling, and Well Installation

The proposed action would include constructing a drill pad, drilling, and installing a monitoring well, and developing the well. The objectives of the proposed actions are to install a groundwater monitoring well to monitor the depth and extent of hexavalent chromium in the regional aquifer. Pursuant to 10 Code of Federal Regulations Part 1022, the 15-day public comment period for this proposed floodplain action commences with publication of this notice and will conclude on October 7, 2022. Following the conclusion of the public comment period, EM-LA will reevaluate alternatives to the proposed floodplain action and the mitigating measures, taking into account all substantive comments received, and prepare a floodplain statement of findings. To submit comments, please email EMLA-NEPA@em.doe.gov. The primary objective for well R-76 is to replace the monitoring capability provided by groundwater monitoring well R-28. In accordance with a July 2017 work plan approved by NMED, a study was conducted at well R-28 of the potential for molasses to be applied in the aquifer as an agent for initiating geochemical reduction that would result in in situ conversion of hexavalent chromium to trivalent chromium (LANL 2017, NMED 2017). Data collected from well R-28 as part of the study showed that the intended chromium reduction was achieved; however, geochemically reducing conditions have persisted in the aquifer around the well, making it unsuitable for water quality monitoring, especially for reduction/oxidation-sensitive constituents, such as chromium and nitrate Replacement of well R-28 will provide for monitoring in an important area of the hexavalent chromium plume where hexavalent chromium concentrations have historically been in the 400-ppb range. Well R-76 will also provide for long-term performance monitoring for hexavalent chromium and related constituents as part of future remediation efforts. An additional objective for well R-76 is to characterize the vertical extent of contamination in the same area of the plume by including a second screened interval at a depth within the Chamita Formation. Well R-76 will be drilled to an approximate depth of 1080 ft below ground surface.

Division 03 -	Concrete.
Division 04 -	Masonry.
Division 05 -	Metals.
Division 06 -	Wood, Plastics, and Composites.
Division 07 -	Thermal and Moisture Protection.
Division 08 -	Openings.
Division 09 -	Finishes.
Division 10 -	Specialties, Signage, Toilet, Bath, and Laundry Accessories, Fire Protection Specialties, Fire Extinguishers, Storage Specialties.
Division 11 -	Equipment.
Division 12 -	Furnishings.
Division 14 -	Conveying Equipment, Scaffolding.
Division 21 -	Fire Suppression.
Division 22 -	Plumbing.
Division 23 -	Heating, Ventilating, and Air Conditioning (HVAC).
Division 26 -	Electrical.
Division 27 -	Communications, Data Communications, Voice Communications, Audio-Video Systems.
Division 28 -	Electronic Safety and Security.
Division 31 -	Earthwork.
Division 32 -	Exterior Improvements, Fences and Gates, Turf and Grasses.
Division 33 -	Utilities, Common Work Results for Utilities, Water Utility Distribution Equipment, Water Utility Pumping Stations, Wastewater Utility Pumping Stations, Sanitary Utility Sewerage Force Mains.
Division 40 -	Process Integration, Water Process Piping.
Division 45 -	Industry-Specific Manufacturing Equipment.
Division 46 -	Water and Wastewater Equipment.