This project will remove a failed septic tank (excavation will be within previously disturbed area) and install a temporary lift station to provide sanitary service for the Mather tent cabins (near the Hetch Hetchy entrance station). The shower/laundry building and restrooms servicing the four tent cabins in the area all discharge to the failing septic system. A new fiberglass or concrete wet well will be installed at the same location. A small duplex pump system will be installed inside the wet well. The pump controls and alarm will be installed on a panel immediately adjacent to the wet well. Power will be extended from the laundry building (building 2015) to the wet well (no change in overall service to the area is anticipated). The power extension will require installation of conduit on the ground surface with a rubberized mat for protection. A plastic or fiberglass temporary holding tank will be installed above ground between the existing restroom buildings. An above ground force main pipe (1.5 inch HDPE pipe) will connect the holding tank and wet well.
The construction of the temporary facilities will be performed by an outside contractor to help facilitate these emergency repairs in a time frame that supports the park's needs. The holding tank will be emptied on a regular basis while the tent cabins are occupied.
This is a temporary solution and the long-term NEPA/NHPA compliance will be addressed when plans are finalized.