Design of Wastewater System

Lake Berryessa, Napa, California

WEST provided design engineering and permitting for the expansion of the Putah Creek Resort wastewater disposal system. Putah Creek Resort is a concessionaire of the United States Bureau of Reclamation located on Lake Berryessa in Napa County, California. The Resort includes approximately 150 mobile homes, 27 motel units, 80 camp sites, a store and restaurant. The Resort operates their own water supply and wastewater collection and disposal systems. Historical operational problems led to releases of wastewater in violation of the State regulations.

WEST conducted extensive studies of the existing wastewater collection and disposal system to identify contributions of infiltration and inflow and limitation to disposal capacity. Studies were also required to demonstrate that the system could be operated without impacts to human health and the environment.

WEST modeled the aerosol transport and was able to demonstrate that the disposal system would not have detrimental impacts. Based on the studies, WEST designed and permitted the expansion of the pond system, replacement of the lift station pumps, and installation of in-pond evaporative spray system that has met disposal capacity requirements. WEST filed for new Waste Discharge Requirements from the California Regional Water Quality Control Board and was able to get them adopted on an expedited schedule.