RBI worked closely with Central Valley Regional Water Quality Control Board staff and management to develop the approach to antidegradation analyses that Board staff require to issue NPDES permits and waste discharge requirements for new or expanded-capacity discharges. Antidegradation analyses assess water quality degradation of proposed new or expanded discharges, effects of the anticipated degradation on receiving water beneficial uses, and whether the water quality degradation is justifiable based on socioeconomic considerations, consistent with both state and federal antidegradation policies. RBI has completed antidegradation analyses for the following clients.
- City of Turlock – RBI assessed water quality degradation from a new seasonal discharge of recycled water produced by the City of Turlock's Regional Water Quality Control Facility to Turlock Irrigation District's Lateral 4 to supplement irrigation supplies.
- City of Brentwood – RBI assessed water quality degradation in Marsh Creek associated with an increased permitted discharge rate for the City of Brentwood Wastewater Treatment Plant due to planned expansion in treatment capacity.
- El Dorado Irrigation District – RBI assessed potential degradation of Carson Creek from an increased permitted discharge rate for the El Dorado Hills Wastewater Treatment Plant due to planned expansion in treatment capacity.
- Ironhouse Sanitary District – RBI assessed water quality degradation from a new discharge to the tidally-influenced San Joaquin River and the infeasibility of expanding existing reclamation, thereby justifying the need for the new surface water discharge. This analysis evaluated degradation to surface water from the new discharge to the river and groundwater from land disposal practices.
- City of Galt – RBI analyzed water quality degradation associated with year-round discharge versus historical seasonal discharge and expanded capacity discharge.
- County of Placer – RBI assessed water quality degradation to Rock Creek and Dry Creek from the expansion and upgrade of the County’s Sewer Maintenance District No. 1 facility.