Solutions for Progress 

Antidegradation Analyses

RBI worked closely with Central Valley Regional Water Quality Control Board (Regional Water Board) staff and management to develop the approach to conducting antidegradation analyses that Board staff now require for new or expanded-capacity discharges. Antidegradation analyses assess water quality degradation of proposed new or expanded discharges and evaluate whether the expected water quality degradation is justifiable based on socioeconomic considerations, consistent with both state and federal antidegradation policies. To determine whether the proposed facility meets best practicable treatment and control (BPTC) requirements, antidegradation analyses is used to evaluate project alternatives and potential options to minimize degradation. RBI has completed antidegradation analyses for the following clients:

  • El Dorado Irrigation District – RBI assessed potential degradation of Carson Creek from an increased permitted capacity for the El Dorado Hills Wastewater Treatment Plant. The assessment quantified water quality changes, effects on beneficial uses, and socioeconomic and water quality implications of implementing project alternatives.
  • Ironhouse Sanitary District – RBI assessed potential 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 both surface water, associated with 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. The analysis focused on impacts to aquatic life and the socioeconomic implications of alternatives to year-round 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.