Heavy rains cause Sonoma Valley wastewater overflows

Sonoma County Water Agency, SONOMA COUNTY GAZETTE

Heavy rainfall from a large atmospheric river resulted in several wastewater overflows within the Sonoma Valley County Sanitation District (District). Nearly 2 inches of rain was measured during a 24-hour period ending Tuesday at 9 a.m. at the Sonoma Valley wastewater treatment plant. Other areas of the valley reported 3 inches of rain overnight.

Wastewater maintenance and work crews, including biologists, responded to nine separate sanitary sewer overflows (SSOs) starting at 2:30 a.m. Tuesday. Sanitation District staff are working to minimize the flows as much as possible, evaluate any impacts to public and environmental health, and will continue to monitor the collection systems.  The State Office of Emergency Services and California Department of Fish & Wildlife were notified.

The majority of the SSOs occurred in the Boyes Hot Springs and Fetters Hot Springs areas, with two overflows in Eldridge. Several of the overflows resulted in wastewater flowing into Sonoma Creek. One reported SSO at the Sonoma Charter School and Flowery Elementary School campus was determined to be a private overflow resulting from a failure of the collection system on school district property. Total volume of the overflows will be calculated at the end of the storm event.

During heavy rain events the District’s wastewater collection system can become overloaded due to inflow and infiltration of rainwater and groundwater into sewer mains. The District is currently implementing a multi-year sewer main replacement project. Another contributing factor to SSOs, which is being addressed by the District, is leaky private sewer laterals and illegal connections of roof downspouts, yard drains, sump pumps and other non-sewer discharges into the sewer system that can greatly increase the amount of wastewater entering the system during storms. The SVSCD Board recently approved an ordinance that will require older laterals to be inspected and repaired, if necessary.

Read more at: Heavy Rains Cause Sonoma Valley Wastewater Overflows