Degraded Bay Area Pipes Cause of Wastewater Spills

The cities of Almonte, Tamalpais, Alto, Homestead Valley and Richardson Bay were found to have damaged collection systems which affect operations of the Sewerage Agency for Southern Marin, SASM, wastewater plant and its discharge to San Francisco Bay waters.

The EPA last week finalized and released inspection reports for five of six sewage collection systems that flow to the Sewerage Agency for Southern Marin wastewater facility.

"The public may be surprised to learn we have many neglected sewage collection systems, which are small, underfunded and undermanaged. These systems will continue to pose threats to San Francisco Bay if communities fail to upgrade and maintain their systems sustainably," said Alexis Strauss, the EPA's Water Division director for the Pacific Southwest region.

"We at the EPA will continue, as we've done elsewhere in California, to work with the California Regional Water Quality Control Boards and the systems directly to achieve long-overdue assessment, repair and replacement," she said.

"The best way to deal with sewer spills is to prevent them from ever occurring," said John Muller, chair to the San Francisco Bay Regional Water Board. "I would prefer to work with local government and other leaders to make sure the Bay Area has the finest infrastructure possible. That is how we all should protect water quality."

On Friday the Regional Water Board issued an order to the Sewerage Agency for Southern Marin requiring a full report on the recent spills to the Bay, and requiring the agency to audit its operations. The audit report is due April 7.

Deteriorating pipes, combined with extreme peak flows from rainwater, overwhelmed the SASM facility, causing the January 25 flows to exceed capacity at the emergency holding basins at the plant, and overflow to San Francisco Bay waters.

The subsequent January 31 spill occurred when the treatment plant failed to operate all of its discharge pumps designed to achieve higher levels of treatment offsite, leading to another spill to Bay waters.

The SASM Board of Directors, upon the recommendation of SASM General Plant Manager Steve Danehy, has authorized an independent investigation to review plant operations and procedures as well as the recent sewage spill and controlled release into Richardson Bay.

The plant is undertaking immediate preventative actions to minimize the occurrence of future spills. Internal notification procedures and notifications to the Regional Water Quality Control Board, the County Health Office, the SASM Board, Mill Valley's Dity Manager, and local cities will be simplified.

When sewage spills occur, prompt posting of affected beaches is required to protect the public. County health departments should be prepared to post waterways immediately when these types of discharges occur.

The City Manager's office will contact local media and post information on the City's website. A quantity of signs will be permanently available to plant staff to post in the incidence of a spill or overflow. City staff from other departments will be available to assist in shoreline posting if needed.

All Treatment Plant staff have been put on notice by the Plant Manager that staffing will be set up in the event of a storm for 24 hour coverage with 2 people on shift.

Critical equipment such as effluent pumps shall be set up in the automatic mode, regardless of the time of year.

The Sewerage Agency of Southern Marin treats wastewater from about 28,000 people in the Mill Valley area. The sewage is collected from homes and businesses in networks of sewer pipes that are owned and maintained by five separate sanitary districts and the city of Mill Valley.

To view the inspection reports, visit: http://www.epa.gov/region09/water/npdes/compliance.html

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