Sonoma’s sewer system under stress

The underground system for collecting and delivering waste to the water treatment facility faces fines unless we all clean up our act.|

The condition of Sonoma’s sewer lines, and their ability to absorb the new residents and visitors that are expected to arrive with the completion of several housing and hotel projects, has a number of locals worried.

Anne Gomez, who has often appeared before the City Council and Planning Commission to complain about the impact of new visitors and residents on the sewer system, even filed a brief in 2014 threatening a class action lawsuit against the Sonoma Valley County Sanitation District, and while the suit didn’t materialize, Gomez’s core argument remains: “The collection system is broken; adding further stress on it can only create more leakage thus further resulting in more pollution which will immediately cause more threat to the health and safety of the citizens of this state and the environment.”

“As a city we are, at present, in a very vulnerable and precarious situation,” wrote Bob Mosher in a recent letter-to-the-editor to the I-T. “Apparently the (Sonoma Valley Sanitation District) has been paying large penalties for our deficient sewer capacity and continuing to pay these avoidable fees rather than fix the problems.”

These and other recent citizen complaints largely stem from a June 2015 “Cease and Desist” order filed by the California Regional Water Quality Control Board, San Francisco, that found significant failures in the District’s collection system, itemized 46 sanitary sewer overflow (SSO) incidents in five years, and levied a whopping $732,300 in penalties.

While neither denying the SSO incidents nor the fines they’ve received, District representatives point out it’s a more complex picture than might first appear. Grant Davis, the general manager of the Sonoma County Water Agency which has operated the Sonoma Valley Sanitation District since 1994, emphasized that nearly all of the overflows were rainfall-related (the others were due to root infiltration and grease blockage), and there were none in the most recent and very wet winter.

“The District’s SSO problem occurs as a result of excess wet weather infiltration and inflow through leaky sewer pipes. The solution is to fix the leaky pipes and/or increase the size of pipes so that larger pipes can carry more peak wet weather flow.”

In fact the District has been engaged in upgrading the collection system for years, moving northward from the Sonoma Valley Reclamation facility on Eighth Street East, up through the City of Sonoma and the Springs toward Glen Ellen, said Kevin Booker, principal engineer for the Sonoma County Water Agency.

“Since 1994, the district has completed approximately 9.7 miles of major capacity and structural improvement projects at a total cost of $14.9 million,” states a series of talking points the District office issued just this week, possibly in response to press and public questions.

The upgrades include new sewer mains of more durable material, of greater diameter – 24-inch PVC pipes instead of 21-inch reinforced concrete – to increase the carrying capacity and reliability of the sewer collection system.

These include the replacement of the sewer main from Fifth Street West to the treatment facility; the District is now planning the replacement of the sewer main from Sixth Street West to Ramon Street. This phase is at the 60 percent design phase, will go along Highway 12, and construction will cost $4.86 million. Future replacement phases will continue toward Agua Caliente, say District officials.

One spur trunk at the Finnish American Hospitality Association (FAHA) on Verano Avenue has just been replaced in the past couple months.

But while the main trunks of the 132-mile collection system are being steadily upgraded, citizen complaint still focuses on new projects that are within the areas already upgraded, specifically the downtown area where the Hotel Sonoma project recently went before the Planning Commission. (Hotel Sonoma is being developed by Kenwood Investments, whose founder Darius Anderson is the principal investor in Sonoma Media Investments, which owns the Index-Tribune.)

David Goodison, the city planning director, recently made a presentation to the Planning Commission and the City Council in the wake of concerns about the West Napa Street “Hotel Sonoma” project. He adamantly stated that Gomez’s and others’ concerns conflate two issues and systems.

“Generally speaking, the issues raised with the collection system regarding new developments don’t have anything to do with peak storm events,” said Goodison. And peak storm events are what prompt the SSOs, the fines, and compliance failures of the district.

Rainfall drainage and sewer collection are different systems, but due to the aged infrastructure of the District’s collection system – and the largely untracked and unregulated accumulated miles of sewer laterals that run from nearly every property in the Valley to the sewer main – the system is not impermeable.

During a heavy rainfall, the ground becomes saturated and water seeps into these sewer laterals, as well as the older main sewer lines. When a sewer overflows, its fluid has nowhere to go but out – up through the manhole and out into the street, or nearby neighborhoods. It’s a clear health and safety concern.

In such storm events, rainfall added to the collection system exceeds the capacity, and even large spills can and have occurred – over 65,000 gallons in a single incident at Rancho Mobile Homes in December 2014, during a storm that produced eight documented SSOs, totaling 145,860 gallons of overflowed sewage. This single storm was a large part of the violations that brought the $723,000 in fines.

But the sewer laterals, while included in the “collection system,” are not part of the Sanitation District’s direct responsibility. Instead, it’s the property owner’s responsibility.

“A major contributor to overflows are private sewer laterals in need of repair,” said District Manager Davis. “Property owners are required to keep sewer laterals (the pipes that run from the home or business to the sewer main) in good condition.”

District officials estimate as many of two-thirds of these lateral pipes are 30 years or older, made of material such as clay, concrete or iron that break down over time, and may be experiencing root infiltration, cracking or displacement. This might be why toilets back up during stormy weather: the homeowner’s lateral pipe from the house to the sewer main is failing, taking in rain water, and unable to handle normal household usage.

The Sonoma Valley County Sanitation District has already begun working up a Sewer Lateral Ordinance, a project to tackle the most permeable and potentially explosive aspect of the sewer crisis – the accumulated miles of privately-owned and maintained lateral sewer lines on almost every property in the Valley.

The District should issue the Sewer Lateral Ordinance in the next couple months – it’s required to do so by July 1, according to the Regional Board’s order – outlining when an inspection of a lateral must occur, a so-called “trigger event.” These might include a blockage repair performed by a licensed plumber, a major remodel, or even the sale of a property.

An underground survey of a lateral (often done by a video cable) can cost several hundred dollars; a repair or replacement can easily run into the thousands.

Ann DuBay of the Sonoma County Water Agency is working to create the Sewer Lateral Ordinance, and understands that homeowners might balk at this added responsibility. “It’s kind of like a roof – you don’t like to think about it until there’s a leak, but as a homeowner you know you’ve got to fix it. It’s the same thing with a sewer lateral.”

Supervisor Susan Gorin, one of the three members of the Sanitation District Board of Directors, agrees. “Everybody needs to recognize they are part of the system, and take the action necessary to be part of the solution,” said Gorin.

Infrastructure failure is a fact of life; keeping up with deteriorating pipes is a concern that both municipalities and their residents share.

Contact Christian at christian.kallen@sonomanews.com

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