Los Osos farmland set for long-awaited sewer

An unremarkable 38-acre plot of land on the outskirts of Los Osos is set to become the focal point of one of the county’s longest-running infrastructure controversies — the Los Osos sewer project.

Some form of sewer system to replace the hundreds of septic systems in the town has been under consideration for the past 30 years.

County public works officials are putting the finishing touches on plans to build the project’s sewage treatment plant on the 38-acre parcel located north of the Los Osos Valley Memorial Park known as the Giacomazzi site.

The treatment plant is just one component of the $165 million project. Sewage collection and effluent disposal systems are also planned for the bayside community of 14,000 residents with about 12,500 directly affected by the sewer project.

In January, the project will face its final regulatory hurdle — the California Coastal Commission.

Twenty-two appeals of the project have been filed with the panel, including one from the commission itself. County supervisors will hold a hearing Nov. 24 to address the commission’s concerns about disposal of the plant’s effluent in hopes of improving the likelihood of a speedy approval.

County officials are also arranging financing for the project. They expect the work to be financed with a combination of state and federal loans and grants and a voter-approved property tax assessment. They expect the project to receive federal stimulus money, with a decision about how much the allocation will be in March.

“When you are doing a project of this size, you don’t just have one source of funding,” project administrator John Diodati said. “You have to go to three or four pots.”

Building a sewage treatment plant anywhere in the Los Osos area would be difficult, and the Giacomazzi site is no exception. It consists of gently rolling hills.

Loss of 38 acres of farmland is just one drawback.

The site must be graded significantly to prepare it for construction. This means that scattered Chumash Indian artifacts as well as remnants of historic farm buildings might be disturbed, said Mark Hutchinson, the project’s environmental manager.

“We don’t expect to find burial sites or anything like that,” he said.

The plant will use an extended aeration treatment process that injects air into the sewage to promote bacterial consumption of pollutants. Officials say they expect any odor the plant produces to be kept onsite.

Another crucial component of the project is across town at an eight-acre parcel known as the Broderson site. This is where about a third of the plant’s treated effluent will be returned to underground aquifers via leach fields in order to replenish groundwater and prevent saltwater intrusion.

The Broderson site sits on a hillside just south of town. The effluent will be discharged into the sandy soil using buried perforated pipes.

Because the leach fields will be underground only fencing will be visible aboveground, Hutchinson said.

The leach fields are part of a larger 88-acre parcel. A variety of restoration work is planned for the site; it’s intended to offset environmental damage caused by other aspects of the sewer system as well as grading done at the mid-town Tri-W site that was part of a previous, failed attempt to build a sewer system.

Restoration work will mostly consist of removing invasive species such as nonnative grasses and some eucalyptus trees. The goal is to improve the site as habitat for the Morro Bay kangaroo rat, a federally listed endangered species.

Reach David Sneed at 781-7930.