RANCHO MURIETA, CA (MPG) - A growing sinkhole beneath Pera Drive, millions of gallons of excess treated wastewater and several other infrastructure projects were highlighted at the Rancho Murieta Community Services District Improvements Committee meeting on Aug. 4.

The committee also received updates on wastewater treatment plant repairs, a planned manganese study, the nearly completed MEC culvert project and a proposed new fee for fire-flow letters.

The committee also spent considerable time debating the proposed third water storage tank, disputes over who controls committee agendas, and a Water Vision Working Group project matrix intended to assign responsibility for long-term water supply projects. Those discussions are covered in separate stories in this edition.

The committee’s most urgent infrastructure discussion centered on a sinkhole that has developed on Pera Drive after storm drain culverts beneath the roadway began failing.

District staff said deteriorating culverts have created both a public safety hazard and a threat to the roadway if repairs are delayed until the rainy season. CSD Utility Supervisor Cory Carskaddon presented a $42,613 proposal from Domenichelli & Associates to perform a site survey, hydraulic analysis, evaluate three repair alternatives, prepare preliminary cost estimates and develop conceptual plans for repairing the storm drain.

Staff emphasized that the proposal covers only the engineering phase. They said the eventual construction project – including replacement of large storm drainpipes, pavement restoration, traffic control and construction – will likely cost several hundred thousand dollars.

The committee directed staff to move the Domenichelli engineering proposal to the Board of Directors for approval at the Aug. 26 meeting.

The committee also directed that Domenichelli expand the proposal into a “cradle-to-grave” agreement that would include final engineering, bidding assistance and construction management. Members agreed the project should be expedited because the roadway cannot safely wait until winter rains arrive.

While the district has spent much of the past year debating future drinking water supplies, Utilities Manager Travis Bohannon reported the wastewater treatment plant continues to face the opposite challenge: disposing of excess treated wastewater before winter storms reduce disposal options.

Bohannon said the district currently has about 138 million gallons of secondary-treated wastewater in storage. Although that is down from approximately 166 million gallons at the same time last year, it remains about 60 million gallons more than the district had two years ago.

Meanwhile, the treatment plant continues to produce approximately 2 million gallons of wastewater each day.

To reduce storage levels, the district continues to deliver recycled water to the Rancho Murieta Country Club for irrigation and to pump water to Van Vleck Ranch three to four times a week after repairing pipeline breaks that had interrupted the program. Bohannon said the repaired line has recently remained in service for about two weeks at a time.

He said he hopes dry weather continues through the end of September – and ideally into October or November – to allow additional reductions before rainfall curtails golf course irrigation and discharge permit restrictions tighten.

Bohannon also evaluated trucking treated wastewater to the Sacramento Regional Wastewater Treatment Plant but concluded the option is not cost-effective. Bohannon said using two tanker trucks for two months would remove only about 2.4 million gallons at an estimated cost of $140,000, making only a small reduction in the district’s inventory. He said APS Environmental has indicated it could assist if conditions worsen during the rainy season, and he plans to continue closely monitoring storage levels and to explain the district’s strategy in an upcoming report to the Board of Directors.

Wastewater Treatment Plant Repairs

The committee also reviewed two significant wastewater treatment plant repair projects.

One involves emergency replacement of electrical wiring and a transformer after a 480-volt power feed burned out. A temporary hard-wired repair has kept the plant operating, and the approximately $13,100 emergency expenditure will be presented to the Board of Directors for ratification.

The second project involves rehabilitation of the plant’s tertiary filter panels, which have suffered extensive corrosion following the district’s conversion to hypochlorite disinfection. Preliminary estimates place the work between $250,000 and $300,000, and the committee directed staff to seek proposals outlining repair options and recommendations.

Bohannon reported the district has completed a request for proposals for a manganese study but he plans to wait until November or December to issue it because manganese concentrations are currently at seasonal lows.

The delay would allow a consultant to be selected and under contract before manganese levels typically increase in hot weather. The committee agreed with the proposed schedule.

The committee also learned that repairs to the Murieta Equestrian Center culvert are approximately 99.5% complete and on schedule. The only remaining work is installation of railings, after which staff plans to provide photographs to the board.

Staff recommended creating a $396 fee to recover district costs for preparing Sacramento Metropolitan Fire District fire-flow letters required for new construction and some accessory dwelling units.

The proposed fee would cover both staff time and engineering services provided by Domenichelli & Associates. The committee agreed to move the fee to the board, with the understanding that district counsel would first review the legal authority for the charge.