Plan for Los Osos groundwater basin approved by judge

A San Luis Obispo Superior Court judge has approved a plan that establishes a path forward for the Los Osos community to protect and restore its groundwater supply.

Judge Martin J. Tangeman approved a stipulated judgment on the Los Osos Basin Plan on Oct. 14, finalizing a court process that began in 2004.

The decision formalizes an agreement between the community’s water purveyors to conserve and help recharge groundwater in the basin. Geological analysis has shown the basin’s supply to be in a critical state of decline from overpumping and a looming threat of seawater intrusion, notably in the lower aquifer at the west end of the basin. The other main source of water, an upper aquifer, is in trouble because of high concentrations of nitrates.

The Los Osos Community Services District filed a lawsuit 11 years ago against the Southern California Water Co. (which changed its name to Golden State Water Co. in 2005), the county of San Luis Obispo and S&T Water Co. — all of which draw water from the basin — over water consumption and water rights.

That litigation led to the drafting of the Los Osos Basin Plan, which establishes a process and timeframes to reach the goals of reversing seawater intrusion, promoting conservation and ensuring the basin will provide a reliable, sustainable water supply that benefits the Los Osos community.

The precise funding mechanisms still need to be worked out, but much of the cost will be borne by residents and businesses in the basin as water suppliers raise rates to cover expenses.

“The idea is that costs will be equitably distributed among water users in the basin,” said county Supervisor Bruce Gibson, whose district covers Los Osos.

About $34 million in programs and infrastructure improvements are identified in the Basin Plan, including about $11 million to build a nitrate removal plant, $5.5 million for conservation efforts, and $18 million for a system that would inject treated wastewater (from a sewage treatment plant now being built) into the aquifer or use it directly for irrigation.

“This is a big step forward in getting the basin back in balance,” Gibson said of the court ruling. “This is a roadmap that has been long in the making. We’ve studied this enough. We have a plan that the court has approved. Given the dire situation with the seawater, we need to get moving on it as soon as possible.”

A Basin Management Committee will be made up of four directors appointed by each of the four litigant parties. The committee will share financial and management authority and be responsible for carrying out the Basin Plan, including determining a sustainable yield for the basin.

“The Basin Plan establishes clear goals and metrics to measure our success,” said Kathy Kivley, the general manager of the Los Osos CSD. “We are pleased with Judge Tangeman’s decision. The cooperation the purveyors have shown should be encouraging for other communities in California facing similar water challenges.”

Gibson said he anticipates that several of the programs in the plan will be underway within a year, and that some work to remove nitrates in the upper aquifer already is underway.

Other programs in the plan include: A monitoring program to analyze groundwater quality and levels from more than 70 wells, infractructure to shift well production to upper and inland aquifers, and conservation caps on customer water use.

Faced with both overpumping in the basin and a 4-year drought, customers of the Los Osos CSD already are limited to 50 gallons of water per person per day.

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