Los Osos groundwater is in danger, and its rescue will be costly

A crisis looms over the heads of Los Osos residents if drastic measures aren’t taken to fend off encroaching saltwater that threatens to permanently damage a major portion of the community’s only water supply — groundwater.

With more water being drawn from the basin than going into it, over-pumping in the area’s lower aquifer is causing ocean intrusion — a situation only worsened by the drought.

The rate of saltwater intrusion could render the basin’s lower aquifer unusable in five years, according to a recently updated plan to sustain the community’s only water resource.

The Los Osos basin’s other main source of groundwater, an upper aquifer, also is in trouble due to high concentrations of nitrates.

In order to preserve the future sustainability of the basin, the three local purveyors that draw water from the ground supply have worked together to develop a plan to save the resource.

After years of negotiations and effort, the agencies and the county of San Luis Obispo are nearing a resolution, they say.

But remedies — consisting of water conservation and recycling programs, and new infrastructure to purify water from the upper aquifer — will cost an estimated $34 million.

Those expenses will be borne by ratepayers who already face the financial burden of paying for a $183 million sewage treatment system, required by the state because of pollution from septic tanks.

According to local government officials, the basin’s survival will depend on collaboration between agencies and a shared commitment to protecting the groundwater supply.

“It’s our only water source,” said Michael Wright, president of the Los Osos Community Services District’s board of directors. “It has to last our community for as long as we have a community.”

A historical perspective

The overdrafting of groundwater in Los Osos can be traced to a spike in population that began in the 1970s. The Los Osos population jumped from about 3,500 in 1970 to nearly 11,000 in 1980.

Over that same time, water production more than doubled from about 730 acre-feet per year to 2,000 acre-feet per year, excluding agricultural use.

By the late 1980s and into the 1990s, water production eclipsed 2,000 acre-feet per year and the community’s population grew to more than 14,000 residents. An acre-foot of water typically serves three families of four per year.

Groundwater pumping in Los Osos

The amount of consumption and battles over water rights led to a lawsuit filed in 2004 by the Los Osos CSD against the Southern California Water Co. (which changed its name to the 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.

As a condition of trying to settle the lawsuit, the parties entered into an agreement to work together on a plan to assess the condition of the basin, provide a historical perspective and come up with comprehensive remedies.

The result is a 332-page Updated Basin Plan for the Los Osos groundwater basin, released in January, that calls for “bold, decisive and immediate actions” to solve the problems of degraded water quality in the upper aquifer and seawater intrusion in the lower aquifer.

According to court documents, a status conference on the lawsuit is scheduled for April 2 in Judge Martin J. Tangeman’s court with the goal of presenting a resolution for the judge’s approval by mid-2015.

A resolution would set “the framework for implementation of a series of projects that are intended to restore the long-term integrity and reliability of the basin as potable water resources for the Los Osos community,” the agency’s lawyers wrote in a joint status conference statement filed in January.

San Luis Obispo County Supervisor Bruce Gibson, whose district includes Los Osos, said a resolution for the judge’s approval within the next few months seems “reasonable and necessary.”

“It can happen this year, and we have to make this happen this year,” Gibson said. “I’ve said publicly, this is long overdue. And remember, this is just the start. The follow-through will be the important action that we will be judged by.”

Overview of the plan

The basin plan calls for a halt to pumping in the western area of the lower aquifer, which is the most threatened by saltwater intrusion from over-pumping.

The deeper, lower aquifer is separated by a layer of compacted clay from the upper aquifer and was tapped because of nitrates in the upper aquifer. The nitrates are believed to have come from septic discharge and farming.

High levels of nitrates in water can be a health hazard, particularly to infants and pregnant or nursing women, by interfering with the body’s ability to carry oxygen in the blood, according to the U.S. Environmental Protection Agency.

The basin plan envisions more water being drawn from the upper aquifer and the central and eastern areas of the lower aquifer, which could require the construction of an $11 million nitrate removal facility.

The plan recommends funding a nitrate removal facility if the county were to allow future development in Los Osos.

The population is about 14,600, and the county is drafting a Los Osos Community Plan and Los Osos Habitat Conservation Plan that anticipate limiting buildout to about 19,850 residents — fewer than the 28,700 residents under current plans.

The new sewage treatment system, which is expected to start operating in 2016, will help relieve pressure on the basin by recycling an estimated 780 acre-feet per year. About 300 acre-feet will be used for irrigation; the other 480 acre-feet will be returned to the groundwater basin by percolating into the aquifers through leach fields.

In addition to drilling new wells and doing more monitoring for saltwater intrusion and nitrates, the basin plan envisions widespread conservation efforts that aim to make Los Osos among the best water-saving communities in the state.

“Although groundwater pumping has declined … that progress is offset by the ongoing drought and lack of freshwater recharge to the basin, and additional conservation is critical,” said Kathy Kivley, general manager of the Los Osos Community Services District.

Even with those measures, officials differ on whether the groundwater supply can handle any more demands.

Since 1988, there has been a moratorium on new home construction until a sewer system is in place, and development permitting also would depend on an adequate water supply.

Gibson said he believes future buildout is possible with careful management.

“We’ll have to stabilize the basin,” Gibson said. “We’ll have to pay the costs associated with infrastructure as well.”

However, Los Osos Community Services District board member Chuck Cesena said the immediate protection of the basin takes utmost priority.

“With saltwater moving in, how can we even think about adding more use right now?” Cesena said. “Any speculation about the future is just speculation.”

Rates and reaction

The Los Osos Community Services District has already begun the process of increasing water rates to pay for infrastructure upgrades, including major projects on pipelines, wells and valves.

Once implemented, customer rates would increase by 50 percent over the next four years.

But the shared responsibility of costs for the new basin infrastructure, including the nitrate removal facility, and new wells, will need to be addressed by all four agencies involved in the lawsuit.

“We’re all in this together in Los Osos, but Los Osos is in this alone,” said Jon-Erik Storm, a Los Osos Community Services District director. “Our choices as a community will determine the future of our water supply.”

The judge in the court case is expected to address how costs are divided in a final stipulated judgment. Each agency will need to raise rates or find other funding to pay for the basin plan projects.

“A lot of people are struggling with the financial burden of the sewer, and the water expenses will add additional costs as well,” Cesena said. “Some people will make it here. Others won’t. … We’re not alone. Other communities around us are going through similar problems.”

Community members in Los Osos say they’re well-aware of the seriousness of water quality problems.

“I’m deeply concerned with the possibility of losing our groundwater supply,” said resident George Mennel. “I think it’s a massive concern not only for me but for many of the people who live here.”

Resident John Olejczak said he sees promise in the county’s recommendations to repurpose septic tanks once the sewer system is operating — channeling stormwater from roofs into the tanks for irrigation use or for toilet flushing, or perforating the tanks so the stormwater percolates into the ground.

“It sounds like channeling that water into the ground could be one of the ways to help the groundwater basin,” Olejczak said.

Homeowners as well as the business community already have supported water-saving efforts, with the most recent being restrictions on most landscape watering to 15 minutes, two days a week, said Michael Wright, the Los Osos Community Services District board president.

“The Vons shopping center installed a drip system, and they had grass, which they have taken out now,” Wright said. “I think people in the community are aware of the drought situation, and they’re taking to heart how they’re watering.”

Still, saltwater intrusion is increasing “and we haven’t shown the ability to slow that down,” Cesena said.

“Nobody can predict rain,” Cesena said. “Salt-water intrusion has already caused us to abandon some of our wells in the lower aquifer. It’s here. It’s bad. How bad it will continue to be we can’t say. But we’ll have to do our best to prevent it.”