Water Agency on ‘vulnerable’ groundwater supply

(By Jay Jasperse | Sonoma County Water Agency). The Sonoma Valley is a wonderful place to live, but this ostensible oasis is quite vulnerable to water supply stresses. Residents of Sonoma Valley rely on a mix of groundwater and surface water to meet the needs of urban areas, rural residents and agriculture.

Groundwater supplies about 59 percent of the valley’s water needs — primarily to rural residents and agriculture. Urban areas primarily rely on imported Russian River water, which makes up approximately 26 percent of the valley’s water supply.

Each of these water sources is vulnerable and presents reliability challenges. Russian River water is pumped a great distance through pipelines that span several fault zones. Sonoma Valley’s groundwater aquifers are generally comprised of finer-grained materials that do not yield a prolific amount of water.

In 2006 the U.S. Geological Survey, in collaboration with the Sonoma County Water Agency (Water Agency), published a report that highlighted concerns about areas facing groundwater declines and salt-water intrusion. In response, a group of stakeholders representing water users and interest groups formed a Basin Advisory Panel (BAP) to develop and implement a Groundwater Management Plan (Plan) to manage this resource proactively and locally.

This Plan was approved by the Water Agency’s Board of Directors in 2007 and is designed to maintain local management of groundwater resources in a collaborative, non-regulatory basis. The program has gained statewide acclaim for taking on contentious groundwater issues in a collaborative grassroots manner and for its success in establishing a voluntary monitoring program of about 150 wells. In addition, the program has received several grants and implemented various studies and projects to improve groundwater conditions.

The BAP’s five-year Plan review concluded that despite these successes, two areas of declining groundwater — near El Verano and southeast of the City of Sonoma — continue to expand and deepen. Clearly more needs to be done. In response, the BAP has begun to identify additional actions to resolve this growing problem.

Drought and climate change will exacerbate the stresses on the groundwater basin. In addition, the new Sustainable Groundwater Management Act of 2014 will significantly change the way groundwater is managed by providing local agencies regulatory and fee collection authorities to achieve sustainable groundwater management. The new law gives the state discretion to assume management responsibilities if local programs fail to meet the law’s requirements. Long-term groundwater declines, compounded by the drought and new legislation, have changed the playing field. A community-wide effort is needed if Sonoma Valley is to successfully locally manage its groundwater resources.

To learn more about the Sonoma Valley Groundwater Management Program go to Sonomacountywater.org/svgroundwater.

Jay Jasperse is the Chief Engineer and Director of Groundwater Management for the Sonoma County Water Agency