photo credit: Courtesy of Sonoma Water
Map showing the boundaries of the Sonoma Valley GSA

There are bountiful water supplies in the Russian River's watershed, but in other nearby parts of Sonoma County, water is not as plentiful.

Critical groundwater declines are threatening long-term water reliability for homes, farms, and businesses just a short drive away in the Sonoma Valley.

Marcus Trotta is a principle hydrogeologist with Sonoma Water and also the plan manager for the Sonoma Valley Groundwater Sustainability Agency. He said the agency, GSA in shorthand, has designated two new Groundwater Sustainability Priority Areas: El Verano and Eastside.

“Those are areas where Sonoma Valley GSA is currently focused on doing both outreach to groundwater users… identifying and evaluating the types of projects and actions that can be taken to address the ground water level declines,” Trotta said.

The primary cause for the declines is over-pumping of deep aquifers, which are slow to recharge compared to more shallow aquifers.

One reason for this imbalance, said Sonoma Water's Pamela Van Halsema, is the varied geology throughout Sonoma County. “You just drive a few miles [and] you're in a different fault zone, you're in a different volcanic area, or you're in a clay area, and like so underground, water behaves differently,” Van Halsema said.

Another factor is the growing impacts of climate change, including more frequent droughts, and fewer, more intense storms that reduce effective groundwater recharge.

Trotta said using recycled water is a key part of the solution. “Right now, there's about a thousand acre-feet being delivered to agricultural users for irrigation and landscaping in portions of Carneros area, and we've already seen how that has helped reverse some decline in groundwater trends in those areas,” Trotta said.

An acre-foot of water is about 300,000 gallons.

Trotta said conservation is another part. “We do have a number of voluntary conservation programs… a voluntary flow metering program that provides information and tools in some cases on how homeowners and land owners can reduce water use.,” Trotta said.

Trotta said the tools can be helpful, no matter where you live.

You can find out more at SonomaValleyGroundwater.org