Sustainability plans approved for major North Bay groundwater basins
SONOMA COUNTY - Plans for ensuring the long-term viability of four major groundwater basins in the North Bay were approved Thursday by state water regulators.
The State Department of Water Resources announced that it gave the okay to plans developed for the Napa Valley Subbasin in Napa County and the Santa Rosa Plain Subbasin, the Petaluma Valley Basin and Sonoma Valley Subbasin in Sonoma County.
The plans were developed by four different local groundwater sustainability agencies under the requirements of the 2014 Sustainable Groundwater Management Act.
The law requires local agencies to reach sustainability within 20 years by implementing measures to ensure that the amount of water taken out of the ground doesn't exceed the amount of water that goes back into the local groundwater basins via precipitation and other things.
"Climate-driven swings between drought and flood make it critical that we capture excess water and store it underground, so it is available during drought periods. Adequate preparation by local agencies is essential to do so," said DWR Director Karla Nemeth in a news release.
Napa's local groundwater sustainability agency worked for 18 months in coordination with a 25-member advisory committee comprised of people from the wine and agricultural industries, various water rights holders, environmental groups and urban water users.
The plan, which was submitted to the state about a year ago, involves monitoring the basin for water level and quality, land subsidence, storage changes, seawater intrusion and the interaction of surface water sources like rivers and streams with the local aquifer, among other things.
"The state just recognized some years ago that that California groundwater basins were dropping and there was no regulation," said Napa County Natural Resources Conservation Manager Jamison Crosby, who helped spearhead the planning process.
Based on existing results that show a depletion of "interconnected surface waters" and groundwater storage, Napa's plan calls for a 10 percent reduction in groundwater pumping, Crosby said.
To reach that goal, the county is initially focused on encouraging voluntary water use reductions, especially by the wine industry, and more stringent permit requirements based on water availability analysis for things like new vineyards, she said.
"In the aggregate, what it means is that groundwater users are going to have to reduce their dependence, they're going to have to cut back," Crosby said.
"A lot of people in the industry have already done a lot to conserve, but I think even for the people in the industry who have been the early adopters (of water conservation methods) I think they don't even necessarily recognize how much more could be done," she said.
Marcus Trotta is a principal hydrogeologist with Sonoma County Water Agency and has been working as a plan manager for the Santa Rosa Plain Subbasin, the Petaluma Valley Basin and Sonoma Valley Subbasin.
Trotta said the approvals allow the local groundwater sustainability agencies to move forward with additional monitoring and data collection and to begin planning the actual projects and management actions needed to achieve or maintain sustainability.
"It's important statewide because groundwater in general accounts for maybe 40 to 50 percent of the overall water supply portfolio for the for the state, but in dry years when there's less surface water it could be much higher than that," Trotta said.
The highest areas of concern are in the basins east and west of the City of Sonoma, where there have been groundwater declines for 20 to 30 years in some cases.
The plans include measures such as expanding the use of recycled water for agricultural irrigation, taking water from the Russian River watershed during wet months and storing it in the groundwater basins via existing wells, as well the possible implementation of more widespread conservation incentives and requirements throughout the region, Trotta said.
A big feature of all the plans statewide is that they are expected to produce more accurate monitoring of groundwater use, which will give local agencies a better understanding of how to modify the plans during the next 20 years or so.
"It's definitely very good news for our local groundwater sustainability agencies," Trotta said.