By BRETT WILKISON
THE PRESS DEMOCRAT
Sonoma County supervisors on Tuesday are set to consider approval of two efforts geared toward closer study and management of the region’s groundwater.
The first is a bid to monitor the county’s groundwater levels, which have dropped in places as pumping outpaces natural recharge. Overpumping has also caused other problems, including the threat of salt water intrusion into groundwater in southern Sonoma Valley.
To head off those problems, state legislators in 2009 passed a law that mandated study of all groundwater basins. Critics said it was a move toward regulation of groundwater use, currently limited by state law.
Local governments can choose not to participate, but they cannot receive state grant funds for water projects if they do so.
The monitoring effort would be overseen by the county’s planning department and water agency. It would combine data from wells already monitored by the state and local governments with data volunteered by landowners, including rural residents and agricultural interests.
Twice a year, that data would be turned over to the state and posted online. The reports would show the general location of monitored wells, water depth and date of measurement. But they would not include pumping rates — which would not be measured — nor would they include the names of participating landowners, which the county can withhold, according to Marcus Trotta, hydrogeologist with the county water agency.
“We want to make sure that (landowners) are comfortable with what data is being submitted to the state and how it is being used,” Trotta said.
Cost for the planning department and water agency through June 2012 is estimated at $265,000.
The second effort is the formation of a groundwater management plan for the Santa Rosa Plain. Pumping from the basin provides water to Sebastopol and the Larkfield-Wikiup area, and supplements supplies for Rohnert Park, Cotati, Santa Rosa and Windsor.
The U.S. Geological Survey is wrapping up a 5-year study of basin water use, movement and quality.
The management plan would outline a non-regulatory strategy to boost groundwater supplies and increase use of recycled water and capture of storm water, Trotta said.
Supervisors are set to approve an initial work schedule for the plan, which is set to take up to two years and cost $560,000. State grants would account for $250,000, with the rest shared by the water agency, cities and water districts.