New groundwater monitoring wells will provide ‘picture’ of underground water connections
During the months of October and November, up to 21 groundwater monitoring wells were drilled near Sonoma County creeks, including some in Sonoma Valley, to provide new information to water managers and the public on the link between groundwater and stream flows. Coordination and construction of the wells are a technical service provided by the California Department of Water Resources (DWR) to Sonoma County’s three Groundwater Sustainability Agencies (GSAs).
Each well is about 50 feet deep, and designed specifically for measuring water levels throughout the year. These measurements, when paired with information about the water flowing in nearby streams, help paint a picture of the link between groundwater aquifers and the surface water in creeks, streams and rivers.
“We can’t see what’s beneath the surface, so these monitoring wells act like underground telescopes. They can help us see how much and when water is available,” said First District Supervisor Susan Gorin, who serves as the chair of the Sonoma Valley GSA.
The connection between groundwater and surface water is an important component of the Groundwater Sustainability Plans that are being prepared by Petaluma Valley, Santa Rosa Plain and Sonoma Valley GSAs. The state-required plans must determine if groundwater pumping is resulting in the loss of water in streams that support endangered and threatened fish and other species.
The monitoring wells are installed by drilling holes that are about eight-inches in diameter, until water is reached (around 50 feet). A narrow, two-and-a-half-inch slotted PVC pipe is fitted into the hole, which is then capped. The wells will then be monitored by GSA staff using instrumentation provided by DWR to track water levels and temperature throughout the year, and will be compared with data from nearby surface water gauges. Each well costs approximately $15,000 to construct and develop. These costs are being paid for by DWR through its Technical Support Services program. DWR has also provided financial assistance in the form of planning grants to help these local agencies develop their groundwater sustainability plans.
The wells are in various locations, including parking lots, vineyards, on road shoulders, creek paths, and other publicly owned land. For more information about local groundwater go to www.sonomavalleygroundwater.org.