Petaluma Valley Groundwater Sustainability Agency's Monitoring Network Improvement Project

Petaluma Valley Groundwater Sustainability Agency's Monitoring Network Improvement Project

In 2014, the state of California enacted the Sustainable Groundwater Management Act (SGMA) which mandated groundwater sustainability throughout the State. SGMA established the framework for managing groundwater resources in medium and high priority groundwater basins. Local Groundwater Sustainability Agencies (GSA) were tasked to manage their groundwater resources in accordance with a Groundwater Sustainability Plan (GSP). The Petaluma Valley Groundwater basin is a medium-priority basin established under SGMA and operates under a DWR-approved GSP. A critical component of groundwater management is having a robust monitoring network to establish a baseline for groundwater levels. Once the current baseline is established, groundwater levels can be compared to historical data to determine long term trends and track the effectiveness of sustainable management criteria in the GSPs and implemented by the GSAs. The Petaluma Valley GSA received a $6.7 million grant from California's Department of Water Resources through its Sustainable Groundwater Management Grant Program. One of the grant components is the planning, siting, design, and installation of up to three multi-level groundwater monitoring wells drilled to depths of up to 500 feet within the GSP area, up to three multi-level groundwater seawater intrusion monitoring wells drilled to depths of up to 300 feet, and up to three shallow wells to monitor interconnected surface water. The specific focus is to provide monitoring data in previously identified groundwater data gaps areas with important features such as fault zones, groundwater basin boundaries, baylands, or proximity to areas of substantial groundwater pumping. The Monitoring Network Improvement Project would expand the Petaluma Valley GSA's monitoring networks through the installation of up to three multi-level deep groundwater monitoring wells, up to three seawater intrusion monitoring wells, and up to three shallow interconnected surface water monitoring wells within the Petaluma Valley Groundwater Basin. The deep groundwater multi-completion wells would range from approximately 100 to 500 feet in depth. Seawater intrusion monitoring wells would range from 200 to 300 feet in depth. Interconnected surface water wells will extend to a depth of approximately 50 feet. Each deep and seawater intrusion well casing would have a diameter of 3 inches and the shallow interconnected surface water monitoring wells would have a casing diameter of 2 inches. The wells would be installed within boreholes with a maximum diameter of 14 inches. The proposed activity includes: 1) well construction permitting; 2) borehole drilling, borehole geophysical logging, and monitoring well construction using portable drilling equipment appropriate for the well location and specifications; 3) elevation survey of surface completion at each well site; 4) well development and sampling; and 5) site clean-up and restoration as necessary. The GSAs have, and will continue to, implement best management practices for siting, construction, and monitoring to minimize or avoid local disruption to communities and resources during these operations. The duration of construction for the entire Project is anticipated to be 12 to 14 months. On the ground activities at each well site will typically occur over a two to four week period. The monitoring wells will provide groundwater information to support and implement long-term sustainable groundwater planning and management and inform projects to help the GSP meet the sustainable groundwater management goals of the Basin.

Penngrove, Petaluma

Sonoma

Citywide, Countywide

Sonoma