Public Hearing on the Recharge Support Project set for April 10, 2025 at 1pm at the Westside Water District. 

RECHARGE SUPPORT PROJECT

I. Introduction
The Colusa Basin Drainage District (“District”) was formed to address subsurface drainage and land subsidence issues in the Colusa Basin. Pursuant to this legislative directive, the District adopted an Integrated Water Management Plan (“Initial Plan”) for studying and supporting projects that promote groundwater recharge, capturing flood waters to bolster water supplies, and protecting agricultural production. Voters of the District approved the Initial Plan and related assessment to fund the Initial Plan in a general election held on November 7, 1995. Two special districts within the District’s boundaries, the Colusa County Water District (“CCWD”) in Division II and the Dunnigan Water District (“DWD”) in Division III, are carrying out multiple groundwater recharge projects and planning on developing future projects. In addition to serving as water supply districts, CCWD and DWD each have a role (either as a member of a JPA or individually) in providing for compliance with the Sustainable Groundwater Management Act in their underlying groundwater basins. In this role, CCWD and DWD are developing in lieu and direct groundwater recharge projects for the sound management of groundwater resources in the Colusa and Yolo Subbasins, respectively. These projects address SGMA’s undesirable results of land subsidence, depletion of interconnected surface water, and the reduction of groundwater storage by redirecting flood waters from the Sacramento Valley into the groundwater basin.

II. Recharge Support Project
Subsidence and reductions in groundwater supply are an issue of special concern in this portion of the District. The District is interested in assisting CCWD and DWD with their groundwater recharge projects, which are directly responsive to that issue, and each of which work to capture otherwise unused, flood, or surplus flows for groundwater recharge. The Recharge Support Project would authorize the District to provide CCWD and DWD with up to $50,000 each for the purpose of carrying out these pilot projects. These pilot projects are located in Divisions II and III of the District and are described more specifically below.
 

Ephemeral Stream Trickle Flow Recharge. CCWD and DWD would redirect excess surface water supplies from the Tehama-Colusa Canal into ephemeral streams overlying the Colusa and Yolo Subbasins. The surface water percolates into the groundwater basin as it flows through the stream’s channel towards the Sacramento River, thus increasing the recharge capabilities of these projects. DWD has already implemented one such trickle flow project on Buckeye Creek with remarkable success.

On-Farm Direct Recharge. DWD is already operating a direct recharge project on a landowner’s agricultural property in the Yolo Subbasin. These projects operate by applying surface water supplies to the property, effectively flooding the field, and allowing that water to percolate. On-farm recharge projects are notable for providing multiple benefits. In addition to augmenting groundwater supplies, on-farm recharge creates habitat for migratory birds and other species.

Percolation Ponds. DWD is proposing to construct percolation ponds in areas with high percolation rates that would allow drainage of excess surface water into the Yolo Subbasin.

A map of these groundwater recharge projects can be found here: https://arcg.is/mOHmr