Colusa Subbasin Groundwater Sustainability Plan Development

Client: Colusa Groundwater Authority, Glenn Groundwater Authority

Funder: California Department of Water Resources

Location: Colusa Subbasin, Colusa and Glenn Counties

Date: 2016 - Present

In 2016, the team led by Davids Engineering was contracted to support Colusa and Glenn Counties in SGMA compliance efforts for the subbasins underlying portions of each county, including the Colusa Subbasin. Through funding from a Proposition 1 SGMA Stressed Basin Grant, our team began laying the technical foundation for Groundwater Sustainability Plans (GSPs) by:

•Completing a detailed review of high-priority data available for establishing the Basin Setting

•Identifying potential data management platforms and groundwater models, and

•Developing initial subbasin water budgets and a preliminary Hydrogeologic Conceptual Model (HCM).

Since 2019, our team has led development of a coordinated GSP that will cover the entire Colusa Subbasin. GSP development has seamlessly built upon prior technical efforts to describe foundational components of the Colusa Subbasin Basin Setting, including the HCM; groundwater conditions; and historical, current, and future conditions water budgets.
Ongoing GSP development efforts have followed key guiding principles:
•The processes for developing and implementing the GSP are iterative and adaptive to achieve sustainability for all beneficial groundwater users while also balancing the needs of local communities and the local economy
•GSP decisions must consider both social and technical information, including both qualitative and quantitative factors affecting all users.
In this spirit, the Davids Engineering team is leading GSP development to ensure regulatory compliance with SGMA and provide a foundation to achieve and maintain sustainability of the Subbasin’s groundwater resources while also maintaining and enhancing local communities, the economy, and the environment. These efforts will culminate in the completion and submittal of a SGMA-compliant GSP by January 2022.

All Projects

Moore Siphon Replacement Project

Dos Rios Ranch SB88 Compliance and Crop Planning Analysis

Hart Ranch On-Farm Irrigation Efficiency Improvements

Orland Project Distribution System Modernization

Water Management Plan Compliance Mapping

Agricultural Development Feasibility Assessment

Analysis of Effects of Water Management on Evapotranspiration from Managed Wetlands

Garden Highway Mutual Water Company Water Control Projects

Richvale Irrigation District Phase I Infrastructure Modernization

Joint Water Districts Board SCADA

Sutter Mutual Water Company Modernization Support

Shasta Valley Groundwater Monitoring

Time Series Evapotranspiration and Applied Water Estimates from Remote Sensing

Customer Delivery Measurement Data Collection and Accounting (RemoteTracker Implementation)

SGMA Technical Support Services and Prop 1 Stressed Basin Grant Project

Efficiency Conservation Definite Plan and Conservation Program

Turlock Irrigation District Agricultural Water Management Plan

Oakdale Irrigation District Agricultural Water Management Plan

Yuba Water Agency Agricultural Water Managment Plan

Feather River Agricultural Water Management Plan (FRRAWMP)

Colusa Subbasin Groundwater Sustainability Plan Development

Madera and Chowchilla Subbasins Groundwater Sustainability Plans

Little Shasta River Efficiency Study

Mill Creek Flow Measurement Improvements

Kettle Spring Improvement Project

Antelope Creek Fish Passage Improvement Project

Conservation Planning and Operations Decision Support