The Basin Setting project began late in 2018 to develop portions of the Groundwater Sustainability Plan (GSP) in each of the three subbasins in Butte County: Vina, Butte, and Wyandotte Creek subbasins.  Our department has contracted with Davids Engineering to conduct the work on behalf of all Groundwater Sustainability Agencies in these subbasins.  The project is funded by the Prop 1 GSP planning grant. 

This PowerPoint provides an overview of the project scope.

The “Basin Setting” portion of the GSP describes characteristics of the subbasin that both change and do not change over time.  Characteristics like the geology, structure and physical characteristics of the aquifer systems, and how water moves in and through the system (such as recharge and pumping areas) generally do not change over time.  This understanding of the basin’s physical characteristics is called the Hydrogeologic Conceptual Model.  This becomes the basis for our understanding groundwater behavior and cause and effect relationships in the groundwater system.  Additional sub-sections of the Basin Setting describe characteristics of the subbasin that do change over time and will likely change in the future, such as changes in climate (affecting water supplies), land use, water demands, etc.  This includes a description of Groundwater Conditions (groundwater levels, water quality conditions, and subsidence if present) and the Water Budget.  The Water Budget is our accounting (quantitative) of the inflows and outflows of water through the surface water and groundwater systems.  Information in the Basin Setting portion of the GSP as well as the description of the Monitoring Network will support and frame future and complex discussions that will occur to define Undesirable Results and thresholds for the successful management of the subbasins through Projects and Actions.

Public Review Process and Next Steps

Summer 2020 brings the completion of the Basin Setting Project and the start of the next phase of GSP development in these subbasins.  Portions of the GSPs for the Vina, Butte and Wyandotte Creek Subbasins will soon be available for public review and comment.  Public review documents will include the draft Basin Setting chapter which includes the hydrogeologic conceptual model, groundwater conditions, and water budget information for the subbasin.  Significant portions of the Monitoring Network chapter will also be available for review.  Upon release the draft chapters will be posted to each subbasin’s website and a notice to all interested parties will inform stakeholders of the 30 day comment period.  Comments will be compiled by staff and provided along with the draft chapters to advisory boards and committees in each subbasin for discussion and potential recommendation.  The timelines and exact comment review periods will vary as the draft chapters from the different subbasins will not all be available at the same time.  They will however all have a 30 day comment period beginning upon their release. 

Although these chapters will not be considered final until they are combined with the rest of the GSP for review and public comment sometime in mid-2021, public review and comment now will provide a good foundation for moving into development of Sustainable Management Criteria (SMC) and other portions of the plans later this summer and fall.  Comments received will also help inform advisory committees and GSA Boards of significant issues that need to be considered during development of SMCs and Projects and Management Actions.

Preliminary Results Presented and Available Online

The Consultant Team for the Basin Setting Project and Department Staff presented preliminary results at a variety of public meetings (most of which were online only).  The table shows a schedule of when and what content was presented in each subbasin.  Links will direct you to the appropriate subbasin web page where meeting agendas and presentations are posted.  Please contact Christina Buck with questions.

Acronyms
GSP-Groundwater Sustainability Plan
SHAC- Stakeholder Advisory Committee
TAC- Butte County Technical Advisory Committee
HCM- Hydrogeologic Conceptual Model

For upcoming meetings and updates on GSP development in each subbasin, visit the subbasin’s webpage:

Butte Subbasin https://www.buttebasingroundwater.org/
Vina Subbasin https://www.vinagsa.org/
Wyandotte Creek Subbasin https://www.wyandottecreekgsa.com/