Wyandotte Creek GSA presents 2024 subbasin status report showing groundwater rebound after wet year

Kelly Peterson, a GSA presenter, told the Wyandotte Creek Groundwater Sustainability Agency board that the GSA has produced a new, illustrated annual status product summarizing hydrology, groundwater use and monitoring for the 2024 water year.

The report covers water year 2024 (Oct. 1, 2023–Sept. 30, 2024) and characterizes 2024 as an "above normal" hydrologic year. Peterson said the wetter conditions, the second non‑dry year in a row, led to rebounds in groundwater levels and reduced demand for pumped groundwater because of greater surface‑water availability.

The report lays out water‑use shares for the subbasin and monitoring results. Peterson said about 97% of groundwater use in the subbasin is agricultural; municipal and rural residential use are small shares. She said spring‑to‑spring groundwater levels rose about one foot in the most recent comparison and that fall levels were about 12 feet higher than the subbasin's measurable objectives for representative wells.

Peterson said storage showed cumulative increases over the past 24 and 10‑year windows — roughly a 1,000 acre‑foot per year increase across 24 years and about 2,000 acre‑feet per year when measured over the last 10 years — and that the Wyandotte subbasin is the one of the three Butte County subbasins showing cumulative surplus. She also summarized groundwater quality monitoring: two multicompletion monitoring intervals at a new well near Lone Tree and Cox recorded salinity exceedances consistent with the well's initial conditions at drilling; staff plan to add data loggers for higher‑frequency monitoring and to work with the Department of Water Resources (DWR) on interpretation.

Peterson highlighted program administration items: the GSA has established a fee structure to fund long‑term operations, the GSA's annual report is posted online, and the agency received about $5,500,000 in DWR grant funding for projects. She said the illustrated packet is intended as a short, shareable summary for board members and advisory committee members and that staff will present the same format to the Wyandotte advisory committee for feedback.

Board members asked clarifying questions about basin boundaries and the rationale for including a small area north of the diversion canal in the GSA's sphere of influence; staff replied that some boundary pieces follow existing water district boundaries and spheres of influence established in earlier municipal service reviews. There was no action requested: the presentation was accepted as information and the meeting proceeded to the next agenda item.

The packet and a technical annual groundwater status report are available on the GSA website, Peterson said; the GSA files annual reports to the state on or before the April 1 deadline.

Ending: The board did not take action on the report beyond accepting it for information. Staff said printed handouts and web‑posted copies will be made available to board members and advisory committee members.