Wyandotte Creek GSA sets groundwater objectives to 2015–2025 average

The Wyandotte Creek Groundwater Sustainability Agency on a voice vote approved amendments that set measurable objectives (MOs) for groundwater levels to the average recorded at each representative monitoring well from 10/01/2015 through 09/30/2025 and established interim milestones (IMs) equal to those MOs.

Becky Fairbanks, GSA project manager, introduced the item and handed the presentation to Ryan (GSA staff), who said the subbasin shows no persistent downward trend and that the proposed change better reflects the basin’s intent to maintain current conditions. "Our recommendation is to update the measurable objective to the average groundwater level at each RMS well, the average being calculated from 2015 through 2025," Ryan said.

Ryan explained the technical rationale: the board previously modified minimum thresholds to protect domestic wells; the proposed MO change avoids setting objectives below historical lows and recognizes year-to-year variability driven by wet and dry years. He described monitoring upgrades completed in March — five new groundwater-level monitoring sites and five stream gauges placed across the subbasin, including locations on the Feather River and Wyandotte Creek — that will feed data into annual reports and the next periodic evaluation.

A board member asked where the current MOs are set; Ryan replied they are "a little bit below the historical low" and that bringing the MOs to the 2015–2025 average would place objectives in the historical mean. He also noted the advisory committee reviewed the method and expressed general consensus.

A board member moved to approve the MO amendment "to establish MOs equal to the average groundwater levels observed between 10/01/2015 and 09/30/2025." The motion was seconded and approved by voice vote. A second motion to set IMs equal to the respective MOs was likewise seconded and passed by voice vote. The transcript records affirmative "aye" votes; it does not record a roll-call tally.

The changes are procedural amendments to how the GSP will define objectives and monitoring triggers; Ryan said data from the new monitoring sites will be incorporated during the five-year periodic evaluation cycle and in annual reporting. The board will continue to rely on monitoring and implement projects as conditions require.

Next steps: the approved amendments will be incorporated into the GSP plan amendments and reflected in upcoming annual reports and the next PRC evaluation cycle.