Greenfield GSA reports ongoing mapping, monitoring of groundwater-dependent ecosystems

The Greenfield City Groundwater Sustainability Agency heard a status report on efforts to map and monitor groundwater-dependent ecosystems across parts of the Salinas Valley.

Curtis, the agency’s general manager, told the board staff and contractors have used aerial photography, USGS maps and targeted field surveys — including California Rapid Assessment Method (CRAM) vegetation assessments — to identify areas where groundwater is within roughly 30 feet of the surface and where riparian and wetland corridors exist. He said those efforts establish a baseline to determine whether conditions change over time and whether groundwater use is affecting ecosystems.

Curtis noted the Salinas River system is more complex than the Arroyo Seco because of reservoir releases, and that previous severe drought led to cottonwood die‑offs and other vegetation changes. He said the agency is replicating the assessment process across subbasins, conducting desktop analyses and periodic field checks to track change.

Why it matters: Groundwater‑dependent ecosystems can be sensitive to changes in groundwater levels and are one of the considerations the agency must account for in implementing its Groundwater Sustainability Plan (GSP). Establishing robust baseline data helps the agency determine whether management actions or protections are needed in the future.

Next steps: The general manager said staff will continue survey work, repeat CRAM assessments periodically, and use the results to inform any future management actions as required by the GSP. He asked the board to be aware of survey activity along river corridors and said staff would keep the board informed.