Seawater Intrusion Contour Maps

Summary

The Monterey County Water Resources Agency analyzed seawater intrusion in the 180-Foot and 400-Foot Aquifers based on 2025 data, finding slight advancements of the 500 mg/L chloride contour in the 180-Foot Aquifer and a delineated 'seawater intrusion review area' in the 400-Foot Aquifer. The Agency added seven new monitoring sites and developed multiple map products to demonstrate geochemical conditions and water quality variability. The analysis also included a depiction of the extent of seawater intrusion as defined by the Pajaro Valley Water Management Agency for areas north of Elkhorn Slough.

Details

Subject

Seawater Intrusion Contour Maps

Summary

The Monterey County Water Resources Agency analyzed seawater intrusion in the 180-Foot and 400-Foot Aquifers based on 2025 data, finding slight advancements of the 500 mg/L chloride contour in the 180-Foot Aquifer and a delineated 'seawater intrusion review area' in the 400-Foot Aquifer. The Agency added seven new monitoring sites and developed multiple map products to demonstrate geochemical conditions and water quality variability. The analysis also included a depiction of the extent of seawater intrusion as defined by the Pajaro Valley Water Management Agency for areas north of Elkhorn Slough.

Report Date

2026-04-20

Report Type

study

Report Title

Review of the 2025 Seawater Intrusion Contour Maps

Authoring Body

Monterey County Water Resources Agency

Reporting Period

2025