Title
Update on Monterey County Water Resources Agency engagement in groundwater management activities
a. Groundwater Monitoring Program
b. Salinas River Discharge Measurement Series
c. Planning and Technical Support for the Salinas Valley Basin Groundwater Sustainability Agency
d. Groundwater Monitoring and Remedial Measures Plan for the Monterey Peninsula Water Supply Project
Report
SUMMARY/DISCUSSION:
a. Groundwater Monitoring Program
In October 2024, the Board of Supervisors of the Monterey County Water Resources Agency (“Agency”) adopted Ordinance No. 5426 and approved the Agency’s Groundwater Monitoring Program (“GMP”) Manual. Since that time, the Agency has implemented the well registration, groundwater elevation monitoring, groundwater quality monitoring for seawater intrusion, and groundwater extraction monitoring components of the GMP. Some components of the GMP occur year-round, such as monthly groundwater level monitoring, while others like water quality monitoring for seawater intrusion are seasonal and occur primarily during the summer months.
In May 2026, Agency staff began the annual water quality sampling of wells in the Deep Aquifers, as described in the “Monitoring Plan for the Deep Aquifers,” which was prepared by the Agency and adopted by the Board of Supervisors of the Agency in December 2025. The results from Deep Aquifers water quality sampling are used to identify changes in water chemistry, discern any indications of seawater intrusion, and provide data to inform the depositional environment and age of groundwater in the Deep Aquifers. As of the date of this report, laboratory analysis of the 2026 Deep Aquifers water quality samples is ongoing.
In June 2026, Agency staff began collecting groundwater samples as part of the program that monitors water quality for seawater intrusion. Production wells in the 180/400-Foot Aquifer, Eastside Aquifer, and Monterey Subbasins are sampled twice per year, in June and August, and monitoring we...
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