Salinas Valley – East Side Aquifer

Statistics

Basin Notes

2003: Bulletin 118 basin description

2018: Draft prioritization comments:

  • Groundwater level decline: Longterm hydrographs show decline.  “In most of the subareas, were seeing historic lows, said MCWRA senior hydrologist Howard Franklin, adding that he expects new data to show that underground seawater intrusion into the basin, which slowed in recent years, has restarted its march down the valley. Santa Cruz Sentinel, 3/5/15
  • Seawater intrusion: This began in the Salinas Valley by the 1930s and now extends more than five miles inland. The Monterey County Flood Control and Water Conservation District built Nacimiento Dam in 1957 and an Antonio Dam in 1965 to provide flood control and to accelerate groundwater recharge to mitigate seawater intrusion. In April 1998, the Monterey County Water Recycling Projects started delivering recycled water for irrigation in lieu of groundwater pumping, effectively slowing the seawater intrusion rate (MCWRA, 2006). Central Coast Groundwater: Seawater Intrusion and other Issues, California Water Foundation, August 4, 2014. 2)The Salinas Valley Water Project is currently being implemented by the Monterey County Water Resources Agency to mitigate groundwater overdraft and seawater intrusion. The project includes mitigation measures such as construction or retrofit of recharge dams, protection of recharge areas, and injection of recycled water into the impacted aquifers.

2018: Final Basin Prioritization: Basin status remains unchanged at high priority.

2022: January 24 – Groundwater Sustainability Plan submitted to DWR

2023: April 27 –  GSP approved by DWR

At-A-Glance

Source: CA DWR
Source: CA DWR

California Water Library Documents About This Basin

Application of Hydrologic Simulation Program—FORTRAN (HSPF) as Part of an Integrated Hydrologic Model for the Salinas Valley, California

U.S. Geological Survey (USGS) | April 8th, 2025

The U.S. Geological Survey (USGS), in cooperation with the Monterey County Water Resources Agency, conducted studies to help evaluate the surface-water and grou

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Salinas Valley Integrated Hydrologic and Reservoir Operations Models, Monterey and San Luis Obispo Counties, California

Monterey County Resources Agency (MCRA) | April 5th, 2025

To evaluate the challenging water management issues in the Salinas Valley, the U.S. Geological Survey, Monterey County Water Resource Agency, and the Salina

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Establishing ecological thresholds and targets for groundwater management

Nature Portfolio (Springer Nature) | April 3rd, 2024

Groundwater is critical for many ecosystems, yet groundwater requirements for dependent ecosystems are rarely accounted for during water and conservation planning. Here w

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Statement of Findings regarding the Approval of the Salinas Valley - East Side Aquifer Subbasin Groundwater Sustainability Plan

California Department of Water Resources (DWR) | April 27th, 2023

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Eastside Aquifer Subbasin Groundwater Sustainability Plan

Salinas Valley Basin Groundwater Sustainability Agency | January 13th, 2022

The 2014 California Sustainable Groundwater Management Act (SGMA) requires that medium- and high-priority groundwater basins and subbasins develop Groundwater Sustainabil

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Salinas Valley Groundwater Basin 180/400-Foot Aquifer Subbasin Groundwater Sustainability Plan

Salinas Valley Basin Groundwater Sustainability Agency | January 3rd, 2020

The 2014 California Sustainable Groundwater Management Act (SGMA) requires that medium and high-priority groundwater basins and subbasins develop Groundwater Sustainabil

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Integrated Regional Water Management Plan for the Greater Monterey County Region

Greater Monterey County Regional Water Management Group | August 31st, 2018

Integrated regional water management (IRWM) is an approach to water resource management in California that is being strongly promoted by the State as a way to inc

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Bulletin 118: California's Groundwater (1980)

California Department of Water Resources (DWR) | January 1st, 1980

Ground water management is a major issue in California.  The Governor's Commission to Review California Water Rights Law, in its December 1978 report, recommends a new g

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GSA Information