Development of Six Groundwater Sustainability Plans for Salinas Valley

M&A was the lead consultant that developed and submitted the Groundwater Sustainability Plan for the 180/400-Foot Aquifer Subbasin in 2020. We managed and developed five other Salinas Valley subbasin GSPs, which were submitted January 2022.


M&A was the lead consulting firm in the development of Groundwater Sustainability Plans (GSPs) for the six separate subbasins within the Salinas Valley Basin. We developed the GSP for the critically over-drafted 180/400-Foot Aquifer Subbasin, which was submitted in January 2020. We worked closely with the Salinas Valley Basin Groundwater Sustainability Agency (SVBGSA) and developed technical content, provided policy strategy, and coordinated with various stakeholders in the five other subbasins. The Salinas Valley Basin is primarily agricultural with an important source of surface water supply, which is managed conjunctively with groundwater pumping to meet agricultural, urban, and domestic needs. Sustainability in the Salinas Valley depends on the joint effort of M&A and other water agencies and regulators to successfully integrate the surface water operations with the groundwater pumping system.


M&A led both the technical aspects of the GSP, such as developing the hydrogeologic conceptual model, and the policy aspects such as developing sustainable management criteria and establishing the projects and actions that will achieve sustainability. Working collaboratively with the GSA and stakeholders, M&A created an approach for jointly developing all six GSPs in the Valley. The approach acknowledged the unique geologic and hydrogeologic aspects of each subbasin, while simultaneously developing unified groundwater management solutions that cross subbasin boundaries and leverage all of the water resources in the Salinas Valley. This innovative approach met the competing objectives of obtaining stakeholder buy-in and having ample resources to solve the Valley’s groundwater problems.

The hydrologic conceptual model developed by M&A provides the hydrogeologic framework or aquifer layering and characterization of the groundwater system. This project involved evaluating and updating a previous investigation of regional and local information regarding physiography, climate, hydrogeology, groundwater levels and groundwater movement, surface water features, recharge, hydraulic properties for the aquifer units, discharge including well pumping, and groundwater salinity.

Water Policy and Economics

  • Developed sustainable management criteria

Groundwater Modeling

  • Developed the hydrologic conceptual model and groundwater budgets

Groundwater Management

  • Provided technical and regulatory advice to the GSA on SGMA requirements
  • Considered local groundwater management planning activities
  • Developed and presented technical content at planning and advisory committee meetings and at GSA Board meetings
  • Developed a roadmap for GSA funding mechanisms during early SGMA implementation
  • Developed grant applications for DWR GSP development and implementation funding

Data Management Services

  • Developed a robust data management and mapping system with a web interface and data download capabilities