To help manage groundwater in the Salinas Valley, M&A is conducting a scientific study of the Deep Aquifers by integrating multiple types of data, collecting new data, and providing recommendations.

Salinas Valley Basin Groundwater Sustainability Agency

Location: Monterey County, California
M&A was retained to conduct a Deep Aquifers Study to fill data gaps and provide scientific guidance to local water managers.


In the Salinas Valley, seawater has intruded shallow aquifers along the coast, so deeper wells were drilled into what are commonly called the Deep Aquifers. With groundwater levels rapidly declining, local water managers question whether the Deep Aquifers are being recharged, how wide the aquifers are, and if there’s a risk of subsidence and further seawater intrusion. The Sustainable Groundwater Management Act requires local agencies to manage these Deep Aquifers, however, it is not understood how extensive the Deep Aquifers are and how much extraction they can support.


The Deep Aquifers Study includes the following:

  • Sorting through the myriad definitions of what constitutes the Deep Aquifers and developing a standard definition on which to base the study
  • Aggregating and analyzing existing data to identify 3 key types of data to collect
  • Partnering with the Ramboll Group and SkyTEM to collect additional geophysical data to map the aquitard that largely distinguishes the Deep Aquifers from overlying aquifers
  • Completing aquifer tests to better understand whether the southern part of the Deep Aquifers is distinct from the northern part
  • Analyzing water quality and isotopes to assess leakage and recharge

Water Policy

  • Assessing economic, administrative, and regulatory constraints on extraction from the Deep Aquifers
  • Evaluating risk associated with not managing the Deep Aquifers

Groundwater Modeling

  • Evaluating existing groundwater model calibration for the Deep Aquifers
  • Developing a water budget using local groundwater models

Groundwater Management

  • Developing guidance for management
  • Synthesizing and integrating data to define the extent of the Deep Aquifers
  • Collecting new data to fill data gaps
  • Recommending monitoring that meets SGMA requirements and the needs of local groundwater management
  • Facilitating interim review of results with other local technical experts
  • Holding stakeholder workshop to increase awareness of the Deep Aquifers and the challenges of sustainable management