Humboldt County Public Works is coordinating the local response to the Sustainable Groundwater Management Act Opens a New Window.  (SGMA). SGMA was signed into law in September 2014 and applies to designated medium- and high-priority basins within the state. Currently there is one medium-priority basin, the Eel River Valley groundwater basin Opens a New Window. , within Humboldt County. SGMA is administered at the state level by the California Department of Water Resources (DWR) and the State Water Resources Control Board.

  • Watch this short video to learn more about groundwater. 

Eel River Valley Groundwater Sustainability Plan Updates

Technical memorandums will be made available as completed on the County’s Groundwater-Eel River Resources webpage for public review.

October 15, 2021 Project Update

In accordance with California Water Code Section 10728.4, the Humboldt County Groundwater Sustainability Agency hereby provides notice of intent to adopt a Groundwater Sustainability Plan for the Eel River Valley groundwater basin (Basin No. 1-010) for compliance with the Sustainable Groundwater Management Act. 


  • November 22, 2021- Draft Groundwater Sustainability Plan will be released for a 30-day review period. If release of the draft plan is delayed, the 30-day review period will be adjusted accordingly.
  • December 2021- An informational report will be provided to the Board of Supervisors at one of the Board’s regularly scheduled meetings. 
  • January 2022- The Board of Supervisors will consider adoption of the Groundwater Sustainability Plan at a public hearing no earlier than 90 days from the date of Notice of Intent. 
  • January 31, 2022- Deadline for submitting the adopted Groundwater Sustainability Plan to the California Department of Water Resources. 

The draft Groundwater Sustainability Plan will be posted on the County’s Groundwater-Eel River Resources webpage.

August 2021 Project Update

Twenty-three (23) new monitoring wells were installed this in April-June 2021 by Fisch Drilling and Clear Heart Drilling to expand the monitoring network.  Groundwater level monitoring, surface water flow monitoring, water use monitoring, water quality sampling, and aquifer characterization are ongoing.  A hydrologic model using the GSFLOW software has been calibrated and analysis of the groundwater basin is currently in progress, in coordination with the U.S. Geological Survey.  The model will be used to support the development of sustainable management criteria.

 A set of memos (brief reports) summarizing the technical studies and data collection will be completed in early September.  A message will be sent out when the full set of memos has been posted to the website.

 Humboldt County plans to conduct a series of stakeholder meetings in late September in coordination with the Humboldt County Resource Conservation District and Western Resource Strategies.  The County will be reaching out to organizations and individuals in early September to schedule those meetings.

 Draft chapters of the Groundwater Sustainability Plan will be released in October for review and public comment.  The Humboldt County Board of Supervisors is expected to consider approving the plan in December 2021 or January 2022.  Unless the deadline is extended by the State, the deadline to submit the plan to the Department of Water Resources is January 31, 2022.  The Groundwater Sustainability Plan will identify future monitoring activities and potential management actions or projects based on the sustainable management criteria. No management actions or projects will be implemented before the plan is approved.

 Documents related to the Groundwater Sustainability Plan and materials from past meetings are available here:

Humboldt County Groundwater Sustainability Agency Formation (May 2020)

Navigate to the Humboldt County GSA Home page for information and documents related to the GSA administration.

Eel River Valley Groundwater Basin

Navigate to the Eel River Valley Groundwater Basin Home or Resources page for information and documents related to the Eel River Valley groundwater basin.

Mad River Valley-Mad River Lowland Groundwater Basin

Humboldt County Comment Letter (August 20, 2018) for Mad River Valley-Mad River Lowland

Sustainable Groundwater Management Act

The Sustainable Groundwater Management Act (SGMA) is a combination of three bills signed by California Governor Jerry Brown in 2014:  Assembly Bill (AB) 1739, Senate Bill (SB) 1168, and SB 1319.  SGMA provides local agencies with the framework to manage groundwater basins in a sustainable manner.  The legislation recognizes that groundwater is most effectively managed at the local level, and local agencies will need to achieve groundwater sustainability within 20 years of submitting a groundwater sustainability plan.  

In SGMA, sustainable groundwater management is defined as management of groundwater supplies in a manner that can be maintained in planning and implementation phases without causing undesirable results.  Undesirable results include significant and unreasonable chronic lowering of groundwater levels, reduction of groundwater storage, seawater intrusion, degraded water quality, land subsidence, and interconnected surface waters.  

SGMA requires that California groundwater basins identified as high or medium priority establish a Groundwater Sustainability Agency and develop a plan for sustainable management by January 31, 2022. If the local GSAs fail to follow the timeline, then the State Water Resources Control Board will step in and intervene in local groundwater management.

Data Viewers and Tools

SGMA Data and Tools

SGMA Data Viewer

2018 SGMA Basin Prioritization Dashboard

Natural Communities Commonly Associated with Groundwater (NCCAG) Data Viewer