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What is Groundwater?


Groundwater is found beneath the Earth’s surface in the spaces between soil, sand, gravel, or rocks. These underground reservoirs, called aquifers, range in size from small pockets of water to vast underground formations. Groundwater is the world’s largest source of freshwater and supports 40 to 60% of California's freshwater needs. 

Groundwater provides essential support to agriculture, industries, and communities while playing a crucial role in sustaining rivers, wetlands, and habitats. Furthermore, California's groundwater is critical in mitigating the impacts of drought because it is available even during dry years; however, long periods of drought or overextraction can lead to groundwater depletion. 

The Sustainable Groundwater Management Act

On September 16, 2014, Governor Jerry Brown signed into law a three-bill legislative package, composed of AB 1739 (Dickinson)SB 1168 (Pavley), and SB 1319 (Pavley), collectively known as the Sustainable Groundwater Management Act (SGMA)

The goal of SGMA is to halt overdraft and achieve locally defined sustainability goals in California’s 94 high and medium priority groundwater basins. SGMA empowers local governments and water agencies within these high and medium priority basins to form Groundwater Sustainability Agencies (GSAs).  The GSAs are required to develop and implement Groundwater Sustainability Plans (GSPs) that provide the framework for how local groundwater resources are managed to achieve long-term sustainability.


GSAs are required to achieve sustainability within 20 years of implementing their respective GSPs. GSPs for critically overdrafted basins (i.e., where groundwater levels are experiencing a significant declining trend) were due in January 2020; while GSPs for medium and high priority basins were due in January 2022. The California Department of Water Resources (DWR) is the oversight agency providing technical assistance and review of GSPs to assess and evaluate whether the plans are compliant with the SGMA. GSPs that are not found compliant with the SGMA are referred to the State Water Resources Control Board, which works with these GSAs to resolve compliance failure issues and conform with the SGMA requirements. All documents submitted by GSA's to DWR can be found on the SGMA Portal.

GSAs are required to carry out projects and management actions to reach their basin sustainability goals. This may include groundwater recharge projects and adaptive management strategies to sustainably manage the groundwater resources. GSAs are required to submit annual update reports to DWR to document water supply and usage, and to update the progress achieved by any projects and/or management strategies implemented since the adoption of the GSP. GSAs are required to perform a five-year update of the GSP by evaluating the success of projects and management actions implemented, and whether projected conditions at the time of the GSP development are accurate compared to observed conditions. The 5-year review may include a reevaluation of the sustainable yield and confirmation of sustainability thresholds established in the GSP. DWR expects plans to adapt over time as conditions change, especially as California experiences ongoing weather extremes and periods of severe drought conditions.

One of the management strategies that every GSA will have to implement is how to address groundwater allocation within basins without adjusting groundwater rights. Groundwater Pumping Allocations under California's Sustainable Groundwater Management Act provides an overview of groundwater rights and methods to approach allocations in the context of SGMA. 

The Yucaipa Groundwater Sustainability Agency

The Yucaipa Groundwater Sustainability Agency (GSA) was formed in 2017 by a Memorandum of Agreement (MOA) between local water purveyors, municipalities, and regional water agencies to jointly develop and implement a Groundwater Sustainability Plan (GSP).   The following members of the GSA decided to  refer to the organization as the Yucaipa Sustainable Groundwater Management Agency, or Yucaipa SGMA to directly link the organization with the Sustainable Groundwater Management Act.


Members of the Yucaipa Sustainable Groundwater Management Agency include:

City of Redlands

City of Yucaipa

San Bernardino Valley Municipal Water District

San Gorgonio Pass Water Agency

South Mesa Water Company

South Mountain Water Company 

Western Heights Water Company

Yucaipa Valley Water District

The roles and responsibilities of the Yucaipa SGMA were set forth in bylaws adopted in May 2018. The Yucaipa SGMA is controlled by a governing board composed of one representative of each of the parties to the Memorandum of Agreement. The officers of the governing board include a president, vice president, secretary, and treasurer. The officers and one alternate are chosen at the first regular meeting held each calendar year. The voting structure for matters pertaining to the establishment and implementation of the administrative components of the Yucaipa GSA are by simple majority (51%) of the voting parties, wherein each member agency holds a single vote. A majority of the board is considered a quorum for purposes of meeting and decision making.

The Plan Manager for the Yucaipa GSA is:

Mark Iverson, President Yucaipa GSA (

Yucaipa Groundwater Sustainability Agency

c/o San Bernardino Valley Municipal Water District

380 East Vanderbilt Way, San Bernardino, California 92408

A Sustainable Groundwater Basin

The SGMA defines sustainable groundwater management as the “management and use of groundwater in a manner that can be maintained during the planning and implementation horizon without causing undesirable results” (California Water Code, Section 10721). Undesirable results, as defined in the SGMA, are any of the following effects caused by groundwater conditions occurring throughout the basin: 

  • Chronic lowering of groundwater levels indicating a significant and unreasonable depletion of supply if continued over the planning and implementation horizon

  • Significant and unreasonable reduction of groundwater storage

  • Significant and unreasonable degradation of water quality, including the migration of contaminant plumes that impair water supplies

  • Significant and unreasonable seawater intrusion

  • Significant and unreasonable land subsidence that substantially interferes with surface land uses

  • Depletions of interconnected surface water that have significant and unreasonable adverse impacts on beneficial uses of the surface water


The sustainability goal for the Yucaipa GSA is to manage groundwater resources for sustainable, long-term use in the Yucaipa Subbasin. Long-term sustainable management includes: 

  • Maintaining sufficient groundwater in storage to allow for ongoing groundwater production that meets the operational demands of the water purveyors and private well users, and the regulatory commitments established in the Yucaipa GSP Plan Area.

  • Ensuring that groundwater production does not result in significant and unreasonable loss of groundwater-dependent ecosystems.

Of the six sustainability indicators outlined by the SGMA, four apply to the Yucaipa Subbasin:

(1) chronic lowering of groundwater levels 

(2) significant and unreasonable reduction of groundwater storage

(3) significant and unreasonable land subsidence

(4) depletions of interconnected surface water

Sustainability criteria were established in the Yucaipa GSP for each of these four sustainability indicators to evaluate when management actions would need to be implemented to prevent undesirable conditions in the Yucaipa Subbasin.


What is SGMA?

Sustainable Groundwater Management Act (SGMA), effective January 1, 2015, requires the regulation of groundwater for the first time in California’s history and provides new authority to local agencies to implement these requirements. The intent of SGMA is to strengthen local management of specified groundwater basins that are most critical to the state’s water needs by regulating groundwater use.

What is a groundwater basin?

A groundwater basin is an area underlain by permeable materials that can store a significant supply of groundwater to wells. Groundwater supplies 40 to 60% of California’s freshwater needs.

What does sustainable management mean?

Sustainable groundwater management is the use of groundwater that can be maintained without causing undesirable results. Undesirable results are defined in SGMA as any of the following:

• Chronic Lowering of Groundwater Levels

• Reduction of Groundwater Storage

• Degraded Water Quality

• Land Subsidence

• Depletions of Interconnected Surface Water

• Seawater Intrusion


What does a Groundwater Sustainability Agency do?

The primary purpose of a Groundwater Sustainability Agency (GSA) is to develop and implement a Groundwater Sustainability Plan (GSP) to achieve long-term groundwater sustainability. GSAs are empowered to implement projects including those related to data collection to understand basin characteristics and community needs, register and meter domestic and agricultural wells, mitigate against overdrafts, implement rules and regulations, and assess fees.


What is a Groundwater Sustainability Plan?

A GSP is the state-mandated plan that establishes the framework for sustainably managing and preserving the beneficial uses of groundwater resource today and into the future. Each GSP will contain an assessment of the basin’s conditions and will include action items to implement the necessary monitoring, management, and enforcement to achieve sustainability.


What authority do GSAs have?

Under SGMA, GSAs are empowered to:

  • Adopt rules, regulations, ordinances, and resolutions

  • Monitor compliance and enforcement

  • Require registration of groundwater extraction facilities (wells)

  • Require appropriate measurement devices and reporting of extractions

  • Investigate, appropriate, and acquire surface water rights, groundwater, and groundwater rights into the GSA;

  • Acquire or augment local water supplies to enhance the sustainability of the groundwater basin

  • Propose and collect fees

  • Adopt and fund a groundwater sustainability plan according to existing laws


How will the implementation of SGMA affect residents in the Yucaipa Subbasin?

Through the successful implementation of SGMA, residents can be assured that a reliable source of water will be available into the future.   Residents who have domestic wells may be asked to supply information about your well or wells, how much water you produce, and what your water quality is like. This information will help the Yucaipa SGMA understand groundwater conditions in the basin, and to ensure that you and other groundwater users like you continue to benefit from this precious resource for years to come.

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