Groundwater Monitoring Program

The Borrego Springs Watermaster conducts monitoring programs for groundwater levels and groundwater quality in the Borrego Springs Subbasin (Basin) pursuant to the Stipulated Judgment and the Groundwater Management Plan (GMP). Generally, the main objectives of the monitoring programs are to collect the data necessary to:

  • Demonstrate progress toward meeting the Sustainability Goal of the GMP, which is to ensure that by 2040 the Basin is operated within its Sustainable Yield without causing Undesirable Results. The main Undesirable Results to be avoided are the significant and unreasonable occurrences of the following Sustainability Indicators: chronic lowering of groundwater levels; reductions in groundwater storage; and degradation of groundwater quality.
  • Inform adaptive management of the Basin to achieve the Sustainability Goal.
  • Improve the Borrego Valley Hydrologic Model (BVHM) in a cost-effective manner that offers the most benefit for the resources expended.

In Spring 2023, the Watermaster updated its Groundwater Monitoring Plan (GWMP), which describes the monitoring objectives, the current monitoring network, frequency of monitoring, constituents monitored, and recommendations for expanding/improving the monitoring programs for both the groundwater-level and groundwater-quality monitoring.

On this page you will find:

  • Expansion of the Groundwater Monitoring Program
  • Current Groundwater Monitoring Networks
  • Semi-Annual Monitoring Reports
  • Public Outreach Effort Information/FAQ
  • Information on Inactive/Abandoned Wells

Expansion of the Groundwater Monitoring Program

The GWMP identified and recommended areas for additional monitoring to improve the groundwater-level and groundwater-quality monitoring programs. Filling these data gaps and expanding the groundwater monitoring networks is intended to improve the understanding of the hydrogeology of the Basin by improved characterization of: seasonal and long-term trends in groundwater quality and groundwater levels; the effects of recharge and GMP implementation on groundwater levels and quality, and the areal and depth-specific distribution of groundwater quality, groundwater elevations, groundwater-flow directions, and hydraulic gradients.

To expand the groundwater monitoring network, the Watermaster used funding from the California Department of Water Resources (DWR) Sustainable Groundwater Management (SGM) grant. The DWR SGM grant allocated $237,000 under Category C for Task 5: Identify and Address Improperly Abandoned Wells and Task 3: Construction Management (to support Task 5). SGM grant funding was used to accomplish the following objectives:

  1. Expand the Watermaster’s groundwater monitoring network to fill in data gaps identified in the GWMP.
  2. Improve the longevity of existing wells in the groundwater monitoring program.

Compared to the monitoring network in the GWMP, a total 21 new wells were added to the monitoring network. The work to expand the monitoring program is documented in a TM describing the expansion of the Monitoring Program and Conversion of Inactive/ Abandoned Wells. The new wells added to the monitoring networks include:

  • 18 wells identified and added through the efforts described in this memo and funded using SGM funding:
    — 13 private wells
    — Five monitoring wells at the Borrego Landfill
  • One new well recently constructed by BWD (an existing participant in the monitoring
    program). This well is monitored by BWD and data is shared with Watermaster staff
    semi-annually.
  • A multi-depth completion well (two wells) constructed using DWR Technical Support
    Services (TSS) funding. These wells are monitored by DWR and the data is shared
    semi-annually with Watermaster staff.

Current Groundwater Monitoring Networks

As of spring 2025, there are 62 wells in the current groundwater monitoring network.

Groundwater Level Monitoring Network – Spring 2025

As of spring 2025, there are 64 wells monitored for groundwater levels. Watermaster staff measures depth-to-groundwater at 35 of the wells in the network and 29 wells have pressure transducers installed which measure groundwater-levels at 15-minutes to 1-hour intervals.

Map of the Current Groundwater Level Monitoring Network (excerpt from Spring 2025 Semi-Annual Monitoring Report)

Groundwater Quality Monitoring Network – Spring 2025

As of spring 2025, there are 43 wells in the current groundwater-quality monitoring network. Watermaster staff collect grab water quality samples at 34 of the 43 wells in the network. BWD staff—the main cooperating monitoring entity—collects grab water quality samples at 9 of the 43 wells (these are BWD municipal supply wells).

Map of the Current Groundwater Quality Monitoring Network (excerpts from Spring 2025 Semi-Annual Monitoring Report)

Semi-Annual Monitoring Reports

The Watermaster currently conducts groundwater-level and groundwater-quality monitoring events in the Spring and Fall of each water year. The data collected from the monitoring event are compiled into a Semi-Annual Monitoring Report, which is presented to the Watermaster Board. Semi-Annual Monitoring Reports include:

Get Involved! Public Outreach Effort

To expand/improve the Groundwater-Level and Groundwater-Quality Monitoring Programs, the Watermaster has asked the Borrego Springs community to help identify well owners that are willing to allow the Watermaster to monitor their well. The following outreach materials are available to any member of the public who wishes to get involved:

  1. Letter to Request Participation
  2. Potential Participant Information Form
  3. Map of the Current Groundwater Monitoring Network
  4. Frequently Asked Questions

Example of a converted monitoring well added to the Groundwater Monitoring Network.

Abandoned Wells in the Basin

A well is considered abandoned when it has not been pumped or used for supplying water for at least one year. Oftentimes, abandoned wells are left unsecured and open at the wellhead, which poses safety concerns for the public and the groundwater Basin.

Interested in learning more about the requirements and process for abandoning a well? Check out this FAQ to learn more!

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