Basin Monitoring Program Task Force

As an outgrowth of the Nitrogen/TDS Task Force, the agencies responsible for implementing the Basin Plan Amendments formed the Basin Monitoring Task Force, and SAWPA was identified to administer/facilitate that effort.

As follow up to the Nitrogen TDS Task Force efforts, a new Task Force was formed in August 2004 consisting of 20 water agencies in the Santa Ana River Watershed to compile and collect monitoring data to evaluate the water quality of the Santa Ana River on an annual basis, and the groundwater basins throughout the watershed every five years. The water agencies responsible for completing these tasks were included in the RWQCB Basin Plan as a result of the January 2004 Nitrogen and TDS Basin Plan Amendment.

Regulatory Links

The Task Force is administered by SAWPA and meets monthly. The primary work tasks include the following:

Preparation of an annual water quality report for the Santa Ana River Reaches 2, 4 & 5 necessary to assure compliance with both surface water objectives of the defined river reaches and the underlying groundwater objectives.

Preparation of a watershed-wide TDS/Nitrogen ambient water quality update every five years to determine the current ambient groundwater quality in the watershed for TDS/Nitrogen.

The completion of a watershed-wide TDS/Nitrogen groundwater monitoring program and annual SAR report is intended to assess current water quality, to determine whether TDS/Nitrate-Nitrogen water quality objectives for management zones are being met or exceeded, and to update assimilative capacity findings. The Task Force has also led past updates of the Santa Ana River waste load allocation model. In short, waste load allocations distribute a share of total TDS and TIN wasteloads to each of the publicly owned treatment works (POTWs) that discharge treated wastewater to the Santa Ana River and its tributaries.

Taskforce Agenda Packets and Meeting Notes

Meeting Date Agenda Meeting Notes Presentations Handouts
May 29, 2024


Presentation 1 Presentation 2

Handout 1 Handout 2

March 4, 2024


Draft Meeting Notes

Presentation 1

Handout 1 Handout 2

January 29, 2024


Meeting Notes

Presentation 1

Handout 1 Handout 2

Santa Ana River Water Quality Reports

These reports fulfill the requirement to prepare an Annual Report of Santa Ana River Water Quality pursuant to the 2004 Basin Plan Amendment. Contained within these reports are water quality data required to implement the surface water monitoring program necessary to determine compliance with the nitrogen and TDS objectives of the SAR and, thereby, the effectiveness of the wasteload allocations.

2022 Report | Appendix B: Water Quality and Flow Data

2021 Report | Appendix B: Water Quality and Flow Data

2020 Report | Appendix B: Water Quality and Flow Data

2019 Report | Appendix B: Water Quality and Flow Data

2018 Report | Appendix B: Water Quality and Flow Data

2017 Report | Appendix B: Water Quality and Flow Data

Recomputation of Ambient Water Quality (AWQ) Reports

As part of the agreement to adopt the 2004 Basin Plan amendment, the affected parties have agreed to recompute ambient water quality for individual management zones every three years. The determination of current ambient quality shall be accomplished using methodology consistent with that employed by the TIN/TDS Taskforce (20-year running averages) to develop the TDS and nitrate water quality objectives included in the 2004 Basin Plan.

Santa Ana River Wasteload Allocation Model (WLAM) Reports

Wasteload allocations for regulating discharges of TDS and total inorganic nitrogen (TIN) to the Santa Ana River, and thence to groundwater management zones recharged by the River, are an important component of salt management for the Santa Ana Basin.

For further information about this project, please contact Ian Achimore at

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