System Operations Permit & Water Management Plan

The System Operation Permit (Permit) represents a unique project by the Brazos River Authority (BRA) that addresses current and future water supply needs throughout the Brazos River basin in a cost-effective and environmentally sensitive manner. On average, nearly six million acre-feet (acft) of water per year pass the southernmost downstream monitoring gage on the Brazos River flowing unused into the Gulf of Mexico. The Permit allows access to a portion of these unused flows and appropriates an immediate, low-cost, and reliable source of water. The Permit also allows the BRA to use naturally occurring flows in the basin and return flows from wastewater treatment plants, in conjunction with the water supply in the 11 existing reservoirs within the BRA water supply system. The uncontrolled natural flow, originating downstream of the BRA’s reservoirs during wet times, can be augmented by releases from BRA reservoirs upstream during dry times and collectively achieve a “system” yield that is greater than the sum of the individual reservoir yields.

A Water Management Plan (WMP), including the Technical Report in support of the WMP (WMP Technical Report), has been incorporated into the Permit and governs the operating principles upon which decisions are made for diversion, storage, and use of water appropriated under the Permit. The Texas Commission on Environmental Quality (TCEQ) issued its final order dated September 16, 2016, approving issuance of the Permit to the BRA, and on November 30, 2016, the Permit was formally issued by the TCEQ.

The TCEQ’s final order directed the BRA to make changes to the WMP and WMP Technical Report so that each conforms with the final order and the Permit. The WMP also includes a conformed accounting plan based on the TCEQ’s adopted approach on return flows and other determinations regarding the amount of the appropriation. The accounting plan was developed to report compliance with the terms and conditions of the Permit and the diversion and use of water under other BRA water rights. On April 2, 2018, the TCEQ Executive Director approved the conformed WMP and WMP Technical Report, associated appendices, and the revised accounting plan, as required by the final order.

The conformed WMP documents are available by clicking the links below. The conformed WMP Technical Report is a lengthy document including six sections or chapters, 18 appendices, and the revised accounting plan. Due to the size of the document, each section has been made available as an individual file to simplify the download process. Click on the blue section links to access each file.

Water Supply

System Operations Drought Study

The Permit issued to the BRA by the TCEQ on November 30, 2016 required the BRA to evaluate the impact of the 2011-2015 drought on the BRA water supply system, and submit its Drought Study to TCEQ within nine months of permit issuance. Two questions were to be addressed:

  1. Did this drought represent a drought worse than the drought of the 1950s, and
  2. Did the drought decrease the amount of water available for appropriation under the Permit?

The purpose of the Drought Study was to update the hydrologic data to include the 2011-2015 drought and evaluate any impacts of the drought on the BRA water supply system. In addressing the first question, the study determined that the drought period that ended in 2015 was worse than the 1950s drought for areas of the Brazos basin upstream and to the northwest of Lake Whitney. For areas downstream and south of Lake Whitney, the 1950s drought remains the worst.

Addressing the second question, the water availability modeling indicated that the amount of water appropriated in the Permit does not need to be reduced.

The Drought Study was submitted to the TCEQ on June 16, 2017. Following review and comment by the TCEQ staff, a revised Drought Study report was submitted to TCEQ on August 4, 2017. The revised Drought Study report was reviewed and accepted by TCEQ. A copy of the final report is available here.

Water Management Plan

Technical Report Supporting the Proposed Water Management Plan


Appendix A-1 Water Rights
Appendix A-2 Agreements and Associated Water Rights
Appendix B-1 Interruptible Water Sale Procedure
Appendix B-2 BRA Policy for Water Sale and Use / Raw Water Sale Procedure
Appendix C-1 Tabulated Projected Demands
Appendix D-1 Williamson County Regional Raw Water System Transmission and Operation Models by CDM
Appendix E-1 Drought Contingency Plan
Appendix E-2 Water Conservation Plan
Appendix F-1 BRA Operations Procedure for Controlled Releases
Appendix F-2 Reservoir Release Options Summary
Appendix G-1 Detailed Demands by River Reach
Appendix G-2 Modeling Appendix
Appendix G-3 Appropriation Model Results
Appendix G-4 Operational Modeling Results
Appendix G-5 Operating Guidelines to Manage Impacts on Fisheries from Reservoir Level Fluctuations
Appendix G-6 Hydrologic Network Relationships and High Flow Pulses
Appendix H Brazos River Authority Accounting Plan