A transformative reservoir project has gained momentum, as the Brazos River Authority approved funding for a contract to deliver a critical surge of water supply, not just locally, but with the potential to improve the overall management of water supply for the BRA system.
The BRA Board of Directors, at its bimonthly meeting March 24, 2025, approved a $9.8 million contract to fund a portion of the permitting and design phase of the Allens Creek Reservoir, a proposed pumped storage reservoir planned for the lower Brazos River Basin.
"It is an exciting project," said Jon King, BRA's chief strategic officer. "There aren't a lot of projects we get to be involved in that have the potential amount of water that Allens Creek does."
The contract with the engineering consulting firm Gannett Fleming, Inc. will include professional services for the extensive studies and analysis required for federal permitting to build the reservoir near the confluence of Allens Creek and the Brazos River.
Between 2030 and 2080, the population of the Brazos River Basin is expected to increase by a staggering 4.6 million people, bringing the total up to more than 10 million residents, according to the 2026 Regional Water Plan.
This proposed reservoir is a strategically located site in the lower basin that will allow the BRA to capture and store Brazos River floodwaters for water supply in a location close to some of the organization's largest users. Significantly, by providing a new water source in the lower basin, the need for releases of water from upstream reservoirs is significantly lessened. The reservoir will also help satisfy regulatory requirements to reduce groundwater pumping, which contributes to land subsidence in the lower Brazos River Basin.
With only three reservoirs in the BRA's Water Supply System being located on the Brazos River itself (Possum Kingdom Lake, Lake Granbury, and Lake Whitney), there are millions of gallons of water that travel the length of the river in excess of environmental needs that are uncaptured, flowing into the Gulf of America unused. The proposed Allens Creek Reservoir will help capture some of the water that would have been lost, further enhancing the water supply options for the entire basin.
Allens Creek Reservoir will make the system more drought-resilient and make water operations more efficient.
All surface water in Texas is owned by the state and held in trust for use by its citizens. The state tasked the BRA with managing water and making it available to municipal, industrial, mining, irrigation, and agricultural interests for beneficial use throughout the Brazos River Basin via water supply contracts. Eleven reservoirs in the BRA water supply system work together to meet a large portion of the basin's water needs. The proposed Allens Creek Reservoir would bring that total to 12. (Learn more about how those 11 work as a system here.)
The recently approved contract covers a series of studies to be completed in less than two years. Gannett Fleming, a firm that has worked on more than 3,000 reservoir and dam projects throughout the US and Canada, will focus on four main areas:
- Surveying services and utilities, including assessing the topography for conceptual design, identifying known utilities within the property, and evaluating potential impact to reservoir design, among other things.
- River geomorphic and sediment transport studies include data collection and field inspection, collecting flow velocity and bank stability, and analyzing the sediment to better inform on pump station locations and embankment protection needs.
- Cultural and environmental resources studies to help inform on conceptual designs and to streamline the planning of future studies and evaluations needed for the permitting application process and reduce uncertainty regarding matters.
- A geotechnical investigation to get a firm understanding of the site’s foundation material and strength.
King said the BRA doesn't have to wait for all of the current study work to be finished before moving on to the next steps. The project team will work concurrently to develop the next phase of work needed to advance the reservoir project.
These studies are significant as they will cover a roughly 9,500-acre site, which is roughly five miles long and three miles wide. The BRA owns the property in Austin County, north of the city of Wallis, that will house the proposed embankment dam, impoundment and associated flowage easements, outlet control structure, spillway, and administrative facilities. The information collected in this effort will be used in future phases of the project to progress permitting and design.
The cost for Allens Creek Reservoir is estimated at $700 million to provide an annual firm water supply of 99,650 acre-feet, the annual water use of about 260,000 families. The overall cost will be refined as the federal Clean Water Act 404 permitting and engineering design process moves forward.
The Allens Creek Reservoir will be the largest project the BRA has undertaken in a very long time, said Matt Phillips, BRA deputy general manager.
"Allens Creek is a massively important project for the BRA. It's a very important project for the basin in terms of future water supply," Phillips said. "These are really exciting times at the BRA."
The reservoir project will be undertaken in multiple phases, including permitting, design, and construction. The permitting process could take between five and 10 years. The permitting and design process will involve the evaluation of all aspects of the project and any potential impacts that it will have on flooding, the environment, and cultural and historical resources. The project will be adapted to mitigate, avoid, or minimize any identified negative impacts. The reservoir also will require permits and authorizations under multiple state and federal regulations including, but not limited to, the US Army Corps of Engineers, the US Environmental Protection Agency, the US Fish and Wildlife Service, the Texas Commission on Environmental Quality, the Texas Historical Commission, and the Texas Parks and Wildlife Department. Once the permitting is complete, the final design and construction phase could take up to another seven years.
Interested in learning more?
- For additional information on the proposed Allens Creek Reservoir, go to https://brazos.org/allenscreek.
- For a complete list of actions the Board of Directors took, go here.
- Watch the full Board meeting here.
- Sign up to be notified of upcoming Board meetings here.
- For any additional questions, email us at information@brazos.org.