As the growth of the Williamson County general area continues to expand, so does its need for water.
The Brazos River Authority is working on a way to address that.
On Monday, Sept. 30, 2024, the Brazos River Authority Board of Directors took another step toward increasing the capacity of raw water supply during drought conditions for use by the cities of Georgetown, Round Rock, and the Brushy Creek Municipal Utility District.
The Williamson County Regional Raw Water Line (WCRRWL) delivers raw water from Stillhouse Hollow Lake to Lake Georgetown for the three Williamson County providers. Without the line, the supply stored in Lake Georgetown would not meet local needs during droughts. Thankfully, there is the neighboring Stillhouse Hollow Lake, which is roughly four times larger than Lake Georgetown and can help meet demand.
Lake Georgetown was once sufficient. But as growth continues to occur those three water users have used up to four times the firm yield that the reservoir can provide. During years when there is a lot of rain, the reservoir supply is enough, and the pipeline doesn't need to operate. But that's not the case during dry years.
The BRA operates the WCRRWL for the cities of Georgetown, Round Rock, and the Brushy Creek Municipal Utility District. To help meet this water supply need, the BRA Board of Directors approved an $11 million expansion project. Approval was given for a professional services agreement with CDM Smith, Inc. for the permitting, engineering, design, bidding, construction phase engineering, and resident project representative services for the project. The upgrade at the WCRRWL intake structure on Lake Stillhouse Hollow will expand the pipeline's pumping capacity to about 56 million gallons per day.
These three water supply users fund all capital improvements and costs associated with BRA operation and maintenance of the pump station and pipeline, said Brad Brunett, the BRA's central and lower basin regional manager, adding the users would reimburse the BRA.
The Williamson County Regional Raw Water Line includes a Stillhouse Hollow Lake intake structure that currently houses four pumps ¬- two 2,500 horsepower pumps and two 1,250 horsepower pumps. These pumps can transfer about 42 million gallons per day through the 28-mile, 48-inch diameter transmission pipeline.
The expansion plan includes the replacement of the current pumps with four new pumps, structural improvements to the intake structure, construction of a new electrical building, an additional electrical service powerline and transformer, and other miscellaneous improvements. In addition, the replacement of about 3,100 feet of the pipeline is needed to withstand increased pressure from the pumping capacity expansion.
A new source of water supply
Also at the meeting, the Board approved executing an application for an extension of the existing deadlines for commencement and completion of construction on the proposed Allens Creek Reservoir.
Under the BRA's permit for water use, there is a requirement that construction of the reservoir begin on or before Sept. 1, 2025, with a completion date on or before Sept. 1, 2030. Based on the current project timeline, the BRA needed to apply for an extension with the Texas Commission on Environmental Quality. The extension requested the commencement date be moved to Sept. 1, 2034, and the completion date be moved to Sept. 1, 2040.
An initial draft of BRA's application was submitted to TCEQ in May for review and comment. The TCEQ had no comments or concerns regarding the draft application.
The Allens Creek Reservoir project is an off-Brazos River water supply lake that will capture excess water during high flow periods and make it available for use during droughts, ensuring a more sustainable water future for the region. Covering about 9,500 acres of land, the projected amount of usable or firm water from the reservoir will provide about 100,000 acre-feet of water annually for municipal, industrial, agricultural, and mining use.
With only three BRA Water Supply System reservoirs located on the Brazos River itself (lakes Possum Kingdom Lake, Granbury, and Whitney), there is a lot of water that travels the length of the river uncaptured, flowing into the Gulf of America. 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.
Unlike the three water supply reservoirs on the river, Allens Creek will not dam the Brazos River. Instead, it will be located near the Brazos. Water will be pumped from the river into the lake during periods when the river experiences above-normal flows from rainfall upstream.
In Texas, to build a reservoir, you must have three things: the property, the water right permit, and a 404 permit from the federal government's U.S. Army Corps of Engineers. The BRA has already secured the first two requirements and will spend the next 10 years working to acquire the federal permit. The reservoir will require permits and authorizations under multiple state and federal regulations, including the U.S. Army Corps of Engineers, the U.S. Environmental Protection Agency, the U.S. Fish and Wildlife Service, the Texas Commission on Environmental Quality, the Texas Historical Commission, and the Texas Parks and Wildlife Department.
At this time, the total cost of the Allens Creek Reservoir is roughly estimated at $700 million. The project's projected cost will be refined as the federal Clean Water Act 404 permitting and engineering design process moves forward.
For a complete list of Board actions from the meeting, go here. Or watch the full Board meeting here.
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