The transmission line upgrade will replace approximately 7.2 miles—about 40,000 linear ft—of aging 16-in. steel cylinder concrete pipe. 

The work highlights a larger challenge facing rural water systems across Texas, where utilities are replacing mid-20th-century transmission lines and expanding groundwater supplies to meet current reliability and regulatory standards.

The transmission project follows a separate $16-million State Water Implementation Fund for Texas (SWIFT) award approved in 2024 to drill up to 10 groundwater wells in the Carrizo-Wilcox Aquifer, one of Texas’ largest groundwater systems stretching from the Louisiana border to south Texas.

Together, the projects form a phased capital program that expands groundwater supply while modernizing the transmission and storage infrastructure needed to deliver that water across the district’s system.

“Yes—the two projects are closely linked,” said Scott Wetzel, senior project manager at STV. The well-field expansion will increase available groundwater supply, he said, but the transmission improvements are needed to move that additional water through the district’s transmission backbone.

“The upgraded transmission main and pressure sustaining system is essential to fully utilize the increased supply,” Wetzel said. “Without these improvements, the older infrastructure would limit the benefit of the new wells.”

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Cross-section diagrams show the geologic layers of the Carrizo-Wilcox Aquifer, one of Texas’ largest groundwater systems extending from East Texas to the Mexico border. The formation supplies municipal, agricultural and industrial water across 66 counties.

Map courtesy of Texas Water Development Board

Engineers plan to replace the pipeline with the same 16-in. dia pipe to preserve system capacity while evaluating higher-durability materials for the new main. According to Wetzel, the project team is considering molecularly oriented PVC and zinc-coated ductile iron pipe with polyethylene encasement for improved corrosion resistance and reduced breakage risk. High-density polyethylene pipe has also been evaluated for potential trenchless installation segments.

Most of the project funding will support pipeline replacement. Additional work includes constructing a 0.5-million-gallon elevated storage tank and installing pressure-stabilization infrastructure to maintain consistent service during peak demand and emergencies.

According to STV, the improvements are expected to stabilize system pressure in the 50–65 psi range, maintain compliance with minimum residual pressure standards and reduce leakage associated with the district’s aging transmission line.

The $29.4-million project represents the total capital cost and will be financed through TWDB, including a $19.4-million low-interest loan and $10 million in principal forgiveness.

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STV says it has worked with the district since 2022, when the firm completed a preliminary engineering assessment and feasibility report that helped identify priority infrastructure upgrades and secure state funding for construction.

The project follows a traditional design-bid-build delivery method, with bid advertisement anticipated in late 2027 and construction expected to begin in early 2028, according to STV. Planning, environmental review, and fieldwork began earlier this year.

Wetzel said that depending on final design decisions, the transmission replacement and storage improvements may be bid as a single construction contract or split into multiple packages.

For smaller utilities across Texas, the Bistone program illustrates how state revolving fund and SWIFT financing are enabling rural districts to replace aging transmission systems while expanding groundwater supply capacity.