Alliance Regional Water Authority Phase 1B Treated Water Pipeline – Segment A

The Alliance Regional Water Authority (ARWA) Phase 1B Treated Pipeline is a critical water infrastructure project designed to provide growing communities in Central Texas with a sustainable source of water. Spanning the I-35 corridor between San Antonio and Austin, Phase 1B includes the construction of four groundwater wells, two elevated storage tanks, two booster pump stations, a new water treatment facility, and five segments of treated water pipeline. Northwest Pipe Company is supplying nearly 17 miles of 42- and 48-inch engineered steel water transmission pipe for Segment A of this project, installed by Garney Construction. The pipeline will convey treated groundwater from the Carrizo-Wilcox Aquifer in east Caldwell County to the cities of San Marcos, Buda, Kyle, and utility districts represented by the Canyon Regional Water Authority.

Segment A utilizes 5,808 LF of 42-inch and 83,160 LF of 48-inch spiralweld steel pipe manufactured at the Northwest Pipe Company facility in Saginaw, TX. All pipe is lined with cement mortar and coated with polyurethane according to project specifications. The majority of the project was installed via open-cut construction, with trenchless methods used for highway and waterway crossings. The engineered steel water transmission system utilizes O-ring gasketed joints for non-restrained areas, and welded bell-and-spigot joints for restrained areas.

To help stakeholders stay within budget, Northwest Pipe Company collaborated with Garney Construction to create a value engineering proposal for Segment A. Our engineers recommended slight material changes, including a marginal reduction in the thickness of the polyurethane coating from 35 to 25 mils DFT, and reducing the wall thickness of the carrier pipe to align with a performance-based approach in accordance with AWWA M11 standards. Once approved, these modifications were incorporated into the specifications for Segment A and later applied to other segments of the project, leading to significant cost savings for the owner.

Northwest Pipe, as always, delivered a top-quality product on time and on budget, which contributed to a seamless pipe installation process. The Northwest service and support team were very responsive and knowledgeable which was a major factor in providing a successful project to the Alliance Regional Water Authority.

Chad Sharbono, Regional Operations Manager | Garney Construction

Segments A and B of the Phase 1B Treated Pipeline project earned prestigious industry recognition, including the Engineering News-Record Award of Merit and the Associated Builders and Contractors – South Texas Chapter Excellence in Construction Award. These accolades highlight the outstanding efforts of Garney Construction crews, who delivered exceptional craftsmanship despite extreme weather challenges, as well as the innovative project design by LAN, Inc., and the success of the ARWA in delivering this vital water infrastructure program.

In addition to Segment A, Northwest Pipe Company supplied 18 miles of 42-inch steel water pipe for Segment D, contributing a total of 35 miles of pipeline to support this critical project. With the capacity to deliver 19 million gallons of clean water per day, the Phase 1B Treated Water Pipeline proactively addresses the increasing demand for water in the growing region. This ARWA project provides a secure and reliable water supply to meet the future needs of the communities it serves, sustaining the well-being of families and supporting a thriving economy in Central Texas.