Building Resilience for Houston’s Water Future: SWSP Segment B1 featuring InfraShield® Is Now Complete
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InfraShield® Geohazard Resistant Steel Pipe Provides Reliable Water Delivery Across Major Fault Zones for the Surface Water Supply Project (SWSP)
The Surface Water Supply Project (SWSP) is a landmark infrastructure program designed to reduce land subsidence and secure a reliable long-term water supply for communities in west Harris County and North Fort Bend County, Texas. A partnership between the West Harris County Regional Water Authority (WHCRWA) and the North Fort Bend Water Authority (NFBWA), the program will deliver treated water from Lake Houston to the west side of Houston near Katy through more than 55 miles of large-diameter pipeline and two new pump stations.
For Segment B1, the project team faced a significant geotechnical challenge: crossing two major fault zones where long-term differential settlement of up to 36 inches is expected. This movement is driven by naturally occurring slip-fault conditions along the project alignment. To accommodate these conditions, the engineer and owner selected Northwest Pipe Company’s InfraShield® Joint System, a patented Geohazard Resistant Steel Pipe (GRSP) technology designed to withstand shifting ground forces.
Project Scope
In total, Northwest Pipe Company supplied six miles of 84- and 96-inch AWWA C200 steel pipe for Segment B1, including more than 3,000 linear feet of InfraShield® pipe for the fault crossings. Black & Veatch served as the engineer and Harper Brothers Construction as the contractor. The pipeline was installed primarily via open-cut installation, plus 19 tunneled sections under major roads and waterways. All sections used single or double lap-welded joints with polyurethane coating.
Meeting the Geohazard Challenge
Conventional options such as butt-welded connections or gasketed couplings carried higher cost and long-term risk for the geohazard conditions encountered along the project alignment. Instead, the team selected the InfraShield® Joint System as the optimal solution for the fault crossings, which uses a strain-based design to improve the resiliency of lap-welded joints. A small projection manufactured into the pipe wall absorbs deformation from settlement or displacement, protecting the welded joint itself. The C200 steel is highly ductile, allowing the pipe wall to withstand strain without loss of containment. Advanced finite element analysis (FEA) verified the joint’s ability to meet the extreme ground displacement demands, and the system’s performance was validated by full-scale testing documented in multiple ASCE papers.
InfraShield® installs in the same way as standard lap-welded C200 pipe, minimizing construction risk and cost. At the start of installation, a Northwest Pipe Company field representative was onsite to support the process. Field joints were polyurethane lined and heat-shrink wrapped before being backfilled with common sand backfill materials.
“At HBC, we are proud to have partnered with Northwest Pipe on this complex project. We’re even more proud of our team’s successful installation of this pipe—being the first company in North America to do so marks a major milestone for us.”
— Corey Garnett, Division Manager – Harper Brothers Construction
Custom Fabrications
Northwest Pipe Company also fabricated custom steel fittings, including: two 84-inch steel shaft risers for Beltway 8 crossings with tee fittings and blind flanges, one 96-inch riser for the White Oak Bayou Shaft with tee and bend fittings, and multiple two-piece elbows and fittings.
Results
In addition to Segment B1, Northwest Pipe Company previously supplied 4.8 miles of 84-inch pipe for Segment C2 and 5.1 miles of 84-inch pipe for Segment C1, for a total of nearly 16 miles of pipeline for the SWSP program.
The last pipe for Segment B1 was laid in August 2025. By combining innovative pipeline design with seamless installation, the project team successfully addressed the geohazard challenges along this critical alignment. The close collaboration between Northwest Pipe Company, Black & Veatch, and Harper Brothers Construction ensured a smooth project planning and construction process, including reliable installation of the InfraShield® Joint System. For WHCRWA and NFBWA, Segment B1 represents a major milestone in the SWSP and a vital achievement toward ensuring long-term water reliability for the Houston metro region.
