Integrated Pipeline (IPL) Segment 19-1 Long Tunnel Crossings

Water Transmission, Trenchless

Steel pipe in field

Pipe Specifications:

45,000 LF of 84-inch spiralweld steel pipe with polyurethane coating and cement mortar lining; 1,720 LF of 99.5-inch steel casing pipe with Permalok® T-5 joints, 1-inch wall thickness, and epoxy coating


Traylor-Sundt Joint Venture

Engineering Firm:

BGE, Inc.


Tarrant Regional Water District

The Integrated Pipeline (IPL) project is a joint venture between Tarrant Regional Water District (TRWD) and the City of Dallas, which adds 150 miles of high-capacity pipeline to ensure a reliable source of water for growing communities in the North Central Texas area.

The IPL Section 19 -1 Long Tunnel Crossings project navigates the IPL path beneath multiple highway, railroad, utility, and waterway crossings. It includes two tunnels mined with an EPB TBM (Earth Pressure Balance Tunnel Boring Machine) and totaling 10,944 LF; two microtunnels totaling 1,727 LF; and a 191 LF hand-mined crossing under a stream channel with low cover. Northwest Pipe Company is providing the carrier pipe for the tunneled and open-cut segments of this project, which includes 45,000 LF of 84-inch spiralweld steel water transmission pipe. The pipe is manufactured with a polyurethane coating and cement mortar lining. The project also utilizes 99.5-inch Permalok® steel casing pipe supplied by NWP for the microtunneled portions, which the steel carrier pipe will pass through once installed. The casing pipe is manufactured in 20-foot sticks with press-fit interlocking Permalok® T-5 joints that provide a weld-free connection.

In addition to this project, NWP previously supplied pipe for IPL Segment 15-2, which utilizes 16,708 LF of 108” engineered steel water transmission pipeline manufactured in 50-foot sections at our facility in nearby Saginaw, Texas.

Phases 1 and 2 of the three-phase IPL system are currently operational and delivering water from three East Texas Reservoirs into the Dallas and Fort Worth metro area. Construction of the Long Tunnel Crossing project is expected to be completed in early 2026. Once fully operational, the project will move up to 350 million gallons of water daily, providing a resilient supply of clean water to the 4.1 million residents served by TRWD and the City of Dallas.