A nearly $120 million, 54-in. water line will move up to 75 million gallons per day of surface water from the Southeast Water Purification Plant to the city of Houston as well as seven cities and water authorities when the project is completed in 2025.
The seven partners include the League City/Gulf Coast Water Authority, Clear Lake City Water Authority, Baybrook Municipal Utility District (MUD) No. 1, Harris County MUD No. 55 and the cities of Webster, Friendswood and Pasadena. Approximately 10 MGD of water will be distributed to the city of Houston’s customers, while its partners will receive 65 MGD of water.
“Typically, for the city of Houston, as the regional treated water provider, they tend to be the one who owns the infrastructure, and they are providing service to other entities outside the city limits or a water system,” says Melissa Mack, vice president and principal at Lockwood, Andrews & Newnam Inc. (LAN). She leads the technical adviser team for the Southeast Transmission Line (SETL) project, which is being delivered via design-bid-build.
“For this project, the city has ventured off into having more of a partnership where there are several owners coming together,” Mack says.
What exists now is an approximately 50-year-old, 42-in., 9-mile line along Highway 3 in Webster near Ellington Field, Mack explains. “The line has had a lot of leaks on it, and they spend a lot of time repairing leaks. It's a major and a main source of supply, so it's very difficult to isolate the line.”
The city decided it would be best to move ahead with a brand new line, rather than trying to fix the existing line, Mack explains. The existing line is also in the Texas Dept. of Transportation’s right-of-way, which TxDOT is planning to expand, “so TxDOT asked the city to relocate the line,” she adds.
“It's a partnership agreement, so each entity is going to have review of the designs; they're going to have their input. It's very collaborative—the monthly design meetings and the like have both the city of Houston and all these partners engaged,” she says.
The waterline will be built in four construction packages. LAN will serve as technical adviser, providing design and easement acquisition support services. The city of Houston has selected four firms to serve as design engineers on the four construction packages: Gunda Corp., Binkley & Barfield Inc., Nathelyne A Kennedy & Associates and Texas American Engineering LLC.
“This venture by the city of Houston, along with its co-participants, will boost the water quantity and the quality to cater to the needs of growing population in the southeast regions of the Houston metropolitan, in addition to reducing the time, resources and dollars spent on fixing the aging infrastructure,” says Panduranga Kuruva, managing engineer of capital projects with Houston Public Works.
Design on the first city project for a 24-in.-dia segment is at 90%, while design on the second segment, a 20-in./16-in./12-in. line, is on hold after having reached 30%. Design also began on the larger 54-in./48-in./42-in. lines in May. Those “designs are progressing to 30% as the design engineers have started receiving survey information for portions of the alignment,” Mack says. “There are portions of the alignment being re-evaluated to avoid conflicts as more information regarding existing infrastructure and requirements within Ellington Field are being identified.”
Navigating around the hundreds of oil-and-gas pipelines in the area is a major challenge, Mack adds. “We're going to need to very carefully consider the cathodic protection design. The fact that we are going to be dealing with so many oil-and-gas pipeline crossings, we want to make sure the waterline itself is protected, to avoid corrosion of those pipelines,” she says.
Current designs also have the new line crossing underneath Highway 3 at three different points, Mack notes.
Per the partnership agreement, League City will finance $52.4 million of the project; the city of Houston will fund $17.2 million, and Friendswood will contribute $12.5 million. More than $9.5 million will come from Webster; Harris County MUD 55 will commit $9.1 million; Baybrook MUD will provide $7.5 million; Clear Lake City Water Authority will fund $9.4 million, and the city of Pasadena will allocate $47,000.
At this point, the design team expects contracts will begin letting in 2024.
“That may sound like an extremely long time for design, but one of the other things that we're working through is easements. We have approximately 220 easements that need to be acquired for the line,” Mack says. “So it's going to take some time on that effort. The designs are going to be essentially completed and put on the shelf, so as soon as easements are acquired, they can let.”