The project includes 44 wells at the remote, 22,000-acre T-Bar Ranch. The wells are approximately 20 in. in diameter and extend to an average depth of 650 ft. Courtesy of Black & Veatch
In the face of dwindling reservoir supplies, the City of Midland is tapping water from beneath a former cattle ranch.
June 18, 2013—In the fall of 2011, Midland, Texas, realized it had a problem. Two of the three reservoirs that supply the city with drinking water had gone dry because of the extreme drought gripping western Texas, and the third was projected to fall to 15 percent of capacity by the summer of 2013.
Luckily, city leaders in 1965 had had the foresight to purchase the 22,000-acre T-Bar Ranch and the accompanying water rights to the land, which is approximately 60 mi south of the city. Despite some doubts within the community, this had been the city’s water supply insurance policy for decades, and now was the time to develop it. But would there be enough time?
“This is absolutely one of the most extreme fast-track projects I’ve ever seen,” says Todd Larson, P.E., a project manager at Black & Veatch, of Overland Park, Kansas, which led the design/build portion of a design/build /finance/operate (D/B/F/O) contract for the project. “I think there were a lot of people wondering if something of this scale could actually be pulled off.”
The Midland County Fresh Water Supply District No. 1, an entity created in 2010 and authorized to raise money for water supply projects via revenue bonds, will deliver the $200-million project. Black & Veatch is providing the engineering and construction of the wells, tanks, pump station, and chlorination facilities; Parkhill Smith & Cooper, of Midland, designed the well field; and Hilliard Energy, also of Midland, secured the land easements required for the pipelines. A subcontract was awarded to Garney Construction, of Kansas City, Missouri, to build the transmission main.
The project encompasses 44 wells dug at the T-Bar Ranch, each approximately 20 in. in diameter and extending an average of 650 ft through dense caliche into the Cenozoic Pecos Alluvium Aquifer. Water from the wells is pumped into a 2 million gal prestressed-concrete holding tank at the site. From there it is pumped to the top of a 550 ft high escarpment to a second prestressed-concrete tank, this one with a 5 million gal capacity.
A prestressed-concrete storage tank at the ranch can hold 2
million gal of water. From there water is pumped to the top of a
550 ft high escarpment, where it is held in a 5 million gal tank
before being pumped into town. Courtesy of Black & Veatch
“The T-Bar Ranch site was not well known,” Larson says. “One of the first things we had to do was send the well drillers out there.” LBG-Guyton Associates, a Texas-based hydrogeology engineering firm, predicted the best spots for creating the wells, Larson says. “We did 50 test wells and were able to plot the final location of the production wells.”
To complete the project within the aggressive 12-month schedule, Larson says, all of the elements of the project were designed and built simultaneously. This meant ordering the 58 mi of 48 in. diameter pipe from three different manufacturers before the design was complete and the easements had been secured.
“We took the first delivery of pipe the first week of June 2012. In the meantime, we were crossing three counties and dealing with 55 private landowners,” Larson says. “Hilliard Energy was working with all of these landowners. They were signing easements and handing [them] off [to our designers, who were] completing the drawings, and the construction activity was coming right behind that.”
The harsh terrain of western Texas complicated this precision relay at times, Larson notes. Sand dunes were found along the original pipeline route. The fine sand and the strong regional winds meant that the dunes could shift by as much as 10 ft in a single day. “These sand dunes are a geological phenomenon,” Larson says. “It’s such fine sand and so soft you really can’t maneuver through it to do your construction work.” The shifting sands forced some changes in the pipeline alignments, he says.
The teams from each company worked together to overcome these obstacles and others. “If the sand and closely coordinating different crews on such a tight deadline wasn’t challenge enough, we were working in an area with 3 percent unemployment,” Larson explains. “Midland has one of the lowest unemployment rates in the nation. Many people are engaged in oil drilling and gas exploration, so there was a limited skilled labor force for us to draw from locally. We relied on personnel from our own construction company for labor and then realized there were no accommodations. As a result we actually had to build our own RV [recreational vehicle] park and bought camper trailers for people to live in. That was the accommodations for our crews for about nine months.”
The project was completed in mid-May, 17 days ahead of schedule and less than 12 months after the June 2012 start. The completed works can provide the city with as much as 20 million gal of water per day and is expected to have a life span beyond 20 years.
Larson says there was a distinct sense of teamwork among those involved in the project, who experienced the need for potable water firsthand. “People had to live in some pretty tough conditions out there, including neighborhood rattlesnakes and tarantulas,” he says. “The remarkable thing was how everybody worked from a common vision. And that’s what you have to do to complete a fast-track project. Everybody saw the City of Midland needed us, and we were on a mission to make it happen for them.”