When city workers broke ground near English Bayou, they hoped to install a new drainage component that could potentially delay the effects of sea level rise.
Instead, they discovered a leak in a nearby water line that had been pouring an average of 3 million gallons of water, worth thousands of dollars, into the city’s storm sewer system each day for years, Assistant City Manager Brandon Cook said.
“It was more than a leak, it seems like,” Cook said. “It was like a wide-open line.”
The city might never have found the leak if it hadn’t been trying to set up the new back-flow prevention devices, City Manager Brian Maxwell said.
Those devices are meant to stop water from backing up into the drainage system’s pipes at times, for example, when tides are running high. That’s especially a problem in Galveston during hard rains because it keeps the system from draining fast enough to prevent street flooding.
But to install a valve, the city needed to ensure the drainage system was empty of water, Maxwell said. A city crew had been pumping 3,000 gallons of water a minute out of the system with no end in sight, he said.
“We could never get it dry,” Maxwell said. “We couldn’t figure out where it was coming from.”
Finally on the weekend of Nov. 18, workers found the leaking water line and capped it to stop the flow, Maxwell said.
“If we hadn’t gone through this exercise in the back-flow prevention, we probably wouldn’t have found the leak,” Maxwell said.
The city has had to buy about 3 million gallons less water each day since it capped the water line, Cook said.
The city purchased an average of 13.6 million gallons of water a day from Nov. 18 to Nov. 29, 2016, Cook said. The city purchased an average of 10.5 million of gallons of water a day in that same time period this year, he said.
If that 3 million gallons a day reduction holds, the city will save $600,000 a year, Cook said.
After the line was capped, five other breaches in the water line occurred and led to several sinkholes forming around the island, Maxwell said. There’s no way to be sure that capping the leaking water line led to the breaches, but it’s a likely scenario given the timing of the breaks, Maxwell said.
The whole situation was a complete surprise, given the city didn’t even know the water line existed before officials found the leak, Maxwell said. The 10-inch line was supposedly abandoned by the city in the 1950s or 1960s and doesn’t appear on any recent city maps, he said.
Maxwell said he had watched water consumption “like a hawk” since he began working for the city in 2011 and hadn’t seen any significant changes. That leads him to believe the leak has been occurring for at least seven years, Maxwell said.
“At least in my tenure here, that leak has probably been occurring,” Maxwell said. “This is a big one.”
Fixing the leak allows the city to try the back-flow prevention devices again, Maxwell said. The city had been testing them at no cost in a pilot program with a Swedish company called Wapro AB, so the only extra money the city had to pay capping the leak was in labor, Maxwell said.
The city will keep trying to make the devices work, Maxwell said.