Published 5:28 pm CST, Thursday, March 5, 2020, on chron.com
Harris County Precinct 4 has begun testing a new method of delaying the release of stormwater into the county’s channel system, which could help prevent or mitigate flooding.
The project, called the Drainage Reuse Initiative, is being funded through Hurricane Harvey bond funding under Harris County Engineering Department management.
Precinct 4’s 25-acre detention basin near Tomball Tollway and Holderrieth Road was given a redesigned outfall structure by the Binkley & Barfield Engineering Firm last year, a Precinct 4 news release stated, doubling the amount of time water can be held in the basin and giving more time for bayous and creeks to drain, reducing downstream flooding.
“Before the modification, the lower portion of the basin would drain within half a day,” Binkley & Barfield Vice President of Infrastructure Steve Albert said. “Now it will hold stormwater for up to four days.”
How it works involves three pipes, the release explained. In addition to the usual 24-inch drainage pipe, which allows water to enter the basin from Willow Creek, another 8-inch pipe sends water from the basin back into Willow Creek and another 24-inch pipe can be raised above basin water levels to let the basin fill and lowered to return drainage to keep the basin at maximum capacity.
Albert said the 24-inch pipe would be lowered during large rainstorms for the basin to empty normally.
“The modification only works for small storms,” Albert said. “During 10-year or 100-year storms, the outfall pipe will operate the same as it always did.”
A two-month study by the company showed the design wouldn’t negatively affect existing drainage around the basin, the release detailed.
This modification is one part of a drainage project, the release stated, and a 12-month study kicked off in January to look at how stormwater is absorbed in the ground at four modified test locations inside the basin. The study will conclude at the end of the year and the four areas will be measured to determine the effectiveness of the test locations.
“This technology has the potential to significantly increase the holding time of other existing basins in a way that brings huge benefits at a relatively reasonable cost,” Precinct 4 Commissioner R. Jack Cagle said.