Willow Fork Drainage District Resuming Diversion Channel Work After Setbacks

Article Image

Posted February 13, 2018

What began as a six-month project has turned into a three-year saga for the Willow Fork Drainage District’s stormwater quality project. Three consecutive storms delayed work or, in the case of Tropical Storm Harvey, undid much of what was completed, according to District Assistant Vice President Wendy Duncan.

In order to mitigate flooding, improve water quality and enhance the surrounding area, the district planned to dredge its diversion channel that runs from just east of the Peek Road bridge to the edge of the Canyon Gate subdivision. It also aimed to build gabions inside the channel, which would collect debris in the water, plant vegetation along its banks and construct trails on top of the channel.

Duncan said WFDD continuously removes silt from its waterways to improve conveyance and quality of life for surrounding neighborhoods.

“Our philosophy is ongoing maintenance,” she said. “We do not wait for a problem to get so bad and then do all the work every 10 years.”

She added WFDD hopes to improve stormwater quality because municipalities in the Greater Houston area are transitioning from groundwater to surface sources for drinking water.

“Knowing that, we want to make sure that when the water leaves our community, that it is in the best possible shape that it can be,” she said.

The nearly $4.5 million diversion channel project is paid for with district operating funds, as WFDD’s rate is $0.185 per valuation. The adjacent trails are paid for with about $525,000 from a $29 million parks bond passed in 2011, according to Matt Klein, a principal at TBG Partners, and Bob Wempe, a principal at engineering design firm AECOM.

TBG Partners, a landscape architecture firm, is handling the trails, and Champions Hydro-Lawn Inc. is doing the dredging work. Wempe said work initially started around March 2015.

Storm setbacks

Efforts stalled as a result of the Memorial Day floods that year, the Tax Day Floods in 2016 and then Harvey. In different spots along the channel, Champions removed between 2 and 5 feet of silt after Harvey, Duncan said.

The diversion channel carries water from the Willow Fork of Buffalo Bayou—which is not maintained by WFDD but rather by Fort Bend County—to the Barker Reservoir. Had the work been done prior to Harvey, Duncan said the surrounding subdivisions would still have flooded.

“We had about 4 or 5 feet of silt, and you could kind of tell because you have this kind of clay bottom,” Duncan said. “But you can’t dig out further from the bottom; otherwise you slow the water and you stagnate it.”

The diversion channel was at capacity when Harvey occurred and it needed to be redredged because the newly excavated slopes were not stabilized prior to the disaster. Remaining work on the diversion channel includes seeding grasses on its banks, planting trees and removing any that died, and installing the trails.

Channel features

Rye, a winter-hardy grass, has been planted along the slopes. The rye will eventually die off in warmer weather, by which point the slopes will have ideally stabilized and can be filled in with Bermuda grasses, Duncan said.

Several gabions have been built inside the channel where it turns eastward next to the Summer Pointe subdivision, and the district began hauling dirt away from the channel’s banks in late January.

Meanwhile, the planned trails along the channel will offer a safer way for children to get to Beck Junior High School in Katy ISD, which backs up to the channel. Once complete, WFDD will have built nearly 21 miles worth of trails since its inception, Klein said.

The original contracts for the diversion channel work were not long enough to cover all of the storm delays, but Duncan said it is not yet known how much the additional work will cost WFDD. As of Jan. 25, dredging was expected to finish by the end of February.

“But again, it’s all contingent upon weather,” Duncan said.

Source: Community Impact Newspaper