Willow Creek Widening and Stormwater Detention Basins Improving Tomball Drainage
Harris County Flood Control District (HCFCD) has a large active construction project underway in Tomball. Phase I of the project stretches about two-thirds of a mile from SH249 to FM2920 on a tributary of Willow Creek as it arcs around a major shopping center near downtown Tomball and Lone Star College/Tomball. The project includes channel widening and deepening; dry and wet stormwater detention basins; and opportunities for recreational trails.
Willow Creek: A Study in Contrasts
The Willow Creek watershed is located in northwest Harris County. It drains about half of the City of Tomball. The tributary highlighted above flows through densely developed shopping and medical center areas on the northern end to agricultural and oil and gas interests on the lower end.
Willow Creek: Present and Future
Willow Creek flows into Spring Creek just upstream of where Spring Creek crosses under I-45. The Willow Creek watershed covers about 54 square miles. The downstream end of the watershed is within the floodplain of Spring Creek.
Willow Creek watershed is mostly undeveloped. Significant development is limited to the City of Tomball and a few residential subdivisions in the lower end. The development rate has not been very rapid. However, officials expect it to increase as the City of Tomball continues to expand and urbanization from Houston stretches northwest.
This project will directly benefit mostly areas on the northwest side of the county. However, it may provide some downstream benefit by holding back water in major floods.
Goal: Contain Runoff from 100-Year Event
Phase 1 of this project began construction activities in January 2021. As funding becomes available, future phases of the M124-00-00 project will continue channel conveyance improvements and construct several more stormwater detention basins from F.M. 2920 to the confluence with Willow Creek. Phase II will also deepen the channel improvements from Phase 1 that you see above.
The overall goal of the M124-00-00 project is to enable the channel to contain the 1-percent (100-year) storm event within the channel banks based on existing watershed conditions.
HCFCD
The total project focuses on conveyance improvements of stormwater in the area, as well as reducing flood risk through construction of stormwater detention basins. Stormwater detention basins reduce flooding risks by taking in and temporarily storing stormwater during heavy rain events and releasing the water back into the waterways when the threat of flooding has passed.
Multiple new detention basins along the M124-00-00 channel will add approximately 390 million gallons of storage capacity (an approximate 2,164 percent increase in current storage capacity) to benefit the Willow Creek watershed. That’s enough to contain a foot of water falling on 1200 acres.
Posted by Bob Rehak on 12/26/2021 based on info from HCFCD.org
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