Harris County Flood Control District
Identifying and undertaking risk reduction projects and maintaining those projects are the primary goals of the Harris County Flood Control District. This special purpose district, created by the Texas Legislature in 1937, is governed by the Harris County Commissioners Court. The Flood Control District’s website provides videos, graphs and charts of stream and rainfall levels, inundation maps, watershed locations, interactive mapping tools, and a Flood Warning System.
Flood Warning System
The Flood Warning System uses 177 gauge stations to show rainfall amounts and water levels in bayous and major streams in real time. These stations are placed on bridges that cross bayous and their tributaries.
Harris County Flood Control District’s Willow Waterhole Bayou stream elevation gauge 445, located at Landsdowne Dr., was installed in early 2016.
The Harris County Flood Control districts spells “gauge” as “gage” to be consistent with the spelling of the United States Geological Survey.
Charts for each of the 177 gauges show stream elevation data, including the bottom level (bed) of the stream and the elevations at which flooding is likely and possible.
Willow Waterhole Bayou
Gauge 445 Readings
Flooding (of streets) is “possible” along Willow Waterhole Bayou when the stream level at Landsdowne Dr. is 51.20 feet high. In contrast, flooding (of structures) is “likely” when the bayou level is 3 feet higher: 54.20 feet high. (Harris County Flood Control District)
The Flood Control District distinguishes between “possible” and “likely” flooding. Possible (51.20 feet) means that some roads near the gauge site may have flooded but probably no structures have. Likely (54.20 feet) means that some structures near the gauge site have probably flooded. In neither case is flooding certain (only likely or possible) because these real-time readings are based on sensors in the stream, not actual measurements of street and structure flooding, which could be affected by clogged drains or other factors.
The graph below shows a quick rise in the bayou’s elevation, followed by a gradual decrease.
Willow Waterhole Bayou Elevation
May 18 and 19, 2021
On Tuesday, May 18, 2021, at 11 PM, after heavy rains, Willow Waterhole Bayou’s water level peaked at about 51.50 feet, indicating possible street flooding near the Landsdowne gauge. By 2:55 PM Wednesday, the level had decreased to 46.37 feet. (Harris County Flood Control District)
Flood Alerts
Gauge station rainfall sensors transmit rainfall amounts via radio frequency every time 0.04 inches of rain is measured. Water level sensors report every 0.10 foot change. Although the gauges transmit data in real time, the actual results are slightly delayed because of the time required for the data to be interpreted and the graphs updated.
Set up email or text alerts for Willow Waterhole Bayou’s Landsdowne gauge.
Find information about the County's Flood Warning System.
A Big Win at Willow Waterhole
In a September 26, 2019, Project Brays press release, the Harris County Flood Control District described how the Willow Waterhole detention basin had prevented flooding that week, less than a year after the basin's completion:
HOUSTON, September 26, 2019 – The Harris County Flood Control District (HCFCD) is already seeing positive benefits from the recently completed work in the Willow Waterhole Detention Basin. While this week’s storms wreaked havoc on much of the area, there was no structural flooding on Landsdowne Drive in Westbury along the Willow Waterhole Bayou, thanks to that work.
This area received 2.08 inches of rain in one hour. The rapid flood waters rose 8.93 feet in two hours and 22 minutes in the Willow Waterhole Bayou. The elevated flow entered the basins through the new weir structures and provided 200 to 300 ac-ft of detention during the rain event. There was a 7.62-foot water surface elevation difference between upstream of Willow Waterhole Detention Basin and downstream, which helped a lot of homes throughout the watershed. The Willow Waterhole Bayou enters Brays Bayou downstream of I-610. Another indication that the work along Project Brays is not only necessary but beneficial as well and there will be more positive outcomes as the work continues and is ultimately completed.
Four bridges are currently under construction, with nine more bridges scheduled to be replaced over the next two years. Residents along the Willow Waterhole Detention Basin and Project Brays in general should remain vigilant about flood warnings but should also feel good about the progress being made to reduce flood damage.