The Harris County Flood Control District is conducting a drainage analysis for the Little White Oak Bayou sub-watershed within the White Oak Bayou watershed. The Flood Control District will analyze the current flooding conditions to identify and propose efficient and cost-effective projects to reduce the risk of flooding.
Little White Oak Bayou is a twelve-mile-long major tributary of White Oak Bayou located on the eastern edge of the White Oak Bayou watershed. Flowing north to south from its headwaters near Houston’s Acres Homes neighborhood to its confluence with White Oak Bayou just north of downtown Houston, Little White Oak Bayou drains an area of approximately 22 square miles. Neighborhoods within the Little White Oak Bayou sub-watershed include portions of Acres Homes, Northline, Near Northside, Independence Heights, and Woodland Heights, among others.
From the mouth of Little White Oak Bayou north to Interstate 610 (the North Loop), the channel is relatively deep, and aside from small projects to address erosion, it has remained in its natural state. This section of the bayou is less prone to coming out of its banks during heavy rain events.
When looking north from the North Loop, much of this section of Little White Oak Bayou is concrete-lined and significantly narrower than downstream of the North Loop. Due to the narrow width of this section of the bayou, some storm events challenge its ability to carry stormwater efficiently and cause the bayou to come out of its banks more frequently.
The Flood Control District’s previous understanding of flooding in the Little White Oak Bayou sub-watershed was based upon older computer models and floodplain maps and was limited to the historical floodplain of the main channel itself. For this analysis, the project team extended the models to include other areas within the sub-watershed that also have a history of extreme inundation, particularly during major storm events over the last few years. This updated analysis, including storm drains and roadside ditches that are owned and maintained by other agencies, produced a flood-risk map that closely correlates to the inundation that has been observed throughout the watershed.
A large portion of Little White Oak Bayou runs parallel and adjacent to Interstate 45 (the North Freeway) and, at three different points, crosses underneath the freeway. Additionally, the bayou flows through a large culvert located under the North Loop/I-45 interchange. Due to the bayou’s proximity to both of these highways, the Flood Control District is working closely with the Texas Department of Transportation’s North Houston Highway Improvement Project team (NHHIP) to ensure any future projects they may undertake do not increase the area’s flood risk.
As part of the Harris County Flood Control District’s 2018 Bond Program, $30 million has been identified for the Little White Oak Bayou watershed; however, it is highly likely that the total cost of proposed projects identified by this analysis will far exceed this amount. Accordingly, the study team is developing a master plan component to assist in the orderly implementation of projects as funding becomes available.
This drainage analysis was initiated in June 2019 and will conclude in early 2021.