Projects & Studies
The Brays Bayou Federal Flood Damage Reduction Project, known as Project Brays, is the largest flood damage reduction program undertaken by the Harris County Flood Control District to date.
A cooperative effort between the Flood Control District and the U.S. Army Corps of Engineers (Corps), Project Brays is an active multi-year, $480 million project that substantially reduces flooding risks in the Brays Bayou watershed. It is the largest partnership project the Flood Control District and Corps have conducted to date.
Encompassing more than 75 individual project components, Project Brays will help to reduce flooding risks by widening 21 miles of Brays Bayou from the Houston Ship Channel to Fondren Road and from West Houston Center Boulevard to State Highway 6, replacing or modifying 32 bridges (including two pedestrian bridges) to accommodate channel modifications and excavating four stormwater detention basins that will hold a collective 3.5 billion gallons of stormwater.
Project Brays work is being done in two primary reaches of the Brays Bayou watershed:
- The Upper Reach includes project components in the section of the Brays Bayou watershed between the Sam Houston Tollway to State Highway 6 near the Barker Reservoir. In 2000, the Flood Control District and Corps signed an agreement that outlined each parties’ responsibilities, the federal-local cost share, and federal reimbursements to the District. Work started in this area while the District and Corps were identifying project components for the Lower Reach.
- The Lower Reach encompasses work in the Brays Bayou watershed east of the Sam Houston Tollway to the Houston Ship Channel. In 2010, the original agreement signed by the District and Corps was amended to include work in this reach.
There is a limit to how fast the Project Brays’ 75 individual project components can be implemented. Logistically, the project must be built in a particular sequence to avoid moving flooding somewhere else.
Construction started with the excavation of the stormwater detention basins in the project’s Upper Reach. The basins hold stormwater during periods of heavy rainfall and slowly release the water back into the bayou as the bayou recedes. As sections of the basins were completed, they held more and more water, allowing the Flood Control District to work on the channel segments in the Upper Reach. The same type of implementation considerations have been applied in the Lower Reach.
Bridge replacements and modifications have been sequenced with the channel work and coordinated with the City of Houston and Texas Department of Transportation to minimize traffic disruptions.
Upper Reach work includes:
- Construction of three detention basins (covering a total of 600 acres and holding a collective 2.9 billion gallons of stormwater storage.
- The widening and deepening of 3.7 miles of Brays Bayou from West Houston Center Boulevard to State Highway 6.
Lower Reach work includes:
- Construction of one detention basin that covers 252 acres and will hold 610 million gallons of stormwater.
- The widening and deepening of 17.5 miles of Brays Bayou from the Houston Ship Channel to Fondren Road.
- The replacement or modification of 30 bridges that cross the bayou to accommodate the additional flow of stormwater.
Environmental features throughout the project area include creating wetlands, planting trees and shrubs, and creating aesthetically pleasing layouts.
Although there is still work to be done on Project Brays, the completion of each stormwater detention basin, channel segment and bridge replacement or modification brings a reduction in flood levels along the bayou. That will continue as the project moves to completion.
When Project Brays is complete, the 1 percent (100-year) floodplain will be removed from 14,000 homes/businesses in the Upper Reach, and from 15,000 homes/businesses in the Lower Reach. In addition, homes at risk of flooding during a 25-year flood event (a flood that has a 4 percent chance of occurring in any given year) will be reduced by 3,470.
Project Funding and Outlook
When the Flood Control District partners with the Corps on a flood risk reduction project, the cost share is based on the project features. The District is responsible for paying for the project’s right-of-way acquisition, utility relocation, and bridge replacement or modification costs. The District also maintains the project after completion. The Corps pays for the project’s design and construction costs. For Project Brays the cost share works out to about 50/50.
Project Brays was originally estimated at $550 million, but cost efficiencies implemented by the Flood Control District have lowered that estimate to $480 million. Cooperative efforts by the Flood Control District, Corps, Harris County, City of Houston, Texas Department of Transportation, Texas Department of Parks and Wildlife, Houston Parks Board and several other local community groups and organizations have allowed the project to move forward at a steady pace, and have allowed the project to maintain that pace during difficult economic times. A continuous stream of federal and local funding has been provided to the Flood Control District and Corps because of the importance of this project to the Houston/Harris County region.
Based on a variety of factors, including sufficient local and federal funding, the earliest that all components of Project Brays will be completed is 2021.
Memorial Day Flood
Very intense rain began falling Monday evening, May 25, 2015, on an already saturated Brays Bayou watershed and continued for several hours. Rainfall in several parts of the watershed exceeded the 100-year rates and volumes. Because the ground was wet, stormwater immediately ran off instead of soaking in, and the underground drainage systems and streets filled quickly. In many locations, flooding occurred from the stormwater runoff trying to reach Brays Bayou and its tributaries. The bayou and tributaries then rose and induced additional flooding.
Project Brays work completed to date went a long way toward preventing the flooding of many homes and businesses that would have flooded prior to project work. For example, the channel and bridge work downstream of Fannin Street helped lower flood levels in the Texas Medical Center area, and the detention basin excavation upstream held back a large volume of stormwater that otherwise would have rushed downstream.
Although completed project components benefited the hardest hit areas, the remaining components being implemented would have provided additional flood relief. Given the severity of the storm though, flooding of roads, cars, and some homes and businesses would not have been avoided.
The Flood Control District is continuing to collect and analyze data from the flood and will produce a report about the event in June 2015.