Barker Reservoir in the context of George Bush Park

Buffalo Bayou is a slow-moving river which flows through Houston in Harris County, Texas. It was formed 18,000 years ago, flowing east for 53 miles (85 km) from Katy, Fort Bend County to the Gulf of Mexico. It flows through and connects many Houston waterways including the Addicks and Barker reservoirs, the Brays Bayou, Carpenters Bayou, Greens Bayou, Sims Bayou, and White Oak Bayou, as well as other natural springs and surface runoff. Additionally, Buffalo Bayou is considered a tidal river downstream of a point 440 yards (400 m) west of the Shepherd Drive bridge in west-central Houston.

As the principal river of Greater Houston, the Buffalo Bayou watershed is heavily urbanized. Its 102-square-mile (260 km) direct drainage area contains a population of over 440,000. Including tributaries, the bayou has a watershed area of approximately 500 square miles (1,300 km).

The Addicks Reservoir and Addicks Dam in conjunction with the Barker Reservoir prevent downstream flooding of Buffalo Bayou in the city of Houston, Texas. Both reservoirs were authorized under the Rivers and Harbors Act of June 20, 1938, which was modified by the Flood Control Acts of 1938, 1954, and 1965. The US Army Corps of Engineers (USACE) completed construction of Addicks Dam and the outlet facility in 1948.

Brays Bayou is a slow-moving river in Harris County, Texas. A major tributary of Buffalo Bayou, the Brays flows for 31 miles (50 km) from the western edge of the county, south of Barker Reservoir along the border with Fort Bend County, east to its convergence with the Buffalo at Harrisburg. Nearly all of the river is located within the city of Houston; it is a defining geographic feature of many neighborhoods and districts, including Meyerland, Braeswood Place, the Texas Medical Center, and Riverside Terrace.

As a result of its central route through Harris County, the Brays Bayou watershed is heavily urbanized. Over 700,000 people reside within its 129-square-mile (330 km) drainage area, which contains 124 miles (200 km) of open-channel waterway, mostly from artificial drainage channels. This high level of development, combined with a relative lack of flood control infrastructure, means Brays Bayou is extremely prone to flash flooding events.