Hydrological, Societal, and Environmental Impacts of Flood Control Reservoir Releases on Downstream Communities using Remote Sensing and Modeling during Hurricane Harvey

Flood control reservoirs are designed to provide flood risk management through regulated storage and release of stormwaters into a receiving conveyance system, such as a stream or bayou. Optimization models and operational plans typically do not consider the downstream societal, environmental, and potential health impacts of reservoir releases. Moreover, downstream hydrologic impacts may be worsened through operational releases of stormwater during high-intensity rainfall events. A holistic approach to reservoir management must include a thorough understanding of various environmental and hydrologic conditions for improved public health. The Addicks and Barker Reservoirs in Houston, Texas were designed to mitigate flooding for the Buffalo Bayou watershed; however, inter-basin transfer occurs from the adjoining Cypress Creek watershed and causes overflow into the reservoirs during moderate to heavy rainfall conditions. A research study was conducted on the Addicks and Barker Reservoirs during Hurricane Harvey to investigate the various hydrological, societal, and environmental challenges involved in an extreme rainfall event, including potential impacts to and from adjacent watersheds. The flood impacts on communities in the Reservoir watersheds, adjacent watersheds, and the receiving downstream watershed of Buffalo Bayou were studied. The downstream watershed comprises diverse urban neighborhoods, a vibrant downtown district, and the Houston Ship Channel. The study was conducted using high-resolution remotely-sensed rainfall and topographic data. The drainage modeling incorporated overflow from Cypress Creek and best-available data for reservoir release operations during Hurricane Harvey. A vulnerability analysis was conducted to evaluate potential flood impacts to affected communities in terms of socioeconomics and health. The findings from the study suggest that hydrologic conditions, environmental challenges, and societal impacts should be incorporated holistically when planning and operating reservoir infrastructure for flood mitigation.