Simplified Conversion of Hydrologic Models for Real-time Inundation Mapping in Harris County, TX during Hurricane Harvey

From August 27 to September 1, 2017, the Water Resources groups at Walter P Moore (WPM) and the University of Texas at Arlington (UTA) worked on a team that collaborated remotely to project maximum flood extents and potential inundation areas along some of Harris County's major creeks and bayous in near real time. The purpose of the effort was to rapidly provide current and forecasted information to aid the Texas Department of Emergency Management (TDEM) in determining locations to deploy personnel and organize emergency response during the course of the storm event. In tandem with the other team members, he Walter P Moore team analyzed seven major stream systems within Harris County using real-time and forecasted rainfall information provided by UTA, available hydrologic and hydraulic models, and GIS software and data to produce inundation maps. In order to rapidly produce inundation maps from incoming radar rainfall data, the team developed a method to utilize pre-determined rating curves with HEC-HMS to compute stage hydrographs at critical locations without involving separate hydraulic models. Because during this period the storm was continually evolving, the team updated inundation maps daily using both measured and forecasted rainfall supplied by the team at UTA. As a check of accuracy, the real-time stage estimates were validated against incoming gauge records where available.