Flood warning toolset for the Medina River in Bandera County, Texas

Abstract

Floods are the most common natural disaster in the United States (Federal Emergency Management Agency, 2019). The Medina River in Bandera County, Texas, is in the Edwards Plateau (fig. 1) (Hill, 1901), where high-intensity rain rates and steep terrain frequently contribute to severe flash flooding capable of causing loss of life and property. For example, the July 5, 2002, flood claimed a total of 12 lives in the central Texas area (National Weather Service, 2019a). The estimated peak discharge during this flood at U.S. Geological Survey (USGS) streamflow-gaging station 08178880 Medina River at Bandera, Tex. (hereinafter "Bandera station"), was 159,000 cubic feet per second (corresponding to a stage or gage height of 38.91 feet), causing significant flooding in Bandera near Mud Creek (fig. 2) and farther downstream (fig. 3) (U.S. Geological Survey, 2018). In 2018, the USGS, in cooperation with the Bandera County River Authority and Groundwater District and the Texas Water Development Board, developed a flood earlywarning toolset to enhance the communication of flood risk and provide emergency management with additional information to

A General Overview of the Risk-Reduction Strategies for Floods and Droughts

“…New techniques, such as the application of commercial microwave links for rainfall observations, the analysis of pictures from cameras, or the crowdsourcing of personal weather stations, are rapidly developing to extend the horizon of monitoring for sustainability [115][116][117][118]. Other than the monitoring task itself, gauging stations according to their locations (e.g., upstream of a watershed) can be used to for flood forecasts at a downstream area [119,120]. The early warning systems based on upstream gauging stations can provide predictions within a watershed but only with a limited lead time.…”

“…If the time of concentration of the watershed is short (i.e., less than a few hours), then the time window of disaster response is also narrow. Efficient numerical models such as HEC-RAS, rapid flood evaluation models, or data-driven models are commonly applied to meet the requirement of a short response time [119,121]. In conclusion, much research has put a lot of effort into remote sensing monitoring technologies such as Synthetic Aperture Radar (SAR) flood detection [122].…”

Flood-inundation maps created using a synthetic rating curve for a 10-mile reach of the Sabinal River and a 7-mile reach of the West Sabinal River near Utopia, Texas, 2021

“…The Medina River flows through Bandera, Tex., in this same flash-flood-prone area (Choi and Engel, 2019). In 2019, as part of the flood-mitigation efforts for the region that includes Utopia and Bandera, the U.S. Geological Survey (USGS), in cooperation with the Bandera County River Authority and Groundwater District and the Texas Water Development Board, developed a flood-preparedness toolset for the Medina River near Bandera, which included expanding the existing network of USGS streamgages and creating a digital flood-inundation map library (Choi and Engel, 2019;Engel and Choi, 2019). It was recognized that a flood-preparedness toolset similar to the one developed for Bandera was needed for the residents and many visitors of Utopia.…”

Flood warning toolset for the Sabinal River near Utopia, Texas

“…In 2021, the USGS, in cooperation with the Bandera County River Authority and Groundwater District and the Texas Water Development Board, developed a flood warning toolset for the Sabinal River near Utopia. This study builds on earlier USGS flood work on the Medina River in Bandera County (Choi and Engel, 2019;Engel and Choi, 2019). The newly developed toolset consists of a newly installed USGS streamgage to collect continuous stream stage data (streamgage 08197970 Sabinal River at Utopia, Tex.…”