RAPID: Forensic Hydrological Field Investigation of the Blanco River Flood - May 2015, Wimberley, TX

University Of Texas At San Antonio, San Antonio TX

Investigators

Abstract

This project will investigate the Texas floods of May 2015 in an around the Blanco River. The unprecedented flood occurred in the towns of Wimberley and San Marcos. Hundreds of homes were damaged or destroyed, two reinforced concrete bridges were washed off their piers (a third received heavy damage), and nearly 100 high water rescues were made. In addition to severe loss of life and infrastructure damage, Texas A&M Forest Service estimates as many as 12,000 trees were damaged or uprooted in the lower portion of the basin. The project will document the extent of flooding and the impact of large woody debris (trees) as a feedback mechanism that may have additionally raided water levels. This project will investigate the Texas floods of May 2015 by 1) documenting high water marks (stage heights) in upland tributaries and along the main stem as well as 2) characterizing the geometry of selected river cross sections containing large woody debris piles. These geographic characterizations will better define floodwave timing, velocity, and stage height. This study will be used in a full forensic hydrological investigation seeking to understand the meteorological, hydrologic, and hydraulic intricacies of the event. The investigator will coordinate his activities among the USGS, Texas A&M Forest Service and the Guadalupe Blanco River Authority.