Comment on egusphere-2022-52

Abstract

Abstract. Increased interest in combining compound flood hazards and social vulnerability has driven recent advances in flood impact mapping. However, current methods to estimate event specific compound flooding at the household level require high-performance computing resources frequently not available to local stakeholders. Government and non-government agencies currently lack methods to repeatedly and rapidly create flood impact maps that incorporate local variability of both hazards and social vulnerability. We address this gap by developing a methodology to estimate a flood impact index at the household level in near-real time, utilizing high resolution elevation data to approximate event specific inundation from both pluvial and fluvial sources in conjunction with a social vulnerability index. Our analysis uses the 2015 Memorial Day flood in Austin, Texas as a case study and proof of concept for our methodology. We show that 37 % of the Census Block Groups in the study area experience flooding from only pluvial sources and are not identified in local or national flood hazard maps as being at risk. Furthermore, averaging hazard estimates to cartographic boundaries masks household variability, with 60 % of the Census Block Groups in the study area having a coefficient of variation around the mean flood depth exceeding 50 %. Comparing our pluvial flooding estimates to a 2D physics-based model, we classify household impact accurately for 92 % of households. Our methodology can be used as a tool to create household compound flood impact maps to provide computationally efficient information to local stakeholders.

Authors 4

1. Matthew Preisser

   The University of Texas at Austin

   Affiliation as printed

   Environmental and Water Resources Engineering, University of Texas at Austin, Austin, Texas, USA

   LBJ School of Public Affairs, University of Texas at Austin, Austin, Texas, USA

2. Paola Passalacqua corresponding

   The University of Texas at Austin

   Affiliation as printed

   Environmental and Water Resources Engineering, University of Texas at Austin, Austin, Texas, USA

3. Richard Patrick Bixler

   The University of Texas at Austin

   Affiliation as printed

   LBJ School of Public Affairs, University of Texas at Austin, Austin, Texas, USA

4. Julian Hofmann Aachen Institute of Hydraulic Eng. & Water Resources Management

   RWTH Aachen University

   Affiliation as printed

   Institute of Hydraulic Eng. & Water Resources Management, RWTH Aachen University, Germany