EGUsphere EGUsphere EGUsphere EGUsphere Copernicus Publications Göttingen, Germany 10.5194/egusphere-2022-122 Evaluating the applicability of a terrain-based floodplain delineation tool for a broad-scale assessment of flood exposure of tailings deposits Pérez-Murillo Gabriel https://orcid.org/0000-0003-0176-6035 1 McIntyre Neil 1 Cohen Raymond C. Z. 2 Prakash Mahesh 2 Centre for Water in the Minerals Industry, Sustainable Minerals Institute, The University of Queensland, Brisbane QLD 4072, Australia Data61, CSIRO, Clayton, VIC 3168, Australia 11 04 2022 2022 1 41 Copyright: © 2022 Gabriel Pérez-Murillo et al. 2022 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://egusphere.copernicus.org/preprints/2022/egusphere-2022-122/ The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2022/egusphere-2022-122/egusphere-2022-122.pdf

<p>Construction and abandonment of mine tailings deposits in river floodplains have created environmental risks associated with the release of toxic substances during floods. Assessment tools are needed to understand levels of risk and to prioritize sites for management. These tools need to be computationally efficient over wide areas, potentially whole river basins, which generally excludes reliance on 2D hydrodynamic models. This research evaluates the applicability of a terrain-based floodplain delineation tool (GFPLAIN) to assess flood exposure of tailings deposits by comparing its results against a 2D hydrodynamic model, the Shallow Water Integrated Flood Tool (SWIFT). For this compassion, the case study area of Copiap&oacute; River Basin (Atacama, Chile) was used to model two flood scenarios, the extreme flood event of March 2015, and a hypothetical flood with a 100-year return period. Overall, the GFPLAIN flood maps showed limitations in reproducing the list of tailings deposits identified as exposed by SWIFT, with some agreement between some of the top 10 deposits prioritized by these tools. We conclude that GFPLAIN, while fast to apply and potentially able to prioritize sites at risk, has limitations in providing an accurate and complete assessment due to its limited consideration of local terrain and flood dynamics.</p>