Abstract

first_page settings Order Article Reprints Open AccessArticle Remote Sensing with UAVs for Modeling Floods: An Exploratory Approach Based on Three Chilean Rivers by Robert Clasing 1,2 [ORCID] , Enrique Muñoz 1,2,*, José Luis Arumí 3,4 [ORCID] , Diego Caamaño 1 [ORCID] , Hernán Alcayaga 5 [ORCID] and Yelena Medina 1,2 1 Department of Civil Engineering, Universidad Católica de la Santísima Concepción, Concepción 4090541, Chile 2 Centro de Investigación en Biodiversidad y Ambientes Sustentables (CIBAS), Universidad Católica de la Santísima Concepción, Concepción 4090541, Chile 3 Department of Water Resources, Universidad de Concepción, Chillán 3812120, Chile 4 Centro Fondap CRHIAM, Concepción 4070411, Chile 5 Escuela de Ingeniería en Obras Civiles, Universidad Diego Portales, Santiago 8370109, Chile * Author to whom correspondence should be addressed. Water 2023, 15(8), 1502; https://doi.org/10.3390/w15081502 Received: 13 March 2023 / Revised: 2 April 2023 / Accepted: 4 April 2023 / Published: 12 April 2023 (This article belongs to the Special Issue A Safer Future—Prediction of Water-Related Disasters) Download Browse Figures Versions Notes Abstract The use of unmanned aerial vehicles (UAVs) has been steadily increasing due to their ability to acquire high-precision ground elevation information at a low cost. However, these devices have limitations in estimating elevations of the water surface and submerged terrain (i.e., channel bathymetry). Therefore, the creation of a digital terrain model (DTM) using UAVs in low-water periods means a greater dry channel surface area and thus reduces the lack of information on the wet area not appropriately measured by the UAV. Under such scenarios, UAV-DTM-derived data present an opportunity for practical engineering in estimating floods; however, the accuracy of estimations against current methods of flood estimations and design needs to be measured. The objective of this study is therefore to develop an exploratory analysis for the creation of hydraulic models of river floods using only UAV-derived topographic information. Hydraulic models were constructed based on DTMs created in (i) the traditional manner, considering the bathymetry measured with RTK-GPS and topography, and via (ii) remote sensing, which involves topography measurement with a UAV and assumes a flat bed in the part of the channel covered by water. The 1D steady-state HEC-RAS model v.5.0.3 was used to simulate floods at different return periods. The applied methodology allows a slightly conservative, efficient, economical, and safe approach for the estimation of floods in rivers, with an RMSE of 6.1, 11.8 and 12.6 cm for the Nicodahue, Bellavista and Curanilahue rivers. The approach has important implications for flood studies, as larger areas can be surveyed, and cost- and time-efficient flood estimations can be performed using affordable UAVs. Further research on this topic is necessary to estimate the limitations and precision in rivers with different morphologies and under different geographical contexts.