Abstract
Along with fluvial floods (FFs), surface water floods (SWFs) caused by extreme overland flow are one of the main flood hazards occurring after heavy rainfall. Using physics-based distributed hydrological models, surface runoff can be simulated from precipitation inputs to investigate regions prone to soil erosion, mudflows or landslides. Geomatics approaches have also been developed to map susceptibility towards intense surface runoff without explicit hydrological modeling or event-based rainfall forcing. However, in order for these methods to be applicable for prevention purposes, they need to be comprehensively evaluated using proxy data of runoff-related impacts following a given event. Here, the IRIP geomatics mapping model, or “Indicator of Intense Pluvial Runoff”, is faced with rainfall radar measurements and damage maps derived from satellite imagery and supervised classification algorithms. Six watersheds in the Aude and Alpes-Maritimes departments in the South of France are investigated over more than 2000 km2 of rural areas during two flash-flood events. The results of this study show that the greater the IRIP susceptibility scores, the more SWFs are detected by the remote sensing-based detection algorithm. Proportions of damaged plots become even larger when considering areas which experienced heavier precipitations. A negative relationship between the mean IRIP accumulation scores and the intensity of rainfall is found among damaged plots, confirming that SWFs preferably occur over potentially riskier areas where rainfall is lower. Land use and soil hydraulic conductivity are identified as the most relevant indicators for IRIP to define production areas responsible for downslope deteriorations. Multivariate logistic regression is also used to determine the relative weights of upstream and local topography, uphill production areas and rainfall intensity for explaining SWF occurrence. This work overall confirms the relevance of IRIP methodology while suggesting improvements to its core framework to implement better prevention strategies against SWF-related hazards.
Highlights
IntroductionWith more extreme precipitations expected in the 21st century due to climate change [1,2], increased attention has to be paid to the understanding and modeling of floods as of now
Licensee MDPI, Basel, Switzerland.With more extreme precipitations expected in the 21st century due to climate change [1,2], increased attention has to be paid to the understanding and modeling of floods as of now.Comparably to river overflowing, inland flood events occurring outside the vicinity of active waterways have had devastating effects worldwide in the past decades
(ORs).DeDepending on the nature of predictors, they need to be computed by taking into account pending on the nature of predictors, they need to be computed by taking into accountthe the range rangeover overwhich whichthey theyroughly roughlyevolve
Summary
With more extreme precipitations expected in the 21st century due to climate change [1,2], increased attention has to be paid to the understanding and modeling of floods as of now. To river overflowing, inland flood events occurring outside the vicinity of active waterways have had devastating effects worldwide in the past decades. They have been observed all around Europe, both in urban and rural areas, and around the Mediterranean border where severe storms happen on a more frequent basis (see [3] for some examples). Switzerland, surface water floods have been estimated accountable for respectively 50% and 45%
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call