Simulation of overland flow in the Domica cave area flood events using the r.sim.water module

Abstract

The flash floods are very important hydrometeorological situations affecting the Domica cave area. The flash floods depend on several factors such as the amount of precipitation, land cover, phenological phase of the vegetation, or soil infiltration rate. This paper focuses on the simulation of flood events occurring in the winter and summer seasons on the Silická plateau. The main aim of the paper is the evaluation of the effects of model parameterisation and interpretation of spatial aspects of the overland flow during the flood events. GRASS GIS software, specifically its r.sim.water module was used for hydro-logical modelling of the surface runoff. The simulation included a detailed digital eleva-tion model calculated from airborne laser scanning data and land cover derived from a detailed orthoimagery map. The infiltration rate parameter and the Manning’s roughness coefficient were estimated based on land cover classes. The simulation produced water depth maps describing flood events. The results showed that during the winter season in 2016, a smaller rainfall intensity was necessary for flood occurrence and that this phenomenon is primarily caused by frozen soil, through which no water is being infiltrated. The simulation of summer flood event in 2017 shows similar results of runoff accumulation but with higher rainfall intensity and infiltration rate. The flash flood event in 2021 turned out to be differ-ent, with such extreme rainfall intensity that even higher infiltration rate was insufficient in slowing the surface runoff. The results also proved the suitability of the chosen method for small-scale high-resolution hydrological simulations. URL: https://www.gcass.science.upjs.sk/