Estimation of the impact of climate change-induced extreme precipitation events on floods

Kamila HLAVČOVÁ; Milan LAPIN; Peter VALENT; Ján SZOLGAY; Silvia KOHNOVÁ; Peter RONČÁK

doi:10.1515/congeo-2015-0019

Kamila HLAVČOVÁ Department of Land and Water Resources Management, Slovak University of Technology
Milan LAPIN Division of Meteorology and Climatology, KAFZM, FMFI, Comenius University
Peter VALENT Department of Land and Water Resources Management, Slovak University of Technology
Ján SZOLGAY Department of Land and Water Resources Management, Slovak University of Technology
Silvia KOHNOVÁ Department of Land and Water Resources Management, Slovak University of Technology
Peter RONČÁK Department of Land and Water Resources Management, Slovak University of Technology

DOI: https://doi.org/10.1515/congeo-2015-0019

Keywords: Extreme 5-day precipitation totals, climate change scenarios, rainfall-runoff modelling, extreme floods

Abstract

In order to estimate possible changes in the flood regime in the mountainous regions of Slovakia, a simple physically-based concept for climate change-induced changes in extreme 5-day precipitation totals is proposed in the paper. It utilizes regionally downscaled scenarios of the long-term monthly means of the air temperature, specific air humidity and precipitation projected for Central Slovakia by two regional (RCM) and two global circulation models (GCM). A simplified physically-based model for the calculation of short-term precipitation totals over the course of changing air temperatures, which is used to drive a conceptual rainfall-runoff model, was proposed. In the paper a case study of this approach in the upper Hron river basin in Central Slovakia is presented. From the 1981–2010 period, 20 events of the basin’s most extreme average of 5-day precipitation totals were selected. Only events with continual precipitation during 5 days were considered. These 5-day precipitation totals were modified according to the RCM and GCM-based scenarios for the future time horizons of 2025, 2050 and 2075. For modelling runoff under changed 5-day precipitation totals, a conceptual rainfall-runoff model developed at the Slovak University of Technology was used. Changes in extreme mean daily discharges due to climate change were compared with the original flood events and discussed.