DBPapers
DOI: 10.5593/sgem2017/31/S12.084

THE IMPACT OF LAND USE CHANGES ON FLOOD REGIME: A CASE STUDY OF THE MYJAVA CATCHMENT

P. Roncak, K. Hlavcova, J. Szolgay, S. Kohnova, E. Lisovszki
Monday 11 September 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-04-1 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 31, 669-676 pp, DOI: 10.5593/sgem2017/31/S12.084

ABSTRACT

This study focuses on the analysis of the impact of land use changes on the flood regime in the Myjava River basin located in the Western Slovakia. The Myjava River basin has an area of 641.32 km2 and is typical for the formation of fast runoff processes, intensive soil erosion and muddy floods. The main factors responsible for the problems with flooding and soil erosion are location, geology, pedology, agricultural land use and cropping practices.
A GIS-based spatially distributed WetSpa rainfall-runoff model was used to simulate mean daily discharges in the outlet of the basin as well as the individual components of the water balance. The model was calibrated on a period between 1997 and 2012 with outstanding results (NS coefficient of 0.702). Various components of runoff (e.g. surface, interflow and groundwater) and several elements of the hydrological balance (evapotranspiration and soil moisture) were simulated under various land use scenarios. Six land use scenarios (‘crop’, ‘grass’, ‘forest’, ‘slope’, ‘elevation’ and ‘real’) were developed. The first three land use scenarios were used to test the ability of the model to simulate the changes in land use. The remaining land use scenarios, which were more realistic, aimed at reducing the maximum runoff. The changes in maximum mean daily discharges were also represented by changes in design floods and cumulative frequency curves.
The first three scenarios exhibited the ability of the WetSpa model to simulate runoff under changed land use conditions and enabled to better parameterize the land use parameters of the model. Other three “more realistic” land use scenarios, based on the distribution of land use classes (arable land, grass and forest) regarding the permissible slopes in the catchment, confirmed the possibility to reduce surface runoff and maximum discharges by applicable changes in land use and land management.
These scenarios represent practical, realistic and realizable solution of land use management and they could be implemented with smaller investments to mitigate soil erosion processes and to enhance the flood protection measures in the Myjava River basin.

Keywords: land use change, land use scenarios, the WetSpa model, maximum discharges