ASSESSMENT OF PEAK FLOW VARIATION DUE TO LANDUSE CHANGE: VIT RIVER CASE STUDY

Abstract

The results of many research projects and studies report that landuse/ landcover change (LULCC) is a major driver of the changes in the hydrological processes within a watershed. Landuse induced landcover changes, e.g., urbanization, deforestation, have a direct impact on the hydrological regime of watersheds thus increasing their vulnerability to extreme hydrological events. In this research the Soil and Water Assessment Tool (SWAT) was used to study the landuse/landcover change impact on the hydrological dynamics within a watershed with respect to peak flow. The physically-based, semi-distributed hydrological SWAT model was applied over Vit river basin in Bulgaria. SWAT was set up with a meteorological information for the period 2015-2020 and the Corine Land Cover (CLC2012) dataset was used to classify the different landuse types in the watershed. The model was further calibrated and validated towards measured discharge data. The rainfall-runoff process in Vit river basin was re-modelled by having the calibrated SWAT model applied using the same meteorological input time series data and a future landcover change scenario. Future landuse/landcover change scenario was selected following the "Sustainable Futures for Europe's Heritage in Cultural Landscapes" project (HERCULES) open mapping platform. The results of the simulations with the CLC2012 and the future landcover shange scenario landuse datasets are presented in this paper. The future landcover change scenario simulated daily discharges were compared against the simulated with the CLC2012 dataset daily discharges. The results of the modelled surface runoff with the two landcover scenarios were also analyzed to evaluate quantitative and spatial distribution changes. Compared to CLC2012, the FLC scenario simulation results showed a tendency toward maximal peak flow increase, higher surface runoff and decrease of minimal streamflow.