VEGETATION AND LAND USE ANALYSIS FOR RUNOFF ESTIMATION IN SMALL FORESTED CATCHMENT: A CASE STUDY OF TAJOVSKÝ BROOK IN SLOVAKIA

Abstract

Flash floods have been in the centre of attention for numerous hydrological studies recently and their magnitude and frequency are projected to increase due to the changing climate. This is especially important in small catchments where a local storm event can cause rapid increase in damage causing discharges. To estimate the possible impacts of a rainfall event, it is necessary to understand the precipitation/runoff conditions. Soil Conservation Service Curve Number (SCS CN) method is widely used and discussed to estimate the effect of land cover and soil moisture conditions on runoff. In this paper, we implement this standard method in the Tajovský brook catchment in Central Slovakia. The individual land cover classes were identified, and weighted CN numbers were established. Forest accounted for 67% of the entire area, grasslands for 19% and built-up areas for 10%. The final CNII number was computed as 60.8. Seven initial abstraction ratio values were tested on a monthly hydrograph data and optimal value was set to 0.01. This suggests the possible most suited regional value of the abstraction ratio that could be used for this type of small (<50 km) forested catchments, but further testing on other catchments and precipitation events would be beneficial.