RAINFALL AND RUNOFF REGIME TRENDS IN MOUNTAIN CATCHMENTS OF CENTRAL EUROPE (CASE STUDY AREA: THE UPPER HRON RIVER BASIN, SLOVAKIA)
Abstract
The paper presents an analysis of changes, the study of causes and interrelationships of hydro-meteorological parameters affecting the runoff regime in mountain catchments of Central Europe. The analyses were conducted in the upper Hron River basin in the central part of Slovakia for the period between 1931 and 2010.
For detecting trends were applied: the mass curve method, linear regression, IHA method and Mann-Kendall test. A period of runoff increase was observed from the 1960s to the 1980s, when its gradual decrease began.
This fact was also confirmed by the higher frequency and extremity of flood events in the period before 1980. IHA method showed, the period 1951-1980 was more water than 1981-2010.
Higher values were recorded for all hydrological indicators (Min, 25pct, Med, 75pct, Max). The Mann Kendall test showed a significant decrease in runoff in the winter season.
A considerable increase in air temperature occurred at all the assessed stations. In terms of snow cover depth, its gradual decrease can be seen at stations at low, middle altitudes and south located stations.
The decrease but also the increase the variability of snow cover depth is one of the causes of decline in winter runoff.