EFFECTS OF DROUGHT ON SLOVENIAN RIVERS FROM 2000-2002

Abstract

A drought was recorded from 2000-2002. It was associated with a period of lower precipitation and was reflected in low water flows and lower groundwater levels. The low water flows were recorded from June to August in 2000 and 2001. In 2002, the low water flows were recorded from the first half of the year up to July. The low water flows in 2000-2002 resulted from a precipitation deficit. Precipitation was below the average during the period 1961-1990. Most precipitation, which was near average amounts, was in western Slovenia. About 95% of the average precipitation fell in the middle of the country (Ljubljana) and between 70% and 80% of the average precipitation during the period 1961-1990 was in the northeastern part (Lendava). The mean air temperature in the last years was 2°C above the norms during the period 1961-1990. But from a hydrological point of view, these years were not extremely dry. The cyclical periods of low water flows were between 10 and 20 years, and the minimum low water flow was not recorded during the period 2000-2002. The year 1993 is still the driest year in the last forty years. But drought is a regional occurrence; in Slovenia, the northeastern part is usually the most affected because the amount of precipitation there is the lowest and the precipitation deficit is the largest.