Relating Hydrological and Meteorological Drought Indices in Order to Identify Causes of low Flows in the Catchment of Blanice River

The relationship between meteorological and hydrological drought is in focus in the catchment of Blanice River (Central Bohemia Region, South Bohemia Region). Drought indices used in and presented are the Standardized Precipitation Index ( SPI ) and the Streamflow Drought Index ( SDI ). Drought was first analyzed from both the meteorological and hydrological point of view, and then the indices were compared in order to identify the importance of preceding period length in the occurrence of hydrological drought. The total area of the catchment is 534 km 2 and is located 50 km southeast of Prague. For the assessment of drought, data from one hydrological gauging station and from a number of meteorological stations were used. The time series used are more than 50 years long. The analyses of precipitation data carried out were supported by GIS application in order to get areal precipitation data based on available station data. Drought indices were calculated on the basis of data for the entire period; however, the analysis of the relationship between SDI and SPI covers only the period from 1961 to 2015 for which the values were available for both considered indices. The results of performed analyses show the correlation between hydrological and meteorological drought indices which is strongest for the reference periods from 3 to 6 months.