Assessment of Summer Drought in 2015 Using Different Indices in the Catchment of Blanice River

Abstract

The year 2015 was characterized by a very low precipitation totals and long rainless periods all over the Czech Republic as well as other central European countries. This fact has attracted the attention of both the public as well as professional society whose focus was recently put more on floods which are hydrologic extremes with more sound impacts. In this paper, the summer period 2015 is in the focus for the catchment of Blanice River (Central Bohemia Region, South Bohemia Region). It was analyzed from both the meteorological and hydrological point of view. Total area of the catchment is 534 km2 and is located 50km southeast of Prague. For the assessment of drought, the data from one hydrological gauging as well as from a number of meteorological stations were used. The time series used for this study are more than 50 years long. Drought indices used for this study and presented in this paper were Standardized Precipitation Index (SPI), Streamflow Drought Index (SDI) and deficit volumes (DV). The analyses of precipitation data carried out for given purpose were supported by GIS application in order to get real precipitation data based on available station data. Drought indexes were calculated on the basis of data for entire period, however the emphasis was put on the data from year 2015. The results of all performed analyses show the significance of the drought event which occurred in summer 2015 with respect to both meteorological and hydrological indices. However, the significance of meteorological drought seems to be higher with respect to the results of analyses carried out. The results also show, that there were even more severe drought episodes in past within the analyzed period.