SPATIAL AND TEMPORAL VARIABILITY OF HYDROLOGICAL DROUGHT IN THE CZECH REPUBLIC

10th International Multidisciplinary Scientific GeoConference - SGEM2010, www.sgem.org, SGEM2010 Conference Proceedings/ ISBN 10: 954-91818-1-2, June 20-26, 2010, Vol. 2, 59-66 pp

ABSTRACT

We analyze long term series of mean monthly river runoff in the period 1931–2007 to
characterize drought severity in 118 gauging stations across the Czech Republic. A
threshold level method is employed using Q95 discharge as the threshold to identify
periods during which the flow is below limit and thus considered as drought. We use
both annual and monthly variable threshold. The drought parameters are the deficit
volume and the duration. We observe the relation between deficit volume and the
physical and geographical conditions of the river basin. The monthly series of deficit
volume were analyzed by means of a modified non-parametric Mann-Kendall test.
Mostly the decreasing trend was found meaning the tendency to less severe drought
episodes at the present. To support this finding, we analyze a series from before 1900 as
well. We also take notice of how dams of different primary function may affect the
particular drought event. The aim of the analysis is to provide the basis for developing
indices for hydrological drought severity definition that are to be used in the preparation
of plans for drought impact mitigation.

Keywords: hydrological drought, deficit volume, drought duration, trend detection