Study of water stress and droughts with indicators using daily data on the Bani river (Niger basin, Mali)

As in most parts of Africa, the Bani basin (Niger River, Mali) is threatened by climate changes. This study focuses on drought hazards and its indicators as derived from the climatic moisture index using the monthly data for the period (1963-2000) in order to examine the Bani basin's vulnerability to water stress. In this study, water deficit (drought) was logically addressed using the standardized precipitation index on a 10-day time step. The inadequacies in the standardized precipitation index while estimating water deficit within the basin based on technical issues result in the usage of the effective drought index (EDI). This robust index is specially designed for daily data computation and uses daily data efficiently while estimating water deficit. Three regions were identified to be threatened by droughts (length, number, and evolution in time) within the basin, using EDI as a tool of investigation. It also shows that droughts seem to be less frequent but of a longer duration due to the increasing trend of total dry days over the study period. Copyright (C) 2009 Royal Meteorological Society