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

Abstract

ABSTRACT: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 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.

Comparison of multi-monthly rainfall-based drought severity indices, with application to semi-arid Konya closed basin, Turkey

“…Smakhtin and Hughes (2007) developed a software which uses monthly algorithm. Akhtari et al (2009), and Roudier and Mahe (2010) found EDI difficult to calculate. Although reasonable, EDI has not received much attention.…”

“…Due to its rainfall-only data requirement, simplicity of calculations, decent reliability, and ability to address a variety of drought related issues, SPI has been used extensively in Turkey (Durdu, 2010;Keskin et al, 2009;Sonmez et al, 2005;Touchan et al, 2005;Turkes and Tatli, 2009), Mediterranean region (Lana and Burgueno, 2000;Lana et al, 2001;Paulo and Pereira, 2006;Salvati et al, 2009;Vicente-Serrano et al, 2004), United States (Budikova, 2008;Guttman, 1999;Hayes, 2000;Hayes et al, 1999;Heim, 2002;Keyantash and Dracup, 2002), and other parts of the world (Edossa et al, 2010;Mishra and Singh, 2009;Ntale and Gan, 2003;Pandey et al, 2008;Patel et al, 2007;Roudier and Mahe, 2010;Stricevic et al, 2011;Zhai et al, 2010).…”

“…Other concepts introduced through EDI were effective precipitation (EP) which is the sum of precipitation with a timedependent reduction function, and (PRN) precipitation needed for return to normal conditions. EDI in its original form is calculated with a daily timestep (Akhtari et al, 2009;Kalamaras et al, 2010;Morid et al, 2006;Roudier and Mahe, 2010), unlike many other DIs. However, its principle can be extended to monthly rainfall data (Morid et al, 2007;Pandey et al, 2008).…”

Detection of Spatial, Temporal and Trend of Meteorological Drought Using Standardized Precipitation Index (SPI) and Effective Drought Index (EDI) in the Upper Tana River Basin, Kenya

“…The resulting time-series EP was used as inputs to calculate its deviation from the mean. Then the return to normal precipitation (RNP) values was determined using the relation adopted from [29]:…”

Drought Monitoring in Chaharmahl-Bakhtiyari Province in Iran

“…It was calculated by McKee et al (1993), Wu et al (2007). SPI index, as one of the most important meteorological drought index, has been used in the world (Guttman, 1999;Pandey et al, 2008;Roudier and Mahe, 2010;etc.). SPI is an index based on the probability of rainfall for various timescale.…”