7.Hydroclimatic Variability and Water Resources in the Upper Cheliff Basin
Madjid Mehaiguene, Fadhila Touhari, Saida Askar, Hayet Messelmi and Mohamed Zouidi
The Upper Cheliff area has experienced seasonal and annual rainfall declines over the last three decades. This variability has particularly increased since the 1980s and has had significant negative impacts on both surface and underground water resources, as well as on the precipitation cycle. The objective of this work is to study the impact of hydroclimatic variability and drought on water resources. The decrease in rainfall clearly led to a downward trend in water supplies. The analysis of the average minimum and maximum temperature during the period from 1968 to 2005 revealed an increase of the minima and maxima with an average of 1.4° C at Khemis Miliana station and 2.5° C at the station of Miliana. The results obtained through the study of the severity of drought, using different indices such as rainfall indices and the standardized precipitation index, confirm the persistence and abundance of deficit years during the last three decades. The static level of the Upper Cheliff water table, during the period from 1990 to 2014,shows an irregular evolution characterized by a decrease during the period of low water, under the effect of the evaporation and a rise during the period of high water, due to the effect of artificial recharge (releases of water from the dam and / or the return of irrigation water). Keywords: Hydroclimatic variability, severity of drought, water resources, Upper Cheliff.