Impact of Climate Variability on Hydrology of the Western Mitidja Watershed, Algeria

Abstract

The objective of this study is to analyze the hydro-climatic regimes of the watershed of Mitidja West, and then try to evaluate the influence of climate on superficial flows. Rainfall data and databank for monthly discharges come from the National Agency of Hydraulic Resources (ANRH), rainfall are recorded from 23 rainfall stations distributed over the watershed and whose size varies from one station to another, and Time series of discharges data are generally from 1987 to 2012, but vary in duration. However, we noted that flows have been subjected to ruptures of 1975 until the middle of the 1980s. However, this reduction is due to a the climate impact associated with precipitation which decrease significantly since the end of the 75 years; or an anthropogenic impact due to the many hydraulic infrastructure development since 1985. Thus, for the simulation of the discharges from the rains, the efficiency of the model to simulate monthly discharges of the basin is given by the analysis of the criterion of Nash, of which it gave satisfactory values ​​superior to (60%), we can say, afterwards, that the GR2M model has a certain efficiency to simulate the discharges in the monthly time step and to guarantee a better understanding of the hydrological behavior of the basin.