Influence of climate variability on water resource availability in the upper basin of Oum-Er-Rabiaa, Morocco

Abstract

This study aims to analyze rainfall data series of four hydrometric stations in a mountainous context in Morocco, over the period 1970–2017. Periods of disruption were identified through statistical approaches based on rupture detection: the Pettitt test, the Bayesian procedure of Lee and Heghinian, and the Buishand test. The results show that the studied series are characterized by several breaks which indicate a variation in the overall trend of the rainfall regime during 1980, 1995, 2000, and around 2010. In addition, a diagnostic of dry and wet years is carried out by applying the Standardized Precipitation Index (SPI); a prolonged period of drought was observed from 1980 to 2010, with the exception of several short-term rainy events, such as in 1994–1996 and the early 2000s. The variability of spring discharge indicates an evolution consistent with that of rainfall; the largest decrease in flow rates was recorded during the period from 1980 to 1993. In addition, periods of abrupt increases were identified, with a maximum recorded in 1994–1996. The phase opposition showed a marked consistency between the North Atlantic Oscillation (NAO), the SPI, and the variability of spring discharge, which provides an overview of the influence of atmospheric circulation on the evolution of precipitation and, consequently, on the availability of water resources in the area.