The impact of climatic variability on water resources in the Ouaoumana River basin in the Middle Atlas of Morocco (November 2021-May 2022)

Abstract

This study is based on the evaluation and quantification of water resources in the Ouaoumana River basin, which is part of the Oum ER-Rabia basin and located in the Middle Atlas. The water resources of this watershed, which serve several purposes (such as filling the Ahmed El Hansali dam and irrigation), are facing numerous disturbances caused by climatic variability, high demand, and the overexploitation of groundwater. To conduct our study, we will rely on two methodologies. The first is a quantitative hydrological methodology based on flow measurements taken at several points along the river, from upstream to downstream, during the period from November 2021 to May 2022. This will generate hydrometric data, allowing us to extract the spatio-temporal variation in flows. The second methodology is statistical and will involve analyzing climatic data (rainfall, temperature) from the Taghzoute station, which is located downstream of the river basin, to better understand the climatic dynamics. The results indicate that the water resources of the Oued Ouaoumana watershed exhibit significant variation from upstream to downstream. The highest flow values are recorded in April, at 323 l/s, during the high-water period. However, in other months, including January, February, and March, the flow ranges between 20 l/s and 85 l/s, primarily due to heavy abstraction by local residents for farmland irrigation along the riverbanks, which creates several problems, especially for biodiversity.