Abhatoo - Centre Nationale de Documentation

Morocco is a Mediterranean country subject to water scarcity and pollution. This phenomenon is more present in his oriental and southern borders. The water quality is an essential condition for the establishment of a management system that will help ensure water supplies in the future. The Hassan Addakhil dam located in the north of Errachidia city, is an outlet for the waters from the Ziz River. It guarantees permanent water supply to all the cities and agglomerations (almost 240 000 inhabitant according RGH 2014) downstream the dam and in addition the drained waters from the dam to allow the irrigation of farmland in the Ziz Valley (4500 ha) and the plain of Tafilalet (22400 ha). The objective of this work is to identify and quantify pollution along the Ziz River upstream of the dam Hassan Addakhil from its major source of Sidi Hamza until the dam. This study investigates the spatial water quality pattern of eight stations located along the Ziz River. It has included the physicochemical analysis to characterize the environment and highlighted the parameters that determine the water quality namely: The conductivity, temperature, pH, major ionic components cations (calcium, magnesium, potassium and sodium), anions (chloride, sulfate, nitrate and bicarbonate), and a set of some trace elements (Iron, manganese, fluoride ...) This work is a fundamental step in the development of protection perimeters around the dam Hassan Addakhil. The study highlighted two water families: Sulfated calcic, and Chloride Sodium. The waters are usually well oxygenated; pH, temperature, and the nitrates and sulfates are considered eligible. An increase in certain trace elements is stored , in particular for arsenic and barium upstream towards downstream, and fluctuations in the levels of iron due to leaching by sediments along the Ziz River. The domestic liquid wastes contribute to the increase of traces elements in the waters.