Suitability of Surface Water from Mouillah Wadi of Algeria for Irrigation Purposes

Abstract

Salinity is one of the most severe environmental factors limiting the productivity of agricultural crops. In this chapter, evaluation of water quality of Mouillah wadi was carried out in order to assess its suitability for irrigation purposes. Mouillah wadi is a subbasin of Tafna watershed which is situated in the north-west of Algeria. It feeds the Hammam Boughrara dam with a capacity of 177 Mm3. This wadi has important sources of pollution contaminating water whose quality deterioration is a direct consequence of the discharge of the effluents of all categories in surface water (industrial and urban wastes). To evaluate the water quality, chemical parameters such as the residual sodium carbonate (RSC), the magnesium hazard (MH) and the permeability index (PI) using US Salinity Laboratory Staff salinity classification and the Wilcox diagram were determined, and seasonal variation diagrams were prepared. The electrical conductivity values show the dam waters to be of marginal quality. The waters of Mouillah wadi are of poor to harmful quality according to Wilcox classification. The calculated values of SAR and % Na plotted on SAR and Wilcox diagrams versus conductivity indicate a good to doubtful use of the dam water for irrigation. High salinity, % Na, Mg hazard and RSC values at Mouillah wadi limit the use for agricultural purposes.