Good or "bad" drawing off?: Some examples of Algerian dams

The procedure of drawing off the sediments by the sluices can reduce the filling ratio of a reservoir; but it must be well employed, and it is not the case for some algerian dams: the drawing off is carried out after the consolidation of mud. According to the measures of density and quantity of the suspended materials drawn off in Algerian dams, we propose two types of drawing off: the "good" one and the "bad" one, with differences in the drawn off mixture density which influences the regime of flowing. To have a good efficacy of the drawing off, a practical method is proposed for the management of dams in and and semi-arid countries.