Analysis of a water supply intake from a silted dam using two-dimensional horizontal numerical modeling: Case of Mechraa Hammadi dam (Morocco)

Abstract

Water resources in Moulouya basin situated in the North East of Morocco depends on Mohammed V and Mechraa Hammadi dams which are old and very impacted by siltation. To water supply of Oujda city and surroundings little towns a new water intake was implemented in Mechraa Hammadi dam reservoir. The better site for the intake location and a syphon type were chosen to ovoid sediment problems generated by the resuspension of particles. Thus, two-dimensional and Horizontal numerical model was developed to analyze the silting of dam especially near the intake location. The objective of this research is to examine sediment conditions surrounding a water intake and their possible repercussions on its operation and their probable impacts on water drinking supply. Numerical modeling analysis allowed to study the water supply intake operation and the risks of production shut-down. Three extreme scenarios were considered to predict the probable shortages and their range of variation. The final results of different simulations for predicting periods of shutdown of drinking water production for each scenario, considering the concentration rate of suspended sediments generated by extreme floods, were presented. Taking into account the plant capacity treatment of sediment turbidity fixed to 30 g/l, the probable duration of shutdown of the drinking water varies between one day and a maximum period of 3 days.