Optimal Heights of Small Dams Series for Rainwater Harvesting, (Iraqi Western Desert as a Case Study)

Abstract

Small dams are a suitable tool for managing, storing and distributing water. In this paper, anew methodology has been introduced to help greatly in water resources planning. Scope of the study includes two phases, the first is to identify sites for dams in Western desert of Iraq (Horan valley) using geographical information system (GIS) according to different criteria. The second stage includes the establishment of a computer model with visual programing to evaluate the optimum height of dams according to an economic aspects based on the lowest evaporation losses and highest storage capacity through a set of equations. This computer program named Optimal Height And Location Model (OHALM). 13 proposed small dams were selected in the region and distributed on upstream, midstream and dawn stream as 3, 5 and 5 respectively. The height values for these dams ranged between 12.5 – 14 m as a maximum water storage level. The results of (OHALM) were compared with the heights of dams currently available in the valley in order to evaluate this model. The relative differences between the water levels calculated from the mathematical model (OHALM) with the water levels of existing dams in the study area area is about 10.4% in upstream , 7.2% in midstream and 7.2% in downstream