Estimating the effects of black porous polyethylene shade covers on evaporation rate in dam reservoirs

One of the most effective techniques to reduce evaporation rate is to use suspended shade covers to create shadow on the water bodies. Black polyethylene is a material that can be used for covering as porous fabric like sheets. In this study, energy balance analysis was used to evaluate the effects of using this type of covers in dam reservoirs on evaporation rate. Minab dam was selected as case study and energy modeling was conducted with respect to different scenarios. Results show that the use of black porous polyethylene can reduce evaporation by an average of 77% and 83% in the case of using single-layer and double-layer, respectively. This amount of evaporation reduction could be lead to reduce 11, 22 and 33 million cubic meters for 30%, 60% and 90% covering scenarios, respectively, for Minab dam reservoir.