Comparison and Measurement of Evaporation From Water Surface of the Reservoirs in Arid Areas and Evaluation of A Glass Cover to Reduce Evaporation

Abstract

Every year, significant amounts of freshwater are disappeared from watersheds by evaporation. Many regions of the world have been struggling with arid and semi-arid climates in recent decades. The problem of water shortage that is induced by water evaporation from lakes and water reservoirs or water use for irrigation and domestic consumption has turned into a grave challenge, especially in summer. The present experimental study focuses on the accurate measurement of evaporation and presents a novel approach to decreasing this phenomenon in the south-east of Iran (Zahedan). For this purpose, four ponds with dimensions of 120x95x70 (length, width, and depth) were constructed in Zahedan's Meteorological Organization field in order to be compared with the results of induced class-A evaporation pan. Two daily time periods (30 days) were selected to measure hydrologic parameters with respect to the spring and summer conditions as well. After the experimental results were evaluated, six relations were extracted for the accurate estimation of evaporation in arid zones. Finally, a composition type of glass physical covers was fabricated and used to decrease evaporation. The cover was made of waste glass, rubber and some glue for the buoyancy. Solar radiation and air free oxygen were allowed to be in contact with the water surface. The results showed that the rate of evaporation decreased by up to 40 percent using these covers just for the 50 percent of the surface covering.