Reducing Evaporative Water Losses from Irrigation Ponds through the Reuse of Polyethylene Terephthalate Bottles

Abstract

Evaporation is one of the sources of water loss from artificial reservoirs used by the agricultural sector. Current methods of covering artificial reservoirs are too costly to be used by poor, small-scale farmers. This paper presents a method for using waste polyethylene terephthalate (PET) bottles to reduce the evaporative losses from open tanks. This water-conservation method was tested using eight evaporation pans with daily water level measurements to record evaporation rate. Four pans were used as controls, two were covered with empty waste PET bottles, and two were covered with bottles partially filled with soil. The experiment showed an average reduction in evaporation by 40% with the PET bottle treatment, with a 90% confidence of reducing evaporation by at least 18%. The addition of soil did not affect the degree of evaporation reduction. Given the local economics of the region surrounding Pune, India, it was found that this intervention can save water at a cost of US$0.09/m[superscript 3].