A Novel Method of Evaporation Suppression in a Water Harvesting System

Abstract

A demonstration agrisystem located in an area receiving less than 250 mm rainfall annually has been constructed through a cooperative program between the City of Tucson and the University of Arizona. Mondell pine, aleppo pine, jojoba, grapes, eucalyptus, olives, and other crops were cultivated in a 4 ha NaC1 treated catchment system designed to concentrate rainfall on plants and channel excess water into a system of storage reservoirs. Evaporation was reduced from an 80 foot diameter above ground reservoir by means of 225,000 plastic film cans, at a cost of approximately 50 cents /ft². Data acquired from evaporation pans indicates a 50 to 70 percent reduction in evaporation of the stored water. Additionally, this research has provided data that 1) demonstrates the economic potential for agriculture of currently retired farmland, 2) investigates the feasibility of applying water harvesting method for agricultgural purposes in a semiarid region, and 3) evaluates water harvesting as an alternative to meet the ever increasing demand for water.