干旱区生态环境知识资源中心

The limited fresh water resources and increasing future demand for water necessitate the importance of optimum use of water; especially in arid/semi-arid regions. The purpose of this study is to examine reducing evaporation losses from open water bodies using palm-frond sheets as cover material. Four open constant-depth water tanks with two different surface areas have been used in the study. The tanks had square and rectangular surface areas. The tanks were covered with two patterns of palm-frond sheets: a) staggered strips-no strips covering half of the surface area (strips-covered), and b) single sheet covering half of the surface area (A 1/2 -covered). Data of cumulative evaporation depths were recorded daily continuously from the covered tanks, as well as from the uncovered tanks, to assess the relative efficiency of evaporation reduction. The results indicated that the strips-covered pattern outperformed the A 1/2 -covered; it reduced the evaporation depth by approximately 20% and 24% for the square and rectangular surface tanks; respectively, when compared to the A 1/2 -covered pattern. Moreover, the strips-covered pattern resulted in approximately 76% less evaporation depth compared to the uncovered reference tanks. Additionally, water quality analyses showed that such palm-based cover materials have insignificant effect on the water quality. These results confirmed that evaporation can be reduced and controlled using environment friendly safe techniques.