Application of Fuzzy Analytical Hierarchy Process in sites determination of rain water harvesting (Case study: Birjand Basin)

Human being nowadays is facing water shortages problems due to various reasons including population growth, drought and reduced rainfall, development of industry and its adverse effects on water resources. The uncontrolled harvesting of groundwater resources has caused a severe drop in water table. On the other hand, loss of runoff from rainfall worldwide and especially in our country is very high and significant. Therefore the optimum use of runoff and uncontrolled surface water resources have to be applied instead of uncontrolled harvesting of groundwater resources. The aim of this study is to determine potential sites rainwater harvesting using Fuzzy Analytical Hierarchy Process. In this study, using max lambda method, fuzzy weighted of criteria were calculated. Then fuzzy layers of criteria with effect of respective weights were combined and finally combined layer was obtained. This layer was classified in five classes of, poor, average, rather good, good and very good. Results showed that the classes were named respectively, 0.635, 8.37, 34.32, 53.7 and 2.97 percent of total plain allocated to him. The final map of Birjand plain from west to the east the plain potential in harvesting rain water increases.