Application of Geospatial Information System and Technique for Order Preference by Similarity to Ideal Solution for sitting water reservoirs Case study: South of Sistan & Balouchestan Province

According to recent study, in 2025, water shortages will be more prevalent among penurious countries; hence, a long term planning for saving water resources is necessary. One of the most important plans is building a dam on perennial rivers and the main step in this process is selecting the best place in watershed. The aim of this study is developing the multi-criteria decision support framework for dam site selection in South of Sistan Balouchestan province. A study has been made by applying GIS and Technique for Order Preference by Similarity to Ideal Solution to select and prioritize potential places for constructing a dam. The criteria for dam site selection have been chosen upon scholar’s ideas and available data. They include Geology, Land use, Sediment, Water Quality, Erosion, Groundwater and Hydrology. Ratio Estimation Procedure has been used to estimate weight of criteria. First, TOPSIS method and GIS have been conflated and a geospatial layer has been created that it’s called “the relative closeness to the ideal solution” that its values are between zero and one. Second, A Model has been created based on streams and topographical conditions. This model evaluates structural height, dam crest length and volume of reservoirs and upon the results of the model, fifteen places have been selected. Finally, the sites have been prioritized by finding their values on the created layer. In conclusion, the best place is A - Kahir dam- that its value is 0.85, the worst site is P that its value is 0.47 as well as Pishin dam is the worst dam amongst all the dams that have been built in the region that its value is 0.62, also the best option is K that is located on the right side branch of Sarbaz river and its value is 0.67.