Dam site selection using an integrated method of AHP and GIS for decision making support in Bortala, Northwest China

Abstract: Constructing dam is a possible solution for remitting the scarcity of irrigation water resource in Bortala, Northwest China. Considering the complexity of dam site selection, Analytic Hierarchy Process (AHP) was chosen in combination of Geographic Information System (GIS) as the method of Multi-Criteria Decision Making on selecting dam site. Precipitation, slope, geological layer, soil type, land cover and drainage order were considered as criteria in this study. A suitability map of constructing dam in Bortala was generated, based on which 8 possible dam sites with relatively high suitability were proposed. According to the suitability map, West Bortala, where the elevation is relatively high, was found to be the densest area with high and very high suitability for constructing dam while Northwest and Central Bortala were found as low or extremely low suitability area for constructing dam. In a percentage describing, 11.8% area of Bortala dropped in the range of high suitability and very high suitability in which only 0.0001% was very high suitability area; 47.6% area of Bortala was found in the range of moderate suitability; 34.1% of Bortala has got low or extremely low suitability. The profile of proposed dams containing cross section and characteristics of dam such as height, width, and volume were generated. Among the proposed dams, there were 2 small dams, 5 medium dams, and 1 large dam proposed with storage capacities varied from 122,506 m3 to 5,033,652 m3.