Use of multi-criteria decision-making for selecting spillway type and optimizing dimensions by applying the harmony search algorithm: Qeshlagh Dam Case Study

摘要

Economic considerations are significantly important in designing a dam and its relatedhydraulic structures. Considering the methods used for economic design ofhydraulic structures such as a spillway, they are also dependent on the constructioncosts of the spillway. In addition to the spillway type and capacity being associatedwith the magnitude of floods. Selecting different options of a spillway, considering alltheir aspects, has always been one of the biggest issues in decision-making.The presentstudy determined the best spillway type (free-flow,stepped, semicircular andcylindrical) for Qeshlagh Dam, Iran, by considering different aspects (costs, time andperformance) and using the TOPSIS method. The obtained dimensions of the spillwayfrom multi-criteriadecision-makingwere then optimized using meta-heuristicHarmony Search Algorithm (HSA). The results identified a free-flowspillway was thebest option in terms of cost and time, whereas a cylindrical spillway is the best choicein terms of performance. The optimal free-flowspillway length is 31.8 m, and heightis 3.45 m, being capable of passing a flood discharge of 452 m~3/s. This discharge wascalculated by a reservoir routing method. Moreover, the obtained solution led to reducingthe spillway construction costs, one of the most important issues in civil engineeringprojects.