Multi-criteria optimization approach to the design of small dams’ systems along mountainous stream beds

Abstract

This paper aims at the optimal design of a system of small solid barrier-type stone dams in a semi-realistic study case, determining the number, location and height of dams and a borrow-pit (BP)'s location for benefit maximization and cost minimization of objectives: (a) maximum flood protection, (b) maximum underlying aquifers' artificial recharge, (c) minimum dams' construction cost and (d) minimum stonework transportation cost. The simplified conceptual model involves no hydraulic simulation; flow characteristics are not considered, while no dam is assumed to affect another dam's benefit/cost values. Hence, all partial benefit/cost values can be separately pre-calculated, for each one of the available dam locations for all available heights and BP locations, deriving from data concerning topography, geology/soil, land uses, construction and transportation costs. Any solution proposing a system of dams of various heights and a BP exhibits a total management value equal to the sum of the respective partial benefit/cost values of each dam. The multi-objective optimization problem is formulated into a single-objective minimization problem; the difference of costs minus benefits is to be minimized. Simple, elitist genetic algorithms (GAs) are used, coupled with sophisticated post-processing of results, able to produce optimized design solutions and strategies. HIGHLIGHTS Optimization of small dam system in mountainous stream basins.; Find optimal dams' locations and heights, and a borrow-pit's location.; Construction and stonework transport costs – flood protection and aquifer recharge benefits = minimum.; A simplified model allows the pre-calculation of benefits/costs and reduces computational load.; The ‘OptiDams’ tool serves as a decision-support tool in the design phase of relevant works.;

Keywords

• artificial recharge
• constraint handling
• flood protection
• genetic algorithms
• hec-ras
• small dams