Cost minimization of groundwater supply to a central tank

Abstract

Minimization of groundwater exploitation cost is examined, considering: (a) pumping from a system of wells up to a central water tank, including friction losses along the connecting pipe network and (b) amortization of network construction. Assuming that the wells are located symmetrically around the tank and directly connected to it, we derived analytically the distance between tank and wells, which minimizes the total cost. Then we compared the minimum cost of this well layout, with that of placing one well at the location of the tank and the rest symmetrically around it. Finally, we dropped any assumption on well layout, we considered that wells are connected to the tank using a minimum spanning tree and we optimized well locations and flow rates using genetic algorithms. For up to 8 wells, the resulting minimum cost is comparable to that of the symmetrical cases, even when the optimal well layout is quite different. Moreover, the analytical solution, derived for the symmetrical case, can serve to evaluate solutions achieved by sophisticated optimization techniques. HIGHLIGHTS Minimizing cost of pumping groundwater from a system of wells to a tank plus amortization of pipe network construction.; Pumping cost includes friction losses along pipe network.; Analytical calculation of minimum cost for symmetrical well layouts.; Cost evaluation for symmetrical well layouts around the tank plus a well at the tank.; Minimization of cost without any well layout constraint, using genetic algorithms.;

Keywords

• analytical solution
• cost minimization
• genetic algorithms
• groundwater resources
• pipe network construction cost
• pumping cost