Enhancing the efficiency of the automatic design of rural drainage network

The discharges used for the design of rural drainage networks depend on the characteristics (storage, time of concentration) of the network itself, and the evaluation of these discharges should be accomplished during the search of optimal network: this leads to time-consuming optimization procedures, and it is desirable to devise efficient numerical alternatives. Two models, EGA and EGA-f, are proposed in order to increase the numerical efficiency of Genetic Algorithms for the solution of the optimal rural drainage network problem: while the EGA procedure is based on the use of the nodal excavation depths as decision variables, the EGA-f procedure improves EGA by freezing temporarily the design discharges during the optimization process. The application of the two models is demonstrated by means of numerical experiments, confirming their superiority over existing Genetic Algorithms for the optimization of rural drainage networks.