A general framework for flood risk-based storm sewer network design

Storm sewer networks are usually designed under a certain predefined design storm. This paper proposes a general framework for a risk-based storm sewer network design, which is capable of taking future risk into account. In the framework, the flood risk evaluation is located within an optimisation loop. The flood risk is obtained by integrating the area under the probabilistic flood consequence curve, which is identified by simulations of sewer system performance under several design storms. The genetic algorithm is adapted for this specific optimisation problem in order to make the procedure computationally efficient. The framework is applied to the designs of a synthetic network and a real-world network. The results show that the general framework is able to identify the network design balancing the construction cost and flood risk.