Optimal flow using convex optimization in a multiple node reservoir system - Haute Sûre Combined Sewer System (Luxembourg)

In this paper, we show how a convex optimization methodology can be used to determine a static solution, representing exit-valve settings in a multi-node reservoir system. A tunedvalve algorithm is used to produce an optimal flow solution and is based on the objective of minimizing overall combined sewer overflow (CSO) reservoir spillage to receiving waters under a combination of dry and wet (strong rain event) episodes. Numerical simulations using an efficient (proxy) flow model under a convex optimization framework were employed to minimize overall spillage in the system. The model simulates network flow in a 24reservoir Haute Sûre combined sewer system (Luxembourg). An optimised solution for reservoir flow output is validated using an InfoWorks CS model; we discuss how this methodology gives a marginally better solution to the standard water balance solution. We also use the technique to “tune” an existing reservoir system, minimizing high rain event CSO spillage.