A flood decrease strategy based on flow network coupled with a hydraulic simulation software

Abstract

Flood is a natural phenomenon, usually sudden and a calamitous event with devastating consequences and serious effects on the society, the environment and the economy. Thus, more and more research efforts have been carried out and many solutions have been implemented in the aim to control their impact. In order to divert or block the excess water due to flooding, hydraulic structures such as retaining walls, retention ponds, dams, etc. are necessary and require the use of operation strategies to manage the complex water system. In this paper, a flood decrease strategy based on the graph theory is proposed in order to manage the control of the water storage and release from reservoirs along the river. This river-Tanks system is modeled by a dynamic network and the management problem is formulated as a minimum cost dynamic flow problem with some additional constraints. Then, this main problem is reduced into a set of low dimensional dynamic sub-problems, for which the dynamic network is extended into a static network solved using a heuristic method. Thereby this single commodity flow problem with additional constraints is modeled as a mixed integer linear program. Finally, the program is combined with a specialized hydraulic simulator to simulate the water transfer and the exchange between the reservoirs and the river. The proposed approach was applied on the Bastillac area and results obtained for a 100-year flood case are given, illustrating that the strategy ensures a weak downstream flow peak and a reduced impact.