A simplified modellling approach for storm water flow optimisation
Fullerton, James N.
PublisherUniversity of Exeter
MetadataShow full item record
During a rainstorm, urban drainage systems channel the storm water to locations where the water can be treated. Many urban drainage systems in the UK are quite old and were originally created to cope with lower population levels. As the rate of urbanisation increase and more surfaces become impermeable, drainage systems re inundated with increasing amounts of water. Over time, urban drainage systems require significant alterations to allow them to channel the increasing levels of storm water flows. A model of the urban drainage system can be created to simulate the effects of storm water in the system when different types of rainstorms are applied to it. Such models can be used to predict the consequences of any alterations to the system. With limited public funding available to improve existing systems, optimisation procedures offer a possible method for identifying the best solution for the least cost. Simulating existing urban drainage models is time consuming, especially with the amount of separate simulations that are required by most optimisation procedures. The aim of this study is the development of a simplified model for an urban drainage system that is primarily designed for speed of calculation. Adapted from a simplified pollution control model, the Packet Approach allows for the rapid evaluation of an urban drainage system model under different rainfall events. Coupled with a Genetic Algorithm optimisation method, the packet approach is easily applied to a basic model to reduce flooding caused by an inefficient drainage network. The scale of the Packet Approach is expanded so that it can be applied to a commercialsized drainage system. The expanded version of the Packet Approach, called FastNett, simulates commercial models and allows for a comparison of flow rate and flood volume to those predicted by alternative commercial software. Once a reasonable comparison is achieved, the model is optimised by FastNett, which dramatically reduces the level of flooding for a minimal cost and in a reasonable calculation time. At the end, several suggestions re given as to how FastNett could be adapted to overcome any of its natural limitations and also to cope with more complicated commercial networks.