Simulation of distributed municipal-scale LID retrofit for CSO mitigation

摘要

A distributed LID retrofit to reduce combined sewer overflow (CSO) events is evaluated in Micropolis, a city simulated in EPANET with detailed housing, geographical, and pipe maps available in GIS-compatible formats. The use of cisterns is considered as a potential way to alleviate CSOs in two distinct ways, either by redirecting rainfall volume away from the sewers, or by acting as short-term greywater storage devices. Water distribution system demands are simulated using demand multipliers from a version of Micropolis which has been modified for a theoretical evaluation of the proposed solutions. Next, precipitation events are simulated in terms of probability, rainfall depth, and storm duration using data from the national climate data center and prepared in Microsoft Excel and an R script. By evaluating the changes in sewage system burden during wet weather events, the potential for lower cost LID retrofits to improve environmental outcomes is evaluated.