Long-Term Continuous SWMM Modeling of Combined Sewers
In the early 1990s, the U.S. Environmental Protection Agency and the New Hampshire Department of Environmental Protection negotiated a consent agreement with the City of Nashua, New Hampshire (population 100,000) to address the problem of combined sewer overflows (CSOs). In 1992 a Phase I CSO study was completed as a first step towards the long-term abatement of these CSOs. A SWMM model of the Nashua combined sewer system was developed in 1996 as a tool to simulate alternatives for CSO control, which included treatment and storage facilities. This chapter describes the development of the model's input, its calibration, and its use for long-term continuous simulations. This model utilized a broad range of SWMM features, including RUNOFF, TRANSPORT, EXTRAN, TEMP, RAIN, and STATISTICS blocks. It demonstrates the feasibility of long-term continuous simulations for urban sewer systems, while also highlighting present limitations of the SWMM model that must be addressed before continuous EXTRAN simulations are practical for larger cities.
This paper is only available in PDF Format:
View full text PDF