CS(AR)-39/98-99 : Implementation and testing of the Storm water management model (swmm) software

Abstract

The EPA's Storm Water Management Model (SWMM) is a large, complex model capable of simulating the movement of precipitation and pollutants from the ground surface through pipe and continuous simulation may be performed on catchments having storm sewers, combined sewers, and natural drainage, for prediction of flows, stages, and pollutant concentrations. The model may be used for both planning and design. The planning model is used for an overall assessment of the urban runoff problem and proposed abatement options. This model is typified by continuous simulation for several years using long-term precipitation data. Catchment schematization is usually "coarse" in keeping with the planning level of analysis. A design-level, event simulation also may be run using a detailed catchment schematization and shorter time steps for precipitation input. The SWMM Windows interface was developed to assist the user in data input and model execution and to make a complex model user-friendly. The Windows interface was developed for the Office of Science and Technology, Standards and Applied Sciences Division of the U.S. Environmental Protection Agency to assist them with the Total Maximum Daily Load (TMDL) program, The Windows interface integrates the SWMM model and data handling needs to make the model implementation user friendly. A brief description of the SWMM model structure is presented in order to facilitate subsequent discussions.

This report is divided into nine sections. Section 2 gives a technical summary of the SWMM model, as well as the model structure, the interaction between the various blocks of SWMM, the input requirements, and the output. Section 3 describes the Windows Implementation of the blocks, including descriptions of the screens sequences, the corresponding blocks, changes made for ease of use, and limitations of the implementation. Section 4 provides minimum hardware requirements and installation information for the Windows SWMM. Section 5 provides the information necessary to use the SWMM interface, including:

• Accessing an Existing File or Opening a New File

• File-Naming Conventions

• Saving Input Files

• Setting Up a Default Editor for Viewing Output Files

• SWMM Windows Interface Commands and Function Keys

• Submitting an Input File to the Model

• Import File Option in SWMM

• Export Function