Welcome to PCSWMM, the spatial decision support system for EPA SWMM5 urban drainage and watershed modeling - now celebrating 25 years of providing innovative modeling techniques to the engineering community.

PCSWMM 2009 incorporates a modern, powerful GIS engine that works seamlessly with the latest GIS data formats, and provides intelligent tools for streamlining model development, optimization and analysis in a comprehensive range of applications.

With full support for the latest, fully dynamic US EPA SWMM5 hydrology/hydraulics engine, PCSWMM provides a scalable (unlimited model sizes), and complete array of professional urban drainage system modeling tools for an affordable price.

Flexible, smart GIS engine

PCSWMM is the most powerful urban drainage modeling application for working with GIS/CAD based data. PCSWMM enables both engineers and GIS professionals to work on the same data, improving workflow and collaboration. PCSWMM supports the leading open standard and proprietary GIS and CAD formats, including ArcGIS, Geomedia SQL, MapInfo, Microstation, AutoCAD, GML, OpenGIS SQL, KML and many others (over 30 vector and raster formats supported), giving you the option to work with whichever file formats are required, greatly increasing the flexibility of both your model building and analysis toolset.

PCSWMM's high-performance, scalable GIS engine provides powerful GIS analysis and hydraulic modeling in a single stand-alone environment, with no other third-party licenses required. You can create, edit, modify, run, map, analyze, design and optimize your GIS based sewer network models and instantly review, query and display simulation results either from within the optimized PCSWMM interface or from within Google Earth, ArcGIS, or the GIS of your choice – its up to you.

PCSWMM automatically maintains a standard, fully accessible US EPA SWMM5 input file at all times. Support is provided for using other SWMM5 data editors (e.g. US EPA SWMM5 interface, or in-house tools), as edits to the input file are detected and the SWMM model GIS layers are automatically updated.

PCSWMM provides direct support for opening, editing, running, plotting and analyzing any existing SWMM5 models, as well as importing/converting SWMM4 models.

Advanced modeling capabilities

Integrating the full US EPA SWMM5 engine, PCSWMM accounts for various hydrologic processes that produce runoff from urban areas. These include:

• time-varying rainfall
• evaporation of standing surface water
• snow accumulation and melting
• rainfall interception from depression storage
• infiltration of rainfall into unsaturated soil layers
• percolation of infiltrated water into groundwater layers
• interflow between groundwater and the drainage system
• nonlinear reservoir routing of overland flow

Spatial variability in all of these processes is achieved by dividing a study area into a collection of smaller, homogeneous subcatchment areas, each containing its own fraction of pervious and impervious sub-areas. Overland flow can be routed between sub-areas, between subcatchments, or between entry points of a drainage system.

PCSWMM also contains a flexible set of hydraulic modeling capabilities used to route runoff, RDII, DWF, and/or external inflows through the drainage system network of pipes, channels, storage/treatment units and diversion structures. These include the ability to:

• handle networks of unlimited size
• use a wide variety of standard closed and open conduit shapes as well as natural channels
• model special elements such as culverts, storage/treatment units, flow dividers, pumps, weirs, and orifices
• apply external flows and water quality inputs from surface runoff, groundwater interflow, rainfall-dependent infiltration/inflow (RDII), dry weather sanitary flow (DWF), and user-defined inflows
• utilize either kinematic wave or full dynamic wave flow routing methods
• model various flow regimes, such as backwater, surcharging, reverse flow, and surface ponding
• apply priority-based, dynamic control rules to simulate the operation of pumps, orifice openings, and weir crest levels.

In addition to modeling the generation and transport of runoff flows, PCSWMM can also estimate the production of pollutant loads associated with this runoff. The following processes can be modeled for any number of user-defined water quality constituents:

• dry-weather pollutant buildup over different land uses
• pollutant washoff from specific land uses during storm events
• direct contribution of rainfall deposition
• reduction in dry-weather buildup due to street cleaning
• reduction in washoff load due to BMPs
• entry of dry weather sanitary flows and user-specified external inflows at any point in the drainage system
• routing of water quality constituents through the drainage system
• reduction in constituent concentration through treatment in storage units or by natural processes in pipes and channels.