Modeling Software Tackles Stormwater Issues
An Oregon-based company offers software designed to manage stormwater and wastewater drainage projects using a 32-bit WindowsRegistered 95/NT application.
The XP-SWMM32 Storm and Wastewater Management Model may be used to model the full hydrologic cycle from stormwater and wastewater flow and pollution generation to simulation of the hydraulics in any combined system of open and/or closed conduits with any boundary conditions.
XP-SWMM32 uses a proprietary self-modifying Dynamic Wave solution algorithm which allows it to use small time steps when required and larger time steps when appropriate. The software does not suffer from the numerical attenuation present in some dynamic wave models which use a matrix solution and large time steps. This is especially important in urban systems where steeply rising hydrographs, requiring responses in seconds or fractions of a second, will predominate.
The program has three layers. There is a stormwater layer for hydrology and water quality generation, a wastewater layer for generation of wastewater flows including storage/treatment for best management practices (BMPs) and water quality routing, and a hydro-dynamic hydraulics layer for the hydraulic simulation of open and closed conduit wastewater or stormwater systems.
A global database contains design and measured storm events, infiltration data, pollutant data and other data required to run the software. The different layers of the software are connected to the global data required for the simulation.
XP-SWMM32 is a link-node model that performs hydrology, hydraulics and quality analysis of stormwater and wastewater drainage systems including sewage treatment plants, and water quality control devices (BMPs).
Typical applications include predicting combined sewer overflows and sanitary sewer overflows, interconnected pond analysis, open and closed conduit flow analysis, major/minor flow analysis, design of new developments, and analysis of existing stormwater and sanitary sewer systems.
In the software, a link represents a hydraulic element of some kind for flow and constituent transport down the system (for example, pipe, channel, pump, weir, orifice regulator, real-time control device, etc.). There are 34 different types of conduits available.
A node represents the junction of hydraulic elements (links) as well as a location for input of flow and pollutants into the drainage system. A node can also represent a storage device such as a pond or lake, or a point junction to represent a point of change in channel or conduit geometry, or a boundary condition in the model, or a watershed.
In the Runoff layer of XP-SWMM32 up to five sub-watersheds may drain to any given node. Each of these sub-watersheds may have up to 10 or more different land uses defined. There is a maximum of 10 different land uses per simulation and a practically unlimited number of land uses stored in the software's global database. Twenty or more different pollutants are allowed in one simulation with a practically unlimited number of pollutants stored in the database.
XP-SWMM32 may be used for simulation time periods ranging from seconds to years. There are nine methods available for computing storm runoff hydrographs for any time period.
The Runoff block generates surface and sub-surface runoff based on either design or measured rainfall (and/or snow melt) hydrographs, antecedent conditions, land use and topography. User defined rainfall data allows the modeler to use data from data loggers for long periods to perform continuous simulations.