xpswmm is a comprehensive software package for dynamic modeling of stormwater, sanitary or combined systems, and river systems. It is used by scientists, engineers and managers to develop link-node (1D) and spatially distributed hydraulic models (2D) for analysis and design. Its use over the last 25 years has made it one of the most stable and well-used simulation software programs in the world.
xpswmm simulates natural rainfall-runoff processes and the hydraulic performance of drainage systems used to manage our water resources. It allows integrated analysis of flow and pollutant transport in engineered and natural systems including ponds, rivers, lakes, overland floodplains and the interaction with groundwater.
Use xpswmm for fully integrated hydrologic and hydraulic modeling – simulate the whole water cycle in one system! This comprehensive software will allow you to model with confidence.
xpswmm is a comprehensive hydrologic and hydraulic modeling environment. It is applied to a wide range of water resource management, design and emergency action planning issues every day by thousands of users:
- Stormwater Management
- Stormwater master plans
- Major/Minor or dual-drainage dystems
- Watershed management master plans
- Contaminant & sediment loading and transport
- Pollutant removal
- 1D/2D Urban flooding
- Detention pond optimization
- Interconnected pond routing
- Stormwater system design
- LID/WSUD and BMP analysis
- Sanitary and Combined Sewer Systems
- Capacity analysis and collection system optimization
- CSO and SSO mitigation planning
- RDII (rainfall-derived infiltration and inflow) studies
- Real-time control system performance
- Water quality analysis
- Floodplain Management and River Systems
- 1D/2D river hydraulic performance
- Floodplain mapping and flood hazard analysis
- Interior drainage (levee-protected areas) analysis
- Culvert and bridge hydraulics
- Fully coupled urban and river drainage systems
Holistic Modeling. Hydrology, Hydraulics and Water Quality. Experts know that a change to one element in a system may affect the performance of the entire system. xpswmm allows you to perform fully integrated system modeling — channels, pipes, streets, control structures, ponds, weirs, pumps, catchments, groundwater table, overland floodplains, rain gardens, infiltration trenches and more.
Model the Real World. You need a tool with model elements that accurately reflect the physical realities of your drainage system. The number of available element types, shapes and control parameters are unparalleled in free or competing proprietary software packages. Minimize the need for approximations and “modeling tricks” by using xpswmm.
Regulatory Approval. Widely used and accepted in private practice, it is also EPA tested and FEMA approved. Countless regulatory organizations are familiar with xpswmm and prefer modeling performed with its powerful tools.
Localization. xpswmm has been customized and localized for many niche markets around the world. Specific hydrologic methods, specialized hydraulic routines and purpose-build output templates will help you model according to local standards.
- Efficient Model Setup
Build your model quickly while having a world of data at your command. Get a model up and running with:
GIS Integration. Dynamically link to almost any external database to build your model and populate model parameter fields. xpswmm, an independent, standalone system, provides versatility to work with data in any ODBC/OLE compliant database; streamlined linkage to ESRI Shapefiles and MapInfo MID/MIF files is pre-configured.
Digital Terrain Model. Create or import land surfaces in xpswmm to allow generation of cross sections of open channels, assignment of 1D node elevations, or computation of overland flow depths/directions (2D hydraulics).
CAD Integration. Work with data from any DXF, DWG, LandXML or 12D file. No need to redraw in xpswmm!
- Accurate Analysis
You want a model with power and versatility when you need answers. Have confidence with:
Dynamic Analysis. xpswmm solves the full St. Venant Equations. Dynamic modeling allows the effects of storage and backwater in conduits and floodplains and the timing of the hydrographs to yield a true representation of hydraulic conditions.
1D/2D Flow. xpswmm can fully couple 1D network flow with 2D overland flow to accurately model interaction between flood waters and drainage systems, including underground pipes and natural channels. xp2D lets you model complex systems as they really are — regardless of where the water goes.
EPA SWMM5. Choose this engine as a solution option rather than the more versatile xpswmm engine if needed. Import and export SWMM5 format files.
WSPG. Choose this engine as a solution option for simple hydraulic analysis. Import older WSPG models, too!
- Versatile Results
You need to view and understand model output easily. Your reputation as a modeler depends on those results. xpswmm gives you options:
Full Results Output Document. This comprehensive text file allows you to review complete model data, computational details and complete results.
XP Tables. View and edit model input/output data in a user-customizable spreadsheet environment.
Profile/Cross Section Plots with Animation. View HGL, water surface elevation and data tables in a customizable plot window.
Flood Mapping. Create color-coded flood depth maps, floodplain boundary maps, flood hazard maps, and base flood elevation (BFE) contour maps.
Animations. Create/watch movies of flow progression over time. See it like it will happen in the real world.
- Value Optioneering
How will a new design or a different flow input affect your system? How can you rapidly assess your options?
Scenario Manager. Examine multiple “what if” scenarios within a single project with full tracking of changes. Run multiple storms automatically. Compare scenario results graphically and in tables.
Design Tools. Automatically identify flow choke points and let xpswmm design remediation (pipe sizes, slopes). Use automated Detention Pond Optimization methods to configure storage.
Real Time Controls. Evaluate operation management plans and practices that produce changing conditions in your model, including time-dependent and condition-controlled elements such as gates and weirs.
LID/BMP/WSUD. Evaluate the impact of various configurations of low impact development (LID) schemes – whether for water quantity control or water quality effects.
- Deliver Your Model
Deliver your model to clients and/or regulators easily and with the confidence that they will see the value in your analysis or design.
xpviewer Encryptor and Free Reader. Your clients and regulators don’t have to own xpswmm to view and approve your model. Users of xpswmm can encrypt a model so that their clients can review it with the free reader software that includes all the powerful tools used to build, optimize, and visualize the model.
EPA Tested, FEMA Approved. xpswmm is approved by the US Federal Emergency Management Authority (FEMA), meeting NFIP criteria for hydraulic or hydrologic projects (DFIRM, CLOMR, LOMR). It was also the first and only proprietary stormwater and wastewater model to be tested by the EPA’s Environmental Technology Verification (ETV) Program.
Model Export. xpswmm model data input and results may be output to various formats that may be preferred for submission/review by your clients including GIS files, graphics, text or tabular data, maps and more.
Expand the functionality of your xpswmm package by adding the following optional components:
- xp2D for Overland Flow
xp2D gives you the power to analyze and predict potential flood extents, depth and velocity and accurately model the interaction of surface and underground systems in an integrated 1D/2D modeling environment. The software can also be effectively used to simulate and analyze tidal surges, dam breaks and breaches on sewer networks.
xp2D simulates the complex hydrodynamics of floods and tides using the full 1D St. Venant equations and the full 2D free-surface shallow water equations.
Read more about xp2D here.
- Multiple Domains for xp2D
The Multiple Domain add-on feature for xp2D allows several domains to be added to a single model. Each domain can have its own grid extents, time step, grid cell sizes and orientation. Separate domains are linked by 2D/2D interface lines.
Multiple 2D Domains are often used to reduce the number of cells in a 2D modeling project. Large cell sizes are used in areas where fine detail is not required or where a large area is to be modeled. Small grid sizes provide more detailed analysis of varying terrain, channels and urban areas. For example, a cell size of 1-2 meters could be used for the flow in a narrow channel of say 10m wide and then a separate 2D grid of 10 meters could be used for a rural floodplain. Flow from one 2D Domain can be joined to another with the new 2D/2D Interface polyline that exchanges flows between the two distinct 2D Grid Extents.
WSPG (Water Surface Profile Gradient) is a hydraulic analysis that computes uniform and non-uniform steady flow water surface profiles and pressure gradients in a network of open channels and closed conduits. This tool originally developed by Los Angeles County has been upgraded by XP Solutions and is available as an add-on module to xpswmm or as a separate standalone product called xpwspg.
Applications include engineered channel design, urban drainage analysis and minor hydraulic loss analysis.
After designing the model using the steady state WSPG solution the model can be switched to a full dynamic analysis in xpswmm. This combination of solutions allows the modeler to have confidence that the proposed design maintains the hydraulic grade line to acceptable levels and that storage facilities are sized correctly for major events.
Read more about xpwspg here.
- Real Time Control
Real Time Control (RTC) elements such as regulators, bendable weirs, and telemetry-controlled pumps are part of xpswmm. These hydraulic elements allow changes to model elements in real time (evaluated at every time step) based on the depths of flow in any node in the model. By using a combination of rating curves and these RTC elements, many control strategies can be evaluated in the program. However, complex situations involving multiple sensors and Boolean logic are only possible by expanding xpswmm with our RTC add-on module. This powerful add-on module extends the existing depth-only RTC to a comprehensive management and design tool.
The RTC add-on module sensors can include any combination of date/time, velocity, flow and water levels and depths at nodes, conduits, pumps, orifices, and weirs. The values of the sensors can be compared to static values and with each other using typical Boolean logic and mathematical operators. For example, a control can be activated if the water level in location A is greater than location B by 2.3 feet.
Numerous hydraulic parameters depend on the type of object being controlled. The parameters that can be modified include: flow, roughness, diameter, water depths, pump on/off levels, well volume and speed factor, weir crest and surface elevation, discharge coefficient and length, and orifice area coefficient.
Additional control properties include Start and Stop time of the control, ramp times and maximum and minimum values. Operators can be concatenated with Boolean operators, and parameters can be compared with other sensors or with absolute values. Real time control can be activated during certain hours of the day, odd/even days, days of the week, months of the year and control can turn on and/or off over a user-defined time period.
A log at every time step can be generated to record the status and values of each sensor as well as the status of the control. For example if all sensors are true then the status of the control can change from INACTIVE to STARTING and the control’s opening status could change from FULLY_CLOSED to PART_CLOSED then FULLY_OPEN.
- XP Viewer
With xpviewer, your clients and other stakeholders associated with your project will have the ability to view and interrogate an encrypted version of your xpswmm models. The xpviewer program allows all software functions except the ability to change, export and solve the model. Therefore your stakeholders can view model animations, query and print the model results and participate in the model development and approval process without being required to purchase a license from XP Solutions.
This is an excellent tool for those customers who wish to share their model with others within or without the organization who do not already own a license of the software, but wish to view the model(s) results. Since the model cannot be changed or resolved with xpviewer the integrity of the created model is preserved. Encryption of an xpswmm model is made possible by upgrading your license with this powerful add-on. The model author then forwards electronically or by CD the encrypted model and results to the third party. The xpviewer can be downloaded from our website by the third party or the installation program provided by the model author with the encrypted model.
How it works
- A license holder of xpswmm purchases the xpviewer add-on module for their license.
- The modeler creates and runs their model to their satisfaction.
- The modeler then “encrypts” the model and sends appropriate encrypted files to the interested parties, along with xpviewer reader (download from this website is available). Please note that the xpviewer reader version sent should match the version of xpswmm that was used to create the model, including Service Packs.
- The receiving party installs the xpviewer reader (and necessary Service Packs). They can then open the model files sent to them and look at the model as if they have their own license.
The following includes basic technical information about xpswmm. For a full description of all aspects of the program, please see our full Technical Description.
xpswmm simulates the complete hydrologic cycle in rural and urban watersheds. Beginning with single or multiple rainfall events and dry weather flows, it models flows through collection, conveyance and treatment systems to the final outfalls. All hydrologic processes including snowmelt, evaporation, infiltration, surface ponding and ground-surface water exchanges are included in the model.
Users may select either design or actual storm events. Rainfall hyetographs may be linked to a model using offline files or assigned from a global list to catchments. Continuous simulation can be used to evaluate Hydromodification and model catchment response to long term rainfall records while including multiple rainfall stations.
Design storms for any duration and return period may be created from a library of rainfall patterns that includes:
- SCS Types: I, IA, II, II Florida Modified, III, B
- Huff Distributions
- Chicago Storm
- AR&R temporal patterns
- UK Summer and Winter Storm Patterns
- Storms from localised templates
- User defined distributions
Each subcatchment can reference a separate hyetograph enabling the modeling of radar rainfall data, localized storm events or the timing of the hyetographs can be adjusted to simulate movement of a storm across a watershed.
There are numerous methods available for computing storm runoff hydrographs for event or continuous simulations. These include:
- Non-linear Runoff Routing (US EPA Runoff Method)
- Laurenson’s Non Linear Runoff Routing (RAFTS)
- SCS Unit Hydrographs using a Curve Number with curvilinear or triangular hydrographs
- Kinematic Wave
- Clark Unit Hydrograph
- Snyder Unit Hydrograph
- Alameda County Snyder and Rational Methods
- Nash Unit Hydrograph
- Santa Barbara Urban Hydrograph
- Time Area
- Rational Method
- LA County Modified Rational Method
- Sacramento and Nolte Hydrograph Methods
- Colorado Urban Hydrograph Procedure (CUHP)
- EPA RTK Unit Hydrograph for RDII
- 5 UK Methods: Variable PR, Wallingford, ReFH, FEH and FSR
Non-Linear Runoff Routing
The primary runoff hydrograph generation method is the EPA SWMM non-linear runoff method. Overland flow hydrographs are generated by a routing procedure using Manning’s equation and a lumped continuity equation. Surface roughness and depression storage for pervious and impervious area parameters further describe the catchment. The subcatchment width parameter is related to the collection length of overland flow and is easily calculated based on the watershed area. Urban, suburban and rural areas of any size may be simulated using non-linear reservoir routing.
The unit hydrograph methods such as SCS, SBUH, Rational, etc. are primarily used for single event simulations. The SWMM runoff method is a deterministic hydrologic method suitable for comprehensive analysis and design including the simulation of LID (WSUD) using catchment surface redirection capabilities.
The xpswmm hydraulics engine solves the complete St. Venant (Dynamic Flow) equations for gradually varied, one dimensional, unsteady flow throughout the drainage network. The calculation accurately models backwater effects, flow reversal, surcharging, pressure flow and tidal outfalls and interconnected ponds. The model allows for looped networks, multiple outfalls and accounts for storage in conduits. Flow can be routed u sing kinematic or diffusive wave methods.
xpswmm uses a proprietary dynamic wave routing procedure. The solution method is inherently stable and has a fast run time by using a self modifying time step. Throughout the simulation, the time step is adjusted to insure stability and flow balance. There are several techniques available to improve the performance of the calculation engine. Additional simulation parameters allow optimization of the solution. They include:
- Global settings for minor losses, flow multipliers, roughness factors
- Courant time step factors
- User defined fixed and relative tolerances
- Minimum time step
- Automatic modification of short conduits
Your xpswmm model can be calculated using the EPA SWMM5 engine. The input file (.inp) and output file (.rpt) are generated when this option is invoked. After solving xpswmm‘s time series graphic result tools are used to display results. For compatibility with older EPA SWMM models the three Version 4 solutions are also available in xpswmm.
The 2D portion of xpswmm (xp2D) is based on the TUFLOW program developed by WBM Oceanics Australia and The University of Queensland. xp2D has incorporated the TUFLOW engine into a user-friendly graphical interface which walks the user through pre-processing of input data and the calculation of the model. Read more about xp2D.
xpswmm simulates the buildup and washoff of contaminants (non-point sources) in catchments, the direct entry of pollutants into sewers (point sources), transport through collection and conveyance systems and the treatment of stormwater and wastewater by natural processes and engineered devices.
Buildup and Washoff
The buildup of any pollutant in a subcatchment may be modeled using the US EPA time dependent Dust and Dirt model. Buildup parameters may be assigned for each pollutant and land use combination in the watershed.
Washoff during rainfall events may be modeled using:
- Event Mean Concentration (EMC)
- Exponential: dependent on flow and availability
- Rating curve: relates concentration to flow
The erosion load can be modeled using the Modified Universal Soil Loss Equation (MUSLE). These results are then presented with the total washoff rate for constituents such as TSS.
Sediment in Pipes
Residual bottom sediment in the pipes may be scoured and deposited again due to the flushing action of the conduit velocity. Scout and deposition is simulated in all conduits in the system.
Water Quality Routing in Conduits
Quality routing is performed by advection and complete mixing in conduits. Each constituent may be subjected to first order decay during the routing process. The decay of one constituent has no effect on other constituents present.
Water Quality Modeling in Storage Units
Quality routing is performed as plug flow or complete mixing in storage units. Storage and treatment devices are simulated as a series and/or parallel network of units each with optional flow-storage routing using the modified Puls method.
The treatment simulation uses either user-defined removal equations or sedimentation theory coupled with particle size-specific gravity distribution for constituents. The user may enter any valid equation to describe the treatment of the various constituents and xpswmm will parse this equation and apply it to the simulation. This treatment train can be simulated in all the models allowing it to represent typical SuDS (BMP and LID) structures and practices.
Best Management Practices (BMPs) or Low Impact Development (LID) strategies may be simulated using the above procedures in xpswmm. The model will quantify the effect of the treatment technology in terms of reduced flow (peak or total volume) and contaminant load. Typical BMP and LID strategies simulated by xpswmm are:
dry detention basins
In addressing sewer overflow problems, the software can identify the volume of spillage, flooding and the concentration of any pollutants or sediment build-up. The modeler may evaluate solutions such as storage, treatment and real-time control adjustments to prevent system failure.
xpswmm‘s graphical environment allows the modeler to create and modify the network interactively on the screen using a mouse and graphic tools. Convenient wizards guide the user through a range of required tasks such as importing external data. The internal knowledge-base “intelligently” reviews the input to prevent incorrect or inconsistent network structures or data from being created.
xpswmm allows the user to layout the network over a CAD (.DXF or .DWG) drawing or a GIS layer (.SHP or .MIF). The ability to include a background image also includes digital pictures such as .ECW, MrSID, .BMP, .JPG, .TIF files.
xpswmm is streamlined to utilize GIS and CAD data for modeling. It has the ability to display raster and vector files as background images from commercial drawing and GIS applications without the purchase of additional software or runtime licenses.
With its integrated GIS link, xpswmm enables you to exchange data with other external databases such as ArcGIS, MapInfo, Asset Management Software, Access and Excel or any other ODBC compliant database.
xpswmm‘s layer control panel allows the management of geospatial data sets including visualization and direct import of geometric objects such as polygons, polylines and points to the appropriate layer.
Both .DXF and .DWG CAD files may be added to any model and used as a spatial reference or for importing points, lines and polygons as xpswmm model objects. The display of any layer in the CAD file can be toggled on/off. Completed models can be exported as .DXF files. LandXML import can also be selected to create DTM and pipe networks from many CAD and GIS programs.
Model results for the entire simulation period may be viewed in any profile, plan or section view. The display of the animation is controlled by a set of DVR like buttons. At any time step the animation may be printed or exported as a graphic file. In the case of 2D animations the user can create .AVI videos of the network plan view to share with other stake holders.
Dynamic Plan Plotting
The results may also be replaced on the plan view with the size and color of the nodes and links changing to reflect changes in the flow, velocity and depth during the simulation period. Instantaneous direction of flow is also indicated and flooded nodes turn red and display water marks.
Scaled plan drawings, including the base map of information, may be generated and output to .DXF files, printers and plotters.
Dynamic Section Views
The results may also be replayed on a multi-panel view presenting a profile, cross sections and hydrographs. Dynamic Sections can be constructed for a single link or contiguous segment of the network.
Dynamic Long Section
A long section or profile for any contiguous segment of the network may be selected for animation of the HGL. The profile displays pipe, manhole geometry, maximum water levels and HGL over the course of the simulation. XP Tables can also be shown in conjunction with this view allowing data editing and results query. Multiple conduits can be shown when dual drainage is being modeled.
Spatial reports of model data and simulation results can be shown onscreen. A box, bracket or drop shadow attached to the link or node will show items such as the peak flow and conduit diameter (select from several hundred available fields). Model results may also be shown in conjunction with thematic plotting or graphical encoding in which the color and size of the links and nodes is dependent on the model data or results.
xpswmm is designed to work on your desktop PC. Requirements for computer power are dependent on the size and complexity of your model, length of simulation, time and other control settings. The following table should be used as a guide:
Processor: Pentium II
RAM: 512 MB
Operating System: Windows XP, Vista, Windows 7 (32 or 64 bit)
Hard Disk: 500MB
Display: 1024 x 768 24 bit color
Video card: 64 MB RAM, Vertex shader version 1.0 or greater. Pixel shader version 1.4 or greater. DirectX 9.0
Processor: Multi Core
Operating System: Windows 7 (32 or 64 bit)
Hard Disk: 100+ GB Solid State Hard Drive
Display: 1920 x 1200 32 bit color
Video card: 512 MB RAM, Vertex shader version 1.0 or greater. Pixel shader version 2.0 or greater. DirectX 9.0