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OpenSWMM Engine
6.0.0-alpha.4
Data-oriented, plugin-extensible SWMM Engine (6.0.0-alpha.4)
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OpenSWMM Engine
6.0.0-alpha.4
Data-oriented, plugin-extensible SWMM Engine (6.0.0-alpha.4)
|
This software is provided on an "as is" basis and the user assumes responsibility for its use. Although a reasonable effort has been made to assure that the results obtained are correct, the authors are not responsible and assume no liability whatsoever for any results or any use made of the results obtained from these programs, nor for any damages or litigation that result from the use of these programs for any purpose.
This reference manual was originally prepared by Lewis A. Rossman, Environmental Scientist Emeritus, U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, and Wayne C. Huber, Professor Emeritus, Oregon State University. Their foundational work on the SWMM water quality model and its documentation is gratefully acknowledged.
See Authors & Contributors for the complete list of authors and contributors.
SWMM is a dynamic rainfall-runoff simulation model used for single event or long-term (continuous) simulation of runoff quantity and quality from primarily urban areas. This document describes the water quality modeling capabilities of SWMM. It covers the simulation of pollutant buildup on land surfaces, their washoff during storm events, transport through the drainage system, and treatment by various control practices. The manual also describes how to model Low Impact Development (LID) controls for managing stormwater runoff quality.
BMP - Best Management Practice
CSO - Combined Sewer Overflow
EPA - Environmental Protection Agency
LID - Low Impact Development
NPDES - National Pollutant Discharge Elimination System
SWMM - Storm Water Management Model
TSS - Total Suspended Solids
TKN - Total Kjeldahl Nitrogen
TP - Total Phosphorus
BOD - Biochemical Oxygen Demand
COD - Chemical Oxygen Demand
TDS - Total Dissolved Solids
TOC - Total Organic Carbon
VSS - Volatile Suspended Solids
FSS - Fixed Suspended Solids
Figure 1-1. Elements of a typical urban drainage system
Figure 1-2. Objects of an OpenSWMM model
Figure 1-3. Processes modelled by OpenSWMM
Figure 1-4. Block diagram of SWMM's state transition process
Figure 1-5. Flow chart of SWMM's simulation procedure
Figure 1-6. Interpolation of reported values from computed values
Figure 1-7. The water quality of this manual: buildup, washoff, transport and reactions across the compartments
Figure 2-1. Hourly domestic sewage time patterns
Figure 2-2. Pollutant Buildup on Land Surfaces
Figure 2-3. Pollutant Washoff During Storm Events
Figure 3-1. Accumulation of solids on urban streets versus time (Sartor and Boyd, 1972)
Figure 3-2. Buildup of street solids in San Jose (from Pitt, 1979)
Figure 3-3. Comparison of buildup equations for a hypothetical pollutant
Figure 3-4. Evolution of buildup after a storm event
Figure 4-1. Washoff of street solids by flushing with a sprinkler system (from Sartor and Boyd, 1972)
Figure 4-2. Comparison of washoff functions
Figure 4-3. Two-stream approach to modeling pollutant washoff
Figure 4-4. Simulated load variations within a storm as a function of runoff rate
Figure 5-1. Representation of the conveyance network in SWMM
Figure 5-2. Comparison of completely mixed reactor equations for time varying inflow
Figure 5-3. Comparison of completely mixed reactor equations for a step inflow
Figure 5-4. Gravity settling treatment of TSS within a detention pond
Figure 6-1. A typical bio-retention cell
Figure 6-2. Flow path across the surface of a green roof
Figure 6-3. Representation of a permeable pavement system
Figure 6-4. Representation of rooftop disconnection
Figure 6-5. Representation of a vegetative swale
Figure 6-6. Different options for placing LID controls
Figure 6-7. Storm event used for the LID example
Figure 6-8. Flux rates through the bio-retention cell with no underdrain
Figure 6-9. Moisture levels in the bio-retention cell with no underdrain
Figure 6-10. Moisture levels in the bio-retention cell with underdrain
Figure 6-11. Flux rates through the bio-retention cell with underdrain
Figure 7-1. Flux-limited advection in the Eulerian engine: the face stencil and a step front under UPWIND and the three MUSCL limiters
Figure 7-2. The five phases of a Lagrangian transport step: drain, mix, release, decay and publish on one conduit's parcel slab
Figure 9-1. The heat budget of a water body: the six surface terms of the net flux by module, and the bed zone's conduction and hyporheic exchange
Figure 10-1. The transport policy matrix: which species class moves in which domain, and the gate ladder the 2D surface passes
Figure 10-2. Buildup and washoff on one mesh cell: land-use slices, accrual, sweeping and the mass handed to the network
Table 1-1. Development history of SWMM
Table 1-2. SWMM's modeling objects
Table 1-3. State variables used by SWMM
Table 1-4. Units of expression used by SWMM
Table 2-1. Sources of contaminants in urban storm water runoff (US EPA, 1999)
Table 2-2. Typical pollutant loadings from runoff by urban land use (lbs/acre-yr)
Table 2-3. Median event mean concentrations for urban land uses
Table 2-4. Potency factors for the Detroit metropolitan area (mg/gram) Source: Roesner (1982).
Table 2-5. Potency factors for the Patuxent River Basin (mg/gram) Source: Aqua Terra (1994).
Table 2-6. Representative concentrations of constituents in rainfall
Table 2-7. Average daily dry weather flow in 29 cities Source: ASCE-WPCF (1969)
Table 2-8. Quality properties of untreated domestic wastewater Source: Metcalf and Eddy, Inc. (2003)
Table 2-9. Unit quality loads for domestic sewage, including effects of garbage grinders Source: Haseltine (1950); Metcalf and Eddy et al. (1971a).
Table 2-10. Autumn water use for six homes near Wheaton, MD Source: Tucker (1967).
Table 2-11. Typical hourly DWF correction factors Source: Metcalf and Eddy, Inc. (2003).
Table 2-12. Required temporal detail for receiving water analysis Source: Driscoll (1979) and Hydroscience (1979).
Table 3-1. Measured dust and dirt (DD) accumulation in Chicago Source: APWA (1969).
Table 3-2. Milligrams of pollutant per gram of dust and dirt (parts per thousand by mass) for four Chicago land uses Source: APWA (1969).
Table 3-3. Summary of buildup function coefficients
Table 3-4. Removal efficiencies from street cleaner path for various street cleaning programs (Pitt, 1979)
Table 3-5. Nationwide data on linear dust and dirt buildup rates and on pollutant fractions (after Manning et al., 1977)
Table 4-1. Units of the washoff coefficient KW for different washoff models
Table 4-2. Percent removals for vegetated swales and filter strips Source: ASCE (2001).
Table 4-3. Buildup/washoff calibration against annual loading rate for high-density residential land use Source: Tetra Tech (2010).
Table 4-4. National EMC's for stormwater Source: CWP (2003).
Table 4-5. EMC's for different regions Source: CWP (2003)
Table 5-1. Treatment processes used by various types of BMPs
Table 5-2. Median inlet and outlet EMCs for selected stormwater treatment practices
Table 5-3. Median pollutant removal percentages for select stormwater BMPs
Table 5-4. Variables available in treatment expressions
Table 5-5. Math functions available in treatment expressions
Table 6-1. Design manuals used as sources for LID parameter values
Table 6-2. Typical ranges for bio-retention cell parameters
Table 6-3. Soil characteristics for a typical bio-retention cell soil
Table 6-4. Typical ranges for green roof parameters
Table 6-5. Typical ranges for infiltration trench parameters
Table 6-6. Typical ranges for permeable pavement parameters
Table 6-7. Typical ranges for vegetative swale parameters
1.13.2