OpenSWMM Water Quality Reference Manual

See Authors & Contributors for the full list of authors and contributors.

DISCLAIMER

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.

ACKNOWLEDGEMENTS

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.

Abstract

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.

Acronyms and Abbreviations

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

List of Figures

Figure 1-1. SWMM's Object Model

Figure 1-2. SWMM's Process Models

Figure 1-3. Simulation Process Overview

Figure 2-1. Pollutant Sources in Urban Areas

Figure 2-2. Pollutant Buildup on Land Surfaces

Figure 2-3. Pollutant Washoff During Storm Events

Figure 3-1. Street Cleaning Effectiveness

Figure 4-1. Pollutant Transport in Drainage System

Figure 5-1. Treatment Processes

Figure 6-1. LID Control Types

Figure 6-2. LID Control Performance

List of Tables

Table 1-1. SWMM Object Types

Table 2-1. Pollutant Types

Table 2-2. Land Use Categories

Table 3-1. Buildup Parameters

Table 4-1. Washoff Parameters

Table 5-1. Treatment Parameters

Table 5-4. Variables Available in Treatment Expressions

Table 5-5. Math Functions Available in Treatment Expressions

Table 6-1. LID Control Parameters

Manual Contents

Chapter 1: Overview — Chapter 1: Overview
Chapter 2 - Urban Runoff Quality — Chapter 2 - Urban Runoff Quality
Chapter 3 - Surface Buildup — Chapter 3 - Surface Buildup
Chapter 4: Surface Washoff — Chapter 4: Surface Washoff
Chapter 5: Transport and Treatment — Chapter 5: Transport and Treatment
Chapter 6: Low Impact Development Controls — Chapter 6: Low Impact Development Controls
Chapter 7: Advection–Reaction–Dispersion Transport — Chapter 7: Advection–Reaction–Dispersion Transport
Chapter 8: Multi-Species Reactions — Chapter 8: Multi-Species Reactions
Chapter 9: Water Age and Heat Transport — Chapter 9: Water Age and Heat Transport
Glossary — Glossary
References — References

Table of Contents