EPA-600/2-76-175a
August 1976
Environmental Protection Technology Series
ASSESSMENT OF MATHEMATICAL MODELS FOR
STORM AND COMBINED SEWER MANAGEMENT
Municipal Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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EPA-600/2-76-175a
August 1976
ASSESSMENT OF MATHEMATICAL MODELS FOR
STORM AND COMBINED SEWER MANAGEMENT
un
By
Albin Brandstetter
Battelle Pacific Northwest Laboratories
Water and Land Resources Department
Richland, Washington 99352
Contract No. 68-03-0251
Project Officer
Chi-Yuan Fan
Storm and Combined Sewer Section
Municipal Environmental Research Laboratory (Cincinnati)
Edison, New Jersey 08817
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
The Municipal Environmental Research Laboratory has reviewed
this report and approved its publication. Approval does not
signify that the contents necessarily reflect the views and
policies of the U.S. Environmental Protection Agency, nor
does mention of trade names or commercial products constitute
endorsement or recommendation for use.
11
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FOREWORD
The Environmental Protection Agency was created because of increasing public
and government concern about the dangers of pollution to the health and welfare
of the American people. Noxious air, foul water, and spoiled land are tragic
testimony to the deterioration of our natural environment. The complexity of
that environment and the interplay between its components require a concen-
trated and integrated attack on the problem.
Research and development is that necessary first step in problem solution and
it involves defining the problem, measuring its impact, and searching for
solutions. The Municipal Environmental Research Laboratory develops new and
improved technology and systems for the prevention, treatment, and management
of wastewater and solid and hazardous waste pollutant discharges from municipal
and community sources, for the preservation and treatment of public drinking
water supplies, and to minimize the adverse economic, social, health, and
aesthetic effects of pollution. This publication is one of the products of
that research; a most vital communications link between the researcher and
the user community.
The objective of the study described herein was the evaluation of compre-
hensive mathematical models for the nonsteady simulation of urban storm and
combined wastewater flow and quality. It is hoped that the application of
appropriate models will aid in the cost-effective design and improvement of
urban wastewater collection and treatment systems.
Francis T. Mayo
Director
Municioal Environmental Research Laboratory
111
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ABSTRACT
Mathematical models for the nonsteady simulation of urban run-
off were evaluated to determine their suitability for the engi-
neering assessment, planning, design and control of storm and
combined sewerage systems. The models were evaluated on the
basis of information published by the model builders and model
users. Seven models were also tested by computer runs using
both hypothetical and real catchment data. Most of the models
evaluated include the nonsteady simulation of the rainfall-
runoff process and flow routing in sewers; a few include also
the simulation of wastewater quality, options for dimensioning
sewerage system components, and features for real-time control
of overflows during rainstorms.
This report was submitted in fulfillment of Contract
No. 68-03-0251 by the Water and Land Resources Department,
Battelle-Pacific Northwest Laboratories, under sponsorship of
the Office of Research and Development, U. S. Environmental
Protection Agency. Work was completed in August 1975.
IV
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CONTENTS
Page
Abstract iv
List of Figures vi
List of Tables xiv
Acknowledgments xix
Sections
I Conclusions 1
II Recommendations 36
III Introduction 43
IV Model Selection 45
V Model Reviews 49
VI Test Data 130
VII Test Results 242
VIII Costs for Computer Application 346
IX Discussion 357
X References 362
XI Glossary 377
XII Appendices 384
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FIGURES (Continued)
No. Page
Runoff for Two-Hour Triangular Rainstorm -
Small Hypothetical Catchment, 96 m (316 ft) Long
31 0.1% Slope, 0% Imperviousness 256
32 " " 50% Imperviousness 257
33 " " 100% Imperviousness 258
34 10% Slope, 0% Imperviousness 259
35 " " 50% Imperviousness 260
36 " " 100% Imperviousness 261
Runoff for Two-Hour Triangular Rainstorm -
Large Hypothetical Catchment, 305 m (1000 ft) Long
37 0.1% Slope, 0% Imperviousness 262
38 " " 50% Imperviousness 263
39 " " 100% Imperviousness , . . 264
40 10% Slope, 0% Imperviousness 265
41 " " 50% Imperviousness 266
42 " " 100% Imperviousness 267
Outflows for Two-Hour Triangular Inflow - Small
Hypothetical Pipe, Free Inflow and Outflow
43 0.05% Slope 281
44 0.5% Slope 282
45 5% Slope 283
Large Hypothetical Pipe
46 0.05% Slope 284
47 0.5% Slope 285
48 5% Slope 286
viii
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FIGURES (Continued)
No. Page
Outflow Concentrations for Constant Inflow
Concentrations With Two-Hour Triangular
Inflow - Small Hypothetical Pipe, Free
Inflow and Outflow
49 0.05% Slope 287
50 0.5% Slope 287
51 5% Slope 288
Large Hypothetical Pipe
52 0.05% Slope 288
53 0.5% Slope 289
54 5% Slope 289
Outflow Concentrations for Triangular Inflow
Concentrations With Two-Hour Triangular Inflow -
Small Hypothetical Pipe, Free Inflow and Outflow
55 0.05% Slope 290
56 0.5% Slope 290
57 5% Slope 291
Large Hypothetical Pipe
58 0.05% Slope 291
59 0.5% Slope 292
60 5% Slope 292
Outflow Concentrations for Inverted Triangular
Inflow Concentrations With Two-Hour Triangular
Inflow - Small Hypothetical Pipe, Free Inflow
and Outflow
61 0.05% Slope 293
62 0.5% Slope 293
IX
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FIGURES (Continued)
No. Page
63 5% Slope 294
Large Hypothetical Pipe
64 0.05% Slope 294
65 0.5% Slope 295
66 5% Slope 295
Comparison of Measured and Computed Runoff for
the Oakdale Avenue Catchment
May 19, 1959 Storm
67 EPA Stormwater Management Model 305
68 Battelle Urban Wastewater Management Model 305
69 Chicago Flow Simulation Program 306
70 Dorsch Hydrograph Volume Method 306
July 2, 1960 Storm
71 EPA Stormwater Management Model 307
72 Battelle Urban Wastewater Management Model 308
73 Chicago Flow Simulation Program 309
74 Dorsch Hydrograph Method 310
July 26, 1960 Storm
75 EPA Stormwater Management Model 311
76 Battelle Urban Wastewater Management Model 312
77 Chicago Flow Simulation Program 314
78 Dorsch Hydrograph Method 315
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FIGURES (Continued)
No. Page
August 2, 1963 Storm
79 EPA Stormwater Management Model 316
80 Battelle Urban Wastewater Management Model 317
81 Chicago Flow Simulation Program 317
82 Dorsch Hydrograph Volume Method 318
Comparison of Measured and Computed Runoff for
Bloody Run Catchment Storm of November 9, 1970
Bank #1 Station
83 EPA Stormwater Management Model 325
84 Battelle Urban Wastewater Management Model 326
85 Chicago Flow Simulation Program 326
Bank #2 Station
86 EPA Stormwater Management Model 327
87 Battelle Urban Wastewater Management Model 327
88 Chicago Flow Simulation Program 328
Longview #1 Station
89 EPA Stormwater Management Model 328
90 Battelle Urban Wastewater Management Model 329
91 Chicago Flow Simulation Program 329
Longview #2 Station
92 EPA Stormwater Management Model 330
93 Battelle Urban Wastewater Management Model 330
94 Chicago Flow Simulation Program 331
XI
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TABLES
No. Page
1 Comparison of Major Model Categories 6
2 Comparison of Hydrologic Features of Models 7
3 Comparison of Hydraulic Features of Models 11
4 Comparison of Water Quality Features of Models .... 15
5 Comparison of Miscellaneous Features of Models .... 19
6 Hypothetical Subcatchment Dimensions 133
7 Hypothetical Subcatchment Characteristics 134
8 Infiltration Rates and Retention Storage Capacities
of Hypothetical Subcatchments 135
9 Hypothetical Catchment Data Combinations 137
10 Summary of Rainstorms for Hypothetical
Catchments 140
11 Two-Hour Constant Rainstorm for Hypothetical
Catchments 142
12 One-Hour Triangular Rainstorm for Hypothetical
Catchments 142
13 Two-Hour Triangular Rainstorm for Hypothetical
Catchments 143
14 Four-Hour Triangular Rainstorm for Hypothetical
Catchments 144
15 Hypothetical Pipe Dimensions 145
16 Hypothetical Pipe Boundary Conditions 146
xiv
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TABLES (Continued)
No. Page
17 Hypothetical Pipe Capacities ..... ..... ...
18 Hypothetical Pipe Data Combinations .......... 152
19 Inflow Hydrograph Shapes for Hypothetical
Pipes ......................... 153
20 Inflow Concentration Shapes for Hypothetical
Pipes ...... . .................. 155
21 Continuous Inflow for Hypothetical Pipes ....... 156
22 One-Hour Triangular Inflow for Hypothetical
Pipes ......................... 157
23 Two-Hour Triangular Inflow for Hypothetical
Pipes ......................... 158
24 Four-Hour Triangular Inflow for Hypothetical
Pipes ......................... 159
25 Inflow Concentrations for Continuous and
Two-Hour Triangular Inflow Hydrographs
for Hypothetical Pipes ................ 161
26 Inflow Concentrations for One-Hour
Triangular Inflow Hydrographs for
Hypothetical Pipes .................. 162
27 Inflow Concentrations for Four-Hour
Triangular Inflow Hydrographs for
Hypothetical Pipes .................. 163
28 Breakdown of Pervious and Impervious Surfaces
in the Oakdale Avenue Catchment ............ 166
29 Physical Characteristics of Subcatchments
of the Oakdale Avenue Catchment ............ 167
30 Estimate of Soil Characteristics fur the
Oakdale Avenue Catchment ............... 170
31 Physical Characteristics of the Sewer Elements
of the Oakdale Avenue Catchment ............ 171
xv
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TABLES (Continued)
No. Page
32 Reliable Rainfall and Runoff Records
for the Oakdale Avenue Catchment 172
Rainfall and Runoff Data for Oakdale
Avenue Catchment
33 Storm of May 19, 1959 177
34 Storm of July 2, 1960 180
35 Storm of July 26, 1960 185
36 Storm of August 2, 1963 191
37 Division of Bloody Run Catchment into
Different Land Uses 195
38 Physical Characteristics of Subcatchments
of the Bloody Run Catchment 198
39 Estimate of Soil Characteristics for the
Bloody Run Catchment 199
40 Physical Characteristics of the Sewer
Elements of the Bloody Run Catchment 202
41 Summary of Available Runoff Records for
Rainstorms of Bloody Run Catchment Selected
for Model Testing 205
Storm of November 9, 1970 - Bloody Run
Catchment
42 Rainfall Data 218
43 Runoff Data 219
44 Suspended Solids Concentrations 220
45 Biochemical Oxygen Demand Concentrations 220
Storm of November 14, 1970 - Bloody Run
Catchment
46 Rainfall Data 221
xvi
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TABLES (Continued)
No. Page
47 Runoff Data 225
48 Suspended Solids Concentrations 227
49 Biochemical Oxygen Demand Concentrations 227
Storm of May 13, 1971 - Bloody Run Catchment
50 Rainfall Data 228
51 Runoff Data 231
52 Suspended Solids Concentrations 233
53 Biochemical Oxygen Demand Concentrations 233
Storm of August 25, 1971 - Bloody Run Catchment
54 Rainfall Data 234
55 Runoff Data 238
56 Suspended Solids Concentrations 240
57 Biochemical Oxygen Demand Concentrations 241
Peak Runoff From Hypothetical Catchments
58 Two-Hour Constant Rainstorm 245
59 One-Hour Triangular Rainstorm 247
60 Two-Hour Triangular Rainstorm 249
61 Four-Hour Triangular Rainstorm 251
Peak Runoff Times From Hypothetical Catchments
62 One-Hour Triangular Rainstorm 253
63 Two-Hour Triangular Rainstorm 254
64 Four-Hour Triangular Rainstorm 255
65 Peak Outflows From Hypothetical Pipes 273
xvn
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TABLES (Continued)
No. Page
66 Peak Weir Overflows From Hypothetical Pipes 275
67 Times of Peak Outflows From Hypothetical Pipes ... 277
68 Extreme Outflow Concentrations of Small
Hypothetical Pipes 278
69 Extreme Outflow Concentrations of Large
Hypothetical Pipes 279
70 Times of Extreme Outflow Concentrations of
Small Hypothetical Pipes 280
71 Times of Extreme Outflow Concentrations of
Large Hypothetical Pipes 280
72 Runoff Comparisons for Oakdale Storms 302
73 Runoff Comparisons for Bloody Run Storms 321
74 Summary of Hypothetical Data Tests 351
75 Computer Processing Times for Hypothetical
Data Tests 352
76 Costs of Computer Runs for Hypothetical
Data Tests 356
XVlll
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ACKNOWLEDGMENTS
The work performed for this study was conducted under contract
No. 68-03-0251 of the U.S. Environmental Protection Agency
with valuable guidance from Messrs. Chi-Yuan Fan (project
officer), Richard Field, and Harry C. Torno. Battelle staff
members contributing significantly include Mr. Larry V. Kimmel,
who performed much of the model and data collection, Mr. Stacy
E. Wise and Ms. Annette S. Myhres, who performed the computer
program conversions and data analyses, Ms. Leila A. Counts,
who edited the report, and Ms. Jan Greenwell, who contributed
significantly to the final report typing and assembly.
The cooperation of model developers and users is greatly appreciated.
X3.X
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SECTION I
CONCLUSIONS
CONTENTS
Page
Summary 3
Battelle Urban Wastewater Management Model 24
British Road Research Laboratory Model 25
Chicago Flow Simulation Program 25
Chicago Hydrograph Method 26
Colorado State University Urban Runoff Modeling 26
Corps of Engineers STORM Model 27
Dorsch Consult Hydrograph-Volume Method 28
Environmental Protection Agency Stormwater Management
Model 28
Hydrocomp Simulation Program 29
Massachusetts Institute of Technology Urban Watershed
Model 30
Minneapolis-St. Paul Urban Runoff Model 30
Seattle Computer Augmented Treatment and Disposal System . 31
SOGREAH Looped Sewer Model 32
University of Cincinnati Urban Runoff Model 32
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CONTENTS (Continued)
Page
University of Illinois Storm Sewer System Simulation
Model 33
University of Massachusetts Combined Sewer Control
Simulation Model 33
Water Resources Engineers Stormwater Management Model . .34
Wilsey and Ham Urban Watershed System 35
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SUMMARY
The reviewed mathematical models are suitable for the simu-
lation of storm and combined sewerage systems or for incor-
poration in comprehensive simulation models. Considerable
differences exist from model to model, however, in the types
of phenomena considered and in the mathematical formulations
for each phenomenon. The model reviews summarize the objec-
tives, advantages, and limitations of each model.
For some applications, models are available with considerable
simplifications in their mathematical detail to reduce input
data requirements, computer storage requirements, and computer
running time. Some models include unnecessary approximations
considering the present state-of-the-art of hydrologic model-
ing and computer capability. Some of the simplifications,
however, are needed for applications to real-time control of
overflows which require repeated simulations within fixed
time constraints on a small process computer with slow execu-
tion times.
The following eleven models were evaluated on the basis of
published information and personal communication with the
model builders and model users:
1. British Road Research Laboratory Model
2. Chicago Hydrograph Method
3. Colorado State University Urban Runoff Modeling
4. Corps of Engineers Hydrologic Engineering Center
STORM Model
5. Hydrocomp Simulation Program
6. Minneapolis-St. Paul Urban Runoff Model
7. Municipality of Metropolitan Seattle Computer
Augmented Treatment and Disposal System
8. University of Cincinnati Urban Runoff Model
9. University of Illinois Storm Sewer System
Simulation Model
10. University of Massachusetts Urban Runoff Model
11. Wilsey & Ham Urban Watershed Model
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The following sever, ire-celt; v/ere also tested by computer runs
using both hypothetical and real catchment data:
1. Battelle Urban Wastewater Management Model
2. Dorsch Hydrograph-Volume Method
3. Environmental Protection Agency Stormwater
Management Model
4. Massachusetts Institute of Technology Urban
Watershed Model
5. Metropolitan Sanitary District of Greater Chicago
Flow Simulation Program
6. SOGREAH Looped Sewer Model
7. Water Resources Engineers Stormwater Management
Model
The following seven models are also listed but documentation
was received too late for detailed reviews:
1. Chicago Runoff and Pollution Model
2. CH2M-Hill Wastewater Collection System Analysis
Model
3. Dorsch Consult Quantity-Quality Simulation Program
4. Illinois State Water Survey Urban Drainage Area
Simulator
5. Norwegian Institute for Water Research Sewerage
System Models
6. Queen's University Urban Runoff Model
7. University of Nebraska Urban Hydrologic Simulator
The tables presented in the following pages provide a quick
overview of the features of each model. Table 1 lists major
model features and indicates whether a certain phenomenon is
being modeled or considered by a model. The table conse-
quently indicates the comprehensiveness of each model. Tables
2 through 5 expand on Table 1 by listing additional categories,
brief statements indicating the mathematical formulations for
particular phenomena, model limitations, and other details
which would be helpful in assessing the applicability of a
model for a particular purpose.
-------
Drafts of these tables were submitted to the model developers
and their comments were incorporated in the final versions.
Not all tables were returned, however, leaving some uncer-
tainties with respect to model formulations of a few models.
These are indicated in the tables.
Tables 1 to 5 can be used to select the most useful model for
a particular application based on features needed for simu-
lating specific storm and combined sewerage system conditions.
Usually the simplest model which simulates the desired phe-
nomena with adequately accurate mathematical formulations
should be selected. Input data requirements and computer
running times generally decrease with decreasing complexity
of the model. Some models include options to suppress por-
tions of the simulation if only selected phenomena are of
interest. Although this feature is not listed in the tables,
it should be considered in the model selection.
Model testing with hypothetical data showed that computer run-
ning time is governed more by efficient formulations of the
overall model logic than by the basic equations used for speci-
fic phenomena. For instance, no consistent pattern in computer
running time was evident between the use of the kinematic and
dynamic wave equation. Consequently, since the dynamic wave
equation can be solved to simulate downstream flow control, back-
water, flow reversal, surcharging, and pressure flow (none of
which can be simulated by the kinematic wave equation) the appli-
cation of models using the dynamic wave equation is recommended,
provided the selected model includes an efficient numerical
algorithm for its solution. Some models require only the
input of typical subcatchment elements and perform hydrologic
computations only for these typical subcatchments, but then
consider the actual locations of all subcatchments for the
overland and sewer flow routing computations. This can save
considerable input preparation and computer running time.
Various models stand out due to their completeness of hydro-
logic and hydraulic formulations, the ease of input data
preparation, the efficiency of computational algorithms, and
the adequacy of the program output. Other models, although
deficient in some of these respects, merit consideration due
to special features which are not included in the more compre-
hensive models but may be required for specific applications.
The following models are consequently recommended for routine
applications:
1. Battelle Urban Wastewater Management Model for real-
time control and/or design optimization considering
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Table 1. COMPARISON OF MAJOR MODEL CATEGORIES
CATCHMENT HYDROLOGY
SEWER HYDRAULICS
WASTEWATER QUALITY
MISCELLANEOUS
LE
ENT
PUT OF SEVER
FJOGRAPHS
UNOF
IMPER
LANCE
TORM
SUR
PRE
DRY-WEA
QUALITY
MW
ITY
SEDIMENTA
AND SCOUR
QUA
REA
WASTEWAT
TREATMEN
ER
ON
•3. •—
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Table 2a. COMPARISON OF HYDROLOGIC FEATURES OF MODELS
BATTELLE
NORTHWEST
BRITISH ROAD
RESEARCH
LABORATORY
CHICAGO FLOW
SIMULATION
CHICAGO
HYDROGRAPH
METHODS
COLORADO STATE
UNIVERSITY
CORPS OF
ENGINEERS
DORSCH CONSULT
ENVI RONMENTAL
PROTECTION
AGENCY
HYDROCOMP
MULTIPLE
CATCHMENT
INFLOWS
YES
YES
YES
YES
YES, BUT ONLY INTO
SINGLE PI PESTKING
FOR ONE CATCHMENT
ONLY
YES
YES
YES
DRY-WEATHER FLOW
HOURLY, DAILY,
AND SEASONAL
PATTERNS*
STRAIGHT LI ME*
HOURLY FLOW*
HYDKOGRAPHS*
HYDROGRAPHS*
NO
DIURNAL PATTERN
COMPUTED FROM LAND
USE
HOURLY, DAILY, AND
SEASONAL PATTERNS*
OR COMPUTED FROM
LAND USE
HYDROGRAPHS*
SUBCATCHMENT
PRECIPITATION
^WEIGHTED AVG. Of
SEVERAL HYETOGRAPHS*
FOR EACH
SUBCATCHMENT
WEIGHTED AVG. OF
SEVERAL HYETOGRAPHS*
FOR EACH
SUBCATCHMENT
NOT MORE THAN ONE
HYETOGRAPH* PER
SUBCATCHMENT
WEIGHTED AVG. OF
SEVERAL HYETOGRAPHS*
FOR EACH
SUBCATCHMENT
NO
ONE HYETOGRAPH*
FOR SINGLE
CATCHMENT
ONE HYETOGRAPH*
PER SUBCATCHMENT,
SPECIAL STATIS-
TICAL ANALYSES
ONE HYETOGRAPH*
PER SUBCATCHMENT
PERCENT OF GAGE
PRECIP., ONE
HYETOGRAPH*
PER SUBCATCHMENT
EVAPORATION
NO
NO
NONLINEAR
FUNCTION OF SOIL
MOISTURE AND DAILY
AvG. AIR TEMPERATURE
FIXED FUNCTION,
INDEPENDENT OF
METEOROLOGICAL
VARIATIONS
NO
CONSTANT KATE*
BETWEEN RAINSTORMS
FOR EACH MONTH
NONLINEAR FUNCTION
OF AIR TEMPERATURE
NO
BASED ON MEAS. POT.
EVAPORATION
AND AVAILABLE
MOISTURE
SNOW ACCUMULATION
AND MELT
NO
NO
BASED ON BUREAU OF
RECLAMATION
ENGINEERING
MONOGRAPH 35 METHOD
NO
NO
DEGREE-DAY METHOD
NO
NO
BASED ON CORPS
OF ENGINEERS
METHOD
GROUNDWATER
SIMULATION
NO
NO
NO
NO
NO
NO
NO
NO
NONLINEAR FUNCTIONS
FOR CONTRIBUTIONS
TO SURFACE FLOW
GUTTER FLOW
NO
AVG. TRAVEL TIME
FROM MANNING
EQU.
NO
KINEMATIC WAVE
EQU. WITH
MANNING EQU.
NO
NO
COMPUTED AS
SURFACE RUNOFF
OR CHANNEL
ROUTING
KINEMATIC WAVE
EQU. WITH
MANNING EQU.
NO
NOTES: BLANK SPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAILABLE
* PROVIDED AS INPUT DATA
** MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
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Table 2b. COMPARISON OF HYDROLOGIC FEATURES OF MODELS
MASSACHUSETTS
INSTITUTE OF
TECHNOLOGY
MINNEAPOLIS-
ST. PAUL
SEATTLE
SOGREAH
UNIVERSITY OF
CINCINNATI
UNIVERSITY OF
ILLINOIS
UNIVERSITY OF
MASSACHUSETTS
WATER RESOURCES
ENGINEERS
WILSEYAND HAM
MULTIPLE
CATCHMENT
INFLOWS
YES
YES
EACH CATCHMENT
REPRESENTED
INDEPENDENTLY
YES
YES
YES
YES. BUT ONLY INTO
SINGLE PIPE STRING
YES
YES
DRY-WEATHER FLOW
HYDROGRAPHS*
DIURNAL PATTERN*
DIURNAL PATTERN*
HYDROGRAPHS*
NO
HYDROGRAPHS*
CONSTANT FLOW*
AVG. FLOW*TRANS-
FORMED INTO HOURLY
AND DAILY PATTERNS
BASED ON LAND USE
NO
SUBCATCHMENT
PRECIPITATION
ONE HYETOGRAPH*
PER SUBCATCHMENT,
STORM CAN BE MOVED
ACROS? CATCHMENT
WEIGHTED AVG. OF
SEVERAL HYETOGRAPHS*
FOR EACH
SUBCATCHMENT
SIX HYETOGRAPHS*
SEVERAL HYETOGRAPHS
OR SYNTHETIC DESIGN
HYETOGRAPH
ONE HYETOGRAPH*
FOR ENTIRE
SEWERAGE SYSTEM
YES**
ONE HYETOGRAPH*
FOR ENTIRE SEWERAGE
SYSTEM, GENERATION
OF SYN. HYETOGRAPH
UP TO THREE
HYETOGRAPHS*PER
SUBCATCHMENT
ONE HYETOGRAPH*
FOR ENTIRE
SEWERAGE SYSTEM
EVAPORATION
PENMAN ECU., BUT
GENERALLY NOT USED
NO
NO
NO
NO
NO
NO
NO
NO
SNOW
ACCUMULATION
AND MELT
BASED ON COR PS
OF ENGINEERS
METHOD
NO
NO
NO
NO
BASED ON CORPS
OF ENGINEERS
METHOD
NO
NO
NO
GROUNDWATER
SIMULATION
NO
NO
NO
NO
NO
NO
NO
NO
NO
GUTTER FLOW
KINEMATIC WAVE
EQU. WITH
MANNING EQU.
NO
NO
NO
OUTFLOW EQUALS
INFLOW DURING
SAME TIME
INTERVAL
KINEMATIC WAVE
EQU. WITH
MANNING EQU.
NO
KINEMATIC WAVE
EQU. WITH
MANNING EQU.
KINEMATIC WAVE
EQU. WITH
MANNING EQU.
00
NOTES: BLANK SPACE INDICATES THAT RELEVANT INFORMATION WAS NOTAVAILABlf
* PROVIDED AS INPUT DATA
**MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 2c. COMPARISON OF HYDROLOGIC FEATURES OF MODELS
BATTELLE
NORTHWEST
BRITISH ROAD
RESEARCH
LABORATORY
CHICAGO FLOW
SIMULATION
CHICAGO
HYDRO GKAPH
METHOD
COLORADO STATE
UNIVERSITY
CORPS OF
ENGINEERS
DORSCH CONSULT
ENVIRONMENTAL
PROTECTION
AGENCY
HYDROCOMP
INFILTRATION ON
IMPERVIOUS AREAS
EXPONENTIAL DECAY
FUNCTION, DEPENDENT
ON CATCHMENT
MOISTURE
NO
NO
NO
NO
CONSTANT FRACTION
OF RAINFALL MINUS
DEPRESSION
STORAGE
NO
NO
NO
OTHER RAINFALL
LOSSES ON
IMPERVIOUS AREAS
INITIAL LOSS*
BEFORE RUNOFF
BEGINS
LOSS AS FUNCTION
OF TIME*
NO
INITIAL LOSS* BEFORE
RUNOFF BEGINS, RE-
COVERY BETWEEN
STORMS
NO
CONSTANT LOSS
RATE* MODIFIED
BY EVAPORATION
INITIAL LOSS*
BEFORE RUNOFF
BEGINS, MODIFIED
BY EVAPORATION
INITIAL LOSS*
BEFORE RUNOFF
BEGINS
INITIAL LOSS*
BEFORE RUNOFF
BEGINS, MODIFIED
BY EVAPORATION
STORM RUNOFF
FROM IMPERVIOUS
AREAS
UNIT
HYDROGRAPH
RAINFALL EXCESS
ROUTED US ING
TIME-AREA
CURVE
CONSTANT FRACTION
OF OVER LAND FLOW
STORAGE
IZZARD'S EQU.
HYDROGRAPHS*
CONSTANT FRACTION
OFRAINFALLMINUS
DEPRESSION
STORAGE
KINEMATIC WAVE
EQU.
KINEMATIC WAVE
EQU. WITH
MANNING EQU.
KINEMATIC WAVE
EQU. WITH
MANN ING EQU.
INFILTRATION ON
PERVIOUS AREAS
MODIFIED HOLTAN
EQU., DEPENDENT ON
SOIL MOISTURE
NO
POLYNOMIAL
REGRESSION EQU.,
DEPENDENT ON
SOIL MOISTURE
MODIFIED HORTON'S
EQU., DEPENDENT ON
SOIL MOISTURE
NO
CONSTANT FRACTION
OF RAINFALL MINUS
DEPRESSION
STORAGE
OPTION TO US EHORTON
OR HOLTAN ECU.
DEPENDENT ON
SOIL MOISTURE
HORTONEQU.,
INDEPENDENT OF
SOIL MOISTURE
EMPIRICAL EQU ,
DEPENDENT ON
SOIL MOISTURE
OTHER RAINFALL
LOSSES ON
PERVIOUS AREAS
INITIAL LOSS*
BEFORE RUNOFF
BEGINS
NO
NO
FUNCTION OF MOISTURE
CONDITIONS,
RECOVERY BETWEEN
STORMS
NO
CONSTANT LOSS RATE*
MODIFIED BY
EVAPORATION
INITIAL LOSS
BEFORE RUNOFF
BEGINS, MODIFIED
BY EVAPORATION
INITIAL LOSS* BEFORE
RUNOFF BEGINS
INITIAL LOSS* BEFORE
RUNOFF BEGINS,
MODIFIED BY
EVAPORATION
STORM RUNOFF
FROM PERVIOUS
AREAS
UNIT HYDROGRAPH
NO
LI NEAR STORAGE
ROUTING OF OVER LAND
FLOW STORAGE
IZZARD'S EQU.
HYDROGRAPHS*
CONSTANT FRACTION
OFRAINFALLMINUS
DEPRESSION
STORAGE
KINEMATIC WAVE
EQU.
KINEMATIC WAVE
EQU. WITH
MANNING EQU.
KINEMATIC WAVE
EQU. WITH
MANNING EQU.
WATER BALANCE
BETWEEN STORMS
NO
NO
ACCOUNTING OF
CATCHMENT MOI STURE,
OVERLAND AND
CHANNEL STORAGE
ACCOUNTING OF
CATCHMENT MOI STURE,
OVERLAND AND
CHANNEL STORAGE
NO'
ACCOUNTING OF
CATCHMENT MOI STURE
AND RESERVOIR
STORAGE
ACCOUNTING OF
CATCHMENT MOI STURE
AND DEPRESSION
STORAGE
NO
ACCOUNTING OF
CATCHMENT MOI STURE,
GROUND AND SURFACE
WATER STORAGE
NOTES: BLANK SPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAILABLE
* PROVIDED AS INPUT DATA
** MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 2d. COMPARISON OF HYDROLOGIC FEATURES OF MODELS
MASSACHUSETTS
INSTITUTE Of
TECHNOLOGY
MINNEAPOLIS-
ST. PAUL
SEATTLE
SOGREAH
UNIVERSITY Of
CINCINNATI
UNIVERSITY Of
ILLINOIS
UNIVERSITY Of
MASSACHUSETTS
WATER RESOURCES
ENGINEERS
WILSEYANDHAM
INFILTRATION ON
IMPERVIOUS AREAS
NO
EXPONENTIAL
DECAY f UNCTION
EMPIRICAL
f UNCTIONS**
SYNTHETIC
RAINfALL EXCESS
NO
NORTON EQU.
NO
CONSTANT RATE*
OTHER RAINfALL
LOSSES ON
IMPERVIOUS AREAS
INITIAL LOSS* BEFORE
RUNOff BEGINS
INITIAL LOSS* BEfORE
RUNOff BEGINS
NO
SYNTHETIC
RAINfALL EXCESS
DEPRESSION LOSS
f UNCTION Of
RAINfALL
YES **
INITIAL LOSS**
BEFORERUNOFf
BEGINS
INITIAL LOSS*
BEfORE RUNOff
BEGINS
YES"
STORM RUNOff
fROM IMPERVIOUS
AREAS
KINEMATIC WAVE
EQU, WITH
MANNING EQU,
UNIT
HYDROGRAPH
UNIT
HYDROGRAPH
(ViUSKINGUM
METHOD
KINEMATIC WAVE
EQU, WITH
MANNING EQU.
KINEMATIC WAVE
EQU. WITH
MANN ING EQU.
CONSTANT f RACTION
Of RAINfALL MINUS
INITIAL LOSS
KINEMATIC WAVE
EQU, WITH
MANNING EQU.
KINEMATIC WAVE
EQl. WITH
MANNING EQU.
INFILTRATION ON
PERVIOUS AREAS
OPTION TO USE
HORTONEQU., HOLTAN
EQU., SCS METHOD,
RUNOff COEff. METHOD
MODIflED HOLTAN
EQU,, DEPENDENT ON
SOIL MOISTURE
EMPIRICAL
fU NOTIONS**
SYNTHETIC
RAINfALL EXCESS
HORTONEQU., WITH
TIME Off SET BASED
ON RAINfALL, INDEP.
Of SOIL MOISTURE
HORTON EQU.
NO
HORTON EQU.
YES**
OTHER RAINFALL
LOSSES ON
PERVIOUS AREAS
INITIAL LOSS*
BEFORE RUNOFF
BEGINS
INITIAL LOSS*
BEFORE fUNOff
BEGINS
NO
SYNTHETIC
RAINFALL EXCESS
DEPRESSION LOSS
FUNCTION OF
RAINfALL AND
INflLTRATION
YES**
NO
INITIAL LOSS*
BEFORE RUNOFf
BEGINS
YES**
STORM RUNOFF
FROM PERVIOUS
AREAS
KINEMATIC WAVE
EQU. WITH
MANNING EQU.
UNIT
HYDROGRAPH
UNIT
HYDROGRAPH
MUSKINGUM METHOD
STORAGE ROUTING
WITH MANNING
EQU.
KINEMATIC WAVE
EQU. WITH
MANN ING EQU.
NO
KINEMATIC WAVE
EQU. WITH
MANNING EQU.
KINEMATIC WAVE
EQU. WITH
MANNING EQU.
WATER BALANCE
BETWEEN STORMS
NO
NO
RUNOFF ADJUSTED
BASED ON
PREVIOUS STORM**
NO
NO
NO
RECOVERY OF
DEPRESSION
STORAGE
NO
NO
NOTES: BLANK SPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAILABLE
* PROVIDED AS INPUT DATA
* * MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 3a. COMPARISON OF HYDRAULIC FEATURES OF MODELS
BATTELLE
NORTHWEST
BRITISH ROAD
RESEARCH
LABORATORY
CHICAGO FLOW
SIMULATION
CHICAGO HYDRO-
GRAPH METHOD
COLORADO STATE
UNIVERSITY
CORPS OF
ENGINEERS
DORSCH
CONSULT
ENVIRONMENTAL
PROTECTION
AGENCY
HYDROCOMP
OPEN CHANNEL
NETWORK
CONVERGING
BRANCH NETWORK
WITH DIVERSIONS
CONVERGING
BRANCH NETWORK
CONVERGING
BRANCH NETWORK
CONVERGING
BRANCH NETWORK
SINGLE STRING OF
PIPES
NO FLOW ROUTING
CONV. AND D IV.
BRANCH AND LOOP
NETWORK WITH OUT
FLOW REVERSAL
CONVERGING
BRANCH NETWORKS
WITH DIVERS IONS
CONVERGING
BRANCH NETWORK
WITH DIVERSIONS
FREE SURFACE
FLOW
KINEMATIC WAVE
EQU., CHARACTER-
ISTIC SOLUTION,
MANNINGEOU.
STORAGE ROUTING,
MANNING EQU.
STORAGE ROUTING,
MANN ING EQU,
STORAGE ROUTING,
MANNING EQU.
DYNAMIC WAVE EQU.,
VARIOUS SOLUTIONS
MANNING OR DARCY-
WEIS BACH EQU.
NO
DYNAMIC WAVE EQU, ,
IMPLICITFINITE DIFF.
SOL, MANNING OR
PRANDTL EQU.
KINEMATIC WAVE EQU.,
EXPLICIT FINITE DIFF.
SOL, MANNING EQU.
KINEMATIC WAVE EQU.,
WITH DIFFUSION
TERM,** MANNING
EQU,
BACKWATER
EFFECTS
NO
NO
NO
NO
DYNAMIC WAVE
EQU.
NO
DYNAMIC WAVE
EQU.
FOR KNOWN DEPTH VS
STORAGE RELATION
AT NOT MORE THAN
TWO LOCATIONS
DIFFUSIONTERM
IN KINEMATIC
WAVE EQU,
FLOW REVERSAL
NO
NO
NO
NO
DYNAMIC WAVE
EQU.
NO
NO
NO
NO
SURCHARGING AND
PRESSURE FLOW
CONSIDERED
INDEPENDENTLY IN
EACH PIPE
NO
NO
NO
NO
NO
DYNAMIC WAVE EQU.
CONSIDERED IN-
DEPENDENTLY IN
EACH PIPE
NO
DIFFERENT PIPE
CROSS-SECTIONS
CIRCULAR PIPE
CIRCULAR AND
RECTANGULAR PIPE,
TRAPEZOIDAL
CHANNEL
CIRCULAR PIPE,
TRAPEZOIDAL
CHANNEL WITH
FLOOD PLAIN
CIRCULAR PIPE,
TRAPEZOIDAL
CHANNEL
CIRCULAR PIPE
NO
VARIOUS STANDARD
SHAPES PLUS
ARBITRARY SHAPES
THIRTEEN STANDARD
SHAPES PLUS TWO
ARBITRARY SHAPES
CIRCULAR PIPE,
TRAPEZOIDAL
CHANNEL WITH
FLOOD PLAIN
INFILTRATION
INTOSeWERSOR
OPEN CHANNELS
NO
NO
NO
NO
NO
NO
CONSTANT RATE *
CONSTANT RATE *
NONLINEAR
FUNCTION
DEPENDENT ON
SOIL MOISTURE
NOTES: BLANK SPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAILABLE
*PROVIDED AS INPUT DATA
**MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 3b. COMPARISON OF HYDRAULIC FEATURES OF MODELS
MASSACHUSETTS
INSTITUTE OF
TECHNOLOGY
MINNEAPOLIS-
ST. PAUL
SEATTLE
SOGREAH
UNIVERSITY OF
CINCINNATI
UNIVERSITY OF
ILLINOIS
UNIVERSITY OF
MASSACHUSETTS
WATER RESOURCES
ENGINEERS
WILSEY AND
HAM
OPEN CHANNEL
NETWORK
CONVERGING AND
DIVERGING BRANCH
AND LOOP NETWORK
CONVERGING
BRANCH NETWORK
WITH DIVERS IONS
NO FLOW ROUTING
CONVERGING AND
DIVERGING BRANCH
AND LOOP NETWORK
CONVERGING
BRANCH NETWORK
CONVERGING
BRANCH NETWORK
SINGLE STRING Of
PIPES
CON VERGING AND
DIVERGING BRANCH
AND LOOP NETWORK
CONVERGING
BRANCH NETWORK
FREE SLJRFACF
FLOW
KINEMATIC WAVE EQU.,
EXPLICIT OR IMPLICIT
FINITE DIFF. SOL,
MANNING EQU.
PROGRESSIVE AVG.
LAG METHOD
NO
DYNAMIC WAVE EQU.,
IMPLICIT FINITE
DIFF. SOL, MANNING
EQU.
TRANSLATION OF HYDRO
GRAPH BY AVG. FLOW
TIMEOFHYDROGRAPH,
MANN ING EQU.
DYNAMIC WAVE EQU.
EXPLICITFINITE DIFF.
SOL, DARCY-
WEISBACHEQU.
DYNAMIC WAVE EQU.,
IMPLICIT FINITE DIFF.
SOL, MANNING EQU.
DYNAMIC WAVE EQU.,
EXPLICIT FINITE DIFF.
SOL, MANNING EQU.
KINEMATIC WAVE
EQU.,** MANNING
EQU.
BACKWATER
EFFECTS
FOR KNOWN DEPTH
VS DISCHARGE
RELATIONSHIP
NO
CONSIDERED ONLY FOR
TRUNK SEWER STORAGE
UPSTREAM OF
REGULATORS
DYNAMIC WAVE
EQU.
NO
DYNAMIC WAVE
EQU.
YES
DYNAMIC WAVE
EQU.
NO
FLOW REVERSAL
NO
NO
NO
DYNAMIC WAVE
EQU.
NO
DYNAMIC WAVE EQU.
DYNAMIC WAVE
EQU.
NO
SURCHARGING AND
PRESSURE FLOW
CONSIDERED
INDEPENDENTLY IN
EACH PIPE
NO
CONSIDERED ONLY FOR
TRUNK SEWER
STORAGE UPSTREAM
OF REGULATORS
YES
NO
NO
NO
CONSIDERED
INDEPENDENTLY
AT EACH JUNCTION**
NO
DIFFERENT PIPE
CROSS -SECTIONS
VARIOUS STANDARD
SHAPES PLUS
ARBITRARY SHAPES
CIRCULAR PIPE
CIRCULAR AND
HORSESHOE PIPE
CIRCULAR AND
EGG-SHAPED PIPE,
TRAPEZ. CHANNEL
ARBITRARY SHAPES
CIRCULAR PIPE
AND RECTANGULAR
CHANNEL
CIRCULAR PIPE
CIRCULAR PIPE
FIVE PIPE SHAPES
TRAPEZOIDAL
CHANNEL
INFILTRATION INTO
SEWERS OR OPEN
CHANNELS
NO
NO
DECAY FUNCTION
OF RAINFALL
HYDROGRAPHS *
NO
NO
NO
CONSTANT RATE *
NO
NOTES: BLANKSPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAILABLE
*PROVIDED AS INPUT DATA
**MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 3c. COMPARISON OF HYDRAULIC FEATURES OF MODELS
BATTELLE
NORTHWEST
BRITISH ROAD
RESEARCH
LABORATORY
CHICAGO FLOW
SIMULATION
CHICAGO
HYDROGRAPH
METHOD
COLORADO STATE
UNIVERSITY
CORPS Of
ENGINEERS
DORSCH
CONSULT
ENVIRONMENTAL
PROTECTION
AGENCY
HYDROCOMP
DIFFERENT
DIVERSION
STRUCTURES
FOUR COMMON
TYPES OF ORIFICE/
WEIR COMBINATIONS
NO
NO
NO
NO
UNDEFINED SHAPE
WEIR AND ORIFICE
TWO TYPES:
UNSPECIFIED SHAPE
OR WEIR
DIVERSION
HYDROGRAPHS*
DIVERSION
COMPUTATION
ORIFICE AND WEIR
EOU. NEGLECTING
DOWNSTREAM
CONDITIONS
NO
NO
NO
NO
EXCESS OVER
STORAGE AND
TREATMENT CAPACITY
OVERFLOWS
WEIR AND ORIFICE EQU.
CONSIDERING UPSTREAM
AND DOWNSTREAM
CONDITIONS
CONSTANT DIVERS ION
OR WEIR EQU.
NEGLECTING DOWN-
STREAM CONDITIONS
DIVERSION
HYDROGRAPHS*
PUMPING STATIONS
NO
NO
NO
NO
NO
NO
NO
CONSTANT DISCHARGE
IF WET WELL EXCEEDS
SPECIFIED DEPTH
PUMPING
SCHEDULE*
STORAGE
FACILITIES
FOR UNDEFINED SHAPE,
ONLY INFLOW
VOLUME COMPUTED
NO
FOR UNDEFINED SHAPE,
NO DEPTH
COMPUTATIONS
NO
NO
EXCESS OVER
TREATMENT CAPACITY
IS STORED
YES
TWO ONLY, MODELS
FOUR TYPES OF OUTLET
STRUCTURES
YES, CONSIDERS BOTH
SPILLWAY AND POWER
TURBINE FLOW
STORAGE
COMPUTATION
COMPUTES INFLOW
AND VOLUME OF
STORMWATER OVER-
FLOW
NO
STORES INFLOW
EXCEEDING SPECIFIED
MAX. OUTFLOW
NO
NO
STORED WATER
RETURNS TO
TREATMENT PLANT
FUNCTION OF SHAPE,
INFLOW AND OUTFLOW
FUNCTION OF SHAPE,
INF LOW AND OUTFLOW
RULE CURVE OPERA-
TION OR PRESET
OUTFLOWS, INCLUDING
POWER FLOWS
COMPUTES AND PRINTS
STAGE HYDROGRAPHS
FOR EACH PIPE REACH
NO
FOR EACH PIPE AND
CHANNEL REACH
NO
AT ANY POINT
NO
FOR EACH SEWER
SYSTEM ELEMENT
COMPUTED, BUT NOT
PRINTED
FOR EACH CHANNEL
REACH AND STORAGE
COMPUTES AND PRINTS
FLOW VELOCITIES
FOR EACH PIPE REACH
NO
NO
FOR EACH
SUBCATCHMENT
AT ANY POINT
NO
COMPUTED FOR EACH
SEWER SYSTEM
ELEMENT, BUT PRINTS
ONLY SELECTED VALUES
COMPUTED, BUT NOT
PRINTED
FOR EACH PIPE AND
CHANNEL REACH AND
STORAGE
NOTES: BLANK SPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAILABLE
• PROVIDED AS INPUT DATA
** MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 3d. COMPARISON OF HYDRAULIC FEATURES OF MODELS
MASSACHUSETTS
INSTITUTE OF
TECHNOLOGY
MINNEAPOLIS-
ST. PAUL
SEATTLE
SOGREAH
UNIVERSITY OF
CINCINNATI
UNIVERSITY OF
ILLINOIS
UNIVERSITY OF
MASSACHUSETTS
WATER RESOURCES
ENGINEERS
WILSEY AND HAM
DIFFERENT
DIVERSION
STRUCTURES
WEIR AND ORIFICE
THREE TYPES OF
COMMON ORIFICE/WEIR
COMB., THREE
SPECIAL STRUCTURES
SIX TYPES OF GATE
CONTROL STURCTURES
RECTANGULAR WEIR
AND ORIFICE INCL.
TIME VARY ING
GATE SETTINGS
NO
WEIR OR GATE FLOW
CONTROL AND
DIVERS I ON AT
OUTLET
NO
WEIRS, GATES OR
ORIFICES, WITH OR
WITHOUT TIDE GATES
NO
DIVERSION
COMPUTATION
WEIR AND ORIFICE
EQU., NEGLECTING
DOWNSTR. COND., OR
DEPTH VS DISCHARGE
ORIFICE AMD WEIR
EOU. NEGLECTING
DOWNSTREAM
CONDITIONS
ORIFICE AND WEIR
EQU.'S CONSIDERING
UPSTR. AND DOWNSTR.
CONDITIONS
ORIFICE AND WEIR
EQU. CONS. UPSTR.
AND DOWNSTR. COND.
AND FLOW REVERSAL
NO
WEIR EQU.
NEGLECTING DOWNSTR.
CONDITION, OR
DEPTH VS DISCHARGE
NO
ORIFICE AND WEIR
EQU. CONS. UPSTR.
AND DOWNSTR. COND.
AND FLOW REVERSAL
NO
PUMPING STATIONS
NO
NO
TWO TYPES:
PROPORTIONAL AND
CONSTANT RATE
YES**
NO
PUMPING RATE CAN
BE OUTLET BOUNDARY
CONDITION
NO
UP TO 3-STAGE
PUMPING STATIONS,
RULE CURVE
OPERATION
NO
STORAGE
FACILITIES
YES, MODELS WEIR
AND ORIFICE
OUTLET
NO
STORAGE IN TRUNK
SEWERS UPSTREAM
OF REGULATORS
YES
NO
YES
NO
YES
NO
STORAGE
COMPUTATION
FUNCTION OF SHAPE,
INFLOW AND OUTFLOW
NO
FUNCTION OF SHAPE,
INFLOW AND OUTFLOW
YES**
NO
FUNCTION OF SHAPE,
INFLOW AND OUTFLOW
NO
FUNCTION OF SHAPE,
INFLOW AND OUTFLOW
NO
COMPUTES AND PRINTS
STAGE HYDROGRAPHS
FOR EACH PIPEAND
CHANNEL REACH
NO
FOR EACH INFLOW
POINT AND JUNCTION
FOR EACH SEWER
SYSTEM ELEMENT AND
COMPUTATIONAL
POINT
COMPUTED FOR EACH
PIPE REACH BUT
NOT PRINTED
FOR EACH SEWER
SYSTEM ELEMENT
AND AT ANY
DESIRED POINTS
FOR EACH PIPE REACH
FOR EACH SEWER
JUNCTION
YES
COMPUTES ANC PRINTS
FLOW VELOCITIES
FOR EACH PIPEAND
CHANNEL REACH
NO
FOR EACH PIPE REACH
FOR EACH SEWER
SYSTEM Elf WENT
AND COMPUTATIONAL
POINT
COMPUTED FOR EACH
PIPE REACH, BUT
NOT PRINTED
FOR EACH SEWER
SYSTEM ELEMENT
AND AT ANY
DESIRED POINTS
FOR EACH PIPE REACH
FOR EACH PIPEAND
CHANNEL REACH
YES
NOTES: BLANKSPACE INDICATES THATRELEVANT INFORMATION WAS NOT AVAILABLE
* PROVIDED AS INPUT DATA
** MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 4a. COMPARISON OF WATER QUALITY FEATURES OF MODELS
BATTELLE
NORTHWEST
BRITISH ROAD
RESEAKCH
LABORATORY
CHICAGO FLOW
SIMULATION
CHICAGO
HYDROGKAPH
METHOD
COLORADO STATE
UNIVERSITY
CORPS OF
ENGINEERS
DOESCH CONSULT
ENVIRONMENTAL
PROTECTION
AGENCY
HYDROCOMP
QUALITY
CONSTITUENTS
/ARBITRARY
CONSERVATIVE
CONSTITUENTS
NO
NO
NO
NO
SUSPENDED AND
SETTLEABLE SOLIDS,
BOD, NITROGEN AND
PHOSPHATE
SEPARATE MODEL,
4ARBITRARY
CONSERVATIVE
CONSTITUENTS
SUSP. AND SETTL
SOLIDS, BOD, COD,
CC-JFORM, N, P04,
01 LAND GREASE
17 CONSTITUENTS
INCLUDING WATER
TEMPERATURE
DRY-WEATHER
QUALITY
HOURLY, DAILY
AND SEASONAL
PATTERNS
NO
NO
NO
NO
NO
DIURNAL PATTERNS
CALCULATED FROM
LAND USE
HOURLY, DAILY AND
SEASONAL PATTERNS*
OR COMPUTED FROM
LAND USE
INFLOW CONCENTRA-
TIONS* OR NONLINEAK
FUNCTION OF INFLOW
HYDROGRAPH
STORM RUNOFF
QUALITY
LI NEAK FUNCTION
OF STORM
DISCHARGE AND
VOLUME
NO
NO
NO
NO
NONLINEARFUNCT. OF
CATCHMENT CHAR. ,
POLL. ACCUMULATION
AND RUNOFF
NONLINEAR FUNCT.
OFCATCHM. CHAR.,
POLL ACCUMUL
AND RUNOFF
NONLINEARFUNCTION
OF CATCHMENT CHAR.,
POLL. ACCUMULATION,
AND RUNOFF
NONLINEARFUNCTION
OF CATCHMENT CHAR.,
POLL. ACCUMULATION
AND RUNOFF
QUALITY
INTERACTIONS ON
CATCHMENTS
NO
NO
NO
NO
NO
BOD, NITROGEN AND
PHOSPHATE DEP. ON
SUSPENDED AND
SETTLEABLE SOLIDS
NO
BOD, NITROGEN AND
PHOSPHATE DEP. ON
SUSPENDED AND
SETTLEABLE SOLIDS
NO
QUALITY ROUTING
IN CHANNELS
ADVECTIONWITH
MIXING BETWEEN
SUCCESSIVE TIME
STEPS
NO
NO
NO
NO
NO
ADVECTIONWITH
PARTIAL MIXING
BETWEEN SUCCESSIVE
TIME STEPS
ADVECTIONWITH
MIXING BETWEEN
SUCCESSIVE TIME
STEPS
ADVECTIONWITH
WEIGHTED MIXING
BETWEEN SUCCESSIVE
TIME STEPS
SEDIMENTATION AND
SCOUR IN CHANNELS
NO
NO
NO
NO
NO
NO, BUT LAND
SURFACE EROSION
BY UNIVERSAL
SOIL LOSS EQU.
NO
SUSPENDED SOLIDS,
CONSIDERING
PARTICLE SIZE
DISTRIBUTION
NO
QUALITY
REACTIONS IN
CHANNELS
NO
NO
NO
NO
NO
NO
NO
FIRST-ORDER BOD
DECAY WITHOUT
INTERACTIONS
VARIOUS REACTIONS
AND INTERACTIONS
NOTES: BLANK SPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAILABLE
* PROVIDED AS INPUT DATA
*» MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 4b. COMPARISON OF WATER QUALITY FEATURES OF MODELS
MASSACHUSETTS
INSTITUTE OF
TECHNOLOGY
MINNEAPOLIS-
ST. PAUL
SEATTLE
SOGREAH
UNIVERSITY OF
CINCINNATI
UNIVERSITY OF
ILLINOIS
UNIVERSITY OF
MASSACHUSETTS
WATER RESOURCES
ENGINEERS
WILSEYAND HAM
QUALITY
CONSTITUENTS
NO
NO
NO
CONSERVATIVE
CONSTITUENTS
AND 1ST-ORDER
DECAY
NO
NO
NO
SUSP. AND SETTL
SOLIDS, BOD, N, P04,
01 LAND GREASE,
17 CONS. CONST.
NO
DRY-WEATHER
QUALITY
NO
NO
NO
NO
NO
NO
NO
AVG. CONCENTRATIONS
TRANSFORMED INTO
DIURNAL PATTERNS
BASED ON LAND USE
NO
STORM RUNOFF
QUALITY
NO
NO
NO
YES*
NO
NO
NO
NONLINEARFUNCT.
OF CATCHMENT CHAR.,
POLL ACCUMULATION
AND RUNOFF
NO
QUALITY
INTERACTIONS ON
CATCHMENTS
NO
NO
NO
NO
NO
NO
NO
ALL CONSTITUENTS
DEPENDENT ON
SUSPENDED AND
SETTLEABLESOLIDS
NO
QUALITY ROUTING
IN CHANNELS
NO
NO
NO
ADVECTION
NO
NO
NO
ADVECTION
NO
SEDIMENTATION
AND SCOUR IN
CHANNELS
NO
NO
NO
NO
NO
NO
NO
NO
NO
QUALITY
REACTIONS IN
CHANNELS
NO
NO
NO
NO
NO
NO
NO
NO
NO
NOTES: BLANK SPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAILABLE
* PROVIDED AS INPUT DATA
** MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 4c. COMPARISON OF WATER QUALITY FEATURES OF MODELS
BATTELLE
NORTHWEST
BRITISH ROAD
RESEARCH
LABORATORY
CHICAGO FLOW
SIMULATION
CHICAGO
HYDROGKAPH
METHOD
COLORADO STATE
UNIVERSITY
CORPS OF
ENGINEERS
DORSCH CONSULT
ENVIRONMENTAL
PROTECTION
AGENCY
HYDROCOMP
QUALITY ROUTING
THROUGH STORAGE
NO
NO
NO
NO
NO
PLUG FLOW
PLUG FLOW
PLUG FLOW OR
INSTANTANEOUS
MIXING
WEIGHTED MIXING
BETW. ONE TO NINE
LAYERS, OUTFLOW
FROM ANY LAYER
QUALITY
REACTIONS IN
STORAGE
NO
NO
NO
NO
NO
NO
NO
NO
VARIOUS
REACTIONS AND
INTERACTIONS**
TREATMENT
FACILITIES
TABULAR FUNCTION
OF FLOW AND
CONCENTRATION
NO
NO
NO
NO
COMPUTES ONLY
INFLUENT FLOW
AND POLLUTANTS
TABULAR FUNCTION OF
FLOW AND
CONCENTRATION
ONE FACILITY ONLY.
EQU.'SFOR NINE
PHYSICAL/CHEMICAL
PROCESSES
NO
QUALITY
INTERACTIONS
DURING TREATMENT
NO
NO
NO
NO
NO
NO
NO
COLIFORM REMOVAL
DEPENDENT ON
SUSPENDED SO LIDS
NO
QUALITY BALANCE
BETWEEN STORMS
NO
NO
NO
NO
NO
FUNCTION OF POL-
LUTANT ACCUMULATION
AND STREET SWEEP ING
FUNCTION OF POLLUTANT
ACCUMULATION AND
STREET SWEEPING
NO
FUNCTION OF POL-
LUTANT ACCUMULATION
AND STREET SWEEP ING
RECEIVING WATER
FLOW SIMULATION
NO
YES
YES
YES
NO
NO
YES
FOR ONE AND TWO-
DIMENSIONAL
REPRESENTATION
YES
RECEIVING WATER
QUALITY
SIMULATION
NO
NO
NO
NO
NO
NO
YES, BUT NO QUALITY
REACTIONS AND
INTERACTIONS
FOR ONE AND TWO -
DIMENSIONAL
REPRESENTATION
YES
NOTES: BLANKSPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAILABLE
* PROVIDED AS INPUT DATA
** MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 4d. COMPARISON OF WATER QUALITY FEATURES OF MODELS
MASSACHUSETTS
INSTITUTE OF
TECHNOLOGY
MINNEAPOLIS-
ST. PAUL
SEATTLE
SOGREAH
UNIVERSITY OF
CINCINNATI
UNIVERSITY OF
ILLINOIS
UNIVERSITY OF
MASSACHUSETTS
WATER RESOURCES
ENGINEERS
WILSEYAND HAM
QUALITY ROUTING
THROUGH STORAGE
NO
NO
NO
INSTANTANEOUS MIXING
1ST-ORDER DECAY
POSSIBLE
NO
NO
NO
EXPONENTIAL
RELEASE FUNCTION
FOR CATCHBASINS
NO
QUALITY
REACTIONS IN
STORAGE
NO
NO
NO
NO
NO
NO
NO
NO
NO
TREATMENT
FACILITIES
NO
NO
NO
NO
NO
NO
NO
NO
NO
QUALITY
INTERACTIONS
DURING TREATMENT
NO
NO
NO
NO
NO
NO
NO
NO
NO
QUALITY BALANCE
BETWEEN STORMS
NO
NO
NO
NO
NO
NO
NO
NO
NO
RECEIVING WATER
FLOW SIMULATION
NO
NO
NO
YES
YES
NO
NO
YES
NO
RECEIVING WATER
QUALITY
SIMULATION
NO
NO
NO
NO
NO
NO
NO
YES
NO
00
NOTES-. BLANK SPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAILABLE
* PROVIDED AS INPUT DATA
•* MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 5a. COMPARISON OF MISCELLANEOUS FEATURES OF MODELS
BATTELLE
NORTHWEST
BRITISH ROAD
RESEARCH
LABORATORY
CHICAGO FLOW
SIMULATION
CHICAGO
HYDROGRAPH
METHOD
COLORADO STATE
UNIVERSITY
CORPS OF
ENGINEERS
DORSCH CONSULT
ENVIRONMENTAL
PROTECTION
AGENCY
HYDROCOMP
CONTINUOUS
SIMULATION
SINGLE STORM
PERIOD, NO WATER
AND QUALITY BALANCE
BETWEEN STORMS
SINGLE STORM
PERIOD, NO WATER
BALANCE BETWEEN
STORMS
CONTINUOUS
SINGLE STORM
PERIOD, WATER
BALANCE BETWEEN
STORMS
CONTINUOUS FLOW
ROUTING IN SINGLE
STRING OF PIPES
CONTINUOUS FOR
SEVERAL YEARS
SINGLE STORM PERIOD,
WATER BALANCE
BETWEEN STORMS
SINGLE STORM
PERIOD, NO WATER
AND QUALITY BALANCE
BETWEEN STORMS
CONTINUOUS FOR
SEVERAL YEARS
TIME INTERVAL
CONSTANT INTERVALS
IN MINUTES (MIN. =
2, MAX. = 60)
CONSTANT INTERVALS
IN MINUTES
CONSTANT INTERVALS
IN MINUTES (MIN. =
5, MAX. = 60)
CONSTANT INTERVALS
IN MINUTES (1MIN.
REQ'D FOR RAIN, CAN
BE MORE FOR RUNOFF)
DEPENDENT ON
NUMERICAL
STABILITY
CONDITION
MUST BE 1 HOUR
CONSTANT INTERVALS
IN MINUTES
CONSTANT INTERVALS
IN MINUTES
MINUTES, HOURLY,
BI-DAILY, DAILY OR
SEMI-MO.;COMPU.
USESM. INTERVALS
MIN, AND MAX,
TIME PERIOD FOR
SIMULATION
MIN. 1HR, MAX.
6HRS OR 56 TIME
STEPS
NO APPARENT
MIN,, MAX. 500
TIME STEPS
MIN. 24 HOURS,
NO APPARENT MAX.
NO APPARENT MIN.,
MAX. 500
MINUTES
NO APPARENT MIN.
OR MAX.
MIN. 24 HOURS,
NO APPARENT MAX.
NO APPARENT MIN.,
MAX. 500 TIME
STEPS
NO APPARENT MIN. ,
MAX. 150 TIME STEPS
NO APPARENT MIN.
OR MAX.
ALLOWS INPUT
OF INITIAL
CONDITIONS
CATCHMENT MOISTURE,
NOT NEEDED FOR
ROUTING
CATCHMENT MOISTURE,
NOT FOR CHANNELS
NO
CATCHMENT
MOISTURE, NOT
FOR CHANNELS
CONSTANT DISCHARGE
IN ENTIRE PIPE
STRING
CATCHMENT MOISTURE
AND QUALITY, NOT
FOR CHANNELS AND
STORAGE
CATCHMENT MOISTURE,
NOT NEEDED FOR
ROUTING
CATCHMENT MOISTURE
AND QUALITY,
CONSTANT FLOW AND
QUALITY IN CHANNELS
FOR ALL SEWER
SYSTEM ELEMENTS
DESIGN
COMPUTATIONS
LEAST-COST SIZES
OF SEWERS, STORAGE
AND TREATMENT
FACILITIES
NO
NO
SIZES PIPES FOR
PEAK FLOW, NO COST
COMPUTATIONS
NO
NO
NO
COSTS OF STORAGE
AND TREATMENT, SIZES
PIPES TO ELIMINATE
SURCHARGING
NO
REAL-TIME CONTROL
DYNAMIC PRO-
GRAMMING FOR
REGULATOR OPERATION
NO
NO
NO
DIFFERENTSCHEMES
WERE INVESTIGATED
NO
NO
NO
FLOW FORECASTING
AND SYSTEM OPER-
ATION WITHOUT
OPTIMIZATION
TESTED ON URBAN
DATA AND APPLIED
TO REAL PROBLEMS
LI Ml TED TESTING
AND APPLICATIONS
EXTENSIVE TEST ING
AND APPLICATIONS
LIMITED TESTING
AND APPLICATIONS
LIMITED TESTING,
EXTENSIVE
APPLICATIONS
TESTED ON EXPER-
IMENTAL PIPE
STRING,
NO APPLICATIONS
LIMITED TESTING
AND APPLICATIONS
MODFRATE TESTING,
EXTENSIVE
APPLICATIONS
MODERATE TESTING,
EXTENSIVE
APPLICATIONS
MODERATE URBAN,
EXTENSIVENONURBAN
TESTING AND
APPLICATIONS
NOTES: BLANK SPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAILABLE
'PROVIDED AS INPUT DATA
"MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 5b. COMPARISON OF MISCELLANEOUS FEATURES OF MODELS
MASSACHUSETTS
INSTITUTE OF
TECHNOLOGY
MINNEAPOLIS-
ST. PAUL
SEATTLE
SOGREAH
UNIVERSITY OF
CINCINNATI
UNIVERSITY OF
ILLINOIS
UNIVERSITY OF
MASSACHUSETTS
WATER RESOURCES
ENGINEERS
WILSEY AND HAM
CONTINUOUS
SIMULATION
SINGLE STORM
PERIOD
SINGLE STORM
PERIOD, NO WATER
BALANCE BETWEEN
STORMS
SINGLE STORM
PERIOD, LIMITED
WATER BALANCE
BETWEEN STORMS
SINGLE STORM
PERIOD NO WATER
BALANCE BETWEEN
STORMS
SINGLE STORM
PERIOD, NO WATER
BALANCE BETWEEN
STORMS
SINGLE STORM PERIOD
UNLESS CONTINUOUS
HYDROGRAPHS
ARE INPUT
CONTINUOUS EXCEPT
FOR SNOW
SINGLE STORM
PERIOD, NO WATER
AND QUALITY BALANCE
BETWEEN STORMS
SINGLE STORM
PERIOD, NO WATER
BALANCE BETWEEN
STORMS
TIME INTERVAL
CONSTANT INTERVAL
IN MINUTES, SET
INTERNALLY FOR
EACH ELEMENT
CONSTANT INTERVAL
IN SECONDS
CONSTANT INTERVAL
IN MINUTES
CONSTANT INTERVAL
IN MINUTES CAN BE
DIFF. FOR EACH HOUR
CONSTANT INTERVAL
IN MINUTES
CONSTANT INTERVAL IN
SECONDS, RESTRICTED
BY NUMERICAL STA-
BILITY CONDITION
MUST BE 1 HOUR
CONSTANT INTERVAL,
RESTRICTED BY
NUMERICAL STABILITY
CONDITION
WIN. AND MAX,
TIME PERIOD FOR
SIMULATION
NOMIN. OR MAX.
NO APPARENT MIN.
OR MAX.
MIN. 3 HOURS, MAX.
24 HOURS
MIN. 1HOUR, NO
APPARENT MAX.
NO APPARENT MIN.,
MAX, 120 TIME STEPS
NO APPARENT MIN.
OR MAX,
MIN, 1HOUR,
MAX. 1 MONTH
NOMIN. OR MAX,
ALLOWS INPUT OF
INITIALCONDITIONS
CATCHMENT MOISTURE,
CHANNEL DISCHARGES
CATCHMENT MOISTURE,
NOT FOR CHANNELS
NO
FOR EACH SEWER
S YSTEM ELEMENT
CATCHMENT MOISTURE,
NOT FOR CHANNELS
CONSTANT FLOW
FOR ALL SEWER
SYSTEM ELEMENTS
CATCHMENT MOISTURE,
NOT FOR CHANNELS
DESIGN
COMPUTATIONS
LEAST-COST SIZES
OF PIPES, STORAGE
AND TREATMENT IN
SEPARATE PROGRAM
NO
NO
NO
NO
SIZES OF PIPES FOR
PEAK FLOW OR MAX.
DEPTH, NO COST
COMPUTATIONS
NO
NO
SIZES OF PIPES FOR
PEAK FLOW
REAL-TIME CONTROL
«
ITERATIVE RUNS WITH
TRIAL REGULATOR
SETTINGS
AUTOM. REGULATOR
OPERATION US ING
RULE CURVES
NO
NO
NO
NO
NO
NO
TESTED ON URBAN
DATA AND APPLIED
TO REAL PROBLEMS
EXTENSIVE TESTING
AND APPLICATIONS
LIMITED TESTING
AND APPLICATIONS
LIMITED TESTING,
ROUTINE APPLICA-
TIONS FOR REAL-TIME
CONTROL
LIMITED TESTING,
MODERATE
APPLICATIONS
LIMITED TESTING,
NO APPLICATIONS
LIMITED TESTING,
NO APPLICATIONS
NO
MODERATE TESTING
AND APPLICATIONS
NJ
O
NOTES: BLANK SPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAILABLE
* PROVIDED AS INPUT DATA
** MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 5c. COMPARISON OF MISCELLANEOUS FEATURES OF MODELS
BATTELLE
NORTHWEST
BRITISH ROAD
RESEARCH
LABORATORY
CHICAGO FLOW
SIMULATION
CHICAGO
HYDROGRAPH
METHOD
COLORADO STATE
UNIVERSITY
CORPS OF
ENGINEERS
DOKSCH CONSULT
ENVIRONMENTAL
PROTECTION
AGENCY
HYDROCOMP
ERROR MESSAGES
LIMITED
LIMITED
LIMITED
LIMITED
LIMITED
MODERATE
EXTENSIVE, PLUS
SEPARATE DATA
CHECKING PROGRAM
(250 MESSAGES)
MODERATE
EXTENSIVE
PRINCIPAL
PRINTED OUTPUT
RAIN, DEPTH, VEL,
DISCH.. STOR., QUAL,
COSTS AND
SIZES FOR DESIGN
DISCHARGE
RAIN, SNOW, DEPTH,
DISCHARGE, STORAGE,
RAIN, VELOCITIES
DISCHARGE, SEWER
DIAMETERS
DEPTH. VELOCITY,
DISCHARGE
RAIN, DISCHARGE,
STORAGE, QUALITY,
LAND EROS ION
DEPTH, DISCHARGE
(SEPARATELY FOR
SANITARY AND STORM
WATER)
RAIN, DISCH., QUAL,
SEWER SIZES,
COSTS OF STORAGE
AND TREATMENT
RAIN, SNOW, SOIL
MOISTURE, DEPTH,
DISCHARGE STORAGE
QUALITY
PRINCIPAL
GRAPHIC OUTPUT
NETWORK DIAGRAM,
RAIN, DISCHARGE,
STORAGE, QUALITY
DISCHARGE
DEPTH, DISCHARGE,
STORAGE
DISCHARGE
NO
STORAGE
UTILIZATION
DEPTH, DISCHARGE
RAIN, DISCHARGE,
QUALITY
DISCHARGE,
QUALITY
UNITS OF
MEASUREMENT
ENGLISH, CONCEN-
TRATIONS METRIC
ENGLISH
ENGLISH
ENGLISH
ENGLISH
ENGLISH, CONCEN-
TRATIONS METRIC
METRIC AND
ENGLI SH
ENGLISH,
CONCENTRATIONS
METRIC
METRIC AND
ENGLISH
COMPUTER VERSIONS
AM) CORE STORAGE
REQUIREMENT
DEC PDP-9,
32K BYTES;
UNIVAC 1108,
64K BYTES
IBM 360
IBM 360.
CDC 6400,
32K BYTES
IBM 1130
8K BYTES
CDC 6400 AND 6600
UNIVAC 1108,
IBM 360/50,
CDC 6600,
70K BYTES
UNIVAC 1108,
CDC 6600
IBM 360 AND 370,
CDC 6400,
UNIVAC 1108.
350K BYTES
IBM 360 AND 370,
240K BYTES
COMPUTER
LANGUAGE
SIMULATION: FORTRAN
IV, 5000 STATEMENTS;
OPTIMIZ.: FORTRAN
V, 2500 STATEMENTS
FORTRAN IV,
1200 STATEMENTS
FORTRAN IV,
650 STATEMENTS
FORTRAN IV
FORTRAN IV
FORTRAN IV,
4400 STATEMENTS
FORTRAN IV,
7000 STATEMENTS
FORTRAN IV,
MORE THAN 10, 000
STATEMENTS
PL/1
COMPUTER PROGRAM
AVAILABLE
YES, DRAFT
DOCUMENTATION
YES
YES
YES, DRAFT USER'S
MANUAL
YES
YES
UNDER USE
AGREEMENT
YES, BEING
EXPANDED WITH NEW
MODEL FEATURES
UNDER USE
AGREEMENT
NOTES: BLANK SPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAILABLE
« PROVIDED AS INPUT DATA
** MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
Table 5d. COMPARISON OF MISCELLANEOUS FEATURES OF MODELS
MASSACHUSETTS
INSTITUTE OF
TECHNOLOGY
MINNEAPOLIS-
ST. PAUL
SEATTLE
SOGREAH
UNIVERSITY OF
CINCINNATI
UNIVERSITY OF
ILLINOIS
UNIVERSITY OF
MASSACHUSETTS
WATER RESOURCES
ENGINEERS
WILSEYANDHAM
ERROR AAESSAGES
MODERATE
LIMITED
ADEQUATE FOR REAL-
TIME OVERFLOW
CONTROL
MODERATE
NONE
MODERATE
LIMITED
MODERATE
PRINCIPAL
PRINTED OUTPUT
RAIN, SNOW, DEPTH,
DISCHARGE, VOLUMES
RAIN. DISCHARGE,
CATCHMENT MOISTURE
CONDITIONS.
REGULATOR STATUS
RAIN, REGULATOR
FLOW DEPTH AND
CONTROL STATUS
DEPTH, VELOCITY,
DISCHARGE, PRESSURE,
STREET FLOOD ING
DEPTH
DISCHARGE
DEPTH, VELOCITY,
DISCHARGE SEWER
DIAMETERS
DEPTH, DISCHARGE
DEPTH, VELOCITY,
DISCHARGE, QUALITY
DISCHARGE, SEWER
DIAMETERS
PRINCIPAL
GRAPHIC OUTPUT
NETWORK DIAGRAM.
RAIN, DISCHARGE
NO
NO
DEPTH, VELOCITY,
DISCHARGE
N!0
DEPTH, DISCHARGE
NO
DEPTH, DISCHARGE
UNITS OF
MEASUREMENT
ENGLISH SOME
METRIC CONVERSIONS
ENGLISH
ENGLISH
METRIC
ENGLISH
ENGLISH
ENGLISH
METRIC AND ENGLISH
ENGLISH
COMPUTER VERSIONS
AND CORE STORAGE
REQUIREMENT
IBM 360/67,
IBM 370/155,
1 BM 370/195
DEC PDP-9,
32K BYTES
XEROX SIGMA 2,
52K BYTES
1 BM 360/65, 65K BYTES
FOR 1000 COMPUTA-
TIONAL POINTS
1 BM 360/65
IBM 360/75,
100 TO 300 K BYTES
CDC 3600
UNIVAC 1108,
CDC 6600,
1 BM 360/50
CDC 6600,
TYM-SHAREXDS940
COMPUTER
LANGUAGE
FORTRAN IV,
MORE THAN
10,000 STATEMENTS
FORT KAN IV
FORTRAN IV
FORTRAN IV,
3000 STATEMENTS
FORTRAN IV,
850 STATEMENTS
PU1 AND ASSEMBLER
LANGUAGE,
3000 STATEMENTS
FORTRAN IV
FORTRAN IV
COMPUTER PROGRAM
AVAILABLE
UNDER USE
AGREEMENT
YES
YES, BUT REAL-TIME
CONTROL FUNCTIONS
ARE SYSTEM SPECIFIC
UNDER USE AGREEMENT
YES
YES
YES
YES
UNDER USE AGREEMENT
to
to
NOTES: BLANK SPACE INDICATES THAT RELEVANT INFORMATION WAS NOT AVAI LABLE
* PROVIDED AS INPUT DATA
* * MATHEMATICAL FORMULATION AND/OR METHOD OF SOLUTION NOT AVAILABLE
-------
hydraulic, water quality and cost constraints, pro-
vided the hydrologic and hydraulic model assumptions
are adequate for particular applications (lumping of
many small subcatchments into few large catchments,
neglect of downstream flow control, backwater, flow
reversal, surcharging, and pressure flow).
2. Corps of Engineers STORM Model for preliminary plan-
ning of required storage and treatment capacity for
storm runoff from single major catchments, considering
both the quantity and quality of the surface runoff
and untreated overflows.
3. Dorsch Consult Hydrograph Volume Method for single-
event flow analysis considering most important hydrau-
lic phenomena (except flow reversal). A Quantity-
Quality Simulation Program for continuous wastewater
flow and quality analysis is now available, but the
model was completed too late for evaluation.
4. Environmental Protection Agency Stormwater Management
Model for single-event wastewater flow and quality
analysis provided the hydraulic limitations of the
model are acceptable (neglect of downstream flow
control and flow reversal, inadequate backwater, sur-
charging, and pressure flow formulation). A new
version patterned after the Corps of Engineers STORM
Model is now available for continuous simulation, but
this version was completed too late for evaluation.
5. Hydrocomp Simulation Program for single-event and
continuous wastewater flow and quality analysis pro-
vided the hydraulic limitations of the model are
acceptable (approximate backwater and downstream flow
control formulation, neglect of flow reversal, sur-
charging, and pressure flow).
6. Massachusetts Institute of Technology Urban Watershed
Model for single-event flow analysis provided the
hydraulic limitations of the model (neglect of back-
water, downstream flow control, backwater, flow rever-
sal, surcharging, and pressure flow), or the use of
a separate model for these phenomena is acceptable.
7. Seattle Computer Augmented Treatment and Disposal
System as an example of an operating real-time control
system to reduce untreated overflows. A more compre-
hensive computer model simulating both wastewater
flow and quality and including mathematical optimi-
zation should be considered, however, for new systems.
23
-------
8. SOGREAH Looped Sewer Model for single-event wastewater
flow and quality analysis considering all important
hydraulic phenomena.
9. Water Resources Engineers Stormwater Management Model
for single-event wastewater flow and quality analysis
considering most important hydraulic phenomena.
The remaining reviewed models do not appear to provide suffi-
cient special features which are not included in the models
mentioned above. Their use may be advantageous, nevertheless,
for certain applications where model assumptions are adequate,
and especially where assistance from the model developers is
easily available.
Following are brief descriptions of each model to give a quick
overview of the available models. Detailed reviews and numer-
ical test results are presented in Sections V and VII through
IX.
BATTELLE URBAN WASTEWATER MANAGEMENT MODEL
The Battelle Urban Wastewater Management Model is intended
primarily for the simulation of large urban catchments. It
simulates the time-varying runoff and water quality in com-
bined sewerage systems consisting of several catchments and
a converging branch sewer network. Up to seven conservative
water quality constituents can be modeled. The model can be
used for a real-time control of overflows during rainstorms
and for least-cost design of sewerage system modifications.
The model is limited to the simulation of single runoff events.
For real-time control of overflows during rainstorms, diver-
sions at controllable regulators are computed using dynamic
programming to maximize the utilization of available sewer,
storage and treatment capacities and minimize pollutant over-
flows. For design studies, sizes of sewers, overflow storage
facilities, treatment plants, and overflow treatment facilities
are computed which will minimize costs for specified constraints
on the quality of overflows and treatment plant effluents.
The model includes special provisions which considerably re-
duce the input data requirements and computer running time.
Data need to be defined only for typical urban subcatchment
elements, rather than all elements, and the appropriate hydro-
logic computations are performed only for these typical ele-
ments. The flow routing, however, considers the actual loca-
tion of the elements.
The model can be used in different modes, using various com-
binations of flow simulation, water quality simulation,
24
-------
real-time overflow control, and least-cost design optimization.
Program improvements are necessary for the efficient implemen-
tation of the real-time control optimization.
The model has been verified on very limited data. The numer-
ical testing indicated that the model is satisfactory for
conditions of slowly varying runoff (where time steps of not
less than 5-minutes are adequate), and where downstream flow
control, backwater, flow reversal, surcharging, and pressure
flow are insignificant.
Comprehensive error diagnostics and the simulation of addi-
tional sewerage system components were programmed in versions
being used by Watermation, Inc., a consulting firm in St.
Paul, Minnesota.
BRITISH ROAD RESEARCH LABORATORY MODEL
The British Road Research Laboratory Model simulates the time-
varying runoff in combined sewerage systems consisting of
several catchments and a converging branch sewer and open
channel network. The model computes surface runoff only from
impervious areas and neglects the contribution of pervious
areas. The model is limited to the simulation of single
runoff events. Water quality, real-time control and design
features are not included.
The model has been tested extensively with urban hydrologic
data. The model appears to produce satisfactory results for
drainage areas of less than 13 km2 (5 mi2) if the impervious
areas directly connected to the storm drainage system comprise
more than 15 percent of the drainage area, and if the fre-
quency of the storm is less than 20 years. The model requires
a minimum of input data, is easy to use, and provides a fairly
accurate means of computing runoff from the paved areas of
urban catchments. Downstream flow control, backwater, flow
reversal, surcharging, pressure flow, and diversion structures
are not modeled.
The Illinois State Water Survey developed a new model based on
the British Road Research method which considers also the run-
off contribution from pervious areas and includes a design
option to size retention basins or circular sewers (Illinois
State Water Survey Urban Drainage Area Simulator).
CHICAGO FLOW SIMULATION PROGRAM
The Chicago Flow Simulation Program is intended primarily for
the continuous simulation of large catchments consisting of
both sewered and nonsewered areas. It simulates the time-
varying runoff in combined sewerage systems and nonurban
25
-------
drainage basins consisting of several catchments and a con-
verging sewer and natural channel network. The flow routing
formulation for natural channels includes provisions for flow
and storage in floodplains. The model can be used for con-
tinuous simulation using hourly or smaller time steps. Water
quality, real-time control, and design features are not
included.
The model is very easy to use, but limited in its applica-
bility by the assumptions inherent in the precipitation-runoff
computations which neglect catchment shape, slope and surface
roughness for sewered areas and impervious areas of nonsewered
areas and assume a constant, surface roughness for all pervious
areas of nonsewered areas. Runoff and routing constants are
internal to the program and may have to be changed for applica-
tion of the model in different areas. Downstream flow control,
backwater, flow reversal, surcharging, pressure flow, and
diversions are not modeled. Model testing on mostly nonurban
areas ranging in size from 12 to 264 km^ (4.7 to 102 mi^)
produced generally satisfactory results.
CHICAGO HYDROGRAPH METHOD
The Chicago Hydrograph Method simulates the time-varying run-
off in combined sewerage systems consisting of several catch-
ments and a converging sewer and open channel network. The
model computes diameters of circular pipes for peak flows.
Although it includes formulations for continuous catchment
moisture accounting, it can be used only for the simulation
of single runoff events due to computer program limitations.
Water quality and real-time control are not included.
The model includes considerable simplifications in the routing
of overland, gutter, sewer, and channel flow which would
appear to limit its accuracy and are not necessary considering
present state-of-the-art of flow routing techniques. Down-
stream flow control, backwater, flow reversal, surcharging,
pressure flow, and diversions are not modeled. The model is
useful primarily for the design of circular sewer pipes. No
model testing using measured urban runoff data is reported by
the model developers.
Separate versions have recently been completed for the con-
tinuous simulation of both wastewater flow and quality using
one-hour time steps (Chicago Runoff and Pollution Model).
COLORADO STATE UNIVERSITY URBAN RUNOFF MODELING
The Colorado State University urban runoff modeling efforts
are included in this review because special research activities
are expected to provide new and improved techniques for the
26
-------
control of overflows and the simulation of nonsteady flow in
pipes. Two parallel efforts are being conducted. One effort
is concerned with the development of concepts for the real-
time control of overflows and the other with physical and
numerical modeling of nonsteady flow in circular pipes.
No computer programs have been developed under the real-time
control research effort which can be used directly for real-
time applications. Valuable concepts evolved under this pro-
gram, however, related to the future direction of urban waste-
water management and the development of automated real-time
wastewater control systems.
Various explicit finite difference solutions of the dynamic
wave equations for gradually varied nonsteady open channel
flow were investigated. The programs are not set up for pipe
networks and diversion structures but merit consideration
for incorporation into comprehensive urban runoff simulation
models.
CORPS OF ENGINEERS STORM MODEL
The Storage, Treatment and Overflow Model (STORM) of the Corps
of Engineers Hydrologic Engineering Center is intended pri-
marily for the evaluation of stormwater storage and treatment
capacity required to reduce untreated overflows below speci-
fied values. The model can simulate hourly stormwater runoff
and quality for a single catchment for several years. Five
water quality constituents are computed for different land
uses: suspended and settleable solids, biochemical oxygen
demand, nitrogen, and phosphorus.
The model does not route the stormwater runoff and quality in
a sewer or channel network. Computations of treatment,
storage and overflow proceed on an hourly basis by simple run-
off volume and pollutant mass balance for the entire catchment.
If the hourly runoff exceeds the treatment capacity, the excess
runoff becomes untreated overflow. If the runoff is less than
the treatment capacity and water is in storage, then the
excess treatment capacity is utilized to diminish the storage
volume.
The model appears useful primarily for preliminary planning
studies to estimate approximate magnitudes of untreated
stormwater overflows for various combinations of storage and
treatment capacities. The model does not consider costs,
however, and repeated runs with different capacities are
required to determine an optimal combination meeting con-
straints on overflows. The model is limited in its application
to stormwater drainage systems since it does not consider
dry-weather flow and quality.
27
-------
DORSCH CONSULT HYDROGRAPH-VOLUME METHOD
The Dorsch Consult Hydrograph-Volume Method simulates the
time-varying runoff in combined sewerage systems consisting
of several catchments and a sewer and open channel network,
including loops and converging and diverging branches. The
flow routing is based on the dynamic wave equations and simu-
lates backwater, surcharging and pressure flow but not flow
reversal. The model also simulates retention basins and
diversion structures. The model is limited to the simulation
of single runoff events. Water quality, real-time control
and design features are not included. A separate model for
continuous simulation of wastewater flow and quality has just
been completed (Quantity-Quality Simulation Program).
This is one of the most complete models for the computation
of runoff from urban catchments and the routing of flows in
sewer networks. The implicit solution of the dynamic wave
equations provides an accurate means of computing flow routing
considering both upstream and downstream boundary conditions
and special hydraulic structures.
This is a proprietary model of Dorsch Consult of Munich,
Germany, which maintains a North American office in Toronto,
Canada. The model has been applied extensively, and model
testing has shown good agreement between measured and com-
puted runoff.
ENVIRONMENTAL PROTECTION AGENCY STORMWATER MANAGEMENT MODEL
The Stormwater Management Model of the U.S. Environmental
Protection Agency is one of the most comprehensive mathe-
matical models for the simulation of storm and combined
sewerage systems. It computes the combined storm and sani-
tary runoff from several catchments and routes the flows
through a converging branch sewer network. It can model two
types of flow diversion structures, three storage basins,
and one overflow treatment plant.
Suspended and settleable solids, biochemical and
carbonaceous oxygen demand, coliform bacteria, nitrogen,
phosphorus, and oil and grease are modeled, and the perfor-
mance and cost of nine unit treatment processes can be com-
puted. A receiving water segment of the model computes the
flows and water quality impact of sewerage system effluents
in receiving waters. The model does not include real-time
control. The model is limited to the simulation of single
runoff events. The model includes an option to size sewers
to eliminate surcharging, but cannot adequately simulate
downstream flow control, backwater, surcharging, pressure
flow and flow reversal.
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Segments of the model have been tested on different sets of
data since adequate data of rainfall, runoff and water quality
were not available for a single catchment to test the com-
plete model. Testing of the runoff flow computations on
catchments ranging in size from 5 to 220.0 ha (13 to 5400 acres)
showed good agreement with measured values. The accuracy of
the water quality computations, particularly the formulations
relating water quality with land use, has not been suffi-
ciently established to be used with confidence for prediction
purposes.
The computer program is very complex and requires a major
effort for its implementation. The input data are arranged
in logical groups, but improvements in the user's manual and
documentation of the model's theoretical bases is needed to
understand the meaning and use of some data. Program improve-
ments, addition of new model features, and a new user's manual
are in progress at the University of Florida. Special work-
shops are being held periodically to instruct potential users
in model use, and assistance is available from the Environ-
mental Protection Agency and private consulting firms for
model implementation.
HYDROCOMP SIMULATION PROGRAM
The Hydrocomp Simulation Program is an improved version of
the Stanford Watershed Model which was the first comprehensive
mathematical model of catchment hydrology. Recently, a sepa-
rate program was developed for the simulation of water quality
in river basins and interfaced with the hydrologic program.
The program is formulated for the continuous simulation of both
water flow and quality from several catchments and the routing
in a converging branch sewer and open channel network. Al-
though originally developed for nonurban areas, modifications
give the program the capability to simulate both sewered and
nonsewered areas. The water quality model simulates 17 water
quality constituents, including their reactions and inter-
actions in natural water bodies. The model does not include
wastewater treatment, real-time control, design, and cost
computations.
The addition of special sewerage system phenomena and elements
is needed to provide the capability to simulate comprehensive
networks. The hydrology formulation may be more complicated
than needed for normal application to urban catchments con-
sidering the lack of available data for calibration purposes.
A major advantage of the model is the capability for con-
tinuous simulation of both water flow and quality in complex
networks since it considers both catchment moisture and water
29
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quality accounting between runoff events and allows time
intervals from a few minutes to bi-monthly. The hydrologic
model has been tested and applied extensively in the United
States and abroad in both nonurban and urban catchments.
Testing of the water quality model is in progress.
This is a proprietary model of Hydrocomp International, Inc.
of Palo Alto, California. User's manuals are available, and
user's workshops are held periodically.
MASSACHUSETTS INSTITUTE OF TECHNOLOGY URBAN WATERSHED MODEL
The Massachusetts Institute of Technology (MIT) Urban Water-
shed Model simulates the time-varying runoff of several catch-
ments and a sewer and open channel network including loops
and converging and diverging branches. The model is limited
to the simulation of single runoff events. Water quality
and real-time control features are not included.
A separate model computes the sizes and costs of sewers,
storage and treatment facilities which will result in the
least-cost combination of alternatives for the elimination of
untreated overflows and the reduction of flooding and sur-
charging. A method based on filter theory can be used to
compute the infiltration coefficients from measured rainfall
and runoff. The original models were developed at MIT under
various projects for the U.S. Office of Water Resources
Research but the models have been modified by Resource Analy-
sis, Inc., for routine applications. The user has to contract
with Resource Analysis, Inc. of Cambridge, Massachusetts, for
routine application of the complete and revised program pack-
age.
The model includes special provisions which considerably re-
duce the input data requirements and computer running time.
Data need to be defined only for typical urban subcatchment
elements, rather than all elements, and the appropriate
hydrologic computations are performed only for these typical
elements. The flow routing, however, considers the actual
location of the elements.
2 2
Testing on 9 ha (23 acres) to 120 km (46 mi ) catchments pro-
duced good agreements between measured and computed runoff
values. The model is being used extensively for engineering
assessments.
MINNEAPOLIS-ST. PAUL URBAN RUNOFF MODEL
The Minneapolis-St. Paul Urban Runoff Model was developed
for real-time forecasting of flows in the major trunk and
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interceptor sewers of the Minneapolis-St. Paul combined
sewerage system. Its purpose was to compute regulator set-
tings which would reduce untreated overflows to the Mississippi
River during rainstorms. The model computes the runoff of
several large catchments, diverts the flows at controllable
regulating structures, and routes them through a converging
branch sewerage network to the treatment plant. The model is
specifically designed for real-time control operation on a
small computer and cannot be used easily for the assessment of
existing or the design of new sewerage systems since it uses a
highly simplified flow routing procedure whose coefficients
have to be calibrated with measured data or derived from more
sophisticated models.
Although the model was designed for continuous simulation by
incorporating provisions for the accounting of catchment
moisture between rainstorms, the necessary formulations were
never added, and the program can be used only for the simu-
lation of single runoff events. The model is no longer used
for real-time control, however, since the required trial
and error procedure with estimates of regulator settings is
too time-consuming, and operator experience with the system
appears to be more efficient for the control of the regulators.
The model does not include water quality, design and cost
computations.
SEATTLE COMPUTER AUGMENTED TREATMENT AND DISPOSAL SYSTEM
The Computer Augmented Treatment and Disposal System (CATAD)
of the Municipality of Metropolitan Seattle (Metro) is an
operating system for real-time control of untreated overflows
from the main trunk and interceptor sewer regulators of the
metropolitan Seattle, Washington, combined sewerage system.
The system does not include a comprehensive mathematical model
for the simulation of runoff from several catchments and the
routing of flows in a sewerage network. Present system opera-
tion is based on computer control of regulators and pumping
stations using real-time data acquisition during rainstorms
and rule curve operation. Water quality is monitored but not
utilized by the scheme. Manual override is possible for
alarm conditions.
Evaluation of the control scheme has shown significant reduc-
tions in untreated overflows compared to uncontrolled con-
ditions. The scheme's effectiveness is impaired, however,
since comprehensive optimization is not used to maximize
utilization of available sewer flow and storage capacity and
to consider the effect of the quality of the overflowed waste-
waters on the receiving water quality.
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SOGREAH LOOPED SEWER MODEL
The Looped Sewer Model of the French consulting firm Societe
Grenobloise d'Etudes et d'Application Hydrauliques (SOGREAH)
simulates the time-varying runoff of combined sewerage systems
consisting of several catchments and a sewer and open channel
network including loops and converging and diverging branches.
The model includes formulations for most hydraulic phenomena
encountered in closed conduit and open channel networks. The
flow routing solves the dynamic wave equations coupled with
equations for special sewer system facilities, such as diver-
sion structures, pumping stations, inverted siphons, and re-
tention basins. The solution considers both upstream and
downstream boundary conditions, backwater, flow reversal,
surcharging, and pressure flow. The model has been expanded
recently to include the advective transport of pollutants.
The model does not include real-time control, design and cost
computations.
The model routing scheme is based on a river basin model devel-
oped by SOGREAH earlier. The firm did not report verification
of the sewer model with urban hydrologic data since the river
basin model verification apparently produced satisfactory
results. This is a proprietary model of SOGREAH of Grenoble,
France. An office is maintained in New York City. The firm
is also represented by Lasalle Hydraulic Laboratory in Canada.
UNIVERSITY OF CINCINNATI URBAN RUNOFF MODEL
The University of Cincinnati Urban Runoff Model simulates the
time-varying runoff of storm sewerage systems consisting of
several catchments and a converging branch sewer and open
channel network. The model does not include provisions for
dry-weather flow, water quality, real-time control, and design.
It is limited to the simulation of single runoff events.
The model includes several simplifications which appear to
reduce the model's accuracy and applicability. These include
the assumption of areal uniformity of rainfall, the neglect
of dry-weather or base flows, the computation of infiltration
from rainfall rather than overland flow depth, the neglect of
catchment moisture conditions in the infiltration computations,
the steady-state formulation for gutter flow routing, and the
neglect of dynamic effects in the sewer flow routing.
Although some encouraging results are reported by the model
developers on a 5.2 ha (12.9 acre) and 964 ha (2380 acre)
catchment, the tests were restricted to fairly simple rainfall
events and required considerable calibration of the infiltration
rate coefficients. Testing by others on a 70 ha (173 acre)
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and 500 ha (1240 acre) catchment in Australia using more com-
plex storm patterns showed considerable differences between
measured and computed runoff values.
UNIVERSITY OF ILLINOIS STORM SEWER SYSTEM SIMULATION MODEL
The University of Illinois Storm Sewer System Simulation Model
computes nonsteady flows in a converging sewerage network
based on a solution of the dynamic wave equations. The solu-
tion considers upstream and downstream flow controls, backwater,
and flow reversal in circular sewers and in-line storage at
sewer junctions. The model does not compute dry-weather flows
from land use or runoff from precipitation but requires inflow
hydrographs to the sewers as input data. Separate general
hydrologic catchment models have been developed, however, and
research for the development of an urban hydrologic model is
in progress for potential interfacing with the flow routing
model. The routing model includes a feature for the sizing
of circular pipes to accommodate peak flows. Costs are not
considered. The model does not include water quality and
real-time control features. A separate model exists for sewer
design using dynamic programming with cost and risk considera-
tions .
The model has not been verified with real sewerage network
data or applied to real systems. Testing of the routing
scheme with experimental pipe data indicates, however, that
high accuracy can be expected.
UNIVERSITY OF MASSACHUSETTS COMBINED SEWER CONTROL SIMULATION
MODEL
The University of Massachusetts Combined Sewer Control Simu-
lation Model simulates the time-varying runoff of several
catchments and a single string of circular sewers. The model
computes runoff from impervious areas only using hourly rain-
fall data. This restricts the model to the simulation of
runoff contributions from pervious areas. A separate computer
program is available to compute synthetic hourly rainfall from
recorded rainfall using a Markov chain model.
The flow routing is accomplished with an implicit solution of
the dynamic wave equations which considers upstream and down-
stream flow control, backwater, and flow reversal. Special
sewerage system facilities, such as diversion and flow control
structures and storage facilities, are not modeled. The model
is formulated for the continuous simulation of runoff for
periods of up to one month, but neglects catchment moisture
balance between runoff events and snow accumulation and melt.
Water quality, real-time control, and design features are not
included.
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The model has not been tested with real catchment data. Test-
ing with hypothetical data indicated that the combination of
hourly runoff computation from rainfall with the implicit flow
routing scheme may be a practical combination for the simu-
lation of large catchments and trunk and interceptor sewers
where short-duration peak discharges may be negligible. Con-
siderable additions would be needed to the program to make it
generally applicable, such as the computation of runoff from
pervious areas, the consideration of a time lag between rain-
fall and runoff, the simulation of evapotranspiration and snow
accumulation and melt, and the expansion of the routing scheme
to sewer networks and special sewerage system facilities.
WATER RESOURCES ENGINEERS STORMWATER MANAGEMENT MODEL
The Stormwater Management Model of Water Resources Engineers,
Inc. (WRE) is a modified version of the Stormwater Management
Model of the Environmental Protection Agency. The model simu-
lates the time-varying combined storm and dry-weather runoff
and wastewater quality of several catchments and a sewer and
open channel network, including loops and converging and diverg
ing branches. The flow routing is based on the dynamic wave
equations and considers both upstream and downstream flow
control, backwater, and flow reversal. The solution is coupled
with hydraulic equations for flow control and diversion struc-
tures and pumping stations. A special formulation computes
surcharging and pressure flow independently for each junction.
Both dry-weather and Stormwater quality are computed for 23
constituents: suspended and settleable solids, biochemical
oxygen demand, nitrogen, phosphorus, oil and grease, and 17
arbitrary conservative constituents. The pollutants are
routed through the sewerage system, but treatment processes
are not modeled. The model does not include real-time control,
design, and cost computations. It is limited to the simulation
of single runoff events. A separate model for receiving
water flow and quality is available but it is not interfaced
with the WRE Stormwater Management Model.
The model includes special provisions which considerably re-
duce the input data requirements and computer running time.
Data need to be defined only for typical urban subcatchment
elements, rather than all elements, and the appropriate
hydrologic computations are performed only for these typical
elements. The flow routing, however, considers the actual
location of the elements.
The model represents a very comprehensive formulation of
sewerage system flow phenomena coupled with water quality
computations. The explicit solution of the dynamic wave
34
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equations requires very small time steps and is time-consuming
on the computer. The model would be needed where the simula-
tion of most modeled hydraulic phenomena is important and
water quality routing is desired. The computation of water
quality from land use characteristics has not been sufficiently
verified.
The model was released to the City of San Francisco and is now
in the public domain. A European office is maintained by
Water Resources Engineers in Hamburg, Germany.
WILSEY AND HAM URBAN WATERSHED SYSTEM
The Wilsey and Ham Urban Watershed System computes the time-
varying stormwater runoff of several catchments and a con-
verging branch sewerage network. A design option sizes circu-
lar pipes for peak flows. The model does not include provi-
sions for dry-weather flow, water quality, and real-time
control. A special feature routes catchbasin inflow exceeding
the free flow capacity of the sewer in the gutter to the next
downstream catchbasin. Downstream flow control, backwater,
flow reversal, surcharging, and pressure flow are not modeled.
The model does not simulate flow control and diversion struc-
tures. The model is limited to the simulation of single run-
off events.
The model includes special provisions which considerably re-
duce the input data requirements and computer running time.
Data need to be defined only for typical urban subcatchment
elements, rather than all elements, and the appropriate hydro-
logic computations are performed only for these typical ele-
ments. The flow routing, however, considers the actual loca-
tion of the elements.
Although sufficient details are not available on the mathe-
matical formulations of the model, it appears to be an
efficient model for the evaluation and design of small storm
sewerage systems for which the limitations of the flow routing
scheme are acceptable. The program has been applied exten-
sively but testing with real catchment data to evaluate model
accuracy has not been reported.
This is a proprietary model of Wilsey and Ham, Inc. of Foster
City, California.
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SECTION II
RECOMMENDATIONS
CONTENTS
Page
Introduction 37
Historical Data Collection 37
Future Data Measurements 37
Model Development 38
Model Formulations 39
Hydrologic Features 39
Hydraulic Features 40
Water Quality Features 41
Miscellaneous Features 42
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INTRODUCTION
Various recommendations for urban hydrologic data collection
and mathematical model development can be formulated from the
model reviews and numerical testing. The recommendations are
intended to guide future development, testing and application
of mathematical models for the engineering assessment, planning,
design and control of storm and combined sewerage systems.
HISTORICAL DATA COLLECTION
The scarcity of reliable urban hydrologic data considerably
limited the testing of model accuracy. To provide a better
data base, the University of Florida is currently collecting
urban catchment characteristics, rainfall, runoff, and water
quality. The data base will make it easier for developers and
the urban planning and engineering community to exercise and
verify existing or new urban hydrologic models. The program
includes indentification of data sources, establishment of data
reliability and accuracy, data collection, arrangement of the
data in common formats, and development of a mechanism for up-
dating and disseminating the data.
FUTURE DATA MEASUREMENTS
The difficulties encountered in obtaining reliable comprehen-
sive data for the testing of the models reviewed in this study
indicate the need for future data collection programs to:
• establish a new data measurement program for selected
urban catchments;
• include urban experimental catchments comprising all land
uses of interest;
• locate these catchments in different climatic zones;
• select catchments where the runoff and water quality can
be identified and measured separately for each major land
use category;
• measure all physical characteristics of a catchment which
influence storm and combined sewer runoff and water
quality;
• measure all data categories required by the most sophis-
ticated mathematical model that may be needed for storm
and combined sewerage system assessments;
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• measure time-varying data at sufficiently short intervals
to identify significant variations in weather, rainfall,
runoff, and water quality;
• measure not only storm runoff, but also dry-weather flow
and snowmelt (including water quality); and
• establish a rigid quality control program to assure con-
sistent data accuracy.
MODEL DEVELOPMENT
The wide variety of model formulations for similar purposes
indicates the need for future model development to:
• identify major use categories and establish model criteria
for each use (i.e., engineering assessment, planning,
design, and control);
• identify model criteria as a function of sewerage system
size and spatial and temporal variability of phenomena to
be modeled;
• develop a standard set of models for each major use cat-
egory;
• develop a model for long-term (over many years) planning
purposes;
• develop an efficient, economical design model for simul-
taneous sizing of sewers, open channels, retention basins,
overflow regulators, and treatment plants;
• disseminate information about existing efficient steady-
state models for street sewer design of small subsystems;
• develop an efficient real-time control model for reducing
combined sewer overflows which will consider both the flow
and quality of the overflows and run on a small process
computer;
• develop a set of models which does not include water qual-
ity to reduce model complexity for applications where
water quality computations are not needed;
• develop criteria for mathematical formulations of each
modeled phenomenon;
• develop model testing criteria to form a common basis for
future model comparisons;
38
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• interface models with current sophisticated receiving
water quality models which consider important interacting
water quality constituents for river basins, estuaries,
and deep stratified lakes and impoundments;
• interface urban hydrologic models that include water qual-
ity simulations with sewage treatment plant models;
• establish more reliable correlations or functional rela-
tionships between specific land uses and the quality of
storm and sanitary runoff;
• investigate water quality changes in sewers and retention
basins and formulate appropriate mathematical equations
for significant physical/chemical/biological reactions and
interactions;
• investigate the effect of numerical dispersion of the
selected mass transport scheme and provide guidelines
to relate the numerical dispersion to actual hydro-
dynamic dispersion and molecular diffusion; and
• develop consistent guidelines for model documentation and
testing to facilitate model comparisons by interested
model users.
MODEL FORMULATIONS
Implementation of the following recommendations would make the
models more generally applicable and easier to evaluate objec-
tively. It would also eliminate many simplistic approaches
which were developed prior to the common availability of com-
puters and are no longer justified in computer models.
Hydrologic Features
Model formulations should:
• include options to read in either cumulative rainfall or
rain intensities at irregular time intervals to eliminate
time-consuming hand conversions of commonly available
data;
• provide the capability in models designed for large catch-
ments to read in data from more than one weather station
and to compute a weighted average for the catchment or
any subcatchment;
39
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• include formulations for catchment moisture accounting
during periods of no rainfall, considering depletion of
soil moisture and depression storage;
• formulate infiltration as a function of actual soil mois-
ture to make the model applicable to all rainfall condi-
tions, not only to events for which the rainfall exceeds
the potential infiltration capacity;
• compute infiltration from overland flow depth rather than
rainfall intensity;
• consider the actual distance and time of overland flow
rather than the catchment length (which may be different)
to compute infiltration;
• compute rainfall losses and overland flow routing sepa-
rately for pervious and impervious areas; and
• consider the locations of impermeable areas in relation
to permeable areas in the computation of overland flow,
if overland flow is not routed separately for each.
Hydraulic Features
Model formulations should:
• include formulations for backwater, flow reversal, down-
stream flow control, surcharging, pressure flow, converg-
ing and diverging branches, loops, and special sewer ele-
ments such as regulators, pumping stations, retention
basins, and tide gates in flow routing schemes for complex
combined sewerage systems;
• replace linear storage routing by the kinematic wave equa-
tion for conditions where backwater, flow reversal, down-
stream hydraulic control, and surcharging are insignifi-
cant; the approximations of linear storage routing schemes
are not justified for computer models;
• print warning statements in models which do not simulate
backwater, flow reversal, downstream hydraulic control,
and surcharging if these conditions occur;
• formulate models which solve the dynamic wave equation to
simulate converging, diverging and looped networks in any
combination;
40
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• compare explicit and implicit solutions of the dynamic
wave equations more thoroughly for large systems with re-
spect to accuracy and efficienty of computation for flow
routing where backwater, flow reversal, downstream hydrau-
lic control, and surcharging need to be modeled;
• simulate the propagation of surcharging in the conduit
network instead of computing it for each conduit indepen-
dently;
• include formulations in comprehensive models for standard
conduit and open channel cross sections and the option to
specify any arbitrary cross section by appropriate input
data;
• base the performance of standard diversion structures (in-
cluding overflow regulators) on the appropriate hydraulic
equations or tables derived from them;
• include provisions in comprehensive programs to add sub-
routines for various types of pumping stations, diversion
structures, retention basins, and retention basin outlet
structures; and
• include provisions to read in operating rules for control-
lable regulator, pumping station, and storage basin oper-
ation.
Water Quality Features
Model formulations should:
• consider hourly, daily and seasonal variations in dry-
weather flow and water quality formulations;
• consider seasonal variations in stormwater quality formu-
lations;
• include formulations for catchment pollutant accounting
during periods of no precipitation (for continuous models
with water quality simulation);
• simulate scour and sedimentation in conduits, open chan-
nels, and storage basins in models simulating pollutant
transport; and
• simulate reactions and interactions of pollutants in stor-
age basins.
41
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Miscellaneous Features
Model formulations should:
• include input of initial conditions in continuous simula-
tion models rather than assuming them to be zero or some
other fixed values;
• incorporate a scheme defining typical catchment and sewer-
age system elements to reduce duplication of input data
and runoff simulation;
• provide the option to obtain output of water flow, depth,
velocity, and water quality concentrations (if simulated)
for any simulated sewerage system element;
• list dimension limitations for all arrays to indicate the
number of sewer elements, time steps, etc., that can be
simulated;
• provide test data deck and output listing for all model
options;
• separate model documentation into theoretical description,
model testing, user's manual, and programmer's manual to
facilitate use of the model by individuals with different
interests; the user's manual should be concise in order
to instruct technicians in setting up data and interpreting
output; it should only refer to the model's theoretical
bases when necessary to clarify use instructions; and
• provide a mathematical expression, or its equivalent de-
fining computer running time as a function of modeled
sewerage system size and length of simulated time period.
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SECTION III
INTRODUCTION
In the past, the most common methods for analyzing and design-
ing urban storm and combined sewerage systems have been based
on the rational formula for rainfall-runoff computations and
steady-state flow equations for sewer network flow analyses.
Recognizing the limitations of these methods for highly complex
systems under dynamic flow conditions, mathematical models have
been developed in recent years to provide better tools for the
analysis of existing and planned sewerage systems and system
improvements.
This study evaluates mathematical models which simulate dynamic
wastewater flow and quality conditions for engineering assess-
ment, control, planning and design of storm and combined sew-
erage systems. The most promising models for practical appli-
cation were tested during the study using hypothetical and real
urban catchment data. Evaluations were made on the bases of
accuracy, cost of use, computer requirements, data requirements,
input data preparation requirements and output options avail-
able to the user. The purpose of the evaluations is to help
the practicing engineer decide which of the models will meet
his requirements.
Mathematical models of catchment hydrology are available which
handle all or any combination of the following phenomena:
• Catchment runoff
• Flow routing
• Water quality
• Costs
Some of the models, however, have been developed for nonurban
catchments and are not directly applicable to urban catchments
without major revisions to account for special urban hydrologic
43
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phenomena such as runoff from pervious and impervious areas,
flow routing in closed conduits, and wastewater quality.
Eighteen models were identified which were specifically devel-
oped or adapted for the dynamic simulation of urban catchments.
All but two of these models include the nonsteady simulation of
the rainfall-runoff process and most models include flow routing
in the sewers. Several models include also the continuous sim-
ulation of wastewater quality. Some models include options for
dimensioning sewer pipes and two of them use mathematical opti-
mization schemes for least-cost design of new sewerage system
components. Three models have provisions for the real-time
control of overflows during rainstorms.
A brief review of these models indicates a tremendous diversity
in scope and purpose, mathematical detail, system elements and
hydrologic phenomena being modeled, size of the system that can
be handled, data input requirements, and computer output. This
diversity, of course, is a result of the varying conditions and
objectives which govern the design and evaluation of individual
sewerage systems.
The state of development of these models also varies signifi-
cantly. Some models have been developed and verified exten-
sively, others have been developed but not verified, while some
have been conceptualized but not carried to the point of appli-
cation. In addition, because no standards exist for evaluating
and comparing models, differing criteria have been used in the
evaluations. The rigor with which the models were tested varies
greatly, from intuitive judgments to graphical comparisons and
more demanding statistical analyses.
These considerations have hindered both the technology transfer
to interested municipalities and consulting engineers and the
routine use of these new methodologies. In fact, due to a
lack of information on data input requirements, model limita-
tions, and program output options combined with often-overstated
claims of capabilities, use of this advanced methodology has
received some criticism.
The objective of this state-of-the-art survey is therefore to
provide the engineer and planner with a readily available ref-
erence containing brief but precise descriptions and evaluations
of all the models available, thus facilitating his selection
of the appropriate model for a particular application.
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SECTION IV
MODEL SELECTION
CONTENTS
Page
Introduction 46
Criteria for Model Selection 46
Selected Models 47
45
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INTRODUCTION
This study was limited to a review of nonsteady simulation
models which can be used for the engineering assessment, plan-
ning, design, and control of storm and combined sewerage sys-
tems. Engineering assessment involves the evaluation of system
performance under various hydrologic and wasteload conditions
to determine problem areas and needs for system improvement.
This may include the determination of undesirable surcharging,
backwater and flooding conditions, the volume and quality of
overflows during rainstorms, and the performance of storage
facilities and treatment plants. For planning purposes, the
effects of both existing and potential hydrologic conditions
and land use decisions on existing and planned sewerage systems
and system components would be studied.
Design involves the computation of sizes of sewers, flow con-
trol and diversion structures and storage and treatment facili-
ties which will meet specified performance criteria. Further
considerations of sewerage system design may include elimination
of undesirable flooding, reduction of untreated overflows, and
better use of existing and planned facilities.
Control involves the regulation of flows to reduce overflows
and improve system efficiency. It may include the regulation
of controllable diversion structures and the operation of stor-
age reservoirs and treatment plants during rainstorms to maxi-
mize system capacity and minimize untreated discharges to re-
ceiving waters. The need for potential system improvements and
implementation of real-time control schemes for manual or fully
automatic control of wastewater flows, storage and treatment
may also be considered in this phase.
CRITERIA FOR MODEL SELECTION
To serve the purposes described above, mathematical models must
consider the spatial nonuniformity of rainfall; the time-varying
runoff resulting from rainstorms of different intensities and
durations; spatial and temporal variations in dry-weather flows;
the effect on hydrograph shapes of different flow travel times
from various catchments; the attenuation of flood peaks during
overland, gutter, and sewer conduit flow routing; and the
operation of flow diversion structures and storage facilities
under dynamic wasteload conditions. The models should be able
to combine the runoff from several catchments and route the
wastewaters within the sewer networks.
Most of the eighteen selected models meet these requirements.
The few exceptions included in the study are models with spe-
cial provisions or advantages for the evaluation of important
46
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aspects of urban catchments and sewerage systems, or with fea-
tures which could improve existing models or provide new model-
ing capability.
All eighteen models were evaluated on the basis of published
information and communication with model developers. In addi-
tion, seven of the more comprehensive models were selected for
testing by computer runs using hypothetical and real catchment
data.
In selecting these models, a minimum requirement was the capa-
bility to consider several raingages, to compute runoff from
several catchments, and to route flows in a converging branch
sewer network. Models which rely heavily on mathematical form-
ulations which cannot be derived readily from catchment and
sewer physical characteristics were not tested, nor were models
whose oversimplification restricts their use unnecessarily,
considering present computer capabilities and the state-of-the-
art of hydrologic modeling. Among the proprietary models se-
lected, one firm did not respond to the request to participate
in the numerical testing.
SELECTED MODELS
The eleven models which were evaluated solely on the basis of
published information in reports by model builders and model
users are:
1. British Road Research Laboratory Model
2. Chicago Hydrograph Method
3. Colorado State University Urban Runoff Modeling
4. Corps of Engineers Hydrologic Engineering Center STORM
Model
5. Hydrocomp Simulation Program
6. Minneapolis-St. Paul Urban Runoff Model
7. Seattle Computer Augmented Treatment and Disposal
System
8. University of Cincinnati Urban Runoff Model
9. University of Illinois Storm Sewer System Simulation
Model
10. University of Massachusetts Urban Runoff Model
11. Wilsey & Ham Urban Watershed Model
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The seven models which were also tested by computer runs are:
1. Battelle Urban Wastewater Management Model
2. Dorsch Consult Hydrograph-Volume Method
3. Environmental Protection Agency Stormwater Management
Model
4. Massachusetts Institute of Technology Urban Watershed
Model
5. Metropolitan Sanitary District of Greater Chicago Flow
Simulation Program
6. SOGREAH Looped Sewer Model
7. Water Resources Engineers Stormwater Management Model
A review of all eighteen models is presented in Section V of
the report, which includes a summary description of each model,
a list of the phenomena considered, brief outlines of the mathe-
matical formulations with comments on their advantages and
shortcomings, and comments on the computer program and output
options. The theoretical background equations of the seven
models selected for numerical testing are presented in Appen-
dix C. The hypothetical and real catchment data used for the
numerical testing are given in Section VI and the numerical
results and evaluations in Sections VII to IX.
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SECTION V
MODEL REVIEWS
CONTENTS
Pac
Introduction 53
Battelle Urban Wastewater Management Model 53
Summary 53
Methods 55
Computer Program 59
Evaluation 60
British Road Research Laboratory Model 60
Summary 60
Methods 61
Computer 62
Evaluation 63
Chicago Flow Simulation Program 63
Summary 63
Methods 64
Computer Program 66
Evaluation 66
Chicago Hydrograph Method 66
Summary 66
Methods 68
Computer Program 69
Evaluation 70
49
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CONTENTS (Continued)
Page
Colorado State University Urban Runoff Modeling 70
Summary 70
Methods 71
Computer Programs 72
Evaluation 72
Corps of Engineers Storm Model 73
Summary 73
Methods 74
Computer Program 75
Evaluation 76
Dorsch Consult Hydrograph-Volume Method 76
Summary 76
Methods 78
Computer Program 79
Evaluation 80
Environmental Protection Agency Stormwater
Management Model 81
Summary 81
Methods 83
Computer Program 87
Evaluation 88
Hydrocomp Simulation Program 89
Summary 89
Methods 92
Computer Program 94
Evaluation 94
Massachusetts Institute of Technology Urban
Watershed Model 95
Summary 95
Methods 97
Computer Program 98
Evaluation 98
50
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CONTENTS (Continued)
Paqe
Minneapolis-Saint Paul Urban Runoff Model 98
Summary 98
Methods 100
Computer Program 101
Evaluation 102
Seattle Computer Augmented Treatment and
Disposal System 102
Summary 102
Methods 104
Computer Program 105
Evaluation 105
SOGREAH Looped Sewer Model 105
Summary 105
Methods 107
Computer Program 108
Evaluation 109
University of Cincinnati Urban Runoff Model 110
Summary 110
Methods Ill
Computer Program 112
Evaluation 112
University of Illinois Storm Sewer System
Simulation Model 112
Summary 112
Methods 114
Computer Program 114
Evaluation 115
University of Massachusetts Combined Sewer Control
Simulation Model 116
Summary 116
Methods 117
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CONTENTS (Continued)
Computer Program 118
Evaluation 118
Water Resources Engineers Stormwater Management
Model , 119
Summary 119
Methods 120
Computer Program 122
Evaluation 123
Wilsey and Ham Urban Watershed System 123
Summary 123
Methods 125
Computer Program 125
Evaluation 125
Other Models 126
Chicago Runoff and Pollution Model 126
CH2M-H111 Wastewater Collection System
Analysis Model 126
Dorsch Consult Quantity-Quality Simulation
Program 127
Illinois State Water Survey Urban Drainage
Area Simulator 127
Norwegian Institute for Water Research
Sewerage System Models 128
Queen's University Urban Runoff Model 128
University of Nebraska Urban Hydrologic
Simulator 129
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INTRODUCTION
Descriptions and reviews of principal model features are pre-
sented in this section to guide the potential model user in
model selection. The general applicability of each model is
summarized, the principal physical phenomena modeled are listed,
the mathematical methods and computer programs are described,
past model testing and applications are referenced, and brief
evaluations are presented. Model equations are not included
in this section to facilitate quick scanning of all model
descriptions. Equations for the seven models tested with com-
puter runs are included in Appendix C.
It is impossible to describe all the features of each model in
a state-of-the-art review and to discuss every model advantage
and limitation based solely on information provided by the model
builders and selected numerical tests. This would be possible
perhaps for evaluations of mathematical models of individual
phenomena, but it becomes a tremendous task when the interactions
of all the submodels of the comprehensive models in this study
must be considered. Only extensive use and experimentation
with a particular model will reveal all its advantages and short-
comings. It is hoped, however, that this review will provide
sufficient information to the potential user to aid him in
selecting the appropriate model for his needs. Once the user
has decided that a particular model may be of interest, careful
study of the documents referenced for the model is recommended
before its computer implementation is begun. This would reveal
model details which, although important, cannot be described
sufficiently in this review.
The model comparisons emphasize evaluation of the complete model,
rather than detailed critiques of submodels of individual phe-
nomena. Formulations of individual phenomena are discussed only
in the context of their use in the complete model and no attempt
is made to discuss all available models for each phenomenon. As
an example, a tremendous variety of models exist for simulating
the rainfall-runoff process alone. No attempt was made to
describe all of them. Rather, only those used in the compre-
hensive urban hydrologic models were reviewed. This type of
evaluation provides the engineer with the information he needs
to select a comprehensive model but does not require him to be
familiar with the many available variations for modeling each
urban hydrologic phenomenon.
BATTELLE URBAN WASTEWATER MANAGEMENT MODEL
Summary
The Battelle Urban Wastewater Management Model (Brandstetter
et al., 1973) is intended primarily for the simulation of major
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sewer system components, such as trunk and interceptor sewers,
regulators, overflow storage facilities, and treatment plants.
It provides a means of evaluating the time-varying performance
of a planned or existing sewerage system under a variety of
rainfall conditions, considering both the time and spacial vari-
tions of rainfall rates without requiring the simulation of every
small sewer, manhole, etc. in the system. Stormwater and sani-
tary runoff and quality of major catchment areas are computed
using hydrologic lumping techniques to arrive at hydrographs
and quality graphs at major regulators and at junctions of major
trunks and interceptors. The runoff is then routed through trunk
and interceptor sewers to the treatment plant. The model is
limited to the simulation of single runoff events.
The model can simulate up to seven conservative wastewater qual-
ity parameters. Quality reactions, with the exception of changes
at treatment facilities, are not modeled. The model determines
the required diversion at control regulators during real-time
rainstorm events in order to minimize wastewater discharges to
receiving waters. The model can also be used for design and
planning studies. It computes sizes and costs of structural
sewer system modifications such as sewers, storage and treatment
facilities which will result in the least-cost combination of
alternatives for improving system performance.
The model has been improved and programmed for an IBM 360 com-
puter by Watermation, Inc., a consulting firm in Saint Paul,
Minnesota. Improvements include formulations for additional
sewerage system elements, such as pumping stations, and the
addition of new error diagnostics. The firm is using the model
for engineering assessments and design purposes.
The Battelle Urban Wastewater Management Model includes the
following features:
1. dry-weather flow and quality of several catchments;
2. several rainfall records;
3. stormwater runoff and quality from pervious and
impervious areas of several catchments;
4. routing of combined wastewater flow and quality
in a converging branch network;
5. circular closed conduits;
6. surcharging and pressure flow;
7. diversion of wastewater flow and quality at
overflow regulators;
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8. filling of overflow storage facilities;
9. wastewater quality improvement at treatment plants
and overflow treatment facilities;
10. regulator diversions for optimal utilization of
sewerage system capacities to minimize untreated
overflows; and
11. least-cost sizes of sewers, overflow storage and
treatment facilities, and main treatment plants
which meet constraints on effluent quality.
The model does not include the following features:
1. dry-weather flow and quality and stormwater quality
from land use characteristics;
2. evapotranspiration;
3. snow accumulation and melt;
4. catchment moisture and water quality balance
during periods of no precipitation;
5. flow and quality routing in gutters;
6. flow and quality routing in loops and diverging
branches;
7. noncircular closed conduits and open channels;
8. downstream flow control, backwater, and flow reversal;
9. emptying of overflow storage facilities;
10. inline storage facilities;
11. sedimentation and scour;
12. wastewater quality decay, reactions and interactions;
and
13. receiving water flow and quality.
Methods
Dry-weather flow and quality is provided as input data in the
form of average values for each catchment and adjustment factors
to account for diurnal (hourly), weekday, and seasonal adjust-
ments. The model does not include provisions to compute either
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dry-weather flow or quality from land use. Storm runoff is
computed from the weighted average rainfall of several raingages
for each catchment. The record of each raingage is provided as
input in the form of cumulative values and can be given at
irregular intervals. This eliminates the need to compute inten-
sities prior to running the program and to read in zeros for
periods of no rain.
Losses are subtracted from the rainfall separately for the per-
vious and impervious areas of each catchment to obtain the excess
precipitation contributing to surface runoff. Losses from
impervious areas, such as wetting of surfaces and retention by
storage in depressions, are assumed to decay exponentially with
time as a function of catchment moisture conditions after an
initial loss is satisfied. Losses from pervious areas include
infiltration and the losses considered for impervious areas.
They are approximated by a modified Holtan infiltration equation
which considers an initial loss that must be satisfied and treats
infiltration as a function of soil moisture content. Morton's
equation, in contrast, if not modified, considers infiltration
only as a function of time, regardless of changes in soil mois-
ture conditions during the rainstorm. A disadvantage of the
Battelle model formulation, however, is that infiltration is
computed from rainfall rather than the depth of water on the
catchment. Consequently, the coefficients of the infiltration
equation must be calibrated to compensate for this approximation.
The excess precipitation is then convoluted with a unit hydro-
graph to determine the storm runoff from each catchment. The
unit hydrographs are derived for ungaged catchments by a method
developed by the Soil Conservation Service. They are computed
using the physical catchment characteristics which include
drainage area, length, slope, soil and vegetation. Refinement
of these unit hydrographs is recommended if concurrent records
of rainfall and runoff are available. For a given catchment,
the same unit hydrograph is used for runoff from both pervious
and impervious areas, which may lead to inaccuracies and cali-
bration problems.
The advantage of the unit hydrograph method over more hydro-
dynamic methods of overland flow routing, such as the use of the
kinematic wave equations, is that large drainage areas of up to
several hundred acres can be treated as a single catchment for
simulation purposes. This allows the simulation of large metro-
politan sewerage systems without the need for defining each
small sewer. The model is therefore particularly suited for the
simulation of major trunk and interceptor sewers. The disad-
vantage of the unit hydrograph method is its approximation of
the basically nonlinear runoff phenomenon by a linear model and
the lack of verification for urban catchments. This is not unique
to this method, however, and other more hydrodynamic methods
56
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suffer from the same deficiency due to the shortage of reliable
runoff data from urban catchments.
The quality of the storm runoff is computed using linear multi-
ple regression equations which relate the concentration of each
pollutant to the storm runoff rate, cumulative runoff during
the storm, and initial conditions. The regression coefficients
have to be provided as input data together with seasonal adjust-
ment factors. There are no provisions in the model to compute
stormwater quality from land use characteristics such as popula-
tion density, type of urban development, street sweeping prac-
tices, etc.
The dry-weather flow and quality are combined with the storm-
water flow and quality for each catchment and routed from each
inlet point through the s'ewers. This includes the combining
of wastewaters and pollutants at sewer junctions. If a regula-
tor is encountered during the routing, the flow is diverted
according to the hydraulic performance of the regulator.
The flow routing is accomplished by the kinematic wave form-
ulation of the equations of motion. The equations consist of
the nonsteady equation of continuity, Manning's equation to
define the energy gradient, and relationships based on the
geometry of circular pipes.
The kinematic wave equations are solved in Lagrangian coor-
dinates (characteristic solution) in order to reduce the need
for knowing initial conditions everywhere in the modeled system
and to facilitate the optimization under transient conditions.
This formulation does not consider downstream hydraulic control,
backwater effects and flow reversal, and approximates surcharg-
ing and pressure flow independently for each pipe.
Convective transport of pollutants is computed using the kine-
matic wave celerity instead of the flow velocity to facilitate
the consideration of both wastewater flows and quality in the
real-time control optimization. The magnitude of the resulting
error in the pollutant travel times has not been evaluated.
The model does not consider hydrodynamic dispersion, scour and
deposition, decay, reactions and interactions between the
pollutants.
At each regulator the quantity of the flow diverted into the
system and that portion overflowed is computed using the appro-
priate weir and orifice discharge equations for each type of
structure. At present, the model simulates four types of fixed
(noncontrollable) regulators: perpendicular weir overflow with
orifice dry-weather outlet (weir may have other angles to flow
direction); sidespill weir with orifice dry-weather outlet;
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leaping weir overflow; and orifice overflow (no weir). The
regulator equations consider only upstream flow conditions and
neglect the effect of downstream conditions on the regulator
discharge.
In addition, the control optimization determines the required
flow diversion at any type of controllable regulator, such as
inflatable rubber dams for the storm overflow outlets in combina-
tion with hydraulically operated gates for diversion of dry-
weather flows. The present version of the model does not,
however, compute the weir height or gate setting which would
produce the required flow diversion.
At regulators and treatment facilities, the cumulative waste-
water volume and pollutant mass of the effluent is computed.
If the overflow is diverted to a storage facility, the cumula-
tive values represent the time history of cumulative inflow to
the storage facility. Diversions to each storage facility are
determined by the control optimization which evaluates the
optimum utilization of all storage facilities for the duration
of the storm runoff. It is assumed that the stored wastewaters
are returned to the system during dry-weather flow periods.
This is not computed, however, in the present version of the
model.
Both overflow and in-line treatment are handled by the model.
The main treatment plant is considered as in-line treatment.
The rate of pollutant removal is determined from tables which
relate flow rate and concentrations with treatment efficiency
for each type of treatment and pollutant. These tables are pro-
vided as input data. The model does not include mathematical
formulations of treatment processes which relate physical
characteristics of the facility with treatment efficiency.
The optimization consists of a two-phase scheme combining design
optimization with optimum control of the sewer system. For
simulation purposes alone the optimization is not activated.
For control purposes alone only the control optimization is
used. For design and planning purposes, the design optimization
is run in conjunction with the control optimization to incorpor-
ate cost savings resulting from the optimum system operation
into the total design.
For real-time operation of a system, the control optimization
computes at regulators the required diversion of flows and
pollutant masses to receiving waters, interceptors, storage
facilities, and treatment plants. Dynamic programming is used
to allocate available sewer, storage facility, and treatment
plant capacities so that the total mass of pollutants entering
the receiving waters through storm runoff is minimized. In
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addition, constraints can be imposed at each regulator on either
the maximum pollutant mass discharge rate or concentration of
the wastewaters overflowed.
For planning and design studies the model can simulate the per-
formance of a sewer system, permitting consideration of potential
alternatives for system improvements. This may include new sewer
lines, regulators, and storage and treatment facilities. The
design optimization determines the most economical combination
of new facilities to perform a specified task: reducing waste
discharges to receiving waters below a specified level or mini-
mizing waste discharges for the amount of investment available.
It provides required sizes and costs of sewer pipes, regulators,
treatment plants, and storage facilities. A modified gradient
technique is employed for the design optimization. This techni-
que considers both the dynamic response of the planned system
as determined by the hydraulic and water quality computations
and the optimum operation of the planned system as determined
by the control optimization.
Computer Program
The program is available to any user. Its documentation, how-
ever, is only in the draft stage. The program is written in
Fortran IV. The Battelle version consists of two main segments:
the hydraulic and water quality computations are programmed for
a DEC PDP-9 computer and the optimization for a Univac 1108
computer. The total program is operated in batch mode using an
interface between the two computers. Programming modifications
in the interface between the two segments of the Battelle ver-
sions are required before the model can be implemented on differ-
ent computers. An IBM computer version of the complete program
is being used by the Control Systems Group of the Department of
Public Utilities of the City of Cleveland (Pew et al., 1972).
IBM versions are also being used by Watermation, Inc., of Saint
Paul, Minnesota.
Most program output is on a hydrostatic printer and includes
tables and plots of rainfall intensities for each catchment,
junction, regulator, storage and treatment facility; water
level, discharge, velocity, wave celerity and Froude number
for each pipe reach; cumulative storage volume for each storage
facility; and size and cost of sewers, storage and treatment
facilities for design optimization. In addition, schematic plots
of the sewerage system showing the sewer layout and locations
of inlets, regulators, junctions, storage and treatment facili-
ties can be obtained. Options are available to suppress any
or all printed and plotted output and to choose only cathode
ray tube displays of selected tables and plots.
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Evaluation
At present, this is the only model which includes mathematical
optimization techniques for both real-time control applications
and for least-cost design purposes. It is the only model which
considers the costs of sewers, storage and treatment facili-
ties in the design optimization. It is also the only model
wh.ich considers wastewater quality objectives in the real-time
and design optimization.
Most limitations resulting from various approximations and
simplifications in the wastewater flow and quality formulations
are described above. The principal limitations which may re-
strict the model's general applicability are the neglect of
downstream hydraulic controls in the flow routing and the neglect
of inline storage facilities and storage in the sewers. Con-
sideration of these aspects would require major model revisions.
Other modifications, such as the addition of formulations for
new types of regulators, other pipe cross sections, pumping
stations, and inverted syphons, can be accomplished by the addi-
tion of appropriate subroutines.
The model can be used only for the simulation of individual
runoff events since it does not include provisions for either
catchment moisture or water quality accounting between rain-
storms. The model has been tested on very limited urban hydro-
logic data and its accuracy has not been sufficiently established.
The Watermation version of the model is being used for engineering
assessments and design purposes.
BRITISH ROAD RESEARCH LABORATORY MODEL
Summary
The British Road Research Laboratory Model simulates the time-
varying runoff in combined sewerage systems consisting of several
catchments and a converging branch sewer and open channel net-
work (Watkins, 1962; Terstriep and Stall, 1969). The model
computes surface runoff only from impervious areas which are
directly connected to the storm drainage system (flow does not
pass pervious areas). The model is limited to the simulation
of single runoff events. Water quality, real-time control and
design features are not included.
The Illinois State Water Survey Urban Drainage Area Simulator
is an extension of this model which simulates also the runoff
from pervious areas and includes an option to either size reten-
tion basins or circular sewers (Terstriep and Stall, 1974).
Model documentation was received too late for a detailed review.
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The British Road Research Laboratory Model includes the following
features:
1. dry-weather flow of several catchments;
2. several rainfall records
3. storm runoff from impervious areas directly
connected to the storm drainage system for
several catchments;
4. flow routing in gutters;
5. routing of combined wastewater flow in a
converging branch network; and
6. circular and rectangular closed conduits and
trapezoidal open channels.
The model does not include the following features:
1. dry-weather flow from land use characteristics;
2. evapotranspiration;
3. snow accumulation and melt;
4. catchment moisture balance between storms;
5. flow routing in loops and diverging branches;
6. downstream flow control, backwater, surcharging,
pressure flow, and flow reversal;
7. flow control and diversion structures;
8. storage facilities;
9. water quality;
10. real-time control;
11. design; and
12. costs.
Methods
Dry-weather or base flow is provided as input data in the form
of a linear function of time. This is probably satisfactory
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for runoff periods of a few hours. The model does not include
provisions to compute dry-weather flow from land use.
Storm runoff is computed from the weighted average rainfall of
several raingages. The rainfall has to be provided in the form
of cumulative values at constant time intervals. Losses are
subtracted from the rainfall according to a function of time
which is defined as input data. Since the model does not con-
sider runoff from pervious areas, which requires the considera-
tion of infiltration, the subtraction of losses from rainfall
without considering the overland flow depth is probably adequate.
The rainfall excess is routed to sewer inlets using average
travel times computed for each hydrograph from Manning's equa-
tion. This appears to be an adequate approximation for storms
of low intensity. For storms of high intensity, however, the
effect of different travel times for different runoff rates is
expected to introduce significant errors into the runoff computa-
tion.
The combined flow is routed from each inlet through the sewers
with a storage routing technique which uses average travel times
computed for each inlet hydrograph from Manning's equation. The
error introduced by this approximation becomes larger as the
flow variations and range of flows increase. The model can be
used for open channels since it includes routing formulations
for trapezoidal open channels in addition to circular and rec-
tangular closed conduits.
The formulation does not consider downstream flow control, back-
water effects, surcharging, pressure flow, and flow reversal.
The model does not simulate flow control and diversion structures
and storage facilities.
The model can be used only for the simulation of individual run-
off events since it does not include provisions for catchment
moisture accounting between rainstorms. The model does not
include design features.
Computer Program
The program is available from the Storm and Combined Sewer Sec-
tion, Advanced Waste Treatment Research Laboratory of the U.S.
Environmental Protection Agency. A user's manual is not avail-
able; the user has to rely on limited information documented in
the references. The program was written in Fortran IV for the
IBM 360/75 computer and Calcomp plotter of the University of
Illinois.
Program output includes printed and plotted rainfall intensities
for each raingage and discharges at sewer junctions and the
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downstream sewer outlet. Water levels and velocities are not
computed.
Evaluation
Model applicability is severely limited since it neglects the
runoff from pervious catchment areas such as gardens, lawns,
and natural areas. This restricts the model's application to
catchments with large portions of paved or impervious areas.
In addition, the approximations in the overland and sewer flow
routing schemes introduce unacceptable errors for flow result-
ing from high intensity storms.
The model was tested by Stall and Terstriep (1972) using data
from ten urban catchments ranging in size from 6 ha (14 acres)
to 21 km2 (8 sq mi). The results indicate that model accuracy
appears to be satisfactory for catchments of less than 13 km2
(5 sq mi) if the impervious areas directly connected to the
storm drainage system comprise more than 15 percent of the total
drainage area and if the frequency of the storm is less than
20 years.
CHICAGO FLOW SIMULATION PROGRAM
Summary
The Chicago Flow Simulation Program is intended primarily for
the simulation of large catchments consisting of both sewered
and nonsewered areas (Lanyon and Jackson, 1972 and 1974). It
simulates the time-varying runoff in combined sewerage systems
and nonurban drainage basins consisting of several catchments
and a converging brach sewer and open channel network. The
flow routing formulation for natural channels includes provi-
sions for flow and storage in flood plains. The model can be
used for continuous simulation using hourly or shorter time
steps. Water quality, real-time control and design features
are not included.
The Chicago Flow Simulation Program includes the following
features:
1. dry-weather flow of several catchments;
2. rainfall, snowfall, air temperature, and wind
velocity at several weather stations;
3. evapotranspiration;
4. snow accumulation and melt;
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5. stormwater runoff from pervious and impervious
areas of several catchments;
6. catchment moisture accounting during periods of
no precipitation;
7. routing of combined wastewater flow in a converging
branch sewer and natural channel network;
8. circular closed conduits and trapezoidal open
channels and flood plains; and
9. in-line storage reservoirs with preset operating
rule.
The model does not include the following features:
1. dry-weather flow from land use characteristics;
2. flow routing in gutters;
3. flow routing in loops and diverging branches;
4. noncircular closed conduits;
5. downstream flow control, backwater, surcharging,
pressure flow, and flow reversal;
6. flow control and diversion structures;
7. water quality;
8. real-time control;
9. design; and
10. costs.
Methods
Dry-weather flow is computed for each catchment from popula-
tion and dry-weather flow per capita for each hour provided as
input data. The model does not include provisions to compute
dry-weather flow from land use.
Storm runoff is computed from rainfall or snowmelt. One weather
station can be specified for each subcatchment. The snowmelt
computations are based on a method of the U.S. Bureau of Rec-
lamation (1966) which requires as input data precipitation at
constant time steps, daily average air temperature and daily
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average wind velocity. The precipitation values have to be
provided as the amount of precipitation which fell in each time
interval.
Originally, the program was formulated for 1-hour time steps
and required at least 1 day of hourly precipitation data as
input. The version furnished to Battelle was modified to accept
shorter time increments, but still requires a minimum of 1 day's
data. This is a considerable inconvenience for small time steps,
especially since a separate data card is used for each time step.
Different formulations are used for the computation of runoff
from rainfall for sewered and nonsewered areas. If the area is
sewered, it is assumed that the rainfall-runoff relationship is
linear and that the water stored on the catchment during a time
step flows into the sewer during the same time step. It is
assumed that all rain falling on impervious areas becomes run-
off and a constant fraction of the rain falling on pervious
areas becomes runoff. This is a serious restriction since it
neglects variations in catchment characteristics such as shape,
slope, and surface roughness and assumes a constant rate of
rainfall loss. Considerable errors are therefore introduced
if much of the catchment is sewered.
For nonsewered areas, it is assumed that all rain falling on
impervious areas becomes runoff. A time delay is introduced,
however, by specifying that a constant fraction of the water
stored on the impervious areas becomes runoff during each time
step. This again neglects the effect of variations in catch-
ment shape, slope and surface roughness on overland flow. For
pervious areas, rainfall losses are computed using an empirical
function relating the losses to rainfall, catchment shape, and
soil moisture. Continuous accounting of soil moisture is
accomplished with an empirical equation which considers deep
percolation and evaporation. Evaporation is defined as a
function of soil moisture at each time step and average daily
air temperature. Linear storage routing is used to compute
overland flow from the pervious areas, considering overland
flow storage, catchment shape and slope but assuming a constant
surface roughness.
Flow routing in both circular sewers and trapezoidal open
channels is accomplished by a storage routing technique using
Manning's equation. The equations for the circular pipes are
simplified by assuming a linear relationship between depth,
cross-sectional flow area, and discharge. The effects of this
approximation on flow routing accuracy have not been determined.
A special provision is incorporated into the model for the con-
sideration of water storage and flow routing in flood plains if
the flow exceeds open channel capacity. The flow routing proce-
dure does not consider downstream flow control, backwater
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effects, surcharging, pressure flow, and flow reversal.
Reservoirs can be simulated with a fixed type of operation which
assumes that all inflow exceeding a specified maximum outflow
is stored. The formulation does not require data on reservoir
and outlet geometry. The model does not simulate other flow
control facilities and diversion structures.
Computer Program
An IBM version of the program is available from the developers
at the Metropolitan Sanitary District of Greater Chicago and
a CDC 6400 version is available from Battelle-Northwest. Both
versions are written in Fortran IV. A complete user's manual
is not available but sufficient information on model formula-
tion and input data requirements is given by Lanyon and Jackson
(1974) and there is a supplementary manuscript describing the
input data formats.
Program output includes input rainfall data, daily rainfall
totals, daily drainage from snowmelt, and end of day snow depths
at each raingage; daily average discharge at selected points;
maximum stage and discharge for each reach; and stage, discharge
and storage for each time step at selected reaches. Velocities
are not computed. Line printer plots can also be obtained for
stage, discharge and storage as functions of time for selected
reaches if the computational time step is one hour.
Evaluation
Model applicability appears limited to large catchments (larger
than 5 km2 = 2 mi ) as a result of the simplifying assumptions
for runoff from pervious and impervious areas of both sewered
and nonsewered areas. The assumptions appear to be adequate for
local conditions of major Chicago drainage basins using continu-
ous simulations with 1-hr time steps. The model could be
made more generally applicable by defining the physical meaning
of the runoff coefficients and defining them as input data
rather than as internal values in the program.
Testing reported by Lanyon and Jackson (1974) for ten monthly
rural catchments with drainage areas ranging from 12 to 264 km^
(4.7 to 102 sq mi) and 3 to 45 percent imperviousness indicated
satisfactory comparisons with measured streamflows for most
tested storms.
CHICAGO HYDROGRAPH METHOD
Summary
The Chicago Hydrograph Method simulates the time-varying runoff
in combined sewerage systems consisting of several catchments
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and a converging branch sewer or open channel network (Tholin
and Keifer, 1959; Keifer et al., 1970). The model computes
diameters of circular sewers for peak flows. Costs are not
considered. The model is limited to the simulation of single
runoff events. Water quality and real-time control are not
included.
The Chicago Runoff and Pollution Model is an extension of the
model for the continuous simulation of both wastewater flow
and quality (City of Chicago, 1972). Model documentation was
received too late, however, for a detailed review.
The Chicago Hydrograph Method includes the following features
1. dry-weather flow of several catchments;
2. several rainfall records;
3. evapotranspiration;
4. storm runoff from pervious and impervious areas of
several catchments;
5. catchment moisture accounting during periods of no
rainfall;
6. flow routing in gutters;
7. routing of combined wastewater flow in a converging
branch network;
8. circular closed conduits and trapezoidal open
channels; and
9. sizing of circular pipes.
The model does not include the following features:
1. dry-weather flow from land use characteristics;
2. snow accumulation and melt;
3. flow routing in loops and diverging branches;
4. noncircular closed conduits;
5. downstream flow control, backwater, surcharging,
pressure flow, and flow reversal;
6. flow control and diversion structures;
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7. storage facilities;
8. water quality;
9. real-time control; and
10. costs.
Methods
Dry-weather flow is provided as input data in the form of hydro-
graphs at constant time intervals for each catchment. The model
does not include provisions for computing dry-weather flow from
land use.
Storm runoff is computed from the weighted average rainfall of
several raingages. Rainfall intensities have to be provided at
1-minute time intervals, a serious limitation. Longer time
intervals can be specified, however, for the runoff and routing
calculations. The program includes an option to compute design
storms of 1 to 100-year frequencies by providing the coefficients
for the design storm equations as input data.
Infiltration losses on pervious areas are computed from Horton's
equation which has been modified to account for actual infiltra-
tion. This would appear to produce a more accurate loss computa-
tion than does the more common use of Horton's equation in other
models which neglect the effect of actual infiltration or soil
moisture on the potential infiltration rate. The Chicago Hydro-
graph Method, however, computes actual infiltration from rain-
fall rather than overland storage depth, thus introducing a
different kind of approximation. After subtracting infiltration
from rainfall, the remaining moisture is reduced by an exponen-
tial function of available depression storage and cumulative
rainfall excess to account for losses due to depression storage.
This formulation is based on the assumption that smaller depress-
ions fill sooner than larger depressions. The remaining moisture
then becomes the overland flow contribution from the pervious
area.
It is assumed that runoff occurs from impervious areas until all
available depression storage is filled.
During dry periods, the potential infiltration is assumed to
recover by a constant rate of 76 mm/hr (3 in./hr). Depression
storage on pervious areas is assumed to recover as a function
of potential infiltration rates. Depression storage on imperviou
areas is assumed to recover fully after 6 hours of dry weather.
The recovery of catchment moisture conditions implicitly con-
siders evaporation but can be considered only a rough approxima-
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tion since it neglects the influence of meteorological variables
other than rainfall.
These formulations appear to give the method continuous simula-
tion capability. Nevertheless it can be used only for the
simulation of single runoff events since the program does not
provide for the input of initial catchment moisture and channel
flow conditions, does not print out final catchment moisture
conditions, and is restricted to simulation periods of less than
500 minutes.
Overland flows from pervious and impervious areas are routed
separately by means of a storage routing technique which uses
empirical functions and is based on a method by Izzard. The
routed overland flows from both pervious and impervious areas
are then combined and routed through the gutters using a storage
routing technique. Routing coefficients relating storage with
discharge must be provided as input data for the overland flow
routing for both pervious and impervious areas and for the gutter
routing. Equations are provided in the user's manual for estimat-
ing the coefficients from catchment and gutter physical character-
istics. The method seems unnecessarily complicated since more
exact and simpler formulations based on the kinematic wave equa-
tions are available.
Flow routing is formulated for circular pipes and trapezoidal
open channels again using a storage routing technique. Manning's
equation is solved for the peak flow of each hydrograph to define
a linear relationship between storage and discharge. The flow
routing procedure does not consider downstream flow control,
backwater effects, surcharging, pressure flow, and flow reversal.
If the diameter is not given for a circular pipe, then the pro-
gram computes the diameter as a function of the peak flow at
the downstream end of the pipe. The program does not compute
the sizes of open channels.
Computer Program
An IBM 1130 version of the computer program written in Fortran
IV and a user's manual (in draft form) is available from the
Department of Public Works, Bureau of Engineering of the City
of Chicago.
Computer output includes rainfall intensities for each raingage
at 1-minute time intervals and the time intervals selected for
the routing; discharge at ten selected times or all time inter-
vals for each subcatchment and reach, the combined flow at each
junction, and the downstream outlet; peak discharge and time of
peak discharge for each subcatchment; peak discharge, peak
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velocity and time of peak discharge for each reach; and the dia-
meter of circular pipes if the diameter was entered as zero.
In addition, the discharge hydrographs can be plotted on an IBM
1627/11 plotter. Water levels and velocities other than peak
velocities are not computed.
Evaluation
The model is suitable for the simulation of nonsteady runoff
from urban and nonurban catchments. It includes considerable
simplifications in the overland, gutter and flow routing which
would appear to limit the model's accuracy and which are not
necessary considering the present state-of-the-art of flow
routing techniques. Routing constants have to be provided as
input data for both pervious and impervious overland flow rout-
ing and the gutter routing. Equations are provided in the manual
for external estimation of the constants, which is an inconven-
ience. The routing coefficients for the sewer and open channel
routing are computed by the program.
Although the model includes provisions for catchment moisture
accounting during periods of no rainfall, it cannot be used for
continuous simulations due to the computer program limitations
described above. A special feature of the model is its design
capability for the sizing of circular sewer pipes, which could
make it attractive in spite of the other limitations.
The model developers do not report any testing of the method
with measured urban runoff data which would allow judgment on
model accuracy.
COLORADO STATE UNIVERSITY URBAN RUNOFF MODELING
Summary
The Colorado State University's urban runoff modeling efforts
are included in this review because these special research
activities are expected to provide new and improved techniques
for the control of overflows and the simulation of nonsteady
flow in pipes.
Two parallel research efforts are being conducted. One is
directed toward the development of automatic control of sewer
systems. The second study is concerned with the physical model-
ing of runoff from rainfall and flow routing in pipes and the
verification of mathematical models using the data derived from
the physical models. Both studies are concerned only with the
estimation of urban runoff and the design of storm sewers and
control based on wastewater flow alone. Wastewater quality and
treatment are not considered.
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Methods
Considerable research is being conducted into the feasibility
and potential techniques for automated real-time control of
overflows in storm and combined sewerage systems. A series of
reports has been published covering various aspects of these
studies, ranging from conceptual development of mathematical
control schemes to the consideration of social and political
aspects of urban wastewater management (Smith et al., 1972;
Grigg et al., 1973 and nine other supporting technical reports).
Although an operational mathematical model for real-time control
has not been developed to date, these efforts are significant
in developing system concepts and the future direction of urban
wastewater management.
Separate research is being conducted at Colorado State University
to investigate various flow routing techniques in circular pipes
(Yevjevich and Barnes, 1970). The investigations have covered
both experimental and numerical studies. A circular conduit
0.91 m (3 ft) in diameter and 250 m (822 ft) long was used to
measure the propagation of flood waves of various configurations.
The experiments provided data for the numerical testing of
various finite difference solutions of the dynamic wave equa-
tions for gradually varied free-surface unsteady flow (the
Saint-Venant equations). Various explicit finite-difference
solutions of the partial differential equations were investi-
gated, including the unstable, diffusing, upstream-differencing,
leap-frog, and Lax-Wendroff schemes. In addition, both first-
order and second-order interpolation schemes of the character-
istic differential equations were studied. It was concluded
that the specified interval scheme of the characteristic
equations using second-order interpolation was the most accurate
of all the methods studied and that the second-order interpola-
tion Lax-Wendorff scheme was the most accurate of all the
explicit methods studied in solving the partial differential
equations.
The diffusing scheme, Lax-Wendroff scheme, and specified
interval scheme of the method of characteristics were computer
programmed for a single string of pipes. The schemes consider
constant flow initial conditions and permit input hydrographs
at various points along the pipe string. The formulations
consider both upstream and downstream hydraulic control, back-
water, and flow reversal. Surcharging and pressure flow are
not considered. The formulations do not provide for junctions
and diversions. Nevertheless, the programs can be viewed as
significant steps toward the formulation of more general flow
routing schemes in circular pipes than the more common and
restrictive storage routing and kinematic wave routing schemes.
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The investigations did not consider implicit finite difference
schemes of either the partial differential equations or the
characteristic differential equations. Implicit methods are
becoming more popular as computer capabilities increase since
they may require less computer time. Explicit methods become
numerically unstable if the selected time step exceeds a maximum
value which depends on the selected finite difference scheme and
the node spacing. Implicit methods allow much longer time steps
with generally very little sacrifice in accuracy. Implicit
methods are more difficult to program, however, than explicit
methods, particularly for large networks with complex boundary
conditions including junctions, diversion structures, pumping
plants, and storage facilities.
Computer Programs
No computer programs have been developed under the real-time
control research effort which are sufficiently operational to
form either a real-time control scheme or significant parts of
such a scheme.
However, computer programs are available for three nonsteady
routing schemes from the Office of Research, Federal Highway
Administration, U.S. Department of Transportation. The programs
are written in Fortran IV for a CDC 6400 and 6600. The programs
compute and print water levels, velocities, and discharges for
any desired point along a pipe string.
Evaluation
Research at Colorado State University related to real-time control
of storm and combined sewerage systems has been limited to the
development of concepts. No operational simulation programs
have been developed, but the concepts will be useful in evalu-
ating the future direction of urban wastewater management and
the development of a real-time wastewater control systems.
The explicit solutions and computer programs of the Saint-Venant
equations for gradually varied unsteady flow in circular pipes
constitute a valuable contribution to the simulation of general
flow conditions in sewers. The methods merit consideration for
incorporation into comprehensive sewerage system simulation
models since they consider upstream and downstream hydraulic
control, backwater, and flow reversal which are not modeled by
the more common formulations based on storage routing and the
kinematic wave equations.
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CORPS OF ENGINEERS STORM MODEL
Summary
The Storage, Treatment and Overflow Model (STORM) of the Corps
of Engineers Hydrologic Engineering Center is intended primarily
for evaluating of the stormwater storage and treatment capacity
required to reduce untreated overflows below specified values
(Corps of Engineers, 1973). The model can simulate hourly
stormwater runoff and quality for a single catchment for several
years. Five water quality constituents are computed for
different land uses: suspended and settleable solids, biochem-
ical oxygen demand, nitrogen, and phosphorus.
The model does not route flows and quality through a sewer net-
work and does not have real-time and design capability. Its
main purpose is the assessment of future needs for treatment
and storage of stormwater under varying land use conditions.
Dry-weather flows and quality are not simulated; consequently
the model is not applicable to combined sewerage systems.
The STORM model includes the following features:
1. rainfall, snowfall, air temperature, and
evaporation at one weather station;
2. evapotranspiration;
3. snow accumulation and melt;
4. stormwater quality for different land uses;
5. suspended and settleable solids, biochemical
oxygen demand, nitrogen, and phosphorus;
6. stormwater runoff and quality from pervious
and impervious areas of a single catchment;
7. catchment moisture accounting during periods
of no precipitation;
8. capacity of storage facilities;
9. hydraulic capacity of treatment facilities; and
10. volume and quality of overflows.
The model does not include the following features:
1. dry-weather flow and quality;
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2. consideration of nonuniform catchment
precipitation distribution;
3. stormwater runoff and quality from more than one
catchment;
4. flow and quality routing in gutters, sewers and
open channels;
5. wastewater quality decay, reactions and inter-
actions ;
6. wastewater quality improvement by treatment;
7. real-time control;
8. design; and
9. costs.
Methods
Hourly stormwater runoff is defined as the product of a runoff
coefficient and hourly rainfall excess. Only one precipitation
record can be used. The runoff coefficient is the weighted
average of empirical runoff coefficients for the pervious and
impervious areas and represents the fraction of rainfall excess
lost to infiltration. The rainfall excess is defined as the
difference between hourly rainfall and losses to depression
storage. The depression storage at the beginning of a rainstorm
is defined as the available depression storage at the end of
the previous rainstorm plus a linear recovery to account for
evaporation during the period of no precipitation. A different
evaporation rate can be specified for each month of the year.
Snowmelt is computed by the degree-day method which requires
mean daily air temperature as input data.
The runoff coefficients, available depression storage, and
depression storage recovery factor have to be derived by
calibration with observed data. Default values are given in
the program but no instructions are provided for estimating
adequate values for ungaged catchments. Dry-weather flow is
not simulated.
The computations for the stormwater runoff quality are based on
formulations first used in the EPA Stormwater Management Model,
which simulated only suspended solids, biochemical oxygen
demand, and coliform bacteria. The STORM model has been expan-
ded to simulate suspended and settleable solids, biochemical
oxygen demand, nitrogen, and phosphorus. Empirical equations
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considering land use, street sweeping practices, and days
between rainstorms define the amount of each pollutant on the
ground at the beginning of a rainstorm. An exponential function
of the runoff rate determines the rate of each pollutant being
washed off the catchment during each hour. The rates of runoff
of BOD, N, and PO, are assumed to be dependent on the rate of
runoff of suspended and settleable solids.
The runoff quality formulations depend on a large number of
empirical coefficients which have been derived from very limited
urban stormwater runoff and quality data. The coefficients are
internal to the program and do not account for variations in
land use and catchment characteristics. Application of the
model in different areas may therefore require programming
changes to modify the coefficients. Input data which may be
difficult to obtain include the daily rate of dust and dirt
accumulation and the percent of each pollutant contained in the
dust and dirt for different land uses. Default values are
provided by the program. Dry-weather quality is not considered
by the model.
Computations of treatment, storage and overflow proceed on an
hourly basis by simple runoff volume and pollutant mass balance.
If the hourly runoff exceeds the treatment capacity, the excess
runoff is put into storage. If the storage capacity is also
exceeded, the excess runoff becomes untreated overflow. If the
runoff is less than the treatment capacity and water is in
storage, then the excess treatment capacity is utilized to
diminish the storage volume.
Plug flow is assumed for the routing of pollutants through
storage. The water quality is not modified in storage. For
treatment, only the hydraulic capacity of treatment facilities
is considered. Stormwater quality improvement by treatment is
not modeled.
Computer Program
The computer program is written in Fortran IV for a UNIVAC 1108
computer and is available from the Hydrologic Engineering
Center of the Corps of Engineers. The simulations require 1-
hour time steps and a minimum of 24 hours of simulation.
Several years of data can be simulated in a single run; the
maximum duration depends only on computer running costs and
the objective of the analysis.
Program output includes hourly precipitation for a single
raingage and various summaries of the stormwater runoff and
quality analysis for selected storm events. These include the
duration and amount of rainfall, the time and amount of
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treatment, the amount of runoff, the utilization and age of
storage, the amount of overflow to receiving waters, and
averages for all selected events. Runoff amounts are defined
in inches and pollutant quality in pounds. In addition, tables
and line printer plots are available indicating the utilization
of storage.
Evaluation
The model is suitable for the continuous simulation of storm-
water runoff and quality from a single urban catchment.
Addition of features for the simulation of dry-weather flow and
quality would be desirable to extend model applicability to
combined sewerage systems.
Limitations on accuracy of the runoff computations are imposed
by the simplified rainfall-runoff formulation, particularly the
assumptions of a constant infiltration loss rate during rain-
storms, a constant evaporation rate between rainstorms, and
immediate runoff of the hourly rainfall excess. The last
approximation would reduce model accuracy as the catchment
size increases and the time of concentration of the runoff
becomes longer than one hour.
The stormwater quality relationships are based on empirical
formulations which have been tested on very limited data and
whose accuracy has not been sufficiently established. It is
therefore not possible to estimate their accuracy for applica-
tion to areas where no records of concurrent urban stormwater
runoff and quality are available for calibration purposes.
The model appears to be useful, however, for general planning
purposes to estimate the relative magnitudes of required
storage and treatment capacities to reduce stormwater overflows
below desired levels. The model computes only the quality of
the overflows to the receiving waters. Addition of the com-
putation of the quality of the treatment plant effluents would
be desirable to obtain the total pollutant load on the receiving
water.
Verification of the complete model is in progress. (Roesner, et.al.,
1974).
DORSCH CONSULT HYDROGRAPH-VOLUME METHOD
Summary
The Dorsch Consult Hydrograph-Volume Method simulates the time-
varying runoff in combined sewerage systems consisting of
several catchments and a closed conduit and open channel net-
work including loops and converging and diverging branches
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(Ritter and Warg, 1971; Koniger, 1972; Koniger and Klym, 1972;
Koniger et al., 1972; Klym et al., 1972; Mevius, 1973; Dorsch
Consult, 1973; and Klym, 1975). The flow routing is based on
a simplified solution of the full dynamic wave equations and
simulates backwater, surcharging, and pressure flow, but not
flow reversal. The model simulates diversion structures and
storage basins. The model is limited to the simulation of
single runoff events. Water quality, real-time control and
design features are not included.
A separate Quantity-Quality Simulation Program has been developed
for the continuous simulation of wastewater flow and quality
(Geiger, 1975). Model documentation was received too late for
a detailed review. A brief description and hypothetical test
results furnished by Dorsch Consult are included in Appendix E.
The Dorsch Consult Hydrograph-Volume Method includes the
following features:
1. dry-weather flow of several catchments;
2. several rainfall records;
3. special statistical analyses of historical
rainfall records to compute design hyetographs
(separate program);
4. stormwater runoff from pervious and impervious
areas of several catchments;
5. evapotranspiration;
6. catchment moisture accounting during periods
of no precipitation;
7. routing of combined wastewater flow in a
network of loops and converging and diverging
branches;
8. various specified closed conduit and open
channel cross sections and any arbitrary shape;
9. backwater, upstream and downstream flow
control, flow reversal, surcharging and
pressure flow;
10. flow control and diversion structures; and
11. retention storage basins.
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The model does not include the following features:
1. dry-weather flow from land use characteristics;
2. snow accumulation and melt;
3. water quality;
4. real-time control;
5. design; and
6. costs.
Methods
Sanitary flow is computed from input data on the average per
capita contribution and the number of residents. A constant
groundwater infiltration rate to the sewers is also provided
as input data. In addition, input data defining an average
base flow, a ratio of the average to the peak hourly flow and
a ratio of the average to the night flow are used to compute
a diurnal pattern of dry-weather flows. At every manhole, a
constant rate of industrial wastewater flow may be provided as
input data. The model does not include provisions to compute
dry-weather flow from land use.
A separate rainfall record can be provided for each subcatchment
to compute surface runoff. A separate program performs special
statistical analyses to compute design storms of specified
frequencies from recorded rainfall events.
Runoff from impervious areas is computed separately from roofs
and streets. No rainfall losses are assumed for impervious
areas without depression storage. An initial loss has to be
satisfied before runoff begins from impervious areas with
depression storage and from pervious areas. In addition,
infiltration losses are computed for pervious areas using
Morton's equation. The statistical distribution of surface
depressions is considered in the runoff and infiltration com-
putations to account for earlier runoff from shallow depressions
and for reduced infiltration when only a part of the area is
covered with water and the rainfall intensity is less than the
infiltration capacity.
Infiltration calculations continue during periods of no rainfall
as long as water is on the pervious areas. Puddles on impervious
areas are reduced by evaporation. Runoff from snowmelt is not
computed.
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Infiltration is computed from overland flow depth, which is
more accurate than computing it directly from rainfall as some
model formulations do. Horton's equation was modified to
account for soil moisture changes during and between rainfall
periods.
Overland flow is computed with the kinematic wave equation using
Manning's equation. The overland flow length is assumed to be
the average width of streets, roofs or lawns within a subcatch-
ment (e.g., flow length on pervious areas = pervious area/sewer
length). A data edit program provides these mean values. This
eliminates the necessity of providing input data for each
urban lot or block. Flow routing in gutters may be treated
like that in sewers.
An implicit finite difference solution of the dynamic wave
equations (the Saint-Venant equations) is formulated for the
routing of nonsteady flows through sewers, open channels, and
retention basins. The formulations consider drop structures
and are coupled with equations computing overflow at diversion
structures. The Manning or Prandtl-Colebrook equation is used
to define the energy losses for the flow routing, and the Poleni
equation computes the diverted flow and overflow at diversion
structures.
An iterative procedure is used to compute depths and discharges
at each time step, starting with estimated values in the first
iteration. First, the new discharges are computed in the
downstream direction and then the new depths are computed in
the upstream direction. Normally 30 iterations are required
for each time step to obtain satisfactory convergence. This
type of numerical solution prevents the computation of flow
reversal although the basic equations include this phenomenon.
Flow reversal can be simulated by inserting hypothetical sewer
segments where flow reversal is expected, and specifying flow
in the direction opposite that in the parallel original segment.
The solution technique, however, considers upstream and down-
stream flow control and backwater. The dynamic wave equation
is solved in such a way that it also simulates surcharging and
pressure flow. The program allows input of both sewer invert,
basement and ground surface elevations and computes flooding
resulting from backwater or surcharging conditions.
The model does not include water quality, real-time control,
design and cost computations.
Computer Program
This is a proprietary model developed by the engineering
consulting firm Dorsch Consult Ingenieurgesellschaft mbH of
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Munich, Germany. A North American office is maintained in
Toronto, Canada. The firm indicated that the model may be
released under certain use and distribution restrictions. The
program is written in Fortran IV and can be run on a Univac
1108 and CDC 6600.
The program can be run in either British or metric units.
Program output includes water surface elevations and discharges
for every desired point in the system. Cumulative inflow and
outflow are printed for diversion structures and retention
basins. The stored volume is also printed for retention basins,
Evaluation
This is one of the most complete and possibly accurate models
for the computation of runoff from urban catchments and the
routing of flows in sewer networks. Extreme detail with respect
to subcatchment discretization is required, however, to calcu-
late accurate overland flow from rainfall. Simplifications are
probably possible to allow larger subcatchment areas without
significant loss in accuracy.
The implicit solution of the Saint-Venant equations provides
an accurate means of computing the flow routing in the sewers
coupled with routing through diversion structures and retention
basins. The consideration of both upstream and downstream
boundary conditions and the computation of backwater is part
of the basic equations and does not have to rely on approximate
methods such as those included in some kinematic wave or stor-
age routing techniques. The implicit solution of the Saint-
Venant equations coupled with diversion equations is complicated
however, and time consuming on the computer as compared to more
approximate methods. To simplify the solution somewhat an
iterative scheme is used which cannot consider flow reversal
(although it is contained in the basic equations).
Although the model formulations are considerably more precise
than most tested models, the increased accuracy demands a
sacrifice in computer time. The model would be needed primarily
where backwater, downstream flow control, diversion structures,
retention basins, and surcharging are important features of
the sewerage system assessment. If these features are not
present or are considered insignificant, simpler models requir-
ing less computer time can be used.
The model has been applied extensively in Germany and Switzer-
land, and moderately in Canada, the U.S.A. and other countries.
Model comparisons with measured runoff data are limited.
Simulations of several storms on the Oakdale Avenue catchment
in Chicago, Illinois, with a drainage area of 19 ha (47 acres)
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resulted in good comparisons between measured and computed run-
off.
ENVIRONMENTAL PROTECTION AGENCY STORMWATER MANAGEMENT MODEL
Summary
The U.S. Environmental Protection Agency's Stormwater Manage-
ment Model is one of the most comprehensive mathematical models
available for the simulation of storm and combined sewerage
systems. It computes the combined storm and sanitary runoff
from several catchments and routes the flows through a conver-
ging branch sewer network (Metcalf & Eddy et al., 1971) . Flow
diversion structures can be modeled and storage can be simulated
for both inline and overflow retention basins. An additional
feature is a receiving water model which includes nonsteady
formulations of hydrodynamics and mass transport for two-
dimensional (vertically mixed) water bodies receiving sewerage
system effluents.
Both dry-weather and Stormwater quality for suspended and
settleable solids, biochemical and chemical oxygen demand,
coliform bacteria, phosphorus, nitrogen, and oil and grease
are computed for each modeled catchment and routed through the
sewerage system. Mathematical formulations which simulate
various combinations of overflow treatment processes for one
treatment facility are included to evaluate the effectiveness
of overflow treatment. The model does not include real-time
control features. The model is limited to the simulation of
single runoff events and inline treatment cannot be simulated.
Cost functions are built into the program to compute the cost
of overflow storage and treatment.
The Stormwater Management Model includes the following features:
1. dry-weather flow and quality of several catch-
ments from land use;
2. several rainfall records;
3. Stormwater runoff and quality for pervious
and impervious areas of several catchments
from land use;
4. light water quality constituents: suspended
and settleable solids, biochemical and chemical
oxygen demand, coliform bacteria, phosphorus,
nitrogen, oil and grease;
5. flow routing in gutters;
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6. routing of combined wastewater flow and quality
in a converging branch network;
7. twelve specified closed conduit cross sections,
a trapezoidal section, and two arbitrary shapes;
8. backwater, surcharging and pressure flow;
9. two types of diversion structures;
10. pumping stations;
11. one overflow and two inline storage facilities
with four types of outlet facilities;
12. sedimentation and scour of suspended solids;
13. first-order water quality decay of BOD;
14. treatment of coliform dependent on suspended
solids;
15. one overflow treatment plant with arbitrary
combinations of nine unit treatment processes;
16. costs of storage and treatment;
17. receiving water flow and quality, and
18. sizing of circular pipes.
The model does not include the following features:
1. evapotranspiration;
2. snow accumulation and melt;
3. catchment moisture accounting during periods
of no precipitation;
4. sewer flow and quality routing in loops and
diverging branches;
5. downstream flow control and flow reversal;
6. water quality reactions and interactions in
the sewers and in storage; and
7. real-time control.
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Methods
Dry-weather flow and quality of eight constituents can either
be provided as average values or computed from land use char-
acteristics such as total population, population density, land
use, residential income and home valuation of each subcatch-
ment. Adjustment factors can be read in for diurnal (hourly)
variations in flow and quality. Weekday adjustment factors
can be read in for all but coliform bacteria. Industrial or
commercial process flows and quality can be input separately.
Rainfall intensities of several raingages can be provided as
input data to compute storm runoff from several catchments.
Only one raingage record can be assigned to a particular sub-
catchment. A more accurate method of representing spatially
nonuniform rainfall would be to compute a weighted average of
the records of all raingages surrounding a subcatchment.
Losses are subtracted separately from the rainfall falling on
pervious and impervious areas. Runoff occurs only when all
depression storage is filled. No other losses are computed
for impervious areas. Evaporative losses are not computed.
For pervious areas, the potential infiltration is computed with
Horton's equation and the actual infiltration depends on the
available overland flow depth. This is a more accurate compu-
tation than basing the infiltration losses on the amount of
rainfall. Horton's equation, on the other hand, computes the
potential infiltration as a function of time only and does not
account for the change in potential infiltration with changes
in soil moisture. The equation is satisfactory as long as the
available moisture is greater than the potential infiltration,
but errors are introduced during low intensity and intermittent
storms when the available moisture is less than the computed
potential infiltration. As a consequence, the infiltration
coefficients of the equation have to be adjusted for different
storms although theoretically they should be based on catchment
soil characteristics only, independent of the storm patterns.
This makes it difficult to use one set of coefficients with
confidence for prediction purposes.
Overland flow is computed separately for pervious and impervious
areas using a kinematic wave formulation with Manning's equa-
tion. A similar formulation is used for the gutter flow
routing. The model formulation assumes that overland flow
length and catchment length are equal. This is satisfactory
for small catchments, such as individual lots and possibly
city blocks, but errors are introduced if the difference
between overland flow and catchment length increases (as
occurs when several city blocks are lumped into a single
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subcatchment). The model assumes that infiltration occurs
throughout the time required for the overland flow to run the
entire length of the catchment. Actual infiltration, however,
may occur only during the time it takes the overland flow to
run the length of a single lot. As a consequence, the computed
infiltration would be greater than the actual infiltration and
the computed runoff hydrograph would be underestimated. Users
of the model apparently compensate for this error by reducing
the infiltration coefficients. A better solution would be to
reformulate the overland flow computation to account for the
fact that infiltration may occur over a shorter distance than
overland flow.
Infiltration from the ground into the sewers accounts for dry-
weather infiltration, wet-weather infiltration, melting resi-
dual ice and snow infiltration, and groundwater infiltration.
Average infiltration values for the entire modeled drainage
basin have to be provided as input data. The entire catchment
infiltration is then apportioned to individual sewers on the
basis of the conduit perimeter and number of joints in each
conduit. A degree-day method is used to compute the infiltra-
tions from snowmelt, but the accumulation of snow and surface
runoff from snowmelt is not modeled. The effect of the infil-
trating water on the quality of the sewage is considered
negligible and not modeled.
Flow routing in the sewers is accomplished with the kinematic
wave equation using Manning's equation. The basic formulation
neglects downstream flow control, backwater, surcharging,
pressure flow and flow reversal. Special formulations are in-
corporated in the model, however, to approximate backwater,
surcharging and pressure flow. General downstream control and
flow reversal are not modeled.
Backwater is modeled by formulating a special backwater element
with an inline storage element of fixed length and simulating
it with a storage routing technique. This requires input data
on flow depth versus storage volume which is difficult to
compute for special sewer shapes (such as horseshoe shapes,
etc.) with a nonzero invert slope. Also, the assumption of a
constant backwater length appears to make the formulation highly
approximate. Since the program permits only two inline storage
elements, backwater can be considered at only two locations in
the entire sewerage system. Also definition of a backwater
element reduces the number of actual storage facilities that
can be modeled.
If surcharging occurs, the model assumes that all water in
excess of full pipe flow capacity is stored in the next up-
stream manhole. The formulation neglects the storage volume
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of the manhole and the actual propagation of the surcharging
farther upstream. The formulation consequently serves only to
conserve volume and to warn the user that surcharging conditions
exist, without adequately computing the phenomenon. Conduits
can be sized by the program to avoid surcharging.
The flow routing scheme is formulated for 12 specified closed
conduit cross-sections and a trapezoidal section. In addition,
two arbitrary conduit shapes can be specified by providing
input data relating the dimensions of each shape to flow area,
hydraulic radius, and discharge.
Two types of flow diversion structures can be modeled. The
first type assumes that all inflow exceeding a maximum value is
overflowed. No data are needed to describe the geometry of
this type. The second type assumes that no overflow occurs
until the inflow exceeds a specified value. In this case, the
depth of flow is found from a linear relationship between flow
and depth and the overflow computed from this depth with a weir
discharge equation. A more accurate formulation would be
possible based on the weir and orifice equations.
Pumping stations can also be modeled. The model assumes that
the pumps begin to operate at a constant pumping rate when the
volume in the wet well reaches a maximum value and continue to
pump until the wet well is pumped dry.
The model can simulate the performance of one overflow and up
to two inline storage facilities. The model computes depth
and volume of storage as a function of the inflow and outflow.
The outflow is computed based on the hydraulic performance of
the following four options of outflow conditions: gravity with
orifice centerline at zero storage tank depth; gravity with
fixed weir; gravity with both weir and orifice; and fixed rate
pumps. Either regularly or irregularly shaped reservoirs can
be specified by different input data. If a reservoir overflows,
program execution terminates.
Stormwater quality is computed as a nonlinear function of
stormwater runoff rate (which includes an exponential decay
with time to account for the higher rates of pollutants being
washed off during the beginning of a storm). Coefficients in
equations for each of the three modeled pollutants account for
different land uses. The equations consider street sweeping
practices and days between rainstorms in defining the amount
of each pollutant on the ground at the beginning of a rainstorm.
The formulations account also for the contribution of accum-
ulated BOD in catchbasins. Many of the coefficients in the
formulations are internal to the program and have been derived
from very limited data of measured stormwater runoff and
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quality. Programming changes may therefore be required to
apply the model to different areas and land use characteristics.
Stormwater and dry-weather qualities are combined at inlet man-
holes and routed through the sewers according to the flow velo-
city of the sewage. Dispersion is not modeled directly, but
by averaging qualities between successive time steps. The
equations consider first-order decay of BOD and sedimentation
and scour of suspended solids. Reactions and interactions
between the pollutants during the routing are not considered.
Plug flow or complete mixing can be specified for the routing
of pollutants through storage facilities. Deposition of sus-
pended solids can be computed, but not resuspension. Reactions
and interactions in storage are not modeled.
Nine overflow treatment processes can be modeled and arranged
by the user in any series or combination. The modeled unit
processes are: bar racks, fine screens, sedimentation,
dissolved air flotation, dissolved air flotation preceded by
fine screens, microstrainers, high rate filters, effluent
screens, and chlorination. Mathematical formulations for each
process relate hydraulic capacity to removal efficiency. The
user does not have the option of varying the process efficien-
cies without changing coefficients internal to the program.
For some processes, however, the amount of chemicals used is
read in to account for their effect on treatment performance.
BOD removal and suspended solids removal are considered indepen-
dently. Coliform removal, however, is defined as a function
of suspended solids removal.
Cost functions are built into the model which compute the cost
of overflow treatment. Separate functions are defined for
each unit treatment process and for storage and pumping if part
of the treatment facility. Annual capital costs, land costs,
and operation and maintenance costs are related to hydraulic
capacity by power functions. The shapes of the cost functions
are defined internally by the program. Costs can be adjusted
by reading in the Engineering News Record Index for regional
adjustments and future expected changes.
The Stormwater Management Model includes also a receiving water
flow and quality segment which is based on the original EPA
dynamic estuary model. Although review of this model segment
is not within the planned scope of this study, it is noted
because it adds considerably to the comprehensiveness of the
Stormwater Management Model. It gives the model the capability
not only of modeling flow and quality in sewerage systems, but
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of assessing the impact of the sewerage system effluents
the receiving water quality.
on
The flow computations of the receiving water models are based
on a simplified explicit finite difference solution of the
one-dimensional dynamic wave equations for nonsteady gradually
varied open channel flow (Saint-Venant equations).
Although the equations are written for one-dimensional flow
only, a special solution technique allows the simulation of
two-dimensional flow fields represented by an irregular grid
of links and nodes. The continuity equation is solved at the
nodes (junctions of the links) and the momentum equation is
solved along the links (channels between the nodes). The
model is very costly to use since very short time steps are
required for numerical stability. The formulation becomes
unstable if the discharges in adjacent channels and storage
volumes of adjacent nodes are not of the same order of magni-
tude.
The model includes the transport of several conservative and
nonconservative water quality constituents, considering first-
order decay. Transport is modeled by convection only and
chemical and biological interactions between different water
quality constituents are not considered. Other receiving water
flow and quality models developed recently for the Environmen-
tal Protection Agency for both steady and nonsteady state
water quality predictions in river basins (including streams,
impoundments and estuaries) consider several water quality
constituents, including chemical and biological reactions and
interactions.
Computer Program
The original version of the computer program, which is available
from the U.S. Environmental Protection Agency, is written in
Fortran IV for an IBM 360/65 computer and is also compatible
for a UNIVAC 1108 computer. There are five main programs which,
depending on computer core storage capacity, can be either
loaded together or in sequence depending on the user's needs.
The program was converted by Battelle-Northwest for a CDC 6400
computer as part of this study. This version allows the
loading of the main programs in any sequence specified by the
user.
Fairly complete documentation of the model was published by
the EPA, including a summary report, user's manual, verifica-
tion and testing report, and program listings. Unfortunately,
no one of these reports presents a complete description of the
theoretical bases and mathematical formulations of the model.
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The equations for some modeled phenomena are described in the
user's manual, and some are not described at all. The reader
must compare the two reports to obtain a fair understanding of
the capabilities and limitations of the complete model and the
meaning of the input data. Also, the user's manual includes
much discussion of model verification and testing which adds
to the report's bulkiness and makes it more difficult to find
essential information for the preparation of input data.
Program output includes tables and line printer plots of rain-
fall intensities for each raingage, combined runoff and quality
for each subcatchment, and routed discharges and water quality
at selected points of the sewerage system. Summaries of treat-
ment effectiveness and costs are also available. Water levels
and flow velocities in the sewers are not computed.
Evaluation
The EPA Stormwater Management Model is one of the most complete
mathematical models available for the assessment and planning
of storm and combined sewerage systems. Consideration of both
wastewater flows and qualities is an important aspect of eval-
uating needed treatment facilities and the impact of sewage
effluents on receiving waters. This is also one of the few
models which include cost computations. Although the model
does not consider costs in the sizing of sewers, the computation
of the costs of overflow storage and treatment should be a
valuable aid to the engineer.
Most model limitations which result from various approximations
and simplifications in the wastewater flow and quality formu-
lations are described above. Program limitations which may
restrict the model's general applicability include the neglect
of downstream hydraulic controls (with the exception of very
rough approximations of backwater and surcharging conditions)
and the absence of formulations for inline treatment and main
treatment plants. Better formulations which consider both
upstream and downstream flow conditions are also needed for
diversion structures.
The model can be used only for the simulation of individual
runoff events since it does not include provisions for either
catchment moisture or water quality accounting between rain-
storms .
The new version of the program includes an option to suppress
the water quality computations and perform the flow simulations
alone. This can save considerable computer time if water
quality computations are not needed.
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The model is very complex and a major effort is required to
implement it. The poorly organized documentation makes it very
difficult for the user to implement the model without many
false starts resulting from misinterpretations of the theoreti-
cal bases of the model and the meaning of some input data.
The model has been tested to some extent on urban hydrologic
data. Due to the lack of available comprehensive measured data
of concurrent rainfall, runoff, and water quality, different
parts of the model were tested with different sets of data.
Numerical testing of the flow computations with data from
catchments ranging in size between 5 and 2200 ha (13 and 5400
acres) showed satisfactory accuracy. The accuracy of water
quality predictions can be expected to be only of the right
order of magnitude. Considerable model improvement, particu-
larly of the formulations relating water quality with land use,
are needed before the water quality model can be used with
confidence.
Improvements are needed in the output formats. The arrangement
of the catchment runoff table makes it difficult to abstract
the hydrograph of a particular subcatchment. Complete output
of routed flow and quality can be obtained at only twenty
selected locations. This is adequate for the evaluation of a
few important locations, such as major outfalls. It is a
serious limitation, however, for the evaluation of an entire
sewerage system since repeated runs of the same data are re-
quired to obtain sufficient information on the adequacy, per-
formance, and utilization of all modeled sewer system elements.
Model improvements are in progress at the University of Florida
under an EPA contract to add snowmelt, to include more accurate
flow and water quality routing schemes, to add new water quality
parameters and unit treatment processes, and to simulate inline
(main) treatment processes (Heaney et al. , 1973). A new and
improved user's manual is being prepared for the revised model
(Huber et al., 1974). The model is also being revised to add
continuous simulation capability for planning purposes (Smith,
1975) . The model is being used by many consulting firms which
can assist cities in model implementation, and a special
program for model dissemination and user assistance was conduc-
ted by the University City Science Center of Philadelphia
(Hagarman and Dressier, 1975).
HYDROCOMP SIMULATION PROGRAM
Summary
The Hydrocomp Simulation Program is one of the most comprehen-
sive mathematical models for the simulation of both rural and
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urban catchments. The water flow computations are based on the
Stanford Watershed Model which was the first comprehensive
mathematical model of catchment hydrology (Crawford and Linsley,
1966). The Hydrocomp Simulation Program, however, is a consid-
erable improvement over the original Stanford Watershed Model,
both with respect to mathematical formulations and data handling
capability (Hydrocomp, 1972) . Recently, a separate program was
developed for the simulation of water quality in river basins
which can be interfaced with the hydrologic and flow routing
program (Hydrocomp, 1973).
The Hydrocomp Simulation Program is formulated for the contin-
uous simulation of water flow and quality from several catch-
ments and routing in converging branch sewer and open channel
networks. Catchment moisture and water quality are accounted
for during periods of no precipitation, so the model can be
used for continuous simulation of several years. Special
features are included for the simulation of impoundments and
diversions, including the flow of water over spillways and
through hydroelectric turbines. Real-time control and design
and cost features are not included.
Seventeen water quality constituents and their reactions and
interactions in natural water bodies can be simulated. The
applicability of the formulations to combined sewage has not
been established.
The Hydrocomp Simulation Program includes the following
features:
1. dry-weather flow and quality of several
catchments;
2. rainfall, snowfall, pan evaporation, air
temperature, dewpoint, solar radiation, and
wind velocity of several weather stations;
3. evapotranspiration;
4. snow accumulation and melt;
5. stormwater runoff and quality from pervious
and impervious areas of several catchments
from land use;
6. catchment moisture and water quality accounting
during periods of no precipitation;
7. groundwater infiltration into sewers and open
channels;
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8. seventeen water quality constituents with
reactions and interactions in natural
(receiving) water bodies;
9. routing of combined wastewater flow and quality
in a converging branch network;
10. circular closed conduits and trapezoidal open
channels with trapezoidal flood plains;
11. upstream and downstream flow control and
backwater;
12. diversion hydrographs;
13. in-line storage reservoirs with rule curve
operation; and
14. water quality decay, reactions, and interactions
in natural (receiving) water bodies.
The model does not include the following features:
1. dry-weather flow and quality from land use;
2. flow reversal, surcharging and pressure flow;
3. sedimentation and scour;
4. water quality decay, reactions and interactions
in sewers;
5. flow and quality routing in loops and diverging
branches;
6. noncircular closed conduits;
7. sewer flow control and diversion structures;
8. pumping stations;
9. wastewater treatment;
10. real-time control;
11. design; and
12. costs.
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Methods
The Hydrocomp Simulation Program includes the most complete
formulation of catchment hydrology of all the models reviewed.
The model computes runoff from pervious and impervious areas
separately and considers evapotranspiration, snowmelt, and soil
moisture accounting.
Precipitation (rain or snow) data is input at constant time
intervals for one or more raingages. Other meteorological data
needed for the evapotranspiration and snowmelt computations
are provided on a daily basis. Not more than one precipitation
record can be assigned to a single subcatchment.
Snow accumulation and melt are computed by a method developed
by the U.S. Corps of Engineers. The equations require data on
precipitation, air temperature, dew point, solar radiation,
and wind velocity. Programming defaults are used if some of
these data are unavailable. Only precipitation and air temper-
ature are essential.
Dry-weather flow and quality data are input at constant time
intervals. Dry-weather quality can also be defined by a power
function of dry-weather flow.
The potential infiltration rate is computed from an empirical
function of soil moisture. The actual infiltration depends on
the rainfall excess after subtracting interception losses
rather than on the overland flow depth. The infiltrated mois-
ture is divided into upper zone and lower zone storage. Upper
zone storage includes depression storage. Part of the upper
zone storage percolates into the lower zone storage and the
rest is divided into overland flow and interflow, which become
channel (or sewer) inflow. The lower zone storage is divided
into a channel inflow contribution and into deep groundwater
storage which does not contribute to surface runoff.
Interception, upper zone, lower zone, and groundwater storage
are depleted by evaporation or evapotranspiration computed as
functions of potential evapotranspiration and available mois-
ture.
Overland flow is routed with a modified kinematic wave formu-
lation using Manning's equation. Several empirical coefficients
internal to the program relate surface detention storage to
overland flow discharge.
Although the model's representation of infiltration, groundwater
percolation and storage, overland flow, groundwater contribu-
tion to surface flow, and evaporation from all moisture sources
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is based on physical concepts, the mathematical formulations
are based largely on empirical relationships. They require
several empirical coefficients, some of which are defined as
soil moisture capacities. The model appears sufficiently
complex that its use for prediction purposes without initial
calibration with measured data may not be very reliable.
Simpler models with fewer empirical coefficients seem adequate
to model infiltration and surface flow contributions in urban
catchments.
Flow routing in sewers and open channels is accomplished
using the kinematic wave equation with Manning's equation. The
solution considers the geometry of circular pipes and of trape-
zoidal open channels with trapezoidal flood plains. A diffusion
term in the kinematic wave equations approximates downstream
flow control and backwater conditions. Surcharging and pressure
flow in sewers is not modeled but a warning is printed if it
occurs. The time step for the routing computations is computed
internally to maintain numerical stability.
Reservoirs and channels can be simulated in the channel network.
Storage capacity has to be defined as a function of depth and
reservoir discharge has to be defined by rule curves relating
disch< rge with time. Diversions are modeled by requiring
diversion hydrographs as input data. Flow control, diversions,
and reservoir outlet structures are apparently not modeled
using appropriate hydraulic equations for weir, gate, and
orifice discharge.
The computation of stormwater quality is based on formulations
first used by the EPA Stormwater Management Model and then
expanded in the Corps of Engineers STORM Model and Water
Resources Engineers Stormwater Management Model. The concen-
tration of each pollutant washed off a catchment is computed
as a nonlinear function of runoff. Special empirical functions
are built in for water quality balance between runoff events
to account for dirt and dust accumulation, natural decay, street
cleaning practices, and different land uses. The pollutant
accumulation between runoff events can vary with the calendar
month. Different values can be specified for pervious and im-
pervious areas. The equations and coefficients have not been
sufficiently tested for reliable predictions without calibra-
tion with measured data.
Pure advection is used to route pollutants through the sewer
and open channel network. Dispersion is approximated by a
weighted average of concentration values at successive time
steps. For receiving water bodies, chemical and biological
reactions and interactions among the seven modeled water quality
constituents are computed. Only one-dimensional flow and water
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quality routing is formulated. Vertical water quality inter-
change can be approximated among three horizontal layers in
impoundments by providing empirical mixing coefficients. The
model documentation does not indicate whether reactions are
computed for sewage. The model does not include formulations
for wastewater treatment, real-time control, or design and cost
computations.
Computer Program
The Hydrocomp Simulation Program is a proprietary model devel-
oped by the consulting firm Hydrocomp International, Inc., of
Palo Alto, California. Separate user's manuals are available
for the flow and water quality computations of the model.
These contain sufficient detail covering the mathematical bases
of the modeled phenomena and the required input data. The
user must contract with Hydrocomp for routine application of
the program. The firm conducts periodic workshops to instruct
potential users in hydrologic simulation methods and applica-
tion of the Hydrocomp Simulation Program.
The computer program consists of four main programs and is com-
patible with IBM 360 and 370 computers with a minimum of 24OK
bytes of core memory. Information is not published which would
allow estimates of computer execution times as a function of
problem size.
Computer output includes precipitation; soil moisture status;
water stages, velocities, discharges, and water quality con-
centrations for all channels and storage; and volume of storage.
Data input and output can be in metric or British units.
Evaluation
The Hydrocomp Simulation Program is the only available hydro-
logic model which can be applied for the continuous simulation
of both water flow and quality in urban and rural watersheds
and channel networks. It was originally developed for the
hydrologic simulation of rural catchments, and recently water
quality computations for natural rivers and impoundments were
added.
Modifications for urban applications include the addition of
separate runoff computations for pervious and impervious areas
and flow and water quality routing in circular closed conduits.
Other model additions, however, would make the model more
generally applicable to urban sewerage systems: for instance,
geometries of different closed conduit cross-sections, hydraulic
equations for different flow control and diversion structures,
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formulations for surcharging and pressure flow, and simulation
of treatment processes.
This hydrologic model has been tested and applied extensively
in many nonurban watersheds in the United States and abroad.
Reported testing on urban data is limited to four catchments
ranging in size from 100 to 1068 ha (248 to 2640 acres) with
less than 22 percent imperviousness (Crawford, 1971) . Compari-
sons between measured and computed runoff for selected storm
events have produced generally good agreement, with some excep-
tions attributed to potentially unreliable measured data. Good
agreement between measured and computed runoff are also
reported for four stream gages in the partially urbanized North
Branch of the Chicago River_drainage basin, which has a drain-
age area of 264 km (102 mi ) and 13 percent imperviousness
(Hydrocomp, 1970). Testing and application of the water
quality model is in progress.
MASSACHUSETTS INSTITUTE OF TECHNOLOGY URBAN WATERSHED MODEL
Summary
The Massachusetts Institute of Technology (MIT) Urban Watershed
Model simulates the time-varying runoff of several catchments
and a sewer and open channel network including loops and con-
verging and diverging branches (Harley et al., 1970). The
model is limited to the simulation of single runoff events.
Water quality and real-time control features are not included.
A separate model includes design features to compute the sizes
and costs of sewers, storage and treatment facilities which
will result in the least-cost combination of alternatives for
the elimination of untreated overflows and the reduction of
flooding and surcharging (Kirshen et al., 1972).
The original model was developed at MIT for the U.S. Office of
Water Resources Research, but the model has been modified by
Resource Analysis, Inc., for its routine application (Schaake
et al., 1973).
The MIT urban Watershed Model includes the following features:
1. dry-weather flow of several catchments;
2. air temperature at one weather station;
3. several rainfall records;
4. special statistical analyses to compute design
hyetographs (separate program);
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5. evapotranspiration;
6. snow accumulation and melt;
7. option to choose one of four different infiltration
equations;
8. stormwater runoff from pervious and impervious
areas of several catchments;
9. catchment moisture accounting during periods of
no precipitation;
10. flow routing in gutters;
11. routing of combined wastewater flow in a converging
network of loops and converging and diverging
branches;
12. various standard closed conduits and open channel
cross-sections and arbitrary shapes;
13. downstream flow control, backwater, surcharging
and pressure flow;
14. flow control and diversion structures;
15. storage facilities;
16. hydraulic capacities of treatment facilities; and
17. least-cost sizes of sewers, overflow storage and
treatment plants meeting constraints on surcharging
and untreated effluent volume (separate program).
The model does not include the following features:
1. dry-weather flow from land use characteristics;
2. catchment moisture accounting during periods of
no precipitation;
3. flow reversal;
4. water quality; and
5. real-time control.
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Methods
Dry-weather flow data for each inlet is input in the form of
hydrograph values at constant time intervals. The model does
not include provisions to compute dry-weather flow from land
use.
Several rainfall intensity records can be provided as input
data. Not more than one rainfall record can be used to compute
runoff from a subcatchment. Special provisions are built into
the model to move a rainstorm across a catchment by specifying
its direction and velocity of movement. A separate model is
available which computes design hyetographs of specified
frequencies from measured rainfall data.
Initial losses to fill depression storage on pervious and im-
pervious areas are subtracted before surface runoff begins.
The Resource Analysis version has four options to compute
infiltration on the pervious areas: Horton's equation, Holtan's
equation, a U.S. Soil Conservation Service method, and a run-
off coefficient method. Infiltration is subtracted from rain-
fall if the last two methods are used, but computed from over-
land flow depth if Horton's or Holtan's equation is used. A
method based on filter theory can be used to estimate the in-
filtration parameters from measured rainfall and runoff (Leclerc
and Schaake, 1973). Snow melt is computed by the Corps of
Engineers degree-day method which requires mean daily air temp-
erature as input data. The Penman equation is programmed to
compute evaporation but generally not used for single runoff
event simulation.
Flow routing is accomplished with the kinematic wave equation.
The equations are solved by a finite difference scheme for
overland flow, flow in gutters, and flow in open channels and
for various standard cross-sections and any arbitrary shape
closed conduits. Downstream flow control and backwater can be
considered if the stage-discharge relationship is known.
Surcharging and pressure flow is computed separately for each
pipe reach. Flow reversal is not modeled. Weir and orifice
flow control and diversion structures can be modeled by their
hydraulic equations.
The design model computes the sizes and costs of circular
sewers, the volumes of overflow storage facilities, and the
hydraulic capacities of treatment plants needed to reduce un-
desirable flooding and surcharging and to eliminate untreated
overflows. Linear programming is used to determine the least-
cost combination of these facilities for a selected design
storm event. The optimization is based on needed hydraulic
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capacities alone and does not consider water quality. It re-
quires catchment runoff hydrographs as input data and uses a
simplified flow routing scheme.
Computer Program
The MIT Urban Watershed Model was developed under a series of
projects for the U.S. Office of Water Resources Research.
Each project covered a different aspect of the overall model
development. The computer programs were written for an IBM
360/67 in Fortran IV. The design program utilizes the linear
programming package of the 1971 IBM Mathematical Programming
System Extended (MPSX). The model's core storage requirement
is not documented. The potential user has to contract with
Resources Analysis, Inc., of Cambridge, Massachusetts, for
routine applications of the model.
Computer output of the model includes tables of rainfall inten-
sities and overland, catchment and channel depth, velocity
and discharge. Samples of program output are not included in
the documentation for the design option but output for this
option includes the volume and duration of flooding for each
sewer and the required sizes and costs of sewer overflow stor-
age facilities and treatment plants.
Evaluation
The MIT model is a useful and efficient tool for the simulation
of urban and nonurban catchments, including both sewer and
natural stream networks where backwater, downstream flow
control and surcharging are not important. Testing of the
model on catchments with drainage areas up to 120 km (46 mi2)
shows good agreement between computed and measured runoff
(Leclerc and Schaake, 1973; Resource Analysis, 1974) . The
model is being used extensively for practical engineering
assessments.
MINNEAPOLIS-SAINT PAUL URBAN RUNOFF MODEL
Summary
The Minneapolis-Saint Paul Urban Runoff Model was developed
for real-time forecasting of flows in the major trunk and in-
terceptor sewers of the Minneapolis-Saint Paul combined sewer-
age system to reduce untreated overflows to the Mississippi
River during rainstorms (Minneapolis-Saint Paul Sanitary Dis-
trict, 1971). The model computes the runoff of several large
catchments, diverts the flows at controllable regulating struc-
tures, and routes them through a converging branch sewerage
network to the treatment plant. It is specifically designed
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for real-time control operation on a small computer and cannot
be used for the assessment of existing or the design of new
sewerage systems since it uses a highly simplified flow routing
procedure whose coefficients have to be calibrated with mea-
sured data or derived from more sophisticated models.
Although the model was designed for continuous simulation by
incorporating provisions for the accounting of catchment mois-
ture between rainstorms, the necessary formulations were never
added and the program can be used only for the simulation of
single runoff events. The real-time control operation, which
is not based on mathematical optimization techniques, requires
repeated trial and error runs with estimates of regulator set-
tings. The model does not include water quality, design, and
cost computations.
The Minneapolis-Saint Paul Urban Runoff Model includes the
following features:
1. dry-weather flow of several catchments;
2. several rainfall records;
3. stormwater runoff from pervious and impervious
areas of several catchments;
4. routing of combined wastewater flow in a
converging network of unspecified sewer
cross-sections;
5. six types of diversion structures;
6. telemetry system for real-time acquisition of
rainfall, flow level, and regulator status data;
and
7. remote control of diversion gates and weirs.
The model does not include the following features:
1. dry-weather and stormwater flow from land use;
2. evapotranspiration;
3. snow accumulation and melt;
4. catchment moisture accounting during periods of
no precipitation;
5. flow routing in gutters;
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6. flow routing in loops and diverging branches;
7. noncircular closed conduits and open channels;
8. downstream flow control, backwater, flow reversal,
surcharging, and pressure flow;
9. pumping stations;
10. storage facilities;
11. water quality;
12. design; and
13. costs.
Methods
Dry-weather flow data is input in the form of average values
for each catchment and adjustment factors to account for diur-
nal (hourly) variations. The model does not include provisions
to compute dry-weather flow from land use. Storm runoff is
computed for each catchment from the weighted average rainfall
of several raingages. The raingage record is input in the
form of cumulative values and can be given at irregular inter-
vals . This is a distinct advantage over the common requirement
of most models that rainfall intensities be furnished at con-
stant time intervals, since it eliminates the need to compute
intensities prior to running the program and to read in zeros
for periods of no rain.
The rainfall excess contribution of each catchment is computed
separately for pervious and impervious areas. Runoff does not
begin until all depression storage is filled. Other losses
are computed for impervious areas by an exponential function
and by a modified Holtan's equation for pervious areas. Both
formulations are functions of cumulative losses and consequent-
ly account for catchment moisture conditions. This is a better
formulation than others which treat potential infiltration as
a function of time only without regard to the actual infiltra-
tion. The Minneapolis-Saint Paul Model, on the other hand,
subtracts all losses from rainfall, which is less accurate
than basing them on overland flow and depth.
The excess precipitation is then convoluted with unit hydro-
graphs to determine the storm runoff from each catchment. The
unit hydrographs are computed from catchment characteristics
(including drainage area, length, slope, soil, and vegetation)
by a method of the U.S. Soil Conservation Service. The same
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unit hydrograph is applied to runoff from both the pervious
and impervious portion of each catchment, which may lead to
inaccuracies and calibration problems.
The unit hydrograph method was selected because of its rapid
computer implementation for the computation of runoff from
large catchments, an important factor in real-time control of
major trunk sewer regulators. It allows the simulation of the
entire Minneapolis-Saint Paul combined sewerage system by only
15 catchments.
The progressive average lag method is used to route the flows
in the sewers. The method requires two empirical coefficients
(an average travel time and the number of upstream flow values
to be averaged to obtain a downstream routed flow value) which
must be obtained by calibration with measured data or by deri-
vation with a different routing method. Since sufficient data
are not available in a sewerage system, the coefficients were
obtained for the Minneapolis-Saint Paul system through solu-
tion of the characteristic form of the dynamic wave equations
for a single pipe. Noncircular pipes were approximated by
circular pipes of equal cross-sectional area. The progressive
average lag method does not require any information on the
geometry of the modeled pipes or open channels once the routing
coefficients are known. It was chosen since it is extremely
fast and was considered sufficiently accurate for real-time
control purposes. It cannot be used for the assessment or
design of sewerage systems where relationships between the
geometry of the conduits and channels and the hydraulic per-
formance of the system are required.
Diversions are computed at regulators using combinations of
orifice and weir equations which depend on the geometric con-
figuration of each structure. The program includes formulations
for the following three common types of structures: perpendi-
cular weir overflow with orifice dry-weather outlet (weir may
have other angles to flow direction), orifice or gate overflow
(without weir), and a structure which overflows when flow ex-
ceeds a preset maximum. In addition, three special regulators
in the Minneapolis-Saint Paul trunk sewers (which probably
would not occur in other systems) were programmed.
Computer Program
The computer program is written in Fortran IV for a DEC PDP-9
computer with 16K words of core memory. The program consists
of seven main programs which are run sequentially. The program
is interfaced with a real-time data acquisition system for rain-
fall, water level and regulator status data. Remote control
of regulator weir and gate positions is accomplished manually.
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Program output includes rainfall intensities and catchment mois-
ture conditions for each catchment and discharges at regulators
and selected interceptor sewer locations. Water depths and
velocities are not computed.
Evaluation
The model is intended primarily for the real-time forecasting
of flows in major trunk and interceptor sewers. It is formu-
lated to run on a small process computer within time constraints
imposed by the real-time forecasting requirement. As a conse-
quence the mathematical formulations include several simplifi-
cations, particularly in the catchment runoff and sewer routing
portions, to stay within the time and core storage constraints
of the small computer. These simplifications make the model
unsuitable for assessment of existing sewerage systems or the
design of new sewerage systems. They merit consideration,
however, for schemes involving real-time data acquisition and
control of overflows during rainstorms.
The model does not include mathematical optimization techniques
to determine optimal regulator settings which would minimize
overflows during rainstorms subject to capacity constraints of
the existing sewerage system and the treatment plant. In its
present form, it has to be run repeatedly with trial values of
regulator settings until the desired regulator operation is
found which would maximize the utilization of system capacity
and minimize overflows. Since this type of operation is time
consuming and fairly inefficient, the model is no longer used
for real-time control. Instead, regulator settings are deter-
mined during a rainstorm by the operators on the basis of
their experience using the telemetered raingage and water level
readings.
SEATTLE COMPUTER AUGMENTED TREATMENT AND DISPOSAL SYSTEM
Summary
The Computer Augmented Treatment and Disposal System (CATAD)
of the Municipality of Metropolitan Seattle (Metro) is an oper-
ating system for the real-time control of untreated overflows
from the main trunk and interceptor sewer regulators of the
metropolitan Seattle, Washington, combined sewerage system
(Municipality of Metropolitan Seattle, 1971; Gibbs and Poole,
1972; Gibbs et al., 1972; Mallory and Leiser, 1973; Leiser,
1974) . Although it does not include a comprehensive mathe-
matical model for the simulation of combined wastewater runoff
at this time, the system is reviewed in this study because of
its capability for automatic computer control of diversion
structures and pumping stations.
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The system includes a small process computer, real-time data
acquisition of rainfall, water level and quality data, and re-
mote automatic computer control of regulators and pumping
stations. The control scheme uses rule curves relating trunk
sewer storage upstream of regulators with time and appropriate
hydraulic equations for each regulator and pumping station to
maximize storage in the sewerage system and minimize untreated
overflows. Each control structure is controlled independently
and potentially undesirable effects on overall system perfor-
mance are handled by manual overrides. Real-time wastewater
quality data are not utilized as criteria for determining
overflow rates and locations.
The Computer Augmented Treatment and Disposal System includes
the following features:
1. rainfall at six raingages (more being added);
2. rule curves for each major trunk and interceptor
sewer regulator relating storage with time for
typical rainfall patterns;
3. hydraulic equations for each diversion structure
to compute discharge considering both upstream
and downstream hydraulic conditions;
4. hydraulic equations for each diversion structure
to compute gate settings required to obtain
desirable regulator discharge;
5. two types of pumping stations;
6. inverted siphons;
7. automatic real-time data acquisition for rainfall,
water levels and quality, and regulator and pumping
station status; and
8. remote automatic computer control of controllable
regulators and pumping stations.
The system does not include the following features;
1. precipitation-runoff computations;
2. flow routing in gutters, sewers and open channels;
3. storage reservoirs;
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4. water quality within the system;
5. design; and
6. costs.
Methods
The Computer Augmented Treatment and Disposal System is opera-
tional to the extent of providing automatic control of sixteen
regulators and two pumping stations. The remote control is
determined using real-time data acquisition of rainfall from
six raingages and water levels upstream and downstream of con-
trollable flow regulating structures and pumping stations.
Rule curves are used to determine the operation of the regula-
tors and pumping stations which will maximize available sewer
storage capacity and minimize untreated overflows.
The rule curves represent sewer storage capacities as functions
of time for the sewer upstream of each controlled regulator
and pumping station. Each curve was developed from runoff
patterns of representative historical rainstorm patterns and
represents the desirable filling schedule for a sewer based on
its storage capacity. The rule curves may be adjusted as storm
patterns vary and as storage requirements change.
Hydraulic equations were programmed in two modes for each type
of regulator. The first mode is used to evaluate regulator
performance under different flow conditions and regulator set-
tings. It computes the regulator discharges for given inflows
and regulator settings. The second (control) mode is used
during the real-time control operation to determine the regula-
tor settings (such as gate heights) which will result in the
desired regulator discharges as determined by the rule curves
for the predicted runoff pattern.
The present control scheme uses simulation at 1/2-hour inter-
vals to compute the required regulator and pumping station
operation for the following 1/2 hour. Regulator and pumping
station controls are then reset at 5- or 10-minute intervals,
depending on the rate of change of the runoff. All flow
level gages at the regulator and pumping stations are scanned
every minute and all raingages every 5 or 10 minutes to pro-
vide the real-time data for the control scheme. The system
is therefore operating in full computer control mode. Manual
override is possible for alarm conditions.
At present, comprehensive optimization is not used to maximize
utilization of available sewerage system flow and storage capa-
city. The effect of flow routing is considered by the control
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system, however, by automatically adjusting flow control struc-
tures if excessive flow conditions occur in the sewers. Dif-
ferent approaches to the development of a comprehensive
sewerage system simulation and control model are being investi-
gated. Separate submodels have been programmed, such as the
computation of runoff from rainfall using the unit hydrograph
method and flow routing in the sewers using the dynamic wave
equations. These submodels have not been combined with the
regulator equations into a comprehensive simulation model for
the entire trunk and interceptor sewerage system.
Computer Program
The computer programs are written in Fortran for a Xerox Sigma
2 computer with 44K words of core memory, of which 31K are used
for the data acquisition and remote control operation (fore-
ground operation) while the remaining 13K are available for
other purposes (background operation). The programs are system
specific and not transferable for general application else-
where.
Evaluation
This is an operational system for real-time automatic computer
control of untreated overflows during rainstorms. The system
has been shown to be very effective in reducing untreated
combined overflows to the receiving waters. The system's
effectiveness could be improved by replacing the rule curve
operation with systematic optimization techniques which maxi-
mize the utilization of available sewer flow and storage capa-
city and consider constraints on the quality of the overflows.
SOGREAH LOOPED SEWER MODEL
Summary
The Looped Sewer Model of the French consulting firm Societe
Grenobloise d'Etudes et d1Applications Hydrauliques (SOGREAH)
simulates the time-varying runoff of combined sewerage systems
consisting of several catchments and a sewer and open channel
network including loops and converging and diverging branches
(SOGREAH, 1973 - 5 reports). The model includes formulations
for most hydraulic phenomena encountered in closed conduit and
open channel networks. The flow routing solves the dynamic
wave equations coupled with equations for special sewer system
facilities, such as diversion structures, pumping stations,
inverted siphons, and retention basins. The solution considers
both upstream and downstream boundary conditions, backwater,
surcharging, pressure flow, and flow reversal. Conservative
water quality constituents can be routed through the sewerage
network.
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The model appears to be limited to the simulation of single
runoff events. Real-time control and design features are not
included. This is a proprietary model and not all details of
the model formulations are available. The firm has North Ameri-
can branch offices in New York City and Lasalle, Quebec, Canada.
The SOGREAH Looped Sewer Model includes the following features:
1. dry-weather flow of several catchments;
2. design hyetographs and hydrographs from catchment
characteristics or several rainfall records;
3. stormwater runoff from pervious and impervious areas
of several catchments;
4. routing of combined wastewater flow in a network of
loops and converging and diverging branches;
5. circular and egg-shaped closed conduits, trapezoidal
open channels, and any arbitrary shapes;
6. backwater, upstream and downstream flow control,
surcharging, pressure flow, and flow reversal;
7. flow control and diversion structures considering
both upstream and downstream flow conditions;
8. inverted siphons;
9. pumping stations;
10. overflow and in-line storage facilities;
11. receiving water flow (separate program); and
12. routing of conservative and first-order decaying
water quality constituents.
The model does not include the following features:
1. dry-weather flow and quality and stormwater quality
from land use characteristics;
2. input of recorded rainfall data;
3. evapotranspiration;
4. snow accumulation and melt;
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5. catchment moisture accounting during periods of
no precipitation;
6. sedimentation and scour;
7. wastewater quality decay, reactions and interactions;
8. real-time control;
9. design; and
10. costs.
Methods
Dry-weather flow data for each inlet is input in the form of
hydrograph values at constant time intervals. The model does
not include provisions for computing dry-weather flow from
land use.
Options exist to read in several rainfall records, move a rain-
storm over a catchment in a specified direction, or compute a
synthetic design rainfall. The synthetic rainfall is defined
by a maximum design rainfall of specified frequency for each
catchment using a formula developed by Caquot. The formula
considers catchment characteristics such as slope, percent
imperviousness, and drainage area and contains eight empirical
coefficients. The maximum design rainfall is transformed into
a design rainfall hyetograph by a second formula which requires
two additional empirical coefficients. The rational formula
or the Horton equation can be used to compute the rainfall
excess hyetograph from either measured or synthetic hyetographs.
The rainfall excess hyetographs are then routed over each catch-
ment to the sewer inlets using the Muskingum flood routing meth-
od. This requires two additional empirical coefficients, one
of which is estimated and the other computed with a formula
suggested by Schaake and Geyer. The formula considers the per-
cent imperviousness and the overland flow length and slope and
contains four additional empirical coefficients. The two
Muskingum coefficients are adjusted from runoff measurements
if available.
The formulations for the catchment runoff do not consider evapo-
transpiration, snow accumulation and melt, and catchment mois-
ture accounting during periods of no precipitation. Consequently,
the model is not suited for continuous simulation of catchment
runoff.
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Flow routing is accomplished with the dynamic wave equations for
nonsteady gradually varied open channel flow (Saint-Venant equa-
tions) . Strickler's equation (same as Mannings's equation) is
used to compute the energy gradient. An implicit finite differ-
ence solution is employed which considers various upstream and
downstream boundary conditions, including the performance of various
types of special sewerage system facilities. The solution tech-
nique computes backwater and flow reversal and special formula-
tions are included to handle surcharging, pressure flow, and flood-
ing at sewer inlets. This gives the model the capability to simu-
late nonsteady flows not only in a converging branch network but
also in diverging branches and loops. Equations for circular and
egg-shaped closed conduits and for trapezoidal open channels are
built into the program. The user can add subroutines for other
cross sections and also read in geometric data for any arbitrary
shapes.
Equations are built into the program to compute the discharge
over weirs and through gates and orifices. Regulator gate
positions can be read in as functions of time. Inverted siphons
and two types of pumping stations can also be simulated. The
equations for these special facilities consider both upstream
and downstream flow conditions and their solutions are coupled
with the solution of the dynamic wave equations for the flow
routing. The model appears to simulate storage facilities but
details on relevant formulations were not available.
The flow routing portion of the model is set up for continuous
simulation. The user can read in initial conditions for every
sewer system element, stop the computations after any number of
simulated hours, and restart the simulation using the final
conditions of the previous run as the new initial conditions.
The model does not include real-time control and design and
cost computations. A water quality program is being developed
and the formulations for routing of conservative and first-
order decaying substances through the sewerage network are
operational. Pollutant transport is computed by an explicit
finite difference solution of the advection equation.
Computer Program
This is a proprietary model developed by the French consulting
firm Societe Grenobloise d'Etudes et d1Applications Hydrauliques
of Grenoble, France. North American representatives are in
New York City and Lasalle, Quebec, Canada. A user's manual
is available in French, but supporting documentation on model
features and formulation is inadequate to fully assess the
model's capabilities and limitations.
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The program consists of five main programs which are loaded in
sequence and coupled through common input/output data files.
The program was written in Fortran IV for an IBM 360/65. The
complete program has about 3,000 Fortran statements.
For program operation, only one of the five main programs is
loaded into core at any one time. The program uses dynamic core
allocation. A core storage requirement of 65K bytes is estimated
for a simulation of 100 sewerage system nodes with 1000 computa-
tional points (where stages and discharges are computed). The
execution time for this system is estimated at 0.25 seconds
for the generation of each 3-hour inlet hydrograph and 2.7
seconds per time step for the routing computations.
Program output includes tables and plots of water depths (or
pressures), velocities and discharges for each computational
point. Program input and output are in metric units.
Evaluation
The SOGREAH Looped Sewer Model includes very comprehensive formu-
lations for the routing of flow in sewerage networks. It can
simulate all nonsteady gradually varied flow phenomena, sur-
charging and pressure flow, and hydraulic performance of special
facilities for complex sewerage systems, including loops and
converging and diverging branches. The implicit solution of
the Saint-Venant equations coupled with equations for special
facilities is complicated, however, and longer computer execu-
tion times can be expected than for simpler models. The length
of the time steps can be changed during the simulation to save
computer time. For example, short time steps can be used dur-
ing rapidly varying flow conditions and longer time steps during
slowly varying flow conditions without loss of accuracy. Numeri-
cal testing indicated that the implicit solution is computa-
tionally as fast as some solutions of the simpler kinematic
wave equation.
The model would be useful primarily where the consideration of
backwater, downstream flow control, diversion structures, re-
tention basins, surcharging, and flow reversal are important
features of the sewerage system assessment. If these features
are not present or are considered insignificant, simpler models
requiring less computer time can be used.
The model is based on a mathematical model for flows in river
basins developed by SOGREAH earlier. Due to satisfactory verifi-
cation results with the river basin model, SOGREAH did not re-
port verification of the sewer model with measured urban rainfall
and runoff data.
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UNIVERSITY OF CINCINNATI URBAN RUNOFF MODEL
Summary
The University of Cincinnati Urban Runoff Model simulates the
time-varying runoff of storm sewerage systems consisting of
several catchments and a converging branch sewer and open channel
network (University of Cincinnati, 1970; Papadakis and Pruel,
1972). The model does not include provisions for dry-weather
flow, water quality, real-time control and design. It is limited
to the simulation of single runoff events.
The University of Cincinnati Urban Runoff Model includes the
following features:
1. one rainfall record;
2. stormwater runoff from pervious and impervious areas
of several catchments;
3. flow routing in gutters;
4. routing of stormwater runoff in a converging branch
network; and
5. circular closed conduits and rectangular open channels.
The model does not include the following features:
1. dry-weather flow;
2. consideration of nonuniform catchment rainfall
distribution;
3. evapotranspiration;
4. snow accumulation and melt;
5. catchment moisture accounting during periods of
no precipitation;
6. flow routing in loops and diverging branches;
7. noncircular closed conduits;
8. downstream flow control, backwater, flow reversal,
surcharging, and pressure flow;
9. flow control and diversion structures;
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10. pumping stations;
11. storage facilities;
12. water quality;
13. real-time control;
14. design; and
15. costs.
Methods
The University of Cincinnati Urban Runoff Model accepts the
input of only one hyetograph for the entire drainage basin.
Although this may be a weighted average of several raingage
records, it neglects the areal nonuniformity of rainfall over
the catchment. Losses to depression storage for both pervious
and impervious areas are subtracted as a function of available
depression storage capacity and cumulative rainfall and losses.
Infiltration on pervious areas is computed with Horton's equa-
tion, with its time origin offset to balance cumulative rainfall
and potential infiltration. This could improve the computation
or infiltration compared to its unmodified use; other inaccura-
cies are introduced, however, since all losses are computed from
rainfall without considering the overland flow depth and stor-
age, and Horton's equation does not consider soil moisture
conditions.
Overland flow is computed by a storage routing technique similar
to the method used by the Stanford Watershed Model and Hydro-
comp Simulation Program. The method uses Manning's equation
and includes several empirical coefficients internal to the
program to relate surface detention storage with overland flow.
The gutter flow routing uses a steady state approach, assuming
that the gutter outflow equals its inflow during the same time
interval.
Flow routing in the sewers is accomplished by a simple trans-
lation of the upstream hydrograph by its average travel time
computed with Manning's equation. The formulation is extremely
approximate, since it neglects the effects of varying travel
times as functions of the discharge. The formulation does not
consider downstream flow control, backwater, flow reversal,
surcharging, and pressure flow. Special sewer system elements,
such as flow control and diversion structures, are not modeled.
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Computer Program
The computer program is written in Fortran IV for an IBM 360
and is available from the University of Cincinnati. The program
has about 800 statements. Its core storage and running time are
not published.
Program output primarily includes discharges at selected points.
Water depths and velocities are not printed.
Evaluation
The University of Cincinnati Urban Runoff Model contains sev-
eral simplifications, as described above, which appear to
severely limit its accuracy. The assumption of uniform rain-
fall distribution, the neglect of dry-weather flows, the computa-
tions of infiltration from rainfall rather than available mois-
ture on the catchment, the neglect of catchment moisture condi-
tions on potential infiltration rates, the steady state flow
routing in gutters, and the sewer flow routing technique neglect-
ing dynamic flow phenomena impose severe constraints on the model's
applicability for complex combined sewerage systems.
Although some encouraging comparisons between measured and com-
puted results have been reported for the 5.2 ha (12.9 acre)
Oakdale catchment in Chicago, Illinois and the 964 ha (2,380
acre) Bloody Run catchment in Cincinnati, Illinois (Papadakis
and Pruel, 1973), they were restricted to single rainfall events
and required considerable calibration, particularly with respect
to the selection of infiltration values. Other testing on the
70 ha (173 acre) Vine Street catchment in Melbourne, Australia
and on the 500 ha (1,240 acre) Yarralumla Creek catchment in
Canberra, Australia using more complex storm patterns showed
considerable differences between measured and computed runoff
values (Heeps and Mein, 1974).
UNIVERSITY OF ILLINOIS STORM SEWER SYSTEM SIMULATION MODEL
Summary
Considerable research is in progress at the University of
Illinois on the development of hydrologic models in general
and urban runoff models in particular. A comprehensive mathe-
matical model combining rainfall-runoff computations for urban
catchments and sewer flow routing in a single computer program
has not been developed.
A model is available, however, for the nonsteady routing of
flows in converging branch sewer networks. It is based on the
solution of the dynamic wave equations which consider upstream
and downstream flow control, backwater, and flow reversal
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(Sevuk, 1973; Sevuk et al., 1973). The model requires hydro-
graphs as input data but could become a component in a compre-
hensive urban hydrologic model including rainfall-runoff compu-
tations. The model does not include water quality and real-
time control features. A design feature determines sizes of
circular pipes for peak flows. Costs are not considered.
Separate hydrologic catchment models have been developed (Chow
and Kulandaiswamy, 1971; Chow and Ben-Zvi, 1973) and research
for the development of an urban catchment model is in progress
for potential interfacing with the routing model.
The University of Illinois Storm Sewer System Simulation Model
includes the following features:
1. dry-weather and storm runoff hydrographs of
several catchments have to be provided as input
data;
2. routing of combined wastewater flow in a converging
sewer network;
3. circular closed conduits;
4. upstream and downstream flow control, backwater,
and flow reversal;
5. weir, gate or pumping station flow controls without
diversions at the outlet;
6. in-line storage facilities; and
7. pipe sizes for peak flow.
The model does not include the following features:
1. dry-weather flow from land use;
2. precipitation-runoff computations;
3. flow routing in gutters;
4. flow routing in loops and diverging branches;
5. noncircular closed conduits and open channels;
6. surcharging and pressure flow;
7. diversion structures;
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8. in-line pumping stations;
9. water quality;
10. real-time control; and
11. costs.
Methods
The University of Illinois Storm Sewer System Simulation Model
is strictly a flow routing model and does not include the
computation of dry-weather flows from land use or the computation
of runoff from precipitation. Inflows to the modeled sewer
network have to be provided in the form of hydrographs as input
data. The flows are routed through a converging network of
circular sewers with the equations for nonsteady gradually
varied open channel flow (Saint-Venant equations). The charac-
teristic partial differential equations are solved by a first-
order explicit finite difference formulation. The Darcy-Weis-
bach equation is used to define the energy gradient. Weir and
gate controls and pumping rates can be specified as downstream
boundary conditions, but diversions are not computed. The
formulation considers upstream and downstream flow control,
backwater, flow reversal, and in-line storage. Surcharging and
pressure flow are not computed.
The model includes a design option for computing the sizes of
circular sewer pipes using an iterative approach. The diameters
of the upstream inlet pipes are first computed for the peak
inflow. The diameters of the remaining pipes of a branch are
then computed based on a kinematic wave routing procedure. The
resulting diameters are then corrected based on the more exact
flow routing scheme using the dynamic wave equations. This
approach will result in a hydraulically sound design but the
solution does not consider costs.
Computer Program
The computer program is written in PL/1 and assembler language
for an IBM 360/75 computer and consists of approximately 3000
statements. The program and a user's manual are available from
the University of Illinois. The program is written specifically
for IBM 360 and 370 systems and would require considerable re-
programming for use on other computers. The program is run with
220k bytes of core memory, but could be run with as little as
100k for small sewerage networks. A memory of at least 300k
bytes is recommended by the authors, however, for efficient
applications.
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Program output includes tables of depths, velocities and dis-
charges, Calcomp plots of depths and discharges at selected
points of the network, and line printer plots of the inflow
hydrographs at the sewer entrances. Pipe sizes are printed
for the design option.
Evaluation
The University of Illinois Storm System Simulation Model includes
a fairly comprehensive formulation of free-surface flow in cir-
cular pipes. It can simulate all nonsteady gradually varied
flow phenomena but does not include provisions for the simula-
tion of surcharging and pressure flow. It cannot simulate
loops and diverging branches and diversion structures.
The explicit numerical solution of the Saint-Venant equations
for special junction and downstream outlet facilities is fairly
straightforward, but can be expected to require long computa-
tion times as a result of the short computational time steps
required to maintain numerical stability. The solution techni-
que includes a special overlapping feature to model large sewer-
age systems in smaller segments, thus increasing the size of
a network that can be simulated with the available computer core
storage capacity. A disadvantage of the method is that two
iterations are required to solve the dynamic wave equations for
the entire network. The resulting increase in computer time is
offset somewhat, however, by allowing different time steps in
different segments of the network.
A special feature of the model is its capability to dimension
circular sewers. The method does not result in a least-cost
solution. It is the only design method among the reviewed
models, however, which considers the complete dynamic wave
equations in the design procedure. Consequently, it can be
expected to produce a more accurate sizing of pipe diameters
than other design methods based on more approximate routing
methods, provided satisfactory design inflows can be defined.
Although the model has the capability for continuous simulation,
the cost of its application for design purposes using several
years of records would be very high.
No application or verification of the model with real urban
catchment and sewerage system data is reported. Testing of
the model with data from laboratory pipe flow experiments and
sensitivity analyses with hypothetical data indicate, however,
that high accuracy can be expected for the routing of flows
through converging networks of circular pipes.
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UNIVERSITY OF MASSACHUSETTS COMBINED SEWER CONTROL
SIMULATION MODEL
Summary
The University of Massachusetts Combined Sewer Control Simula-
tion Model simulates the time-varying runoff of several catch-
ments and a single string of circular sewers (Ray, 1972). The
model computes surface runoff from impervious areas only using
hourly rainfall data which may be computed by a separate Markov
chain model. The flow routing is accomplished with an implicit
solution of the dynamic wave equations which consider upstream
and downstream flow control, backwater and flow reversal. Spec-
ial sewerage system facilities, such as diversion structures and
storage facilities, are not modeled. The model is formulated
for continuous simulation but neglects evapotranspiration and
snow accumulation and melt. Water quality, real-time control,
and design features are not included.
The University of Massachusetts Combined Sewer Control Simula-
tion Model includes the following features:
1. one rainfall record;
2. generation of synthetic hourly rainfall;
3. stormwater runoff from impervious areas of several
catchments;
4. routing of combined wastewater flow through a single
string of circular pipes; and
5. upstream and downstream flow control, backwater,
and flow reversal.
The model does not include the following features:
1. dry-weather flow from land use characteristics;
2. consideration of nonuniform distribution of
catchment precipitation;
3. evapotranspiration;
4. snow accumulation and melt;
5. catchment moisture balance during periods of
no precipitation;
6. stormwater runoff from pervious areas;
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7. flow routing in gutters;
8. flow routing in loops, converging and diverging
branches;
9. noncircular closed conduits and open channels;
10. surcharging and pressure flow;
11. flow control and diversion structures;
12. pumping stations;
13. storage facilities;
14. water quality;
15. real-time control;
16. design; and
17. costs.
Methods
Dry-weather flow data can be input as a constant flow value for
each catchment. One rainfall hyetograph can be input for the
entire catchment. Hourly rainfall can be computed from a
Markov chain model using recorded rainfall data to generate
synthetic rainfall. A sixth-order Markov chain determines the
lengths of dry and wet periods and a first-order Markov chain
computes hourly precipitation values during the wet periods.
The Markov chain model allows the evaluation of potential rain-
fall events which have the same statistical properties as the
recorded events but which occur in different sequences of wet
and dry periods.
Surface runoff from pervious areas is neglected. For impervious
areas, it is assumed that all rain falling during an hour be-
comes surface runoff during the same hour after an initial loss
has been satisfied. Moisture recovery during dry periods (such
as evapotranspiration) is not considered. The model is formulated
for continuous simulation of periods up to one month but does not
consider snow accumulation and melt.
The combined wastewater flow is routed through a single string
of circular pipes with multiple inlets for the runoff from the
modeled subcatchments. The flow routing is accomplished by an
implicit finite difference solution of the dynamic wave equations
for nonsteady gradually varied open channel flow (Saint-Venant
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equations). The friction slope is defined by Manning's equation.
The solution considers upstream and downstream flow control,
backwater, and flow reversal. The model, however, appears to
assume free outfall at the downstream end of the pipe string and
does not simulate special flow control and diversion structures.
Computer Program
The computer program is written for a CDC 3600 and consists of
two main programs. The first is used to compute synthetic hourly
rainfall for each subcatchment from recorded rainfall and the
second routes the combined wastewater flow from several sub-
catchments through a single string of pipes. Details of the
program, such as computer language, number of statements, and
estimates of computer running times, are not published. The
computer program is available but a user's manual has not been
written.
Computer output includes rainfall intensities for each subcatch-
ment and discharges and depths at selected points of the pipe
string.
Evaluation
The University of Massachusetts Combined Sewer Control Simula-
tion Model is of interest since it includes the continuous genera-
tion of hourly synthetic rainfall and the only implicit solution
of the Saint-Venant equations for circular pipes among the gen-
erally available models. These two features merit consideration
for incorporation into more comprehensive sewerage system models.
The implicit flow routing scheme would require extensive modifica-
tion and expansion, however, to include special boundary conditions
not considered in the present version. To be more generally
applicable, a model would have to simulate a network of sewers,
diversion and flow control structures, and storage facilities.
The computation of runoff using hourly values restricts the model
to the evaluation of large systems where rainfall-runoff response
times are accordingly long. The addition of a runoff model for •
pervious areas, the consideration of a time lag between the occur-
rence of rainfall and its resulting runoff and the simulation of
evapotranspiration and snow accumulation and melt would be necess-
ary to make the model a truly continuous simulation model.
The model has not been tested with real catchment data. Testing
with hypothetical and experimental pipe data was inadequate to
indicate model accuracy. The testing indicated, however, that
the matching of hourly runoff computations with the implicit
dynamic flow routing technique is practical, since the routing
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technique allows equally long time steps provided they do not
obscure significant runoff peaks of shorter duration. This
limitation would make the model most useful for the simulation
of large catchments and sewer pipes, such as the lumping of
smaller subcatchments to compute inflows and routing only in
major trunk and interceptor sewers without the need to simulate
every block and lateral sewer.
WATER RESOURCES ENGINEERS STORMWATER MANAGEMEiSFT MODEL
Summary
The Stormwater Management Model of Water Resources Engineers,
Inc. (WRE) is a modified version of the Stormwater Management
Model of the U.S. Environmental Protection Agency. It simulates
the time-varying combined storm and sanitary runoff and waste-
water quality of several catchments and a sewer and open channel
network, including loops and converging and diverging branches
(Shubinski and Roesner, 1973).
The flow routing procedure is based on the dynamic wave equations
which consider backwater, flow reversal and both upstream and
downstream flow control. A special formulation is built in for
the solution of surcharging and pressure flow. The solution is
coupled with the hydraulic equations for flow control and diver-
sion structures considering both upstream and downstream flow
conditions. The model simulates overflow storage basins but
not in-line storage facilities.
Both dry-weather and Stormwater quality are computed for six
constituents: suspended solids, settleable solids, biochemical
oxygen demand, nitrogen, phosphorus, and oil and grease. The
pollutants are routed through the sewer system but treatment
processes are not modeled. A separate model for simulating
both flow and quality in receiving waters is available (Chen
and Orlob, 1972).
The model does not include real-time control and design features
and is limited to the simulation of single runoff events. The
model has been released to the City of San Francisco and is in
the public domain.
The WRE Stormwater Management Model includes the following
features:
1. dry-weather flow and quality of several catchments
from land use;
2. several rainfall records;
3. Stormwater runoff and quality for pervious and
impervious areas of several catchments;
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4. six water quality constituents: suspended solids,
settleable solids, biochemical oxygen demand,
nitrogen, phosphorus, and oil and grease;
5. BOD concentrations of stormwater runoff dependent
on suspended and settleable solids runoff;
6. contribution of catchbasins to stormwater quality;
7. routing of combined wastewater flow and quality in
a network of loops and converging and diverging
branches;
8. five closed conduit cross-sections and trapezoidal
open channel;
9. backwater, upstream and downstream flow control,
flow reversal, surcharging, and pressure flow;
10. weir, gate, and orifice control and diversion
structures considering both upstream and downstream
flow conditions;
11. pumping stations; and
12. overflow storage basins.
The model does not include the following features:
1. evapotranspiration;
2. snow accumulation and melt;
3. catchment moisture balance during periods of no
precipitation;
4. flow routing in gutters;
5. water quality decay, reactions and interactions in
the sewers and in storage;
6. real-time control;
7. design; and
8. costs.
Methods
Average values of dry-weather flow and concentrations of the six
modeled water quality constituents are provided as input data
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and varied to account for time and land use differences by
internal functions. Five different land uses are considered.
Rainfall intensitites for several raingages can be provided to
compute runoff from several catchments. Only one raingage can
be assigned to a particular subcatchment. Runoff is computed
separately for pervious and impervious areas and begins after
all depression storage is filled. Horton's equation is used to
compute the potential infiltration and the actual infiltration
depends on the depth of overland flow. No adjustments are made
in the potential infiltration rates to account for changing soil
moisture conditions. Other losses, such as evapotranspiration,
are not considered.
Overland flow is computed separately for pervious and impervious
areas using the kinematic wave equation with Manning's equation.
Special formulations are built into the program to eliminate
the need to provide input data for each urban lot or block.
Larger subcatchments can be defined and data are needed only to
describe the geometry and characteristics of an average block
in each subcatchment, the number of blocks per subcatchment,
and the average length of each subcatchment. The formulation
not only simplifies data preparation, but distinguishes between
the overland flow length of lots or blocks (which influences
infiltration) and the subcatchment length (which may not influence
infiltration).
Flow routing in the sewers is accomplished with the dynamic wave
equations for nonsteady gradually varied open channel flow
(Saint-Venant equation). Manning's equation defines the energy
gradient. A special explicit finite difference solution is
used which is similar to the method first developed by WRE for
the EPA Dynamic Estuary Model (Shubinski et al., 1965). The
link-node approach solves the continuity equation at nodes
(junctions or sewer connections) and the momentum equation along
links (sewer reaches).
The solution technique considers both upstream and downstream
flow control, backwater, and flow reversal and is linked with
hydraulic equations for special sewerage system elements. This
gives the model the capability to simulate flows in converging
branch networks, diverging branches, and loops. The flow rout-
ing is formulated for circular, rectangular, horseshoe, basket-
handle, and egg-shaped closed conduits and trapezoidal open
channels.
Explicit solutions of the dynamic wave equations are simpler to
program than implicit solutions but must use very short compu-
tational time steps to remain numerically stable. As a result,
explicit solutions are faster per time step, but require more
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time steps than implicit solutions to obtain the same level of
accuracy.
Special formulations are built into the model to simulate sur-
charging and pressure flow. If surcharging occurs, the Hardy-
Cross method is used to compute the extent of surcharging and
pressure flow in the sewerage network.
Hydraulic equations are built into the model and linked with
the flow routing formulation to simulate flow control and diver-
sion structures consisting of weirs, gates, and orifices and
considering both upstream and downstream flow control. Up to
three-stage pumping stations can be simulated with the pumping
rates specified by rule curves. Overflow storage basins can
be simulated but details on their mathematical representation
were not available. Inline storage basins cannot be simulated.
The stormwater quality formulations are similar to the EPA model.
Stormwater runoff concentrations are computed for each modeled
constituent as a function of the runoff rate and account for
the rate of dirt and dust accumulation between rainstorms and
for street cleaning practices. A special formulation is included
to compute the pollutant contribution of catchbasins. The
equations contain many empirical coefficients which have been
derived from very limited data and may not be generally applic-
able. Many of the coefficients are internal to the program and
programming changes are necessary to calibrate them with measured
data.
Stormwater and dry-weather quality are combined at sewer inlets
and routed through the sewers according to the flow velocity
of the sewage. Dispersion, sedimentation and scour, water qual-
ity decay, reactions and interactions are not modeled. Numerical
dispersion may be expected as a result of the finite difference
solution of the transport equation. The model does not compute
wastewater treatment.
Real-time control, design, and cost computations are not included
in the model. Although a separate receiving water flow and qual-
ity model is used by WRE, it is not interfaced with the Storm-
water Management Model.
Computer Program
The computer program consists of three main programs which are
run sequentially. Model documentation does not describe details
of the computer program. The program is available.
Program output includes tables of discharges and water quality
for the modeled subcatchments, tables of stage, velocities,
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discharges, concentrations and mass flow rates for selected
sewer system elements, and line printer plots of stage, dis-
charge and concentrations.
Evaluation
The Stormwater Management Model is the only model which includes
a very complete formulation of sewerage system hydraulics and
the simulation of wastewater quality. It can simulate all non-
steady gradually varied flow phenomena, surcharging and pressure
flow, and the hydraulic performance of special sewerage system
facilities for complex sewerage systems including loops and con-
verging and diverging branches. The explicit solution of the
dynamic wave equation requires longer computer times than simpler
routing schemes, however, and is limited to severe stability
conditions with respect to the length of the computational time
step.
The model would be useful primarily where the consideration of
backwater, downstream flow control, flow reversal, surcharging
and flow control and diversion structures are important features
of the sewerage system assessment. If these features are not
present or are insignificant, simpler models requiring less
computer time can be used.
The model can be used only for the simulation of single runoff
events since it does not include provisions for either catchment
moisture or water quality accounting between rainstorms. A
model limitation is the absence of formulations for treatment
plants to assess the impact of sewerage system effluents on
receiving water quality.
The ability to read in typical urban block data, rather than
detailed data, for each modeled block is a major advantage.
This, coupled with the distinction between pervious area length
and catchment length, is expected to give better accuracy for
coarser catchment discretizations than is provided by models
which do not make this distinction.
Model verification with data from the 19 ha (47 acres) Northwood
catchment in Baltimore, Maryland and the 1540 ha (3800 acres)
Selby Street catchment in San Francisco shows good agreement
between measured and computed runoff. Water quality predictions
for the Selby Street catchment are of the right order of magni-
tude.
WILSEY AND HAM URBAN WATERSHED SYSTEM
Summary
The Wilsey and Ham Urban Watershed System computes the time-
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varying stormwater runoff of several catchments and a converging
branch sewerage network (Amorocho, 1972). The model does not
include provisions for dry-weather flow, water quality, and real-
time control. A design option sizes circular sewer pipes for
peak flows. The model is limited to the simulation of single
runoff events. This is a proprietary model and not all details
of the model formulations are available.
The Wilsey and Ham Urban Watershed System includes the following
features:
1. one rainfall record;
2. stormwater runoff from impervious and pervious
areas of several catchments;
3. flow routing in gutters;
4. routing of stormwater runoff in a converging
network of circular sewers; and
5. design of circular sewers.
The model does not include the following features:
1. dry-weather flow;
2. consideration of nonuniform distribution of
catchment precipitation;
3. evapotranspiration;
4. snow accumulation and melt;
5. catchment moisture balance during periods
of no precipitation;
6. flow routing in loops and diverging branches;
7. noncircular closed conduits and open channels;
8. downstream flow control, backwater, flow reversal,
surcharging and pressure flow;
9. flow control and diversion structures;
10. pumping stations;
11. storage facilities;
12. water quality;
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13. real-time control; and
14. costs.
Methods
The model does not consider dry-weather flow and computes only
stormwater runoff from one rainfall record for the entire catch-
ment. Losses are subtracted to account for interception and
infiltration from rainfall on the impervious and pervious areas
but details of the loss computations are not available. The
model includes a special feature which allows the definition
of typical urban subcatchment elements by appropriate data des-
cribing their physical characteristics. This greatly reduces the
amount of data preparation since it eliminates repetition of
data for subcatchment elements of similar characteristics.
Overland flow is routed to the gutters by an approximation of
the kinematic wave equation. A kinematic wave formulation is
also used for flow routing in standard shapes of gutters. Com-
puter time is saved by performing these computations only for
the basic catchment elements, rather than all catchment elements,
and combining the resulting runoff hydrographs in the proper
sequences as defined by their occurrence in the actual catchment.
Flow routing in a converging system of circular sewers is accom-
plished by the kinematic wave equation with Manning's equation.
A special feature routes catchbasin inflow exceeding the free
flow capacity of the sewer in the gutter to the next downstream
catchbasin. In the design mode, the sewer pipe diameter is
increased to accomodate the entire inflow under free flow con-
ditions. The model does not compute backwater, flow reversal,
surcharging and pressure flow. Costs are not considered in the
design.
Computer Program
Details of the computer program and estimates of running times
are not available. The program is written in two versions to
run on a CDC 6600 computer and on Tymshare's XDS 940 system.
The program is available under a special use agreement.
Computer output includes discharges at selected points of the
network and pipe diameters for the design option.
Evaluation
Although sufficient details are not available on the mathematical
formulations of the model, it appears to be an efficient model
for the evaluation and design of small storm sewerage networks
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for which the limitations of the flow routing scheme are accept-
able. The program can be expected to be very efficient both
with respect to input data preparation and computer running
times due to its special features for the standardization of
typical subcatchment elements.
The model has been applied extensively by Wilsey and Ham for
storm sewerage system evaluations and design. Testing of the
model with real catchment data to evaluate its accuracy has not
been reported.
OTHER MODELS
Documentation was received too late for a detailed review of
several models. A brief description of each model is given
below, model documentation is listed in Section IX - References,
and addresses of the model developers are given in Appendix A -
List of Sources of Computer Programs.
Chicago Runoff and Pollution Model
The Chicago Runoff and Pollution Model was developed by the
City of Chicago Department of Public Works for the continuous
simulation of the time-varying runoff and water quality in
combined sewerage systems consisting of several catchments and
a converging branch sewer and open channel network (City of
Chicago, 1972). The model can simulate periods of several
years using 1-hour time steps. The model can simulate sur-
charging and diversion structures. Water quality simulations
include the computation of biochemical oxygen demand and sus-
pended solids as functions of storm runoff, the consideration
of dry-weather flow and quality (provided as input data), the
computation of water quality improvement by treatment (as
tabular function of flow), and catchment water quality balance
between rainstorms. The model does not include real-time con-
trol, design, and cost computations. The rainfall-runoff and
flow routing portions of the model use methods included in the
computer version of the Chicago Hydrograph method. A separate
model is available for nonsteady receiving water flow and
quality simulation.
The computer program is written in Fortran IV for IBM 1130 and
IBM 370/158 computers. The program and a draft user's manual
is available. The program has been tested and applied.
CH2M-HJ11 Wastewater Collection System Analysis Model
The CH2M-Hill Wastewater Collection System Analysis Model
simulates the time-varying runoff in a combined sewerage sys-
tem consisting of several catchments and a converging branch
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sewer and open channel network with special structures such
as diversions and pumping stations (O'Neal et al., 1974). The
model is based on formulations of the U.S. Environmental Pro-
tection Agency Stormwater Management Model, but was adapted to
run on small computers. Present versions operate on an IBM
1130 and a DEC PDP-10. Water quality and receiving water
simulation is not included at present. The model is being
tested with data from the City of Portland, Oregon.
Dorsch Consult Quantity-Quality Simulation Program
The Dorsch Consult Quantity-Quality Simulation Program is
intended for single event or continuous simulation of the
time-varying runoff and water quality in combined sewerage
systems consisting of several catchments and a closed conduit
and open channel network including loops and converging and
diverging branches (Geiger, 1975). Both runoff and water
quality concentrations from catchment areas are calculated
by a unit hydrograph method, considering different land uses
including residential, commercial, industrial, and mixed. The
flow routing through the sewerage network is based on the
dynamic wave equations. Statistical analyses are incorporated
to provide monthly and annual flow and pollutant duration
curves for any node in the network. Four conservative water
quality constituents can be routed.
Catchment runoff quality formulations are currently for bio-
chemical oxygen demand and settleable solids. Formulations
are also planned for carbonaceous oxygen demand, suspended
solids, coliform bacteria, chloride, and nutrients. The model
does not include real-time control, design and cost compu-
tations.
The computer program is written in Fortran IV for a UNIVAC 1108
computer and accepts both English and metric units of measure-
ments. The program has been tested and applied. This is a
proprietary program of Dorsch Consult Ingenieurgesellschaft
mbH of Munich, Germany. A North American office is maintained
in Toronto, Canada.
A more detailed description provided by Dorsch Consult is
included in Appendix E - Additional Model Test Results. It
also includes water quality routing results for the hypothe-
tical pipe data described in Section VI - Test Data.
Illinois State Water Survey Urban Drainage Area Simulator
The Illinois State Water Survey Urban Drainage Area Simulator
was developed by the Illinois State Water Survey for single-
event simulation of time-varying runoff in combined sewerage
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systems consisting of several catchments and a converging
sewer and open channel network (Terstriep and Stall, 1974).
The model is based on a computer version of the British Road
Research Laboratory Model, but computes also the runoff from
pervious areas and includes the option to either size circular
sewers or retention basins. The design option is based on
hydraulic considerations alone and does not consider costs.
The model does not include real-time control and water quality
computations.
The computer program is written in Fortran IV for an IBM 360/75
computer. It has been tested extensively. The program and a
user's manual are available.
Norwegian Institute for Water Research Sewerage System Models
The Norwegian Institute for Water Research developed four com-
puter models for the evaluation of flows and water quality in
combined sewerage systems: a sewer network, treatment plant,
sludge treatment, and economic model (Lindholm, 1972 and 1974).
The sewer network model computes the single-event or continuous
(to one year) runoff and biochemical oxygen demand from several
catchments and routes them through a converging branch sewerage
system with diversions, pumping stations and storage facilities
The program computes also the sizes of sewers required to pre-
vent surcharging, and the cost of the entire sewerage network.
The sewage treatment plant model computes the removal of BOD
and phosphorus for five unit processes, which can be arranged
in different configurations, using empirical relationships.
The model is run in conjunction with the sewer network model
to determine optimal combinations of storage and treatment
using a trial-and-error procedure.
Capital and operating costs are computed in the sewer network
and treatment plant model and the separate cost-analysis model.
Detailed descriptions of the sludge treatment and cost-analysis
model and information on model testing with measured data were
not available. The computer programs are written in Fortran
IV for a UNIVAC 1108 computer.
Queen's University Urban Runoff Model
The Queen's University Urban Runoff Model simulates the time-
varying runoff in a combined sewerage system consisting of
several catchments and a converging sewerage network (Watt,
1975). Runoff is computed from rainfall with the unit-hydro-
graph method, and routed through the sewers with a simple
time-offset method using Manning's equation. Special sewerage
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system structures and water quality are not simulated. The
model does not include real-time control, design, and cost
features. The program has been tested with real catchment
data.
University of Nebraska Urban Hydrologic Simulator
The University of Nebraska Urban Hydrologic Simulator computes
the time-varying runoff from several catchments and routes them
through a converging closed conduit network (Surkan, 1973;
and Surkan and Kelton, 1974). The model assumes that storm
runoff is a constant fraction of the rainfall, and that pipe
flow velocities are a linear function of distance only. Special
sewerage network structures, water quality, real-time control,
design, and cost features are not included. The model has been
tested with real catchment data. The program is written in
Fortran IV. The program and user's instructions are available.
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SECTION VI
TEST DATA
CONTENTS
Page
Introduction 131
Hypothetical Data 132
Hypothetical Catchment Data 133
Hypothetical Pipe Data 145
Real Catchment Data 164
Description of the Oakdale Avenue
Catchment 164
Monitoring System of the Oakdale Avenue
Catchment 169
Rainfall and Runoff Data of the Oakdale
Avenue Catchment 169
Description of the Bloody Run Catchment 194
Monitoring System of the Bloody Run
Catchment 201
Rainfall and Runoff Data of the Bloody
Run Catchment 201
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INTRODUCTION
For purposes of comparing model performance, numerical testing
of the seven most comprehensive models was conducted in this
study using both hypothetical and real catchment data. The
purpose of the testing was to show that different models with
different mathematical formulations for the same phenomena will
produce differing results given the same input data. The test-
ing consequently provides useful information to the model user
by indicating ranges of applicability for each model. Most of
the models reviewed were tested and verified by the model
developers and subsequent model users on very limited data
because sufficiently complete and reliable urban catchment,
precipitation, runoff, and water quality data were unavailable.
Quite commonly, only portions of a model were tested on measured
data. Sometimes different portions of a model were tested with
data from different catchments since comprehensive data were
not available from a single catchment, especially when both
flow and quality data were required, and only in rare instances
were two or more models tested on the same data. Testing with
the hypothetical data shows the sensitivity of each model to
model parameter variations, while testing with real catchment
data provides information on model accuracy as well.
The reviewed models require widely varying detail with respect
to the spatial discretization of data describing the catchment
and sewerage system. Some models require extremely detailed
information (such as sizes and slopes of individual roofs,
driveways, lawns, gutters, etc.) while others can lump areas
of several hundred acres into single subcatchments. Great
differences exist also between the models with respect to the
required time discretization for precipitation, runoff and
water quality data and simulation time steps. Some models
require time steps of less than one minute to satisfy numerical
stability conditions, while others can be run with hourly or
daily data.
The model testing with real catchment data required the collec-
tion of available data on urban catchment and sewer system
characteristics, precipitation, runoff, and wastewater quality.
A large number of data sources were investigated and data for
several U.S. cities were collected. Selected data were digi-
tized in the computer formats required by the models being
tested. It became rather difficult, however, to find real
catchment data which provided sufficient detail to satisfy the
input data requirements of all models. Additional difficulties
which were encountered included missing information on physical
characteristics of the subcatchments and sewerage systems,
uncertainties in watershed infiltration characteristics and
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moisture conditions, insufficient documentation of the instru-
mentation and data analysis techniques used during the measure-
ment periods, and uncertainties in the accuracy of the measured
rainfall, runoff, and water quality data.
Great reluctance was expressed by model developers, therefore,
to run real catchment data whose accuracy was uncertain and
over whose collection they had no control. The use of hypo-
thetical data eliminated these uncertainties. Consequently,
the model testing concentrated on hypothetical data. All
seven models were tested with the same set of hypothetical data
but only the Battelle, Chicago Flow Simulation, EPA Stormwater
Management and Dorsch models were also tested on the same set
of real catchment data.
The numerical testing concentrated on the most common features
of the selected models, the rainfall-runoff simulations and the
flow and quality routing. Special features such as snowmelt,
the simulation of treatment processes, real-time control and
design aspects were not tested. The hypothetical data testing
was applied separately to the rainfall-runoff formulations and
the routing procedures to examine the response of the formula-
tions of each phenomenon to physical parameter variations.
Testing with the real catchment data served the objectives of
testing the interactions of the runoff computations for several
catchments and the routing of flows and quality through a sewer
network.
This section lists the selected test data. The results of test-
ing seven models by computer runs with these data are described
in the following section.
HYPOTHETICAL DATA
The hypothetical data runs were not intended to portray accuracy
but to determine the sensitivity of the models to parameter
variations. The data were also selected with the objective of
determining limits of applicability of the models, such as the
ability to handle surcharging and backwater conditions. In
addition, the hypothetical data runs provided information on
the cost of running each model.
Two independent sets of hypothetical data were used. One set
tests the rainfall-runoff relationship for various catchment
conditions. The second set tests the sewer flow routing (and
water quality routing, if applicable) for various combinations
of pipe parameters.
132
-------
Hypothetical Catchment Data
The data selected for the hypothetical catchment tests represent
two different catchment sizes, two orientations of each catchment,
ten combinations of physical catchment characteristics, two
different antecedent conditions and four different rainstorms.
This makes a total of 320 data combinations.
The selected catchment dimensions are given in Table 6. The
drainage areas of 0.465 and 4.65 ha (1.115 and 11.5 acres)
represent a range of common sizes generally used by the tested
models to simulate urban subcatchments. Although some models
use smaller discretizations and others can simulate several
hundred acres as a single subcatchment, these sizes are repre-
sentative of most model requirements. Rectangular shapes were
selected since most models require this approximation for the
overland flow routing on irregularly shaped catchments.
Length-to-width ratios of 1:2 and 2:1, respectively, were
selected for the catchments. These represented two orientations
of the flow (as shown in Figure 1) to test the effect of the
catchment shape approximation on the shape of the runoff hydro-
graph. The dimensions were 48.2 x 96.4 m (158 x 316 ft) for
the small catchments and 152.4 x 304.8 m (500 x 1000 ft) for
the large catchments.
The physical catchment characteristics selected are listed in
Table 7. Five different ratios of pervious and impervious areas
were chosen, ranging from completely pervious to completely
impervious (0, 25, 50, 75, and 100 percent imperviousness),
to test the effect of correctly estimating this catchment
property on the runoff hydrographs and to test the relative
importance of the contribution of runoff from pervious and
Table 6. HYPOTHETICAL SUBCATCHMENT DIMENSIONS
Shape
number
1
2
3
4
Length
m
96
48
304
152
.4
.2
.8
.4
ft
316
158
1000
500
m
48
96
152
304
Width
.2
.4
.4
.8
ft
158
316
500
1000
0.
0.
4.
4.
Area
ha
465
465
645
645
acres
1
1
11
11
.15
.15
.48
.48
Note: Length is parallel, width is perpendicular to direction
of overland flow.
133
-------
FLOW
DIRECTION
K-LENGTH-^
PLAN, ORIENTATION*?
FOR SUBCATCHMENTS
#11-20 AND 31-40
T
1
FLOW
DIRECTION
LENGTH
PLAN, ORIENTATION*!
FOR SUBCATCHMENTS
11-10 AND 21-30
Figure 1. Sketch of hypothetical
subcatchment orientations
Table 7. HYPOTHETICAL SUBCATCHMENT CHARACTERISTICS
Characteristics
Values
Subcatchment imperviousnessy percent 0, 25, 50, 75 and 100
Subcatchment slope (in direction of
flow), percent
Manning's n of pervious area
Manning's n of impervious area
Infiltration decay rate of pervious
area, seconds"!
0.1 and 10
0.25
0.025
0.001
Note: The infiltration decay rate is defined by Horton's
infiltration equation.
134
-------
impervious areas to the total catchment runoff. Catchment slopes
of 0.1 and 10 percent, representing the common range of catchment
slopes, were chosen to test the effect of overland flow routing
formulations on the runoff hydrograph. Average values of 0.025
and 0.25 for Manning's n were used for the impervious and per-
vious areas, respectively. The influence of variations in
catchment surface roughness was not tested.
Two initial conditions, representing initially dry and wet catch-
ment moisture conditions, were tested. Infiltration rates and
surface retention (depression) storage values are given in
Tables 7 and 8. The values correspond to data requirements
for Horton's infiltration equation, which is used by most models,
and the definition of surface water storage in depressions which
Table 8. INFILTRATION RATES AND RETENTION STORAGE
CAPACITIES OF HYPOTHETICAL CATCHMENTS
Dry initialSaturated initial
condition condition
Units
Maximum infiltration rate
of pervious areas
Minimum infiltration rate
of pervious areas
Maximum infiltration rate
of impervious areas
Minimum infiltration rate
of impervious areas
mm/hr
50.8
12.7
0.0
0.0
in./hr
2.0
0.5
0.0
0.0
mm/hr
12.7
12.7
0.0
0.0
in.
0
0
0
0
/hr
.5
.5
.0
.0
Units
mm
in.
mm
in.
Retention storage capacity
of pervious areas 5.1 0.20 0.0 0.0
Retention storage capacity
of impervious areas 1. 3 0 .05 0 .0 0 .0
Notes: The infiltration rates are defined by Horton's
infiltration equation. The retention storage capacities
represent the amount of rain which has to fall before
runoff begins.
135
-------
does not become surface runoff. The selected potential infiltra
tion rates for pervious areas are 50.8 mm/hr (2.0 in./hr) for
dry conditions and 12.7 mm/hr (0.5 in./hr) for saturated con-
ditions. An infiltration decay rate of 0.001 sec was chosen.
Zero infiltration was.assumed for impervious areas. The reten-
tion storage capacity is 5.1 mm (0.20 in.) for pervious and
1.3 mm (0.05 in.) for impervious areas under dry conditions.
A difficulty arises in defining the retention storage capacity
for saturated conditions as a result of model limitations.
Ideally, the models should define the potential storage capacity
independent of moisture conditions, but allow input data defin-
ing the depth of moisture in the depressions at the beginning
of the simulation. Most models, however, do not make this
distinction and a zero retention storage capacity has to be
defined for initially saturated conditions. This, however,
introduces errors into the infiltration and overland flow com-
putations in those models which consider the actual depth of
water in the depressions for these computations.
The variations in slope, imperviousness and initial conditions
result in 20 subcatchments for each size and orientation. The
data combinations for each set of 20 subcatchments are given
in Table 9. Each subcatchment was assumed to drain into an
independent manhole where the input hydrograph of each sub-
catchment was obtained. Gutter routing was not considered.
Figure 2 shows two arrangements of the sets of 20 subcatchments
for simulation purposes. Deviations from this arrangement were
required, however, to meet specific model requirements and
limitations.
Four hypothetical rainstorms were used to test the response of
the selected models to different durations and intensities of
rainfall. One rainstorm represented a constant rainfall of
25.4 mm/hr (1.0 in./hr) intensity and 2 hr duration; the remain-
ing three were triangular rainstorms of 1, 2, and 4 hr duration
and 101.6, 50.8, and 25.4 mm/hr (4, 2, and 1 in./hr) peak inten-
sity, respectively. The four rainstorms had a total rainfall
of 50.8 mm (2 in.). A summary of the rainfall data is presented
in Table 10 and the rainfall intensity and cumulative rainfall
hyetographs are shown in Figures 3 and 4. A time step of
5 minutes was suggested for the simulation runs and both inten-
sities and cumulative values are tabulated in Tables 11 to 14
in response to different input requirements by different models.
The effect of different time discretizations was not tested.
136
-------
Table 9. HYPOTHETICAL CATCHMENT DATA COMBINATIONS
UJ
Subcatchment
number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Length
m
152.4
152.4
152.4
152.4
152.4
152.4
152.4
152.4
152.4
152.4
304.8
304.8
304.8
304.8
304.8
304.8
304.8
304.8
304.8
304.8
ft
500
500
500
500
500
500
500
500
500
500
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
Width
m
304.8
304.8
304.8
304.8
304.8
304.8
304.8
304.8
304.8
304.8
152.4
152.4
152.4
152.4
152.4
152.4
152.4
152.4
152.4
152.4
ft
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
500
500
500
500
500
500
500
500
500
500
Area
ha
4.645
4.645
4.645
4.645
4.645
4.645
4.645
4.645
4.645
4.645
4.645
4.645
4.645
4.645
4.645
4.645
4.645
4.645
4.645
4.645
acres
11.48
11.48
11.48
11.48
11.48
11.48
11.48
11.48
11.48
11.48
11.48
11.48
11.48
11.48
11.48
11.48
11.48
11.48
11.48
11.48
Slope ,
percent
0.1
0.1
0.1
0.1
0.1
10.0
10.0
10.0
10.0
10.0
0.1
0.1
0.1
0.1
0.1
10.0
10.0
10.0
10.0
10.0
Imperviousness ,
percent
0
25
50
75
100
0
25
50
75
100
0
25
50
75
100
0
25
50
75
100
-------
Table 9 (Continued). HYPOTHETICAL CATCHMENT DATA COMBINATIONS
00
Subcatchment
number
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Length
m
48.2
48.2
48.2
48.2
48.2
48.2
48.2
48.2
48.2
48.2
96.4
96.4
96.4
96.4
96.4
96.4
96.4
96.4
96.4
96.4
ft
158
158
158
158
158
158
158
158
158
158
316
316
316
316
316
316
316
316
316
316
Width
m
96.4
96.4
96.4
96.4
96.4
96.4
96.4
96.4
96.4
96.4
48.2
48.2
48.2
48.2
48.2
48.2
48.2
48.2
48.2
48.2
ft
316
316
316
316
316
316
316
316
316
316
158
158
158
158
158
158
158
158
158
158
Area
ha
0.465
0.465
0.465
0.465
0.465
0.465
0.465
0.465
0.465
0.465
0.465
0.465
0.465
0.465
0.465
0.465
0.465
0.465
0.465
0.465
acres
1.15
1.15
1.15
1.15
1.15
1.15
1.15
1.15
1.15
1.15
1.15
1.15
1.15
1.15
1.15
1.15
1.15
1.15
1.15
1.15
Slope,
percent
0.1
0.1
0.1
0.1
0.1
10.0
10.0
10.0
10.0
10.0
0.1
0.1
0.1
0.1
0.1
10.0
10.0
10.0
10.0
10.0
Imperviousness,
percent
0
25
50
75
100
0
25
50
75
100
0
25
50
75
100
0
25
50
75
100
-------
11
12
13
14
1^
16
17
18
19
20
1 — *-
2 »-
3 ^
4 — •-
5 ^
6 •"
7 — *~
8 — *-
9 — *-
10 — ^
1/1
z
o
o
z
o
o
s
s
CATCHM
SIMILAR ARRANGEMENT
FOR SUBCATCHMENTS *21 - 40
ARRANGEMENT #1
11
12
13
14
15
16
1Z-
18
19
20
11
12
13
14
15
16
17
18
19
20
NOTE: NOT NECESSARY TO
MODEL GUTTERS
ON
AL C
2 E
CATCHM
AL CONDITIONS
SUBCATCHMENTS 1-10 WITH DRY INIT
1 *-
2 *-
i
3 *-
4 *-
5 »•
6 ^
7 *-
8 *-
9 *-
10 >•
-» 1
-« 2
-i — 3
-« 4
-* 5
-« 6
-« 7
-« 8
-« 9
-* — 10
1=1
z
o
o
e
<
<
o
CATCHMENT #1 WITH
SUBCATCHMENTS 1-10
SIMILAR ARRANGEMENT FOR
CATCHMENT #2 WITH
SUBCATCHMENTS 21-30
CATCHMENT #2 WITH
SUBCATCHMENTS 11-20
SIMILAR ARRANGEMENT FOR
CATCHMENT 14 WITH
SUBCATCHMENTS 31-40
ARRANGEMENT 02
Figure 2. Suggested arrangements of hypothetical
subcatchments for computer runs
139
-------
Table 10., SUMMARY OF RAINSTORMS FOR HYPOTHETICAL CATCHMENTS
Storm
number Shape
Rainfall
duration,
hours
Maximum
intensity
Total
rainfall
mm/hr in.'/hr
mm
in.
1
2
3
4
Constant
Triangle
Triangle
Triangle
2
1
2
3
25.4 1.0 50.8 2.0
101.6 4.0 50.8 2.0
50.8 2.0 50.8 2.0
25.4 1.0 50.8 2.0
140
-------
L
1
0
2^
1
n
V~T~ ' ' ' 1 1 1 V
RAINSTORM #1
A 1 I 1 A
V V
^ RAINSTORM #2
\\jr
1 \ .RAINSTORM #3
I \ /
1 ,\\f RAINSTORM #4
l/\.\ -.../ A
A 16-- ( \ \ " I 1 A.
3U.O
25.4
"E
E
- 50.8 £
25.4
n
0 v 9 10 11 12 13 14 15 24
TIME, HOURS
Figure 3. Hypothetical catchment hyetographs
(rain intensities)
i i i i i i
RAINSTORM #1
- RAINSTORM #2
RAINSTORM #3
RAINSTORM 14
0 9 10 11 12 13 14 15 24
Figure 4. Hypothetical catchment hyetographs
(cumulative rain)
141
-------
Table 11. TWO-HOUR CONSTANT RAINSTORM
FOR HYPOTHETICAL CATCHMENTS
Time
step
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Clock time
hr :min
10:00
10:05
10:10
10:15
10:20
10:25
10:30
10:35
10:40
10:45
10:50
10:55
11:00
11:05
11:10
11:15
11:20
11:25
11:30
11:35
11:40
11:45
11:50
11:55
12:00
12:05
Rain
mm/hr
0.0
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
0.0
intensities
in./hr
0.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
l.oO
1.00
1.00
1.00
0.00
Cumulative
mm
0.0
2.1
4.2
6.4
8.5
10.6
12.7
14.8
16.9
19.1
21.2
23.3
25.4
27.5
29.6
31.8
33.9
36.0
38.1
40.2
42.3
44.5
46.6
48.7
50.8
50.8
rain
in.
0.00
0.08
0.17
0.25
0.33
0.42
0.50
0.58
0.67
0.75
0.83
0.92
1.00
1.08
1.17
1.25
1.33
1.42
1.50
1.58
1.67
1.75
1.83
1.92
2.00
2.00
Note: Intensities represent averages for time interval
preceding indicated clock time.
Table 12. ONE-HOUR TRIANGULAR RAINSTORM
FOR HYPOTHETICAL CATCHMENTS
Time
step
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Clock time
hr :min
10:00
10:05
10:10
10:15
10:20
10:25
10:30
10:35
10:40
10:45
10:50
10:55
11:00
11:05
Rain
mm/hr
0.0
8.5
25.4
42.3
59.3
76.2
93.1
93.1
76.2
59.3
42.3
25.4
8.5
0.0
intensities
in./hr
0. 00
0.33
1.00
1.67
2.33
3.00
3.67
3.67
3.00
2.33
1.67
1.00
0.33
0.00
Cumulative
mm
0.0
0.7
2.8
6.4
11.3
17.6
25.4
33.2
39.5
44.5
48.0
50.1
50.8
50.8
rain
in.
0.00
0.03
0.11
0.25
0.45
0.70
1.00
1.31
1.56
1.75
1.89
1.97
2.00
2.00
Note: Intensities represent averages for time interval
preceding indicated clock time.
142
-------
Table 13. TWO-HOUR TRIANGULAR RAINSTORM
FOR HYPOTHETICAL CATCHMENTS
Time
step
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Clock time
hr :min
10:00
10:05
10:10
10:15
10:20
10:25
10:30
10:35
10:40
10:45
10:50
10:55
11:00
11:05
11:10
11:15
11:20
11:25
11:30
11:35
11:40
11:45
11:50
11:55
12:00
12:05
Rain
mm/hr
0.0
2.1
6.4
10.6
14.8
19.1
23.3
27.5
31.7
36.0
40.2
44.4
48.7
48.7
44.4
40.2
36.0
31.7
27.5
23.3
19.1
14.8
10.6
6.4
2.1
0.0
intensities
in./hr
0.00
0.08
0.25
0.42
0.58
0.75
0.92
1.08
1.25
1.42
1.58
1.75
1.92
1.92
1.75
1.58
1.42
1.25
1.08
0.92
0.75
0.58
0.42
0.25
0.08
0.00
Cumulative rain
mm
0.0
0.2
0.7
1.6
2.8
4.4
6.4
8.6
11.3
14.3
17.6
21.3
25.4
29.5
33.2
36.5
39.5
42.2
44.5
46.4
48.0
49.2
50.1
50.6
50.8
50.8
in.
0.00
0.01
0.03
0.06
0.11
0.17
0.25
0.34
0.44
0.56
0.69
0.84
1.00
1.16
1.31
1.44
1.56
1.66
1.75
1.83
1.89
1.94
1.97
1.99
2.00
2.00
Note: Intensities represent averages for time interval
preceding indicated clock time.
143
-------
Table 14. FOUR-HOUR TRIANGULAR RAINSTORM
FOR HYPOTHETICAL CATCHMENTS
Time
step
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Clock time
hr :min
10:00
10:05
10:10
10:15
10:20
10:25
10:30
10:35
10:40
10:45
10:50
10:55
11:00
11:05
11:10
11:15
11:20
11:25
11:30
11:35
11:40
11:45
11:50
11:55
12:00
12:05
12:10
12:15
12:20
12:25
12:30
12:35
12:40
12:45
12:50
12:55
13:00
13:05
13:10
13:15
13:20
13:25
13:30
13:35
13:40
13.45
13:50
13:55
14:00
14:05
Rain intensities
mm/hr
0.0
0.5
1.6
2.6
3.7
4.8
5.8
6.9
7.9
9.0
10.1
11.1
12.2
13.2
14.3
15.3
16.4
17.5
18.5
19.6
20.6
21.7
22.8
23.8
24.9
24.9
23.8
22. 8
21.7
20.6
19.6
18.5
17.5
16.4
15.3
14.3
13.2
12.2
11.1
10.2
9.0
7.9
6.9
5.8
4.8
3.7
2.6
1.6
0.5
0.0
in./hr
0.00
0.02
0.06
0.10
0.15
0.19
0.23
0.27
0.31
0.35
0.40
0.44
0.48
0.52
0.56
0.60
0.65
0.69
0.73
0.77
0.81
0.85
0.90
0.94
0.98
0.98
0.94
0.90
0.85
0.81
0.77
0.73
0.69
0.65
0.60
0.56
0. 52
0.48
0.44
0. 40
0.35
0.31
0.27
0.23
0.19
0.15
0.11
0.06
0.02
0.00
Cumulative rain
mm
0.0
0.0
0.2
0.4
0.7
1.1
1.6
2.2
2.8
3.6
4.4
5.3
6.4
7.5
8.6
9.9
11.3
12.7
14.3
15.9
17.6
19.4
21.3
23.3
25.4
27.5
29.5
31.4
33.2
34.9
36.5
38.1
39.5
40.9
42.2
43.3
44.5
45.5
46.4
47.2
48.0
48.6
49.2
49.7
50.1
50.4
50.6
50.8
50.8
50.8
in.
0.00
0.00
0.01
0.02
0.03
0.04
0.06
0.09
0.11
0.14
0.17
0.21
0.25
0.29
0.34
0.39
0.44
0.50
0.56
0.63
0.70
0.77
0.84
0.92
1.00
1.08
1.16
1.23
1.31
1.37
1.44
1.50
1.56
1.61
1.66
1.71
1.75
1.79
1.83
1.86
1.89
1.91
1.94
1.96
1.97
1.98
1.99
2.00
2.00
2.00
Note: Intensities represent averages for time interval
preceding indicated clock time.
144
-------
Hypothetical Pipe Data
The data selected for the hypothetical pipe tests represent
two different pipe diameters and three invert slopes. In addi-
tion, two types of upstream and downstream boundary conditions
were specified. The first assumes free inflow into the upstream
end of the pipes and free outfall at the downstream end. The
second assumes a storage tank at the upstream end of the pipe
and a diversion structure at the downstream end. Four inflow
hydrographs, each with three inflow quality constituents, were
specified for the flow and water quality routing. This makes
a total of 48 data combinations.
The hypothetical pipe dimensions are given in Table 15. The
pipe diameters of 0.61 and 3.66 m (2 and 12 ft) represent circu-
lar pipe sizes normally encountered in sewerage networks which
may be analyzed by dynamic mathematical models. Three slopes
(0.05, 0.5 and 5 percent) were selected to represent average
and extreme values. Only one value of surface roughness repre-
sented by a Manning's n of 0.01 was tested. The pipe is 3048 m
(10,000 ft) long to provide sufficient length to adequately
show the effect of different routing schemes on the hydrograph
shapes.
The selected pipe boundary conditions are summarized in Table 16
and a schematic for the second boundary condition (upstream
storage tank and downstream regulator) is shown in Figure 5. The
axis of the pipe is at the elevation of the bottom of the storage
tank; that is, the bottom half of the pipe continues through the
storage tank. The diameter of the storage tank is twice that of
the pipe. The depth of the storage tank is 3.35 m (11 ft) for
the small pipe and 7.92 m (26 ft) for the large pipe. The top
of the tank is assumed to be at ground level.
The diversion structure represents a typical overflow regulator.
It consists of an overflow weir with a height equal to the pipe
radius and a dry-weather orifice outlet with a diameter equal
to the pipe radius. The elevation of the orifice invert is at
Table 15.
Characteristic
Diameter
Length
Slope
Manning ' s n
HYPOTHETICAL PIPE DIMENSIONS
0.61
3048
0.05
0.01
Dimensions
and 3.66 m (2 and 12
m (10,000 ft)
, 0.5 and 5 percent
ft)
145
-------
Table 16. HYPOTHETICAL PIPE BOUNDARY CONDITIONS
Boundary Condition #1
Upstream boundary: free inflow without time delay or
energy loss.
Downstream boundary: free outfall.
Boundary Condition #2
Upstream boundary: open circular storage tank with the
following characteristics:
Tank diameter = twice pipe diameter
Tank height = 3.35 m for 0.61 m pipe
(11 ft for 2 ft pipe)
Tank height = 7.92 m for 3.66 m pipe
(26 ft for 12 ft pipe)
Elevation of
tank bottom = elevation of pipe axis (bottom half of
pipe continues through storage tank)
Elevation of
tank top = ground elevation
Assume orifice discharge from tank into pipe according to
orifice equation (or equivalent):
Q = C A (2g H)1/2 (1)
where
Q = orifice discharge in m /sec or cfs
C = 0.60 = orifice discharge coefficient
(non-dimensional)
A = orifice flow area (cross sectional area of
flow through orifice) in m2 or ft2
g = acceleration of gravity = 9.81 m/sec2
(32.2 ft/sec2)
H = depth of water in tank in m or ft
above centroid of orifice flow area
146
-------
Table 16 (Continued). HYPOTHETICAL PIPE BOUNDARY CONDITIONS
Downstream boundary: regulator consisting of weir and
circular orifice immediately upstream of weir, both with
free outfall with the following characteristics:
Weir height = 1/2 pipe diameter
Orifice diameter = 1/2 pipe diameter
Elevation of
orifice invert = elevation of pipe invert
Assume orifice discharge according to orifice equation
(or equivalent) as defined by equation (1) above.
Assume weir discharge according to weir equation (or
equivalent):
Q = C A H1/2 (2)
where
3
Q = weir discharge in m /sec or cfs
1/2
C = weir discharge coefficient = 1.66 m /sec
(3.00 ft1/2/sec)
- 2
A = cross-sectional area of flow over weir in m^ or ft
H = depth of flow above weir in m or ft
147
-------
00
GROUND
SURFACE
\
OPEN
CIRCULAR
STORAGE
TANK
SECTION A-A
D = DIAMETER OF
CIRCULAR PIPE
FLOW
DIRECTION
•• —
PIPE LENGTH
ORIFICE
SECTION B-B
Figure 5. Sketch of hypothetical pipe for boundary condition
(sketch shows upstream storage tank and downstream
regulator as specified for boundary condition #2;
free inflow into and outflow from pipe is assumed
for boundary condition #1)
#2
-------
the elevation of the pipe invert. The orifice is located
directly upstream of the weir. Free outfall is assumed for
the flow passing the orifice and weir. Provided the tested
models included the computation of diversions and the appro-
priate hydraulic equations, the orifice discharge was defined
by the common orifice discharge equation (1) and the weir dis-
charge by the common weir equation (2) as given in Table 16.
The orifice discharge coefficient was assumed to be 0.60 and
the weir discharge coefficient 1.66 ml/2/sec (3.00 ft^/^/sec).
The flow area in equation (2) is defined as the actual cross-
sectional area of flow above the weir crest given by the flow
depth and the circular shape of the pipe. Most models, however,
approximate the flow area by a rectangle of width equal to the
width of the weir crest.
The dimensions of the storage tanks and diversion structures
were selected in a manner which would produce complete filling
of the tank and overflow at the top of the tank for certain
inflow hydrographs. If overflow occurred, it was assumed that
the excess flow was lost and did not return to the pipe after
recession of the water level below the tank top.
The variations in pipe diameter, slope, and boundary conditions
result in 12 different pipe combinations which were arranged
for simulation purposes as shown in Figure 6. Deviations from
this arrangement were required, however, to meet specific model
requirements and limitations. A summary of hypothetical pipe
capacities for each combination, including maximum, full,
90 percent and 9 percent of full pipe flow, is given in Table 17,
The discharge values were computed with Manning's equation. The
data combinations for each pipe are summarized in Table 18.
Four inflow hydrograph shapes were selected to test the various
model routing schemes. They represent a continuous constant
inflow equal to 90 percent of full pipe flow and three triangu-
lar inflow hydrographs of 1, 2, and 4 hr durations. The tri-
angular inflow hydrographs have a peak flow of 90 percent of
full pipe flow and a constant flow before and after the tri-
angular inflow equal to 10 percent of peak flow (9 percent of
full flow). These inflow hydrographs are summarized in
Table 19 and the hydrograph shapes are shown in Figure 7. The
beginning time of the triangular inflow hydrographs was set at
10:00 a.m. for models which require the input of clock times.
Three conservative inflow water quality constituents were
specified for each inflow hydrograph to test the water quality
routing schemes of the models. The testing of the water quality
routing assumed pure convection. Hydrodynamic dispersion,
decay, reactions and interactions were not tested. The inflow
qualities were assumed to represent a continuous constant con-
centration of 100 mg/1, a triangular shape with a peak concen-
tration of 100 mg/1 and zero concentration before and after
149
-------
PIPE 1
INFLOW MANHOLE 1 O K> JUNCTION MANHOLE 1
^ 2 O
LU o;
!ti 3
=*= z
z o
O O
PIPE?
7C* O 7
)3
S o
§3
O 8
S7 Q
CNJ i i UJ
=#= LU a;
^- £ l-1-1
09 lit
O
CQ
6 o
11 <
10
•o 10
O i—
QQ CO
•o n
126^ ^—o
12
Figure 6. Suggested arrangement of hypothetical
pipes for computer runs (it may not be
necessary to model connecting pipes)
150
-------
Table 17. HYPOTHETICAL PIPE CAPACITIES
Discharge
Pipe
number
1,2
3,4
5,6
7,8
9,10
11,12
Diameter
m
0.81
0.81
0.81
4.86
4.86
4.86
ft
2
2
2
12
12
12
Slope,
percent
0.05
0.50
5.00
0.05
0.50
5.00
Maximum
m3/sec
0.202
0.638
2.017
23.973
75.477
239.730
cfs
7.12
22.52
71.21
846.50
2665.15
8465.03
Full
m^/sec
0.187
0.590
1.867
22.197
70.194
221.972
cfs
6.59
20.85
65.94
783.80
2478.59
7837.99
Q! = 90%
m^/sec
0.168
0.532
1.681
19.977
63.174
199.775
of full
cfs
5.94
18.77
59.35
705.41
2230.73
7054.19
Q2 = 9%
m^/sec
0.017
0.053
0.168
1.998
6.317
19.978
of full
cfs
0.59
1.88
5.94
70.54
223.07
705.42
Notes: Odd numbered pipes for boundary condition #1, even numbered pipes for boundary
condition #2. Discharges computed with Manning's equation using n = 0.01.
-------
Table 18. HYPOTHETICAL PIPE DATA COMBINATIONS
Pipe —
number i
1 0
2 0
3 0
4 0
5 0
6 0
7 4
8 4
9 4
10 4
11 4
12 4
Diameter
m
.81
.81
.81
.81
.81
.81
.86
.86
.86
.86
.86
.86
ft
2
2
2
2
2
2
12
12
12
12
12
12
Slope,
percent
0
0
0
0
5
5
0
0
0
0
5
5
.05
.05
.50
.50
.00
.00
.05
.05
.50
.50
.00
.00
Upstream
storage and
downstream
regulator
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
Maximum
m /sec
0
0
0
0
1
1
19
19
63
63
199
199
.168
.168
.532
.532
.681
.681
.977
.977
.174
.174
.775
.775
inflow
cfs
5
5
18
18
59
59
705
705
2230
2230
7054
7054
.94
.94
.77
.77
.35
.35
.41
.41
.73
.73
.19
.19
Minimum
m /sec
0
0
0
0
0
0
1
1
6
6
19
19
.017
.017
.053
.053
.168
.168
.998
.998
.317
.317
.978
.978
i n f 1 ow
cfs
0.59
0.59
1.88
1.88
5.94
5.94
70.54
70.54
223.07
223*. 07
705.42
705.42
Note: Minimum inflows apply only to triangular inflows.
-------
Table 19. INFLOW HYDROGRAPH SHAPES
FOR HYPOTHETICAL PIPES
Shape
number
1
2
3
4
Runoff
duration, Maxium Minimum
Shape hours inflow inflow
Constant Continuous 90% of 9% of
Triangle 1 full full
Triangle 2 pipe pipe
Triangle 4 flow flow
0
j^
"s
C£
° Q2
S u
1 Ql'
0
(/I
5 Q2
0
QI-
Q2
0
0
A A
Vii iii i V
A A
v / v
INFLOW SHAPE #1
All III 1 A
V v
A. INFLOW SHAPE #2
A
AV l | III 1 Av
v v
A
/V™"
A / \ A
AV | Av
v V
y^^^S. INFLOW SHAPE #4
A / \ A
AV | | III 1 Av
V 9 10 11 12 13 14 15 V24
TIME, HOURS
Figure 7. Hypothetical pipe inflow hydrograph shapes
153
-------
the triangular shape, and an inverted triangular shape with a
minimum of 0 mg/1 and a constant concentration of 100 mg/1
before and after the triangular shape. The durations of the
triangular concentration shapes are identical to the triangular
inflow hydrographs. A 2-hr duration was specified for the
continuous inflow hydrographs. These inflow concentration
shapes are summarized in Table 20 and shown in Figure 8. A
time step of 5 minutes was suggested for the simulation runs.
The hypothetical inflow hydrograph values for each pipe are
tabulated at these time intervals in Tables 21 to 24 and the
hypothetical inflow concentrations in Tables 25 to 27. The
effect of different time discretizations was not tested.
It should be noted that some models allow the input of hourly
values of dry-weather flow and quality and provide for linear
interpolation at specified constant time intervals. This
greatly simplifies the input of the hypothetical inflow hydro-
graphs and concentrations.
154
-------
Table 20. INFLOW CONCENTRATION SHAPES
FOR HYPOTHETICAL PIPES
Shape
number
1
2
3
Shape
Constant
Triangle
Inverted
triangle
Concentration
duration,
hours
Continuous
n
(note;
Maximum
concentration
mg/i
100
100
100
Minimum
concentration
mg/i
100
0
0
Note: Assume a base of two hours for the triangular concen-
trations when used with the continuous flow hydrographs, and
a base equal to the base of the triangular inflow hydrographs
when used with the triangular inflow hydrographs.
QUALITY II FOR ALL INFLOW SHAPES
FOR INFLOW
SHAPE 12
QUALITYI3-. FOR|NFLQW
r SHAPED
QUALITY I FOR
13 !lNFLOW_
QUALITY | SHAPE
12 J *4
9 10 11 12 13
TIME, HOURS
14 15 24
Figure 8. Hypothetical pipe inflow concentrations
155
-------
Table 21, CONTINUOUS INFLOW FOR HYPOTHETICAL PIPES
Inflow
Clock pipe #1 s #2 pipe #3 & #4 pipe #5 & #6 pipe #? & #8 pipe #g & #1Q pipe #11 & #12
Time time, —^ r* -* — - - —
step hr:min m /sec cfs m /sec cfs mj/sec cfs mj/sec cfs m-ysec cfs mj/sec cfs
1 10:10 0.168 5.94 0.532 18.77 1.681 59.35 19.977 705.41 63.174 2230.73 199.773 7054.19
2 10:05
3 10:10
4 10:15
5 10:20
6 10:25
7 10:30
8 10:35
9 10:40
10 10:45
11 10:50
12 10:55
i
i
'
I
1
'
1
1
I
j
1
13 11:00 0.168 5.94 0.532 18.77 1.681 59.35 19.977 705.41 63.174 2230.73 199.773 7054.19
14 11:05
15 11:10
16 11:15
17 11:20
18 11:25
19 11:30
20 11:35
21 11:40
22 11:45
23 11:50
24 11:55
25 12:00 0.168 5.94 0.532 18.77 1.681 59.35 19.977 705.41 63.174 2230.73 199.773 7054.19
Note: Assume constant inflows equal to the initial and final tabulated value before and after the tabulated time steps.
-------
Table 22. ONE-HOUR TRIANGULAR INFLOW FOR HYPOTHETICAL PIPES
ui
-o
Time
step
1
2
3
4
5
6
7
8
9
10
11
12
13
Clock
time,
hr :min
10:00
10:05
10:10
10:15
10:20
10:25
10:30
10:35
10:40
10:45
10:50
10:55
11:00
Inflow
Pipe #1
m-Vsec
0.017
0.042
0.067
0.092
0.118
0.143
0.168
0.143
0.118
0.092
0.067
0.042
0.017
& 12
cfs
0.59
1.48
2.37
3.26
4.15
5.04
5.94
5.04
4.15
3.26
2.37
1.48
0.59
Pipe #3
m^/sec
0.053
0.133
0.213
0.292
0.372
0.452
0.532
0.452
0.372
0.292
0.213
0.133
0.053
& #4
cfs
1.88
4.70
7.52
10.34
13.16
15.98
18.77
15.98
13.16
10.34
7.52
4.70
1.88
Pipe #5
mVsec
0.168
0.420
0.672
0.925
1.177
1.429
1.681
1.429
1.177
0.925
0.672
0.420
0.168
& #6
cfs
5,94
14.83
23.73
32.63
41.53
50.43
59.35
50.43
41.53
32.63
23.73
14.83
5.94
Pipe #7
m-Vsec
1.998
4.995
7.991
10.988
13.984
16.981
19.977
16.981
13.984
10.988
7.991
4.995
1.998
& 18
cfs
70.54
176.35
282.16
387.97
493.78
599.59
705.41
599.59
493.78
387.97
282.16
176.35
70.54
Pipe #9
mVsec
6.317
15.793
25.269
34.745
44.221
53.697
63.173
53.697
44.221
34.745
25.269
15.793
6.317
& #10
cfs
223.07
557.68
892.28
1226.89
1561.49
1896.10
2230.70
1896.10
1561.49
1226.89
892.29
557.68
223.07
Pipe #11
mVsec
19.977
49.943
79.910
109.876
139.842
169.808
199.775
169.808
139.842
109.876
79.910
49.943
19.977
& #12
cfs
705.42
1763.55
2821.68
3879.81
4937.94
5996.07
7054.20
5996.07
4937.94
3879.81
2821.68
1763.55
705.42
Note: Assume constant inflows equal to the initial and final tabulated value before and after the tabulated time steps.
-------
Table 23, TWO-HOUR TRIANGULAR INFLOW FOR HYPOTHETICAL PIPES
un
00
Time
step
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Clock
time,
hr :min
10:00
10:05
10:10
10:15
10:20
10:25
10:30
10:35
10:40
10:45
10:50
10:55
11:00
11:05
11:10
11:15
11:20
11:25
11:30
11:35
11:40
11:45
11:50
11:55
12:00
Inflow
Pipe fl
m /sec
0.017
0.029
0.042
0.055
0.067
0.080
0.092
0.105
0.118
0.130
0.143
0.155
0.168
0.155
0.143
0.130
0.118
0.105
0.092
0.080
0.067
0.055
0.042
0.029
0.017
& #2
cfs
0.59
1.04
1.48
1.93
2.37
2.82
3.26
3.71
4.15
4.60
5.04
5.49
5.94
5.49
5.04
4.60
4.15
3.71
3.26
2.82
2.37
1.93
1.48
1.04
0.59
Pipe #3
m /sec
0.053
0.093
0.133
0.173
0.213
0.253
0.293
0.333
0.372
0.412
0.452
0.492
0.532
0.492
0.452
0.412
0.372
0.333
0.293
0.253
0.213
0.173
0.133
0.093
0.053
& #4
cfs
1.88
3.28
4.69
6.10
7.51
8.92
10.32
11.73
13.14
14.55
15.95
17.36
18.77
17.36
15.95
14.55
13.14
11.73
10.32
8.92
7.51
6.10
4.69
3.28
1.88
Pipe #5
nrVsec
0.168
0.294
0.420
0.546
0.672
0.798
0.925
1.051
1.177
1.303
1.429
1.555
1.681
1.555
1.429
1.303
1.177
1.051
0.925
0.798
0.672
0.546
0.420
0.294
0.168
& #6
cfs
5.94
10.39
14.84
19.29
23.74
28 .19
32.64
37.09
41.55
46.00
50.45
54.90
59.35
54.90
50.45
46.00
41.55
37 .09
32.64
28.19
23.74
19.29
14.84
10.39
5.94
Pipe #
m^/sec
1.998
3.496
4.994
6.493
7.991
9.489
10.987
12.486
13.984
15.482
16.980
18.479
19.977
18.479
16.980
15.482
13.984
12.486
10.987
9.489
7.991
6.493
4.994
3.496
1.998
7 & #8
cfs
70.54
123.45
176.35
229.26
282.16
335.07
387.98
440.88
493.79
546.69
599.60
652.50
705.41
652.50
599.60
546.69
493.79
440.88
387.98
335.07
282.16
229.26
176.35
123.45
70.54
Pipe #9 & #10
mvsec
6.317
11.055
15.793
20.531
25.269
30.007
34.745
39.483
44.221
48 .959
53.697
58.435
63.173
58.435
53.697
48.959
44.221
39.483
34.745
30.007
25.269
20.531
15.793
11.055
6.317
cfs
223.07
390.37
557 .68
724.98
892.28
1059.58
1226.89
1394.19
1561.49
1728.79
1896.10
2063.40
2230.70
2063.40
1896.10
1728.79
1561.49
1394.19
1226.89
1059.58
892.28
724.98
557.68
390.37
223.07
Pipe #11 & #12
m-Vsec
19.977
34.960
49.944
64.927
79.910
94.893
109.876
124.859
139.842
154.826
169.809
184.792
199.775
184.792
169.809
154.826
139.842
124.859
109.876
94.893
79.910
64.927
49.944
34.960
19.977
cfs
705.42
1234.48
1763.55
2292.61
2821.68
3350.74
3879.81
4408.87
4937.94
5467.01
5996.07
6525.13
7054.20
6525.13
5996.07
5467 .01
4937.94
4408.87
3879.81
3350.74
2821.68
2292.61
1763.55
1234.48
705.42
Note: Assume constant inflows equal to the initial and final tabulated value before and after the tabulated time steps.
-------
Table 24, FOUR-HOUR TRIANGULAR INFLOW FOR HYPOTHETICAL PIPES
en
vc
Time
step
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Clock
time,
hr :min
10:00
10:05
10:10
10:15
10:20
10:25
10:30
10:35
10:40
10:45
10:50
10:55
11:00
11:05
11:10
11:15
11:20
11:25
11:30
11:35
11:40
11:45
11:50
11:55
12:00
Inflow
Pipe #1
m /sec
0.017
0.023
0.029
0.036
0.042
0.048
0.055
0.061
0.067
0.074
0.080
0.086
0.092
0.098
0.105
0.111
0.118
0.124
0.130
0.137
0.143
0.149
0.155
0.162
0.168
& #2
cfs
0.59
0.81
1.04
1.26
1.48
1.71
1.93
2.15
2.37
2.60
2.82
3.04
3.27
3.49
3.71
3.93
4.15
4.38
4.60
4.83
5.05
5.27
5.49
5.72
5.94
Pi£e 13
m /sec
0.053
0.073
0.093
0.113
0.133
0.153
0.173
0.193
0.213
0.233
0.253
0.273
0.293
0.313
0.333
0.353
0.372
0.392
0.412
0.432
0.452
0.472
0.492
0.512
0.532
& #4
cfs
1.8%
2.58
3.29
3.99
4.70
5.40
6.10
6.81
7.51
8.21
8.92
9.62
10.33
11.03
11.73
12.44
13.14
13.84
14.55
15.25
15.96
16.66
17.36
18.07
18.77
Pipe #5
re /sec
0.168
0.231
0.294
0.357
0.420
0.483
0.546
0.609
0.672
0.735
0.798
0.861
0.925
0.988
1.051
1.114
1.177
1.240
1.303
1.366
1.429
1.492
1.555
1.618
1.681
& 16
cfs
5.94
8.16
10.38
12.61
14.83
17.06
19.28
21.51
23.74
25.96
28.19
30.41
32.64
34.87
37.09
39.32
41.54
43.77
46.00
48.22
50.45
52.67
54.90
57.12
59.35
Pipe 1
jn /sec
1.998
2.747
3.496
4.245
4.995
5.744
6.493
7.242
7.991
8.740
9.489
10.238
10.988
11.737
12.486
13.235
13.984
14.733
15.482
16.232
16.981
17.730
18.479
19.228
19.977
7 & #8
cfs
70.54
96.99
123.45
149.90
176.35
202.81
229.26
255.71
282.16
308.62
335.07
361.52
387.98
414.43
440.88
467.33
493.79
520.24
546.69
573.15
599.60
626.05
652.50
678.96
705.41
Pipe 19
3 .
m /sec
6.317
8.686
11.055
13.424
15.793
18.162
20.531
22.900
25.269
27.638
30.007
32.376
34.745
37.114
39.483
41.852
44.221
46.590
48.959
51.328
53.697
56 .066
58.435
60.804
63.173
& #10
cfs
223.07
306.72
390.37
474.02
557.68
641.33
724.98
808.63
892.28
975.93
1059.58
1143.23
1226.89
1310.54
1394.19
1477.84
1561.49
1645.14
1728.79
1812.44
1896.10
1979.75
2063.40
2147.05
2230.70
Pipe 111
m /sec
19.977
27.469
34.960
42.452
49.943
57.435
64.927
72.418
79.910
87.401
94.893
102.384
109.876
117.368
124.859
132.351
139.842
147.334
154.825
162.317
169.809
177.300
184.792
192.283
199.775
& #12
cfs
705.42
969.95
1234.49
1499.02
1763.55
2028.08
2292.62
2557.15
2821.68
3086.21
3350.75
3615.28
3879.81
4144.34
4408.88
4673.41
4937.94
5202.47
5467.01
5731.54
5996.07
6260.60
6525.14
6789.67
7054.20
-------
Table 24 (Continued). FOUR-HOUR TRIANGULAR INFLOW FOR HYPOTHETICAL PIPES
Inflow
Time
step
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
ClOCK
time,
hr :min
12
12
12
12
12
12
12
12
12
12
12
13
13
13
13
13
13
13
13
13
13
13
13
14
:05
:10
:15
:20
:25
: 30
:35
:40
:45
:50
:55
:00
:05
: 1 0
:15
:20
:25
:30
: 35
:40
:45
-.50
:55
:00
Pipe #1
m /sec
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.162
.155
.149
.143
.137
.130
.124
.118
.111
.105
.099
.092
.086
.080
.074
.067
.061
.055
.048
.042
.036
.029
.023
.017
&
#2
cfs
5
5
5
5
4
4
4
4
3
3
3
3
3
2
2
2
2
1
1
1
i
1
0
0
.72
.49
.27
.05
.83
.60
.38
.15
.93
.71
.49
.27
.04
.32
.60
. 37
.15
.93
. 71
.48
.26
.04
.81
.59
Pipe #3
m /sec
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.512
.492
.472
.452
.432
.412
.392
.372
.353
. 333
.313
.293
.273
.253
.233
.213
.193
.173
.153
.133
.113
.093
.073
.053
&
#4
cfs
18
17
16
15
15
14
13
13
12
11
11
10
9
S
3
7
6
C
5
4
3
3
2
1
.07
.36
.66
.96
.25
.55
.84
.14
.44
.73
.03
.33
.62
.92
.21
.51
.81
.10
.40
.70
.99
.29
.58
.83
Pipe #5
m
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
/sec
.618
.555
.492
.429
.366
.303
.240
.177
.114
.051
.988
.925
. 861
. 798
.735
.672
.609
. 546
.483
. 420
.357
.294
.231
.168
&
#6
cfs
57
54
52
50
48
46
43
41
39
37
34
32
30
28
25
23
21
19
17
14
12
10
8
5
.12
.90
.67
.45
.22
.00
.77
.54
.32
.09
.87
.64
.41
.19
.96
.74
.51
.28
.06
.83
.61
.38
.16
.94
Pipe #
m /sec
19
18
17
16
16
15
14
13
13
12
11
10
10
9
8
7
7
6
5
4
4
3
2
1
.228
.479
.730
.981
.232
.482
.733
.984
.235
.486
.737
.988
.238
. 489
.740
.991
.242
.493
.744
.995
.245
.496
.747
.998
/ &
#8
cfs
678
652
626
599
573
546
520
493
467
440
414
387
361
335
308
282
255
229
202
176
149
123
96
70
.96
.50
.05
.60
.15
.69
.24
.79
.33
.88
.43
.98
.52
.07
.62
.16
.71
.26
.81
.35
.90
.45
.99
.54
Pipe #9 & #10
m /sec
60
58
56
53
51
48
46
44
41
39
37
34
32
30
27
2 5
22
20
18
15
13
11
8
6
.804
.435
.066
.697
.?28
.959
.590
.221
.852
.483
.114
.745
.376
.007
.638
.269
.900
.531
.162
.793
.424
.055
.686
.317
cfs
2147
2063
1979
1896
1812
1728
1645
1561
1477
1394
1310
1226
1143
1059
975
892
808
724
641
557
474
390
306
223
.05
.40
.75
.10
.44
.79
.14
.49
.84
.19
.54
.89
.23
.58
.93
.28
.63
.98
.33
.68
.02
.37
.72
.07
Pipe #11 t, ifl2
m3
192
184
177
169
162
154
147
139
132
124
117
109
102
94
87
79
72
64
57
49
42
34
27
19
/sec
.283
.792
.300
.809
.317
.825
.334
.842
.351
.859
.368
.876
.384
.893
.401
.910
.418
.927
.435
.943
.452
.960
.469
.977
cfs
6789
6525
6260
5996
5731
5467
5202
4937
4673
4408
4144
3879
3615
3350
3086
2821
2557
2292
2028
1763
1499
1234
969
705
.67
.14
.60
.07
.54
.01
.47
.94
.41
.88
.34
.81
.28
.75
.21
.68
.15
.62
.08
.55
.02
.49
.95
.42
Note: Assume constant inflows equal to the intitial and final value before and after the tabulated time steps.
-------
Table 25. INFLOW CONCENTRATIONS FOR CONTINUOUS AND
TWO-HOUR TRIANGULAR INFLOW HYDROGRAPHS
FOR HYPOTHETICAL PIPES
Time
step
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Clock
time,
hr :min
10:00
10:05
10:10
10:15
10:20
10:25
10:30
10:35
10:40
10:45
10:50
10:55
11:00
11:05
11:10
11:15
11:20
11:25
11:30
11:35
11:40
11:45
11:50
11:55
12:00
12:05
Quality #1
mg/i
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
Concentrations
Quality #2
mg/Jl
0.00
8.33
16.67
25.00
33.33
41.67
50.00
58.33
66.67
75.00
83.33
91.67
100.00
91.67
83.33
75.00
66.67
58.33
50.00
41.67
33.33
25.00
16.67
8.33
0.00
0.00
Quality #3
mg/£
100.00
91.67
83.33
75.00
66.67
58.33
50.00
41.67
33.33
25.00
16.67
8.33
0.00
8.33
16.67
25.00
33.33
41.67
50.00
58.33
66.67
75.00
83.33
91.67
100.00
100.00
Note: Assume constant concentrations equal to the initial
and final tabulated value before and after the tabulated
time steps.
161
-------
Table 26. INFLOW CONCENTRATIONS FOR ONE-HOUR
TRIANGULAR INFLOW HYDROGRAPHS FOR
HYPOTHETICAL PIPES
Time
step
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Clock
time,
hr:min
10:00
10:05
10:10
10:15
10:20
10:25
10 : 30
10:35
10:40
10:45
10:50
10:55
11:00
11:05
Quality #1
mg/£
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
Concentrations
Quality 12
mg/£
0.00
16.67
33.33
50.00
66.67
83.33
100.00
83.33
66.67
50.00
33.33
16.67
0.00
0.00
Quality 13
mg/H
100.00
83.33
66.67
50.00
33.33
16.67
0.00
16.67
33.33
50.00
66.67
83.33
100.00
100.00
Note: Assume constant concentrations equal to the initial
and final tabulated value before and after the tabulated
time steps.
162
-------
Table 27. INFLOW CONCENTRATIONS FOR FOUR-HOUR
TRIANGULAR INFLOW HYDROGRAPHS FOR
HYPOTHETICAL PIPES
Time
step
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Clock
time,
hr:min
10:00
10:05
10:10
10:15
10:20
10:25
10:30
10:35
10:40
10:45
10:50
10:55
11:00
11:05
11:10
11:15
11:20
11:25
11:30
11:35
11:40
11:45
11:50
11:55
12:00
12:05
12:10
12:15
12:20
12:25
12:30
12:35
12:40
12:45
12:50
12:55
13:00
13:05
13:10
13:15
13:20
13:25
13:30
13:35
13:40
13:45
13:50
13:55
14:00
14:05
Quality fl
mg/J,
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
Concentrations
Quality #2
mg/Jl
0.00
4.17
8.33
12.50
16.67
20.83
25.00
29.17
33.33
37.50
41.67
45.83
50.00
54.17
58.33
62.50
66.67
70.83
75.00
79.17
83.33
87.50
91.67
95.83
100.00
95.83
91.67
87.50
83.33
79.17
75.00
70.83
66.67
62.50
58.33
54.17
50.00
45.83
41.67
37.50
33.33
29.17
25.00
20.83
16.67
12.50
8.33
4.17
0.00
0.00
Quality 13
mg/fl.
100.00
95.83
91.67
87.50
83.33
79.17
75.00
70.83
66.67
62.50
58.33
54.17
50.00
45.83
41.67
37.50
33.33
29.17
25.00
20.83
16.67
12.50
8.33
4.17
0.00
4.17
8.33
12.50
16.67
20.83
25.00
29.17
33.33
37.50
41.67
45.83
50.00
54.17
58.33
62.50
66.67
70.83
75.00
79.17
83.33
87.50
91.67
95.83
100.00
100.00
Note: Assume constant concentrations equal to the initial and
final tabulated value before and after the tabulated time steps.
163
-------
REAL CATCHMENT DATA
An attempt was made to select three real catchments with drain-
age areas covering three orders of magnitude which had reliable
concurrent rainfall, runoff, and water quality data. Since no
small catchment was found which also had quality data, the
Oakdale Avenue catchment in Chicago, Illinois, with a drainage
area of 5.22 ha (12.9 acres) was selected because it had
reliable rainfall and runoff data. An intermediate size catch-
ment was selected which had rainfall, runoff, and water quality
data, but it was subsequently discovered that the data were
unreliable. It was then too late in the study to find sub-
stitute data. The Bloody Run catchment in Cincinnati, Ohio,
with a drainage area of 964 ha (2380 acres) was selected to
represent a large catchment. It has rainfall, runoff, and
water quality data. Difficulties were encountered, however,
in ascertaining the reliability of the data, most of which had
to be scaled from plotted hyetographs, hydrographs, and water
quality graphs since only small portions were available in
tabular form.
Description of the Oakdale Avenue Catchment
The Oakdale Avenue catchment is located in an urban area about
6 miles northwest of downtown Chicago, Illinois, (Tucker, 1968).
This catchment is 5.22 ha (12.9 acres) in size (approximately
2-1/2 blocks long by one block wide) and consists entirely of
residential lots and adjoining streets (Figure 9). A break-
down of the extent of pervious and impervious surfaces in the
drainage area is given in Table 28.
The backbone of the drainage system consists of a 76-cm (30-in.)
diameter reinforced concrete combined sewer that drains east
along Oakdale Avenue for about two blocks. The existing 76-cm
(30-in.) combined sewer was installed in 1958 and replaced a
smaller combined sewer of inadequate stormwater capacity. The
76-cm (30-in.) combined sewer drains into a 3.20 m x 3.20 m
(10.5 ft x 10.5 ft) concrete combined trunk sewer that drains
north toward the North Branch of the Chicago River.
As shown in Figure 10, the catchment was divided into 13 sub-
catchments for the runoff simulations. Each of the 13 subcatch-
ments has its individual inlet manhole. In Figure 10, the ele-
ments of the sewer system (subcatchments, pipes, and manholes)
are numbered for identification. Table 29 gives physical
characteristics of the subcatchments, which vary in size from
0.33 ha (0.82 acres) to 0.65 ha (1.60 acres). The impervious-
ness of the subcatchments varies from 39.5 to 56.5 percent.
Ground slopes vary from 0.37 to 0.90 percent. Manning's rough-
ness coefficient was assumed to be 0.012 or 0.013 for the imper-
vious areas and 0.350 for the pervious areas.
164
-------
m
IIIIIIJIHIII
4
f !
-H "J!
-^
'P "
A
N £
RAINGAGE
A155'
•••••h>i • iT "••••'
liiiiiliiiiiilliiii iiiiiiiiiiiniliil
—: W OAKDALE AVENUE
'5"
I|||||IIIIIMIIIII|| IIIIIIIIIIIIUIJ1!
• • • •
TOrnf • • • i-if"
' '!
i i
i ____ J
-\
O MANHOLE
SEWER
I BUILDING
0 100 200
FEET
FLOW MEASUREMENT
VAULT
0 25 50
METERS
Figure 9. Map of Oakdale Avenue catchment, Chicago,
Illinois, showing land use and sewer layout
-------
Table 28. BREAKDOWN OF PERVIOUS AND IMPERVIOUS
SURFACES IN THE OAKDALE AVENUE CATCHMENT
Drainage area
Land use ha acres
Impervious area:
Draining directly to
combined sewer:
Houses 1.02 2.52
Streets 0.64 1.58
Alleys 0.23 0.58
Garages 0.11 0.27
Sidewalks
to street 0.04 0.11
to alley 0.04 0.09
Subtotals 2.08 5.15
Draining indirectly to
combined sewer:
Public walks 0.23 0.57
Private walks 0.06 0.15
Subtotals 0.29 0.72
Total impervious area: 2.37 5.87
Pervious area:
(grassed, etc.)
Total pervious area: 2.85 7.05
Total drainage area: 5.22 12.92
166
-------
Table 29. PHYSICAL CHARACTERISTICS OF SUBCATCHMENTS
OF THE OAKDALE AVENUE CATCHMENT
Inlet
Subcatchment manhole
number number
1
2
3
4
5
6
7
8
9
10
11
12
13
1
2
3
4
5
6
7
8
9
10
11
12
13
Length
m
212.4
74.4
212.4
166.1
78.9
78.3
75.6
147.8
195.0
174.0
78.9
80.5
68.0
ft
697
244
697
545
259
257
248
485
643
571
259
264
223
Width
m
30.5
45.7
24.4
12.2
48.8
61.0
48.8
24.4
12.2
27.4
48.8
61.0
48.8
ft
100
150
80
40
160
200
160
80
40
90
160
200
160
Drainage
area Imperviousness
ha
0.65
0.34
0.52
0.20
0.38
0.48
0.37
0.36
0.24
0.48
0.38
0.49
0.33
acres
1.60
0.84
1.28
0.50
0.95
1.18
0.91
0.89
0.59
1.18
0.95
1.21
0.82
percent
44.0
44.0
51.7
55.4
39.5
41.7
40.5
54.0
56.5
47.4
40.6
40.6
43.1
Ground
, slope,
percent
0.60
0.90
0.60
0.90
0.90
0.90
0.90
0.37
0.90
0.37
0.90
0.90
0.90
Manning's n
imperv.
area
0.013
0.012
0.013
0.013
0.012
0.012
0.012
0.013
0.013
0.013
0.012
0.012
0.012
pervious
area
0.350
0.350
0.350
0.350
0.350
0.350
0.350
0.350
0.350
0.350
0.350
0.350
0.350
Note: Length is in the direction of flow, width is perpendicular to direction of flow, for a rectangular
area of equal size as actual subcatchment area.
-------
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LEVERGNE
RAINGAGE
1 U-1551-*)
S
@ , 0 . j
0 iB O/
n._J____j/
r /
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FLOW MEASUREMENT
VAULT
LECLAIRE
CD SUBCATCHMENT
LH INLET MANHOLE
i SEWER PIPE
=Z STREETS AND ALLEYS
0 80 160
FEET
i 1 1
0 25 50
METERS
Figure 10
Map of Oakdale Avenue catchment showing
subcatchments and sewer system elements
-------
As shown in Table 30, the maximum infiltration, the minimum
infiltration, and the decay rate of infiltration were assumed
to be 63.5 mm/hr (2.50 in./hr), 11.4 mm/hr (0.45 in./hr), and
0.00115 sec" , respectively. The overall volumes of retention
storage on the pervious and the impervious areas were assumed
to be 5.08 mm (0.20 in.) and 2.03 mm (0.08 in.), respectively.
As shown in Table 31, the diameters of the sewer pipes vary
from 25 cm (10 in.) to 76 cm (30 in.). The pipe slopes vary
from 0.30 to 4.20 percent. The Manning coefficients of these
pipes were assumed to be 0.012.
Monitoring System of the Oakdale Avenue Catchment
The rainfall-runoff measuring and recording systems were
installed in conjunction with the new 76-cm (30-in.) combined
sewer operation in 1959. Runoff has been measured with a
Simplex 76-cm (30-in.) type "S" parabolic flume housed in a
vault located on the corner of Lamon and Oakdale Avenues.
Rainfall measurements have been conducted using a tipping
bucket raingage which is located about one block north of
the drainage area on top of Falconer Elementary School. No
runoff water quality measurements were conducted.
The raingage and a transmitter in the flow measuring vault are
connected to remote recorders through leased telephone lines.
The data instrumentation, transmission, and recording systems
operate only during periods of rainfall. The system is put
into operation when the first 0.25 mm (0.01 in.) of rain tips
the bucket in the raingage.
Rainfall and Runoff Data of the Oakdale Avenue Catchment
Rainfall and runoff in the Oakdale Avenue catchment have been
periodically measured and recorded since 1957 by the Chicago
Department of Public Works, Bureau of Engineering. Storm data
considered reasonably reliable by the Bureau of Engineering
are identified in Table 32. Detailed rainfall and runoff data
for these storms have been reported by Tucker (1968).
In the present study, the rainstorms on the following four
dates were selected to test several methods of computing urban
runoff quantity: May 19, 1959; July 2, 1960; July 26, 1960;
and August 2, 1963. These rainstorms were selected since they
represent a typical range of possible combinations of rainfall
intensities and durations.
169
-------
Table 30. ESTIMATE OF SOIL CHARACTERISTICS
FOR THE OAKDALE AVENUE CATCHMENT
Units
Item
Metric
British
Pervious areas:
Retention storage capacity
Maximum infiltration rate
Minimum infiltration rate
Infiltration decay rate
Impervious areas:
Retention storage capacity
Maximum infiltration rate
Minimum infiltration rate
Infiltration decay rate
5.1 mm
63.5 mm/hr
11.4 mm/hr
0.00115 sec
2. 0 mm
0.0 mm/hr
0.0 mm/hr
0.0 sec"
-1
0.20 in.
2.50 in./hr
0.45 in./hr
0.00115 sec
0.08 in.
0.00 in./hr
0.00 in./hr
0.00 sec"
-1
Notes: The infiltration rates are defined by Horton's
infiltration equation. The retention storage capacities
represent the amount of rain which has to fall before
surface runoff begins.
170
-------
Table 31. PHYSICAL CHARACTERISTICS OF SEWER ELEMENTS
OF THE OAKDALE AVENUE CATCHMENT
Pipe
number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Downstream
junction Diameter
number
4
4
4
5
6
7
9
9
11
9
12
13
14
—
m
0.25
0.30
0.25
0.38
0.38
0.46
0.46
0.25
0.53
0.25
0.53
0.61
0.61
0.76
ft
0.83
1,00
0.83
1.25
1.25
1.50
1.50
0.83
1.75
0.83
1.75
2.00
2.00
2.50
Length
m
51.8
39.6
32.0
48.8
53.3
48.5
53.0
15.2
50.6
13.7
51.8
41.8
40.2
13.4
ft
170
130
105
160
175
159
174
50
166
45
170
137
132
44
Invert
slope,
percent
0.71
0.72
1.08
0.45
0.45
0.40
0.40
3.78
0.35
4.20
0.35
0.30
0.30
0.30
Manning ' s
n
0.012
0.012
0.012
0.012
0.012
0.012
0.012
0.012
0.012
0.012
0.012
0.012
0.012
0.012
171
-------
Table 32. RELIABLE RAINFALL AND RUNOFF RECORDS
FOR THE OAKDALE AVENUE CATCHMENT
Date of storm
Remarks (no. of flow peaks)
May 19, 1959
July 29, 1959
October 6, 1959
July 2, 1960
July 22, 1960
July 26, 1960
August 20, 1960
September 18, 1960
October 14, 1960
April 24, 1961
August 31, 1961
July 2, 1962
April 17, 1963
April 19, 1963
April 29 & 30, 1963
May 4, 1963
June 19, 1963
July 13, 1963
August 2, 1963
August 24, 1963
September 22, 1964
Good peak flow (1)
Good peak flow (1)
2 small peaks, long period of rainfall
3 peaks, 3rd peak - flume was flooded
Small peak flow (1)
Medium peak flow (3)
2 peaks, 1st peak unreliable
Medium peak flow (1)
Small peak flow (1)
Small peak flow (2)
2 peaks, 1st peak unreliable
4 peaks, 4th peak - flume was flooded
Medium peak flow (2)
Good peak flow (1)
Medium peak flow (2)
2 small peaks, 1st peak unreliable
Medium peak flow (1)
Small peak flow (5)
Medium peak flow (2)
Small peak flow (2)
Small peak flow (2)
172
-------
The storm of May 19, 1959, (Figure 11 and Table 33) had high
intensity rainfall of a short duration followed by low inten-
sity rainfall of a long duration. This storm generated runoff
with one good peak. The storm of July 2, 1960, (Figure 12 and
Table 34) had lighter long-duration rainfall followed by
heavier short-duration rainfall. Runoff produced by this storm
had three peaks and the last peak was the largest. Since the
flume was flooded at the flow measuring location during the
last high-intensity rainfall, the recession curve of the last
peak was not recorded.
The storm of July 26, 1960, (Figure 13 and Table 35) had rela-
tively light long-duration rainfall which resulted in successive
small peaks of runoff. The storm of August 2, 1963, (Figure 14
and Table 36) had two high intensity, short duration rainfalls
which produced two successive medium peaks of runoff.
Figure 11. Rainfall Hyetograph and Runoff Hydrograph for
the Storm of May 19, 1959 - Oakdale Avenue
Catchment
173
-------
0.M
.23
1 9
HOURS
2.M
2.25
Figure 12a. Rainfall Hyetograph and Runoff Hydrograph for
the Storm of July 2, 1960 -Oakdale Avenue
Catchment
T'fME. HOUR'S*
3.5t
3.75
4.M
L29
Figure 12b. Rainfall Hyetograph and Runoff Hydrograph for
the Storm of July 2, 1960 -Oakdale Avenue
Catchment
174
-------
£*
fes-
a
.3
•o
t.N
2.N
o
S»?
2.25
Figure 13a. Rainfall Hyetograph and Runoff Hydrograph for
the Storm of July 26, 1960 -Oakdale Avenue
Catchment
"B D UUUU UUU UUUUUUUUI I U U U U U U UU UUlt
2.M
Figure 13b. Rainfall Hyetograph and Runoff Hydrograph for
the Storm of July 26, 1960 -Oakdale Avenue
Catchment
175
-------
*•
BSi
<~>
-------
Table 33. RAINFALL AND RUNOFF DATA FOR THE
STORM OF MAY 19, 1959 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Rain intensities
mm/hr
15.2
0.0
15.2
0.0
0.0
45.5
45.5
45.5
45.5
91.2
61.0
61.0
15.2
30.5
45.5
15.2
15.2
15.2
30.5
30.5
15.2
0.0
15.2
30.5
30.5
0.0
15.2
0.0
15.2
0.0
0.0
0.0
0.0
0.0
0.0
15.2
0.0
15.2
0.0
0.0
0.0
0.0
0.0
15.2
0.0
0.0
0.0
0.0
0.0
0.0
in . /hr
0.60
0.00
0.60
0.00
0.00
1.80
1.80
1.80
1.80
3.60
2.40
2.40
0.60
1.20
1.80
0.60
0.60
0.60
1.20
1.20
0.60
0.00
0.60
1.20
1.20
0.00
0.60
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.00
0.60
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.00
Cumulative rain Runoff
mm
0.3
0.3
0.5
0.5
0.5
1.3
2.0
2.8
3.6
5.1
6.1
7.1
7.4
7.9
8.6
8.9
9.1
9.4
9.9
10.4
1C. 7
10.7
10.9
11.4
11.9
11.9
12.2
12.2
12.4
12.4
12.4
12.4
12.4
12.4
12.4
12.7
12.7
13.0
13.0
13.0
13.0
13.0
13.0
13.2
13.2
13.2
13.2
13.2
13.2
13.2
in.
0.01
0.01
0.02
0.02
0.02
0.05
0.08
0.11
0.14
0.20
0.24
0.28
0.29
0.31
0.34
0.35
0.36
0.37
0.39
0.41
0.42
0.42
0.43
0.45
0.45
0.47
0.48
0.48
0.49
0.49
0.49
0.49
0.49
0.49
0.49
0.50
0.50
0.51
0.51
0.51
0.51
0.51
0.51
0.52
0.52
0.52
0.52
0.52
0.52
0.52
mj/sec
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.007
0.033
0.048
0.085
0.142
0.184
0.202
0.205
0.198
0.188
0.177
0.170
0.164
0.149
0.142
0.135
0.130
0.125
0.120
0.115
0.113
0.109
0.105
0.092
0.081
0.074
0.067
0.062
0.054
0.051
0.045
0.041
0.040
0.035
0.034
0.033
0.031
0.030
0.028
0.027
0.025
cfs
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.25
1.15
1.70
3.00
5.00
6.50
7.15
7.25
7.00
6.65
6.25
6.00
5.80
5.25
5.00
4.75
4.60
4.40
4.25
4.05
4.00
3.85
3.70
3.25
2.85
2.60
2.35
2.20
1.90
1.80
1.60
1.45
1.40
1.25
1.20
1.15
1.10
1.05
1.00
0.95
0.90
177
-------
Table 33 (Continued).
RAINFALL AND RUNOFF DATA FOR THE
STORM OF MAY 19, 1959 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
Rain intensities
mm/hr
0.0
15.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
15.2
0.0
15.2
0.0
0.0
0.0
0.0
15.2
0.0
0.0
15.2
0.0
0.0
15.2
0.0
0.0
15.2
0.0
0.0
0.0
0.0
0.0
15.2
0.0
0.0
0.0
0.0
15.2
0.0
15.2
0.0
15.2
0.0
15.2
0.0
15.2
0.0
15.2
0.0
0.0
in./hr
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.60
0.00
0.60
0.00
0.00
0.00
0.00
0.60
0.00
0.00
0.60
0.00
0.00
0.60
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.60
0.00
0.60
0.00
0.60
0.00
0.60
0.00
0.60
0.00
0.60
0.00
0.00
Cumulative rain
mm
13.2
13.5
13.5
13.5
13.5
13.5
13.5
13.5
13,5
13.5
13.7
13.7
14.0
14.0
14.0
14.0
14.0
14.2
14.2
14.2
14.5
14.5
14.5
14.7
14.7
14.7
15.0
15.0
15.0
15.0
15.0
15.0
15.2
15.2
15.2
15.2
15.2
15.5
15.5
15.7
15.7
16.0
16.0
16.3
16.3
16.5
16.5
16.8
16.8
16.8
in.
0.52
0.53
0.53
0.53
0.53
0.53
0.53
0.53
0.53
0.53
0.54
0.54
0.55
0.55
0.55
0.55
0.55
0.56
0.56
0.56
0.57
0.57
0.57
0.58
0.58
0.58
0.59
0.59
0.59
0.59
0.59
0.59
0.60
0.60
0.60
0.60
0.60
0.61
0.61
0.62
0.62
0.63
0.63
0.64
0.64
0.65
0.65
0.66
0.66
0.66
Runoff
m-Vsec
0.024
0.023
0.022
0.021
0.020
0.019
0.018
0.017
0.016
0.016
0.203
0.199
0.195
0.203
0.210
0.214
0.218
0.222
0.226
0.229
0.237
0.245
0.252
0.260
0.268
0.287
0.306
0.336
0.344
0.363
0.363
0.363
0.363
0.363
0.363
0.356
0.348
0.340
0.333
0.325
0.024
0.024
0.025
0.026
0.026
0.027
0.028
0.028
0.029
0.031
cfs
0.86
0.82
0.78
0.74
0.70
0.67
0.64
0.61
0.58
0.55
0.53
0.52
0.51
0.53
0.55
0.56
0.57
0.58
0.59
0.60
0.62
0.64
0.66
0.68
0.70
0.75
0.80
0.88
0.90
0.95
0.95
0.95
0.95
0.95
0.95
0.93
0.91
0.89
0.87
0.85
0.85
0.85
0.88
0.90
0.93
0.95
0.98
1.00
1.03
1.10
178
-------
Table 33 (Continued).
RAINFALL AND RUNOFF DATA FOR THE
STORM OF MAY 19, 1959 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm, Rain intensities Cumulative rain Runoff
minutes mm/hr
101 15.2
102 0.0
103 0.0
104 0.0
105 0.0
106 0.0
107 0.0
108 0.0
109 0.0
110 0.0
111 15.2
112 0.0
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
in./hr mm in.
0.60 17.0 0.67
0.00 17.0 0.67
0.00 17.0 0.67
0.00 17.0 0.67
0.00 17.0 0.67
0.00 17.0 0.67
0.00 17.0 0.67
0.00 17.0 0.67
0.00 17.0 0.67
0.00 17.0 0.67
0.60 17.3 0.68
0.00 17.3 0.68
mj/sec
0.033
0.035
0.037
0.039
0.040
0.039
0.037
0.035
0.033
0.030
0.029
0.028
0.027
0.026
0.024
0.024
0.022
0.021
0.020
0.018
0.018
0.017
0.016
0.015
0.014
0.014
0.014
0.014
0.014
0.013
0.013
0.013
0.013
0.013
0.011
0.011
0.011
0.011
0.011
0.010
0.010
0.009
0.009
0.009
0.009
0.008
0.008
0.008
0.008
0.007
cf s
1.18
1.25
1.32
1.36
1.42
1.36
1.30
1.25
1.15
1.05
1.03
1.00
0.95
0.90
0.85
0.83
0.78
0.75
0.70
0.65
0.62
0.59
0.56
0.53
0.50
0.50
0.50
0.50
0.50
0.45
0.45
0.45
0.45
0.45
0.40
0.40
0.40
0.37
0.37
0.35
0.35
0.33
0.33
0.31
0.31
0.29
0.29
0.27
0.27
0.25
Note: Intensities represent averages for time interval preceding
indicated clock time.
179
-------
Table 34. RAINFALL AND RUNOFF DATA FOR THE
STORM OF JULY 2, 1960 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
1
2
3
4
5
6
/
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Rain intensities
mm/hr
30.5
76.2
45.5
61.0
30.5
15.2
15.2
15.2
15.2
15.2
15.2
30.5
15.2
15.2
0.0
15.2
0.0
0.0
15.2
0.0
0.0
15.2
15.2
0.0
0.0
15.2
15.2
0.0
15.2
0.0
15.2
0.0
0.0
0.0
15.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
15.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
in./hr
1.2Q
3.00
1.79
2.40
1.20
0.60
0.60
0.60
0.60
0.60
0.60
1.20
0.60
0.60
0.00
0.60
0.00
0.00
0.60
0.00
0.00
0.60
0.60
0.00
0.00
0.60
0.60
0.00
0.60
0.00
0.60
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Cumulative rain
mm
0.5
1.8
2.5
3.6
4.1
4.3
4.6
4.8
5.1
5.3
5.6
6.1
6.4
6.6
6.6
6.9
6.9
6.9
7.1
7.1
7.1
7.4
7.6
7.6
7.6
7.9
8.1
8.1
8.4
8.4
8.6
8.6
8.6
8.6
8.9
8.9
8.9
8.9
8.9
8.9
8.9
8.9
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
in.
0.02
0.07
0.10
0.14
0.16
0.17
0.18
0.19
0.20
0.21
0.22
0.24
0.25
0.26
0.26
0.27
0.27
0.27
0.28
0.28
0.28
0.29
0.30
0.30
0.30
0.31
0.32
0.32
0.33
0.33
0.34
0.34
0.34
0.34
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
Runoff
m^/sec
0.006
0.006
0.006
0.028
0.028
0.028
0.057
0.057
0.057
0.085
0.085
0.085
0.085
0.130
0.130
0.130
0.113
0.113
0.113
0.085
0.085
0.085
0.085
0.085
0.057
0.057
0.057
0.057
0.057
0.057
0.064
0.064
0.065
0.065
0.064
0.064
0.057
0.057
0.057
0.048
0.048
0.048
0.048
0.048
0.031
0.031
0.028
0.028
0.028
0.026
cfs
0.20
0.20
0.20
1.00
1.00
1.00
2.00
2.00
2.00
3.00
3.00
3.00
3.00
4.60
4.60
4.60
4.00
4.00
4.00
3.00
3.00
3.00
3.00
3.00
2.00
2.00
2.00
2.00
2.00
2.00
2.25
2.25
2.30
2.30
2.25
2.25
2.00
2.00
2.00
1.70
1.70
1.70
1.70
1,70
1.10
1.10
1.00
1.00
1.00
0.90
180
-------
Table 34 (Continued).
RAINFALL AND RUNOFF DATA FOR THE
STORM OF JULY 2, 1960 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
Rain intensities
mm/hr
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
15.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
in . /hr
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.00
0,00
o.'oo
0.00
0.00
0.00
0.00
0.00
0,00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Cumulative rain Runoff
mm
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
in.
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.36
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
m-Ysec
0.026
0.026
0.026
0.026
0.026
0.026
0.026
0.026
0.026
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
cfs
0.90
0.90
0.90
0.90
0.90
0.90
0.90
0.90
0.90
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.40
0.40
0.40
0..40
0.40
0.40
0.40
0.40
0.40
0.40
181
-------
Table 34 (Continued).
RAINFALL AND RUNOFF DATA FOR THE
STORM OF JULY 2, 1960 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
Rain intensities
mm/hr
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
15.2
0.0
0.0
0.0
0.0
15.2
0.0
0.0
0.0
15.2
0.0
0.0
15.2
0.0
0.0
15.2
15.2
0.0
15 .2
0.0
0.0
0.0
0.0
15.2
15.2
0.0
0.0
0.0
15.2
61.0
45.5
15.2
15.2
15.2
15.2
0.0
in./hr
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.60
0.00
0.00
0.60
0.00
0.00
0.60
0.60
0.00
0 .60
0.00
0.00
0.00
0.00
0.60
0.60
0.00
0.00
0.00
0.60
2.40
1.80
0.60
0.60
0.60
0.60
0.00
Cumulative rain
mm
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.7
9.7
9.7
9.7
9.7
9.9
10.2
10.2
10.2
10.4
10.4
10.4
10.7
10.7
10.7
10.9
11.2
11.2
11.4
11.4
11.4
11.4
11.4
11.7
11.9
11.9
11.9
11.9
12.2
13.2
14.0
14.2
14.5
14.7
15.0
15.0
in.
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.38
0.38
0.38
0.38
0.38
0.39
0.40
0.40
0.40
0.41
0.41
0.41
0.42
0.42
0.42
0.43
0.44
0.44
0.45
0.45
0.45
0.45
0.45
0.46
0.47
0.47
0.47
0.47
0.48
0.52
0.55
0.56
0.57
0.58
0.59
0.59
Runoff
m-Vsec
0.011
0.011
0.011
0.011
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.010
0.011
0.013
0.013
0.014
0.016
0.017
0.020
0.020
0.020
0.020
0.020
0.035
0.037
0.038
0.043
0.043
0.043
0.043
0.043
0.043
0.043
0.057
0.057
0.057
0.057
0.057
0.127
cf s
0.40
0.40
0.40
0.40
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.35
0.40
0.45
0.45
0.50
0.55
0.60
0.70
0.70
0.70
0.70
0.70
1.25
1.30
1.35
1.50
1.50
1.50
1.50
1.50
1.50
1.50
2.00
2.00
2.00
2.00
2.00
4.50
182
-------
Table 34 (Continued).
RAINFALL AND RUNOFF DATA FOR THE
STORM OF JULY 2, 1960 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
Rain intensities
mm/hr
15.2
15.2
15.2
45.5
61.0
76.2
76.2
76.2
76.2
76.2
76.2
61.0
61.0
45.5
45.5
45.5
30.5
30.5
30.5
30.5
30.5
15.2
15.2
15.2
30.5
30.5
30.5
15.2
15.2
15.2
15.2
0.0
15.2
15.2
30.5
76.2
76.2
61.0
0.0
15.2
0.0
15.2
0.0
0.0
15.2
0.0
0.0
0.0
0.0
15.2
in./hr
0.60
0.60
0.60
1.80
2.40
3.00
3.00
3.00
3.00
3.00
3.00
2.40
2.40
1.80
1.80
1.80
1.20
1.20
1.20
1.20
1.20
0.60
0.60
0.60
1.20
1,20
1.20
0.60
0.60
0.60
0.60
0.00
0.60
0.60
1.20
3.00
3.00
2.40
0.00
0.60
0.00
0.60
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.60
Cumulative rain Runoff
mm
15.2
15.5
15.8
16.5
17.5
18.8
20.1
21.3
22.6
23.9
25.2
26.2
27.2
27.9
28.7
29.5
30.0
30.5
31.0
31.5
32.0
32.3
32.5
32.8
33.3
33.8
34.3
34.5
34.8
35.1
35.3
35.3
35.6
35.8
36.3
37.6
38.9
39.9
39.9
40.1
40.1
40.4
40.4
40.4
40.6
40.6
40.6
40.6
40.6
40.9
in.
0.60
0.61
0.62
0.65
0.69
0.74
0.79
0.84
0.89
0.94
0.99
1.03
1.07
1.10
1.13
1.16
1.18
1.20
1.22
1.24
1.26
1.27
1.28
1.29
1.31
1.33
1.35
1.36
1.37
1.38
1.39
1.39
1.40
1.41
1.43
1.48
1.53
1.57
1.57
1.58
1.58
1.59
1.59
1.59
1.60
1.60
1.60
1.60
1.60
1.61
m-vsec cfs
0.127 4.50
0.127 4.50
0.127 4.50
0.113 4.00
0.112 3.95
0.112 3.95
0.227 8.00
0.312 11.00
0.411 14.50
0.481 17.00
0.493 17.40
0.487 17.20
0.481 17.00
0.459 16.20
0.439 15.50
0.425 15.00
0.411 14.50
0.402 14.20
0.397 14.00
0.391 13.80
0.374 13.20
0.363 12.80
0.340 12.00
0.326 11.50
0.312 11.00
0.297 10.50
0.283 10.00
0.269 9.50
0.268 9.45
0.297 10.50
0.334 11.80
0.340 12.00
Measuring
flume flooded;
no runoff
record for
remainder of
storm.
183
-------
Table 34 (Continued).
RAINFALL AND RUNOFF DATA FOR THE
STORM OF JULY 2, 1960 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
Rain intensities
mm/hr
0.0
0.0
0,0
15.2
0.0
0.0
15.2
0.0
0.0
0.0
15.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
15.2
0.0
in./hr
0.00
0.00
0.00
0.60
0.00
0.00
0.60
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.60
0.00
Cumulative rain Runoff
mm
40.9
40.9
40.9
41.2
41.2
41.2
41.4
41.4
41.4
41.4
41,6
41.6
41.6
41.6
41.6
41.6
41.6
41.6
41.6
41. .6
41.6
41.8
41.8
in. mj/sec cfs
1.61
1.61
1.61
1.62
1.62
1.62
1.63
1.63
1.63
1.63
1.64
1.64
1.64
1.64
1.64
1.64
1.64
1.64
1.64
1.64
1.64
1.65
1.65
Note: Intensities represent averages for time interval preceding
indicated clock time.
184
-------
Table 35. RAINFALL AND RUNOFF DATA FOR THE
STORM OF JULY 26, 1960 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Rain intensities
mm/hr
91.2
61.0
15.2
30.5
0.0
15.2
0.0
0.0
0.0
0.0
0.0
15.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
n.o
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
in./hr
3.60
2.40
0.60
1.20
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
o.oo •
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Cumulative rain Runoff
mm
1.5
2.5
2.8
3.3
3.3
3.6
3.6
3.6
3.6
3.6
3.6
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
in.
0.06
0.10
0.11
0.13
0.13
0.14
0.14
0.14
0.14
0.14
0.14
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
m3/sec
0.007
0.007
0.007
0.014
0.028
0.028
0.028
0.028
0.028
0.062
0.071
0.071
0.071
0.071
0.057
0.057
0.057
0.057
0.057
0.034
0.034
0.034
0.034
0.034
0.021
0.021
0.021
0.021
0.021
0.017
0.017
0.017
0.017
0.017
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
cf s
0.25
0.25
0.25
0.50
1.00
1.00
1.00
1.00
1.00
2.20
2.50
2.50
2.50
2.50
2.00
2.00
2.00
2.00
2.00
1.20
1.20
1.20
1.20
1.20
0.75
0.75
0.75
0.75
0.75
0.60
0.60
0.60
0.60
0.60
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
185
-------
Table 35 (Continued).
RAINFALL AND RUNOFF DATA FOR THE
STORM OF JULY 26, 1960 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
Rain intensities
mm/hr
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
in./hr
0:00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Cumulative rain
mm
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
in.
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
Runoff
mVsec
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.011
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.909
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.007
0/007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
cfs
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
186
-------
Table 35 (Continued).
RAINFALL AND RUNOFF DATA FOR THE
STORM OF JULY 26, 1960 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
•118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
Rain intensities
mm/hr
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
15.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
15.2
0.0
0.0
in. /hr
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.60
0.00
0.00
Cumulative rain
mm
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.3
4.3
4.3
in.
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.17
0.17
0.17
Runoff
m^/sec
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
cfs
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
187
-------
Table 35 (Continued).
RAINFALL AND RUNOFF DATA FOR THE
STORM OF JULY 26, 1960 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
Rain intensities
mm/hr
15.2
15.2
15.2
15.2
15.2
15.2
0.0
15.2
0.0
15.2
15.2
15.2
0.0
0.0
15.2
0.0
15.2
0.0
15.2
15.2
0.0
0.0
15.2
0.0
15.2
15.2
15.2
15.2
15.2
0.0
0.0
0.0
15.2
0.0
15.2
0.0
15.2
0.0
0.0
0.0
0.0
15.2
0.0
0.0
15.2
15.2
0.0
0.0
15.2
0.0
in./hr
0.60
0.00
0.00
0.60
0.00
0.60
0,60
0.60
0.60
0.60
0.00
0.00
0.00
0.60
0.00
0.60
0.00
0.60
0.00
0.00
0.00
0.00
0.60
0.00
o.oo
0.60
0.60
0.00
0.00
0.60
0.00
0.60
0.60
0.60
0.60
0.60
0.60
0.00
0.60
0.00
0.60
0.60
0.60
0.00
0.00
0.60
0.00
0.60
0.00
0.60
Cumulative rain
mm
4.6
4.6
4.6
4.8
4.8
5.1
5.3
5.6
5.8
6.1
6.1
6.1
6.1
6.4
6.4
6.6
6.6
6.9
6.9
6.9
6.9
6.9
7.1
7.1
7.1
7.4
7.6
7.6
7.6
7.9
7.9
8.1
8.4
8.6
8.9
9.1
9.4
9.4
9.7
9.7
9.9
10.2
10.4
10.4
10.4
10.7
10.7
10.9
10.9
11.2
in.
0.18
0.18
0.18
0.19
0.19
0.20
0.21
0.22
0.23
0.24
0.24
0.24
0.24
0.25
0.25
0.26
0.26
0.27
0.27
0.27
0.27
0.27
0.28
0.28
0.2t>
0.29
0.30
0.30
0.30
0.31
0.31
0.32
0.33
0.34
0.35
0.36
0.37
0.37
0.38
0.38
0.39
0.40
0.41
0.41
0.41
0.42
0.42
0.43
0.43
0.44
Runoff
m^/sec
0.007
0.007
0.007
0.007
0.009
0.009
0.009
0.009
0.009
0.028
0.028
0.028
0.028
0.028
0.054
0.054
0.054
0.054
0.058
0.600
0.058
0.058
0.058
0.058
0.054
0.054
0.054
0.054
0.054
0.048
0.045
0.045
0.045
0.048
0.054
0.057
0.057
0.057
0.057
0.057
0.085
0.085
0.085
0.092
0.092
0.092
0.092
0.092
0.085
0.082
cf s
0.25
0.25
0.25
0.25
0.30
0.30
0.30
0.30
0.30
1.00
1.00
1.00
1.00
1.00
1.90
1.90
1.90
1.90
2.05
2.10
2.05
2.05
2.05
2.05
1.90
1.90
1.90
1.90
1.90
1.70
1.60
1.60
1.60
1.70
1.90
2.00
2.00
2.00
2.00
3.00
3.00
3.00
3.00
3.25
3.25
3.25
3.25
3.25
3.00
2.90
188
-------
Table 35 (Continued).
RAINFALL AND RUNOFF DATA FOR THE
STORM OF JULY 26, 1960 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
Rain intensities
mm/hr
0.0
0.0
0.0
0.0
15.2
0.0
0.0
0.0
0.0
15.2
0.0
0.0
0.0
15.2
0.0
15.2
0.0
0.0
0.0
15.2
0.0
15.2
0.0
15.2
15.2
15.2
15.2
15.2
15.2
15.2
15.2
15.2
15.2
0.0
0.0
0.0
15.2
15.2
0.0
0.0
0.0-
15.2
0.0
0.0
0.0
15.2
0.0
0.0
0.0
15.2
in./hr
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.00
0.00
0.00
0.60
0.60
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.60
0.00
0.60
0.00
0.00
0.00
0.60
0.00
0.60
0.00
0.60
Cumulative rain
mm
11.4
11.7
11.9
12.2
12.5
12.7
13.0
13.2
13.5
13.5
13.5
13.5
13.7
14.0
14.0
14.0
14.0
14.2
14.2
14.2
14.2
14.5
14.5
14.5
14.5
14.7
14.7
14.7
14.7
14.7
15.0
15.0
15.0
15.0
15.0
15.2
15.2
15.2
15.2
15.5
15.5
15.8
15.8
15.8
15.8
16.0
16.0
16.3
16.3
16.5
in.
0.45
0.46
0.47
0.48
0.49
0.50
0.51
0.52
0.53
0.53
0.53
0.53
0.54
0.55
0.55
0.55
0.55
0.56
0.56
0.56
0.56
0.57
0.57
0.57
0.57
0.58
0.58
0.58
0.58
0.58
0.59
0.59
0.59
0.59
0.59
0.60
0.60
0.60
0.60
0.61
0.61
0.62
0.62
0.62
0.62
0.63
0.63
0.64
0.64
0.65
Runoff
m3/sec
0.082
0.082
0.078
0.078
0.082
0.085
0.085
0.085
0.085
0.122
0.122
0.122
0.122
0.122
0.099
0.099
0.099
0.085
0.085
0.071
0.071
0.071
0.071
0.071
0.051
0.051
0.051
0.051
0.051
0.043
0.043
0.043
0.043
0.043
0.043
0.043
0.043
0.043
0.043
0.031
0.031
0.031
0.031
0.031
0.037
0.037
0.037
0.037
0.037
0.045
cfs
2.90
2.90
2.75
2.75
2.90
3.00
3.00
3.00
3.00
4.30
4.30
4.30
4.30
4.30
3.50
3.50
3.50
3.00
3.00
2.50
2.50
2.50
2.50
2.50
1.80
1.80
1.80
1.80
1.80
1.50
1.50
1.50
1.50
1.50
1.50
1.50
1.50
1.50
1.50
1.10
1.10
1.10
1.10
1.10
1.30
1.30
1.30
1.30
1.30
1.60
189
-------
Table 35 (Continued).
RAINFALL AND RUNOFF DATA FOR THE
STORM OF JULY 26, 1960 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
Rain intensities
mm/hr
15.2
0.0
15.2
15.2
15.2
15.2
15.2
0.0
15.2
15.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
15.2
15.2
0.0
0.0
0.0
0.0
15.2
15.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
15.2
15.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
15.2
0.0
0.0
0.0
in./hr
0.60
0.00
0.60
0.60
0.60
0.60
0.60
0.00
0.60
0.60
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.60
0.60
0.00
0.00
0.00
0.00
0.60
0.60
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.60
0.60
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.60
0.00
0.00
0.00
Cumulative rain
mm
16.8
16.8
17.0
17.3
17.5
17.8
18.0
18.0
18.3
18.5
18.5
18.5
18.5
18.5
18.5
18.5
18.5
18.5
18.5
18.8
19.1
19.1
19.1
19.1
19.1
19.3
19.6
19.6
19.6
19.6
19.6
19.6
19 .6
19.6
19.6
19.6
19.6
19.8
20.1
20.1
20.1
20.1
20.1
20.1
20.1
20.1
20.3
20.3
20.3
20.3
in.
0.66
0.66
0.67
0.68
0.69
0.70
0.71
0.71
0.72
0.73
0.73
0.73
0.73
0.73
0.73
0.73
0.73
0.73
0.73
0.74
0.75
0.75
0.75
0.75
0.75
0.76
0.77
0.77
0.77
0.77
0.77
0.77
0.77
0.77
0.77
0.77
0.77
0.78
0.79
0.79
0.79
0.79
0.79
0.79
0.79
0.79
0.80
0.80
0.80
0.80
Runoff
m3/sec
0.045
0.045
0.045
0.045
0.057
0.057
0.057
0.057
0.057
0.079
0.081
0.082
0.081
0.081
0.071
0.071
0.057
0.057
0.057
0.048
0.048
0.048
0.048
0.048
0.034
0.034
0.034
0.034
0.034
0.028
0.028
0.028
0.028
0.028
0.026
0.026
0.026
0.026
0.026
0.023
0.023
0.023
0.023
0.023
0.026
0.026
0.026
0.026
0.026
0.027
cfs
1.60
1.60
1.60
1.60
2.00
2.00
2.00
2.00
2.00
2.80
2.85
2.90
2.85
2.85
2.50
2.50
2.00
2.00
2.00
1.70
1.70
1.70
1.70
1.70
1.20
1.20
1.20
1.20
1.20
1.00
1.00
1.00
1.00
1.00
0.90
0.90
0.90
0.90
0.90
0.80
0.80
0.80
0.80
0.80
.0.90
0.90
0.90
0.90
0.90
0.95
Note: Intensities represent averages for time interval preceding
indicated clock time.
190
-------
Table 36. RAINFALL AND RUNOFF DATA FOR THE
STORM OF AUGUST 2, 1963 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Rain intensities
mm/hr
15.2
15.2
15.2
15.2
15.2
15.2
15.2
30.5
15.2
45.5
30.5
30.5
30.5
30.5
30.5
15.2
0.0
0.0
0.0
15.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
in./hr
0.60
0.60
0.60
0.60
0.60
0.60
0.60
1.20
0.60
1.80
1.20
1.20
1.20
1.20
1.20
0.60
0.00
0.00
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Cumulative rain Runoff
mm
0.3
0.5
0.8
1.0
1.3
1.5
1.8
2.3
2.5
3.3
3.8
4.3
4.8
5.3
5.8
6.1
6.1
6.1
6.1
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
in.
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.09
0.10
0.13
0.15
0.17
0.19
0.21
0.23
0.24
0.24
0.24
0.24
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
m3/sec
0.007
0.007
0.007
0.006
0.006
0.007
0.007
0.009
0.014
0.018
0.031
0.043
0.057
0.074
0.102
0.123
0.136
0.137
0.133
0.123
0.116
0.108
0.092
0.081
0.071
0.064
0.057
0.051
0.047
0.043
0.041
0.034
0.030
0.028
0.027
0.025
0.023
0.021
0.020
0.018
0.015
0.017
0.016
0.015
0.014
0.014
0.014
0.014
0.014
0.013
cfs
0.25
0.24
0.23
0.22
0.20
0.23
0.26
0.30
0.50
0.65
1.10
1.50
2.00
2.60
3.60
4.35
4.80
4.85
4.70
4.35
4.10
3.80
3.25
2.85
2.50
2.25
2.00
1.80
1.65
1.50
1.45
1.20
1.05
1.00
0.95
0.87
0.82
0.75
0.70
0.65
0.52
0.59
0.56
0.53
0.50
0.50
0.50
0.50
0.50
0.45
191
-------
Table 36 (Continued).
RAINFALL AND RUNOFF DATA FOR THE
STORM OF AUGUST 2, 1963 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm,
minutes
51
52
53
54
55
56
57
58
59
60
61
62
63
S4
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
Rain intensities
mra/hr
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
30.5
45.5
91.2
15.2
15.2
15.2
0.0
15.2
15.2
30.5
30.5
30.5
30.5
45.5
45.5
45.5
15.2
30.5
30.5
15.2
15.2
15.2
15.2
0.0
0.0
15.2
0.0
in./hr
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.20
1.80
3.60
0.60
0.60
0.60
0.00
0.60
0.60
1.20
1.20
1.20
1.20
1.80
1.80
1.80
0.60
1.20
1.20
0.60
0.60
0.60
0.60
0.00
0.00
0.60
0.00
Cumulative rain
mm
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.9
7.6
9.1
9.4
9.7
9.9
9.9
10.2
10.4
10.9
11.4
11.9
12.5
13.2
14.0
14.7
15.0
15.5
16.0
16.3
16.5
16.8
17.0
17.0
17.0
17.3
17.3
in.
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.27
0.30
0.36
0.37
0.38
0.39
0.39
0.40
0.41
0.43
0.45
0.47
0.49
0.52
0.55
0.58
0.59
0.61
0.63
0.64
0.65
0.66
0.67
0.67
0.67
0.68
0.68
Runoff
m3/sec
0.013
0.013
0.013
0.013
0.011
0.011
0.011
0.011
0.011
0.010
0.010
0.010
0.010
0.010
0.009
0.009
0.009
0.009
0.009
0.007
0.007
0.007
0.007
0.007
0.009
0.028
0.047
0.071
0.077
0.078
0.079
0.082
0.086
0.099
0.113
0.129
0.150
0.164
0.167
0.169
0.164
0.160
0.149
0.142
0.132
0.126
0.113
0.106
0.094
0.085
cfs
0.45
0.45
0.45
0.45
0.40
0.40
0.40
0.40
0.40
0.35
0.35
0.35
0.35
0.35
0.30
0.30
0.30
0.30
0.30
0.25
0.25
0.25
0.25
0.25
0.30
1.00
1.65
2.50
2.70
2.75
2.80
2.90
3.05
3.50
4.00
4.55
5.30
5.80
5.90
5.95
5.80
5.65
5.25
5.00
4.65
4.45
4.00
3.75
3.30
3.00
192
-------
Table 36 (Continued).
RAINFALL AND RUNOFF DATA FOR THE
STORM OF AUGUST 2, 1963 - OAKDALE
AVENUE CATCHMENT
Time from
beginning
of storm, Rain intensities
minutes mm/hr in./hr
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
12j
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
Cumulative rain Runoff
mm in. m3/sec
0.079
0.072
0.061
0.058
0.052
0.050
0.045
0.040
0.035
0.033
0.031
0.030
0.027
0.026
0.024
0.023
0.021
0.020
0.018
0.019
0.017
0.016
0.016
0.015
0.014
0.014
0.014
0.014
0.014
0.013
0.013
0.012
0.017
0.021
0.023
0.021
0.020
0.018
0.017
0.016
0.014
0.014
0.013
0.012
0.011
0.011
0.011
0.011
0.011
0.011
cfs
2.80
2.55
2.15
2.05
1.85
1.75
1.60
1.40
1.25
1.15
1.10
1.05
0.95
0.90
0.85
0.80
0.75
0.70
0.65
0.67
0.60
0.57
0.55
0.52
0.50
0.50
0.50
0.50
0.50
0.45
0.44
0.42
0.60
0.75
0.80
0.75
0.72
0.65
0.60
0.55
0.51
0.48
0.45
0.43
0.40
0.40
0.39
0.39
0.39
0.38
Note: Intensities represent averages for time interval preceding
indicated clock time.
193
-------
Description of the Bloody Run Catchment
The Bloody Run catchment is located in the northwest section of
Cincinnati, Ohio. The catchment is an urban drainage area
comprised of 964 ha (2380 acres) of rolling terrain and diversi-
fied land use, drained by a combined sewerage system designed
for a 10-year frequency (University of Cincinnati, 1970).
Topographically, the area is characterized by two main valleys
running approximately east and west. Most of the commercial
and industrial sections are located in these valleys. The
residential housing is found on the ridges. This watershed
has an average population of about 30 persons/ha (12 persons/
acre) and about 45 percent of its area is pervious. Approxi-
mately 55 percent of the area is residential; 17 percent com-
mercial; 5 percent industrial; and 22 percent open land and
parks. A more detailed division of the basin into different
land uses is presented in Table 37 and Figure 15.
Sewer, topographical and zoning maps were used to divide the
Bloody Run catchment into 37 subcatchments for the runoff simu-
lations. It was intended that each area should include one
major type of land use and incorporate an individual inlet
manhole (University of Cincinnati, 1970). The resulting divi-
sion, together with the sewer system, is shown in Figure 16.
The subcatchments and the elements of the sewer system (pipes
and manholes) are numbered for identification. Physical
characteristics of these subcatchments are presented in Table 38.
The subcatchments varied in size from 7.25 ha (17.9 acres) to
101.3 ha (250.2 acres); the imperviousness varied from 4.9 to
81.4 percent, and the ground slopes from 1.2 to 11.3 percent.
Manning's roughness coefficients were assumed to be 0.013 for
impervious areas and 0.250 for the pervious areas.
Table 39 indicates estimates of soil characteristics for this
catchment. The maximum infiltration, the minimum infiltration
and the decay rate of infiltration were assumed to be 72.2 mm/hr
(3.00 in./hr), 13.2 mm/hr (0.52 in./hr) and 0.00113 sec"1. The
depths of retention storage were assumed to be 4.67 mm (0.184 in.)
for pervious areas and 1.57 mm (0.062 in.) for impervious areas.
The Bloody Run sewer network is a combined system with a main
trunk line that splits into three branches following the valleys
of the drainage basin, as shown in Figure 17. The map shows
the layout of all sewers with dimensions greater than 69 cm
(27 in.). The sewer outfall is located at the southwestern tip
of the catchment and discharges into an interceptor leading to
the Mill Creek Wastwater Treatment Plant. Overflows from storms
are discharged directly into Mill Creek through an open channel.
Manholes are located wherever there is a significant change in
pipe size, direction or slope. Each of the 37 subcatchments
has its individual inlet manhole.
194
-------
Table 37. DIVISION OF BLOODY RUN CATCHMENT
INTO DIFFERENT LAND USES
Area
number
0-1
0-2
0-3
0-4
0-5
0-6
0-7
0-8
RS-1
RS-2
RS-3
RS-4
RS-5
RS-6
RS-7
RM-1
RM-2
RM-3
RM-4
C-l
C-2
C-3
C-4
1-1
1-2
S-l
S-2
H
ha
15.6
7.6
111.3
3.7
14.0
14.0
55.9
13.0
11.2
45.7
64.8
160.3
87.4
31.6
55.7
11.2
34.6
23.3
4.7
15.9
15.4
64.8
18.6
3.7
32.2
14.0
16.2
15.8
962.2
Area
acres
38.5
18.8
275.0
9.2
34.5
34.5
138.0
32.2
27.6
113.0
160.0
396.0
216.0
78.0
137.5
27.6
85.5
57.5
11.5
39.2
38.0
160.0
46.0
9.2
79.5
34.5
40.0
39.0
2376.3
Land use
Open land and parks
Residential,
single- family
Residential,
multi- family
Commercial
Industrial
Schools
Hospital
Total area
housing
housing
195
-------
Ti
"-
r^
/•?
,'V
} '' '
_ -»-' ' 1
x -'"'V'
/- H / ^RM-1
/ -, — / >
A°i; Li
I RS-1
U . 0-3
x V
X ^
/ 0-1 ;' t--N
, \
,-j-~-i RS-2 \
., -l /x- ">• >*_ _.
v_/ _ ^> V. ^
*~ •* *••%
VN t~r — i
RS-3 / V) V 1
%> ul
^T
- - - , 1 [ RM-3 |
r, /' C-3 -^ S.
u C-l / — J\
^^ C 0-5 1
/\ \ i
/ \ 5 ,-rl^ pc c 1
s-,/ \,/|- «" xs ,'
j « ) » r;;:—- ,
~~1 ' \ * 1 s-1 \
K, RM-2 V ^ ,'
lO-4 V \ i | i 0-7
• — ^^ ; v-1-— --- i
( ~.N ' v -•*
/ N ' " \
\ V V '-2 RS-6
' ' "-N /•" N^ ' „
X \ / 0-8 "v-^ «M-4 }
" ~i ~\l^ ^— t S
LJ-^ -, V-t-=^ s
RS-7
\ s
r"
\x
- ^
— "I Rs-4 r"""~v- /
I \ S-2 / ( ° ' OPEN WND AND PARKS
. ~\ / ? RS - RESIDENTIAL SINGLE FAMILY HOUSING
l ^^ ^ RM - RESIDENTIAL MULTI-FAMILY HOUSING
^ ,*" ^ ) C - COMMERCIAL
V.^,J I - INDUSTRIAL
S - SCHOOLS
H - HOSPITAL
Figure 15. Map of Bloody Run catchment, Cincinnati-, Ohio,
showing different land uses
-------
vo
10
3«
2-
SUBCATCHMENT
MANHOLES I (ODD
INPUT MANHOLES/
SEWER CONDUIT (EVEN NUMBERS)
Figure 16. Map of Bloody Run catchment showing subcatchments
and sewer system elements
-------
Table 38. PHYSICAL CHARACTERISTICS OF SUBCATCHMENTS
OF THE BLOODY RUN CATCHMENT
vo
oo
Inlet
Subcatchment manhol
number number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
1
9
15
17
19
21
25
27
31
33
35
37
39
41
43
43
45
47
51
53
57
59
61
65
71
75
77
87
89
91
93
95
97
97
97
101
105
e Length
m
1527.4
800.4
770.2
190.5
353.7
457.2
934.8
419.1
1390.5
228.6
342.9
419.1
419.1
705.9
819.3
438.9
757.7
342.9
381.0
342.9
266.7
342.9
324.0
476.1
476.4
303.0
228.6
342.9
304.8
343.8
378.9
275.5
254.8
253.0
255.4
2316.5
742.5
It
5011
2626
2527
625
1062
1500
3067
1375
4562
750
1125
1375
1375
2316
2688
1440
2486
1125
1250
1125
875
1125
1063
1562
1563
994
750
1125
1000
1128
1243
904
836
830
838
7600
2436
Width
m
466.3
346.9
384.7
1253.3
474.9
295.7
298.7
518.5
728.2
800.1
453.2
789.7
464.2
115.8
355.7
1069.9
487.1
211.2
625.8
501.7
548.0
470.9
1088.4
750.4
255.7
399.3
387.1
711.7
637.3
595.6
705.0
793.1
396.2
800.1
990.3
216.4
266.7
ft
1530
1138
1262
4112
1558
970
980
1701
2389
2625
1487
2591
1523
380
1167
3510
1598
693
2053
1646
1798
1545
3571
2462
839
1310
1270
2335
2091
1954
2313
2602
1300
2625
3249
710
875
Drainage Ground
area Imperviousness, slope,
ha
71.2
27.8
29.6
23.9
15.4
13.5
27.9
21.7
101.3
18.3
15.5
33.1
20.2
8.2
29.1
46.9
36.9
7.2
23.8
17.2
14.6
16.1
35.3
35.7
12.2
12.1
8.9
24.4
19.4
20.5
26.7
21.9
10.1
20.3
25.3
49.4
19.8
acres
176.0
68.6
73.2
59.0
38.0
33.4
69.0
53.7
250.2
45.2
38.4
81.8
49.8
20.2
72.0
116.0
91.2
17.9
58.9
42.5
36.1
39.9
87.1
88.3
30.1
29.9
21.9
60.3
48.0
50.6
66.0
54.0
25.0
50.1
62.5
122.0
49.0
percent
33.7
28.7
53.5
34.7
36.8
38.9
73.3
56.8
51.9
58.5
81.4
54.5
10.8
34.7
20.7
45.6
64.5
24.5
39.8
39.7
42.3
46.4
60.8
38.7
44.6
71.7
56.4
48.7
39.9
29.7
5.0
4.9
16.8
10.9
39.5
49.7
33.8
percent
3.1
3.8
4.4
3.0
11.2
10.5
3.2
9.0
4.0
2.0
4.3
3.2
5.0
3.5
3.5
3.7
2.3
4.0
2.2
1.5
4.2
2.5
5.7
6.3
8.3
6.4
5.9
4.3
3.6
6.6
4.9
2.5
2.7
2.3
1.2
6.6
7.1
Manning ' s n
imperv .
area
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
pervious
area
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
Note: Length is in direction of flow, width is perpendicular to direction of flow, for a rectangular ares
of equal size as the actual subcatchment area.
-------
Table 39. ESTIMATE OF SOIL CHARACTERISTICS
FOR THE BLOODY RUN CATCHMENT
Units
Item
Metric
British
Pervious areas:
Retention storage capacity
Maximum infiltration rate
Minimum infiltration rate
Infiltration decay rate
Impervious areas;
Retention storage capacity
Maximum infiltration rate
Minimum infiltration rate
Infiltration decay rate
4 .7 mm
76.2 mm/hr
13.2 mm/hr
0.184 in.
3.00 in./hr
0.52 in./hr
0.00115 sec'1 0.00113 sec"1
1 - 6 mm
0.0 mm/hr
0.0 mm/hr
0.0 sec"
0.62 in.
0.00 in./hr
0.00 in./hr
0.00 sec"
Notes: The infiltration rates are defined by Horton's
infiltration equation. The retention storage capacities
represent the amount of rain which has to fall before
surface runoff begins.
199
-------
O
O
r
^^APPROXIMATE CATCHMENT BOUNDARY
OUTLET .'
O SAMPLING POINT
A RAIN GAGE
Figure 17. Map of Bloody Run catchment showing sewer layout
and raingage and runoff sampling locations
-------
The sizes, slopes and lengths of the sewer pipes are tabulated
in Table 40. This sewer system utilizes circular pipes with
69 cm (27 in.) to 229 cm (90 in.) diameters, semi-circular
pipes with widths and heights, respectively, of 3.05 m (10 ft)
by 2.44 m (8 ft), 3.35 m (11 ft) by 2.74 m (9 ft) and 3.66 m
(12 ft) by 2.74 m (9 ft), and a rectangular pipe 4.57 m (15 ft)
wide by 3.05 m (10 ft) high. The pipe slopes vary from 0.28 to
5.70 percent. Manning's roughness coefficients of these pipes
were assumed to be 0.013. Cross sections were available for
three of the noncircular sewers (Figure 18).
Monitoring System of the Bloody Run Catchment
Three raingages manufactured by the Belfort Instrument Company
were used to measure and record automatically the accumulative
mass curve of each rain. The raingages consisted of a weighing
mechanism in a prebalanced collection system which caused a pen
to trace changes on a chart. The charts recorded up to 152 mra
(6 in.) of total rainfall. Figure 17 shows the locations of
the three raingages: the Laidlaw and Ridge raingages are located
immediately southwest and southeast of the study area, respec-
tively, and the Woodward raingage is located in the center of
the western half of the Bloody Run catchment.
Runoff for the Bloody Run catchment was measured at five stations
along the sewer network, as shown in Figure 17. These stations,
which are named the Outlet, Longview #1, Longview #2, Bank #1,
and Bank #2 monitoring stations, recorded runoff over a 3-year
period from 1970 through 1972. Samples for water quality
analysis were taken during the stormwater runoff. The flow-
measuring apparatus consisted of a compressor, a manometer,
and a Taylor pressure type recorder. The recorder measured
the pressure due to the depth and velocity of water flowing
in the sewer by bubbling air through a long tube inserted into
the water. Manning's equation was used to compute discharge
from the measured pressure.
Rainfall, Runoff, and Wastewater Quality Data of the
Bloody Run Catchment
Four rainstorms were selected for model testing from the records
of rainfall, runoff, and wastewater quality for approximately
50 rainstorms. Detailed data for these storms have been reported
by the University of Cincinnati (1970 and 1972). The four storms
were selected on the basis of three major criteria: 1) exist-
ence of raingage records for all three raingages; 2) reliability
of the collected data as indicated by the University of
Cincinnati Urban Runoff Project; and 3) variation in hydrograph
shape (intensity and duration of runoff quantity) at the Outlet
monitoring station.
201
-------
Table 40. PHYSICAL CHARACTERISTICS OF THE SEWER
Pipe
number
2
4
6
8
10
12
14
16
18
20
22.
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
96
98
100
102
104
106
Upstream Diameter
manhole or height Width
number m ft m
1
3
7
9
5
11
13
15
17
19
21
25
23
29
31
27
33
35
37
39
43
45
47
49
51
53
55
57
59
61
63
65
67
69
71
73
75
77
79
81
83
85
87
89
91
41
95
93
97
101
99
103
105
1.4
1.4
1.2
1.2
1.7
1.8
1.9
1.8
1.8
2.0
2.1
1.5
2.3
1.5
1.5
2.4
2.4
2.4
2.7
2.7
2.7
2.7
2.4
1.4
1.1
0.9
2.0
1.1
2.0
1.7
1.5
1.4
2.0
1.8
1.7
1.7
1.7
1.2
1.2
1.1
0.9
0.8
0.7
1.2
1.1
3.0
1.2
3.0
3.0
1.4
3.0
3.0
3.0
4.
4.
4.
4.
5.
6.
6.
6.
6.
6.
7.
5.
7.
5.
5.
8.
8.
8.
9.
9.
9.
9.
8.
4.
3.
3.
6.
3.
6.
5.
5.
4.
6.
6.
5.
5.
5.
4.
4.
3.
3.
2.
2.
4.
3.
10.
4.
10.
10.
4.
10.
10.
10.
50
50
00
00
50
00
25
00
00
50
00
00
50
00
00
00 3.05
00 3.05
00 3.05
00 3.35
00 3.35
00 3.66
00 3.66
00
50
50
00
50
50
50
50
00
50
50
00
50
50
50
00
00
50
00
75
25
00
50
00 4.6
00
00 4.6
00 4.6
50
00 4.6
00 4.6
00 4.6
ft
10.00
10.00
10.00
11.00
11.00
12.00
12.00
15.00
15.00
15.00
15.00
15.00
15.00
Length
m
120.
210.
115.
142.
97.
105.
175.
141.
435.
436.
202.
45.
377.
228.
213.
213.
274.
133.
449.
106.
510.
436.
181.
88.
70.
23.
213.
63.
135.
331.
141.
144.
381.
283.
111.
123.
243.
146.
108.
77.
118.
104.
99.
261.
518.
667.
51.
236.
150.
215.
152.
474.
101.
ft
1
1
9
3
4
2
9
0
4
5
4
6
5
6
4
4
3
6
2
7
0
9
5
8
5
2
0
8
0
0
2
9
6
6
3
4
9
6
0
3
7
2
3
5
2
5
8
2
9
3
4
3
8
394
689
380
467
319
345
577
462
1428
1432
664
149
1238
750
700
700
900
438
1473
350
1673
1433
595
291
231
76
698
209
442
1086
463
475
1251
930
365
404
800
481
354
253
389
342
325
858
1700
2190
170
775
495
706
500
1556
334
.0
.3
.4
.0
.4
.3
.0
.7
.5
.0
.0
.7
.5
.0
.0
.0
.0
.3
.6
.0
.1
.4
.4
.2
.2
.0
.7
.3
.8
.0
.4
.5
.9
.4
.0
.7
.2
.0
.4
.6
.4
.0
.9
.0
.0
.0
.0
.0
.0
.5
.0
.0
.0
Invert
slope,
percent
2.60
2.30
2.20
2.60
1.40
0.90
1.00
1.40
1.80
1.25
1.10
1.00
1.30
1.20
1.00
0.70
0.70
0.70
0.40
0.40
0.30
0.28
0.60
1.30
2.40
3.40
0.90
2.10
0.80
1.30
1.50
1.50
0.86
1.00
1.90
2.30
1.10
1.57
2.18
5.70
1.42
1.67
1.65
2.10
1.50
0.28
0.90
0.32
0.32
0.50
0.32
0.34
0.34
Manning's
n
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.013
Note: Diameters are for circular pipes, heights and widths for
non-circular pipes.
202
-------
2.74m
(91)
61m
-0")
-"
R = 5.17m R =
(16--11-1/2") ,(5'-6")
SEMICIRCULAR SEWER CROSS-SECTION
12' X 9' AT MONITORING STATION LONGVIEW II
SEMICIRCULAR SEWER CROSS-SECTION
11' X 9' AT MONITORING STATION LONGVIEW #2
ro
o
U)
3.05m
R - 7.05m no'-O")
(23'-1-1/2") ( '
RECTANGULAR SEWER CROSS-SECTION
15' x 10' AT MONITORING STATION OUTLET
Figure 18. Cross-sections of noncircular sewers of Bloody Run catchment
-------
The dates of the selected rainstorms are November 9, 1970;
November 14, 1970; May 13, 1971; and August 25 and 26, 1971.
Table 41 lists the numbers of tables and figures which present
the measured rainfall, runoff and wastewater quality data for
tne selected storms. As indicated by the blank spaces in
Table 41, not all parameters were measured at all stations
for all four storms. Communication with the University of
Cincinnati indicated, however, that these storms represent
a fair compromise between completeness of data, reliability
of data, and variety of rainfall and runoff shapes and
durations.
The storm of November 9, 1970, (Figures 19-21 and Tables 42-45)
had two light, short-duration rainfalls interspersed by a long
dry period. The first rainfall was relatively larger than the
second one, but the runoff produced by this storm shows two
small peaks of about equal magnitude. Suspended solids and
BOD were measured for about 1 hour during the early part of
the storm. Water quality data are not available for this
storm at the Outlet monitoring station.
The storm of November 14, 1970, (Figures 22-24 and Tables 46-49)
had relatively light and constant rainfall over a long duration.
The runoff at the Outlet monitoring station had three large
peaks, with irregular forms in the early half of the storm.
The three peaks were followed by lower and fairly constant
runoff which gradually decreased to the dry weather discharge.
Suspended solids and BOD were measured for about 1 hour during
the middle of the storm period.
The storm of May 13, 1971, (Figures 25-27 and Tables 50-53)shows
two rainfall periods, the first heavier than the second. The
rainfall pattern is similar to the storm of November 9, 1970,
but the May 13, 1971 rainfall lasted longer and produced higher
intensities. The time interval between the two rainfall periods
for this storm was also shorter than for the November 9, 1970
storm. The resulting runoff at the Outlet monitoring station
shows one large peak during the early part of the storm and a
small peak near the end of the storm. Suspended solids and BOD
were measured for about 1-1/2 hours, starting approximately
1 hour after the beginning of the rainfall.
The storm of August 25 and 26, 1971, (Figures 28-30 and Tables
54-57) had short duration but very intensive rainfalls which
occurred intermittently over a 10-hour period. The runoff was
measured only during the first 3 or 4 hours of the storm,
reflecting only the first and second rainfall bursts. The
runoff at the Outlet monitoring station shows two large peaks
with relatively short intervals between them. Suspended solids
and BOD were measured only during the early stage of the storm.
204
-------
Table 41. SUMMARY OF AVAILABLE RUNOFF RECORDS FOR RAINSTORMS
OF BLOODY RUN CATCHMENT SELECTED FOR MODEL TESTING
Date of
Storm
November 9,
1970
November 14,
1970
May 13,
1971
August 25
& 26, 1971
Recorded Data
Runoff
Suspended solids
BOD
Runoff
Suspended solids.
BOD
Runoff
Suspended solids
BOD
Runoff
Suspended solids
BOD
Monitorinq station
Outlet Longview tl Longview #2 Bank 11 Bank #2
Table *
43
47
51
52
53
55
56
57
Fiqure #
19
22
25
26
27
28
29
30
Table *
43
45
47
49
51
Figure #
19
21
22
24
25
Table #
43
45
47
49
51
55
Figure #
19
21
22
24
25
28
Table t
43
44
45
47
48
49
51
55
Fiqure I
19
20
21
22
23
24
25
28
Table ft
44
45
48
49
51
55
Fiqure #
20
21
23
24
25
28
O
Ul
-------
- LfllDLflW
s
- RIDSE
2--o!
ffl
UJ
cs
Q
- VOODVRRD
CD OUTLET
i r-
22.00 23.
—i
24.ee
3D
rn
o
17.98
~~l 1
ia.ee i9.ee
—i
ae.ee
21 ee 22
TIME, HOURS
2s.ee 26.ee
Figure 19a. Rainfall Hyetographs and Runoff Hydrographs
for the Storm of November 9, 1970.-
Bloody Run Catchment
206
-------
1 LONSVIEW NO. 1
2 LONGVIEV NO. 2
3 BflNK NO. 1
I7.N
ie.M
Figure 19b. Runoff Hydrographs for the Storm of
November 9, 1970 - Bloody Run Catchment
26.88
*J
it
58-
3 BflNK NO. 1
1 BflNK NO. 2
—1
23.88
~I
29.88
17.88
18.
18.88
28.80
T^ME. HOURS'"
24.88
26.88
Figure 20. Suspended Solids Concentrations for the Storm
Runoff of November 9, 1970 - Bloody Run
Catchment
207
-------
or „
ocS
§*•
CJ
o
CJ
R-
1 LON6VIEV NO. 1
2 LONGVIEV NO. 2
3 BRNK NO. 1
4 BRNK NO. 2
1
1
1
1
1
- 1 - 1 - 1
17.00 18.80 19.W 29.98 21.98 22.98 23.98 24.98 25.99 26.98
TIME. HOURS
Figure 21. Biochemical Oxygen Demand Concentrations for
the Storm Runoff of November 9, 1970 - Bloody
Run Catchment
208
-------
- LfllDLftV
«.
S
- RIDGE
S--i
e-Hs-
7.00
- WOODWRRD
o OUTLET
1 LONGVIEW NO. 1
»-•
, AS'
*S' i' i ^4^
-------
2 LONGVIEW NO. 2
3 BflNK NO. 1
7.M
8.M
9.00
10.00
1.00 12.00
"":. HOURS
13.00 14.00 1S.00 16.00
Figure 22b. Runoff Hydrographs for the Storm of
November 14, 1970 - Bloody Run Catchment
Ss-
3 BflNK NO. 1
ft BflNK NO. 2
7.00 e.M 9,
.00 10.00 11.00 12.00
TIME. HOURS
13.00 14.00 15.00 16.00
Figure 23. Suspended Solids Concentrations for the Storm
Runoff of November 14, 1970 - Bloody Run
Catchment
210
-------
1
i-
o
o
is-
1 LON6VIEV NO. 1
2 LON6VIEW NO. 2
3 BflNK NO. 1
4 BflNK NO. 2
7.M
6.M
9.N
10.90
11.00 12.
TIME, HOURS
12.00
13.00
1(1.00
15.00
16.
Figure 24. Biochemical Oxygen Demand Concentrations for
the Storm Runoff of November 14, 1970 -
Bloody Run Catchment
211
-------
"F
"8
LfllDLfflf $"-
c5
Irl
- RIDGE
-§
i [ -«
S
-------
1 LONGVIEW NO. 1
2 LONGVIEW NO. 2
3 BflNK NO. 1
4 BflNK NO. 2
3.N
I.M
3.M
6.88
/fME. HOURif
9.88
18.88
11.88
Figure 25b. Runoff Hydrographs for the Storm of
May 13, 1971 - Bloody Run Catchment
12.88
• OUTLET
8.N
1.88
3.88
6.88
9.88
18. N
11.88
12. N
Figure 26. Suspended Solids Concentrations for the Storm
Runoff of May 13, 1971 - Bloody Run Catchment
213
-------
I-
gt
/'
t—t
k
53
(_>
s
OUTLET
3.00
I.M
5.M
6.N
T7fME. HOURS"
9.1
19.«
U.M
12.00
Figure 27. Biochemical Oxygen Demand Concentrations for
the Storm Runoff of May 13, 1971 - Bloody
Run Catchment
214
-------
- LRIDLRW
84-?
8
"\l ""
- RIDGE
u
J
Lr
8-
£
g-
g
- WOODWARD
OUTLET
2 LONGVIEW NO. 2
11M
15. M
'. HOURS'
23. M
Figure 28a. Rainfall Hyetographs and Runoff Hydrographs
for the Storm of August 25, 1971 -
Bloody Run Catchment
215
-------
3 BflNK NO. 1
4 BftNK NO. 2
11.00
15.90
16.00
17.00
TIH?. HOURS*"
20.90
21. t
Figure 28b. Runoff Hydrographs for the Storm of
August 25, 1971 - Bloody Run Catchment
o
•—0
is
gs-
o
o
2
R'H
o OUTLET
1 1 1
14.98 15.00 16.00 17.00
1 1 1 1
.00 19.00 20.00 21.00 22.00 23.00
ME. HOURS
Figure 29. Suspended Solids Concentrations for the
Storm Runoff of August 25, 1971 - Bloody
Run Catchment
216
-------
-
R-
OUTLET
P+r
i
»+J
I
i
29.
21.M
22.99 23.99
Figure 30. Biochemical Oxygen Demand Concentrations for
the Storm Runoff of August 25, 1971 - Bloody
Run Catchment
217
-------
Table 42. RAINFALL DATA OF THE STORM OF NOVEMBER 9, 1970 -
BLOODY RUN CATCHMENT
NJ
M
00
Rain intensities
Time,
hr :min
18:00
18:05
18:10
18:15
18:20
18:25
18:30
18:35
18:40
18:45
18:50
18:55
19:00
19:05
19:10
19:15
19:20
19:25
19: 30
19:35
19:40
19:45
19:50
19:55
20:00
20:05
20:10
Woodward
raingage
mm/hr
0.0
3.0
6.1
3.0
3. 0
1.5
4.6
1.5
1.5
1.5
3.0
1.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.5
1.5
1.5
0.0
in. /hr
0.00
0.12
0.24
0.12
0.12
0.06
0.18
0.06
0.06
0.06
0.12
0.06
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.06
0.06
0.06
0.00
Ridge
raingage
mm/hr
0.0
3.0
6.1
3.0
3. 0
3.0
1.5
1.5
1.5
1.5
6.1
6.1
6.1
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
0.0
in. /hr
0.00
0.12
0.24
0.12
0.12
0.12
0.06
0.06
0.06
0.06
0.24
0.24
0.24
0.12
0.12
0.12
0.12
0.12
0.12
0.12
0.12
0.12
0.12
0.12
0.12
0.00
Laidlaw
raingage
mm/hr
0.0
4.6
4.6
4.6
3.0
1.5
1.5
3.0
1.5
1.5
1.5
1.5
1.0
1.0
0.5
0.0
in. /hr
0.00
0.18
0.18
0.18
0.12
0.06
0.06
0.12
0.06
0.06
0.06
0.06
0.04
0. 02
0.02
0.00
Cumulative rain
Woodward
raingage
mm
0.0
0.3
0.8
1.0
1.3
1.4
1.8
1.9
2.0
2.2
2.4
2.5
2.5
2.5
2.5
2.5
2. 5
2.5
2.5
2.5
2.5
2.5
2.7
2.8
2.9
2.9
in.
0.00
0.01
0.03
0.04
0.05
0.06
0.07
0.08
0.08
0.09
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.11
0.11
0.12
0.12
0.12
Ridge
raingage
mm
0.0
0. 3
0.8
1.0
1.3
1.5
1. 7
1.8
1.9
2.0
2.5
3.0
3.6
3.8
4.1
4. 3
4.6
4.8
5.1
5. 3
5.6
5.8
6.1
6.4
6.6
6.6
in .
0.00
0.01
0.03
0.04
0.05
0.06
0.07
0.07
0.08
0.08
0.10
0.12
0.14
0.15
0.16
0.17
0.18
0.19
0.20
0.21
0.22
0.23
0.24
0.25
0.26
0.26
Laidlaw
raingage
mm
0.0
0.4
0.8
1.1
1.4
1.5
1. 7
1.9
2.0
2.2
2.3
2.4
2.5
2.5
2.6
' 2.6
in .
0.00
0.02
0.03
0.05
0.06
0.06
0.07
0.08
0.08
0.09
0.09
0.10
0.10
0.10
0.10
0.10
Note: Intensities represent averages for time interval preceding indicated clock time.
-------
Table 43. RUNOFF DATA OF THE STORM OF NOVEMBER 9, 1970 -
BLOODY RUN CATCHMENT
Runoff
Time
hr :min: sec
17:
17:
17:
17:
18:
18:
18:
18:
18:
18:
18:
18:
19:
30:00
37:30
45:00
52:30
00:00
07:30
15:00
22:30
30:00
37:30
45:00
52:30
00:00
19:07:30
19:
19:
19:
19:
19:
19:
20:
20:
20:
20:
20:
20:
20:
20:
21:
15:00
22:30
30:00
37:30
45:00
52:30
00:00
07:30
15:00
22:30
30:00
37:30
45:00
52:50
00:00
Outlet
m^/sec cfs
0.361
0.361
0.425
0.467
0.510
0.595
0.722
1.020
2.124
3.398
2.761
3.101
2.528
2.336
2.528
2.336
2.124
2.082
1.678
1.381
1.062
0.828
0-25C
0.637
0.637
0.658
0.637
0.616
0.616
12
12
15
16
18
21
25
36
75
120
97
109
89
82
89
82
75
73
59
48
37
29
30
22
22
23
22
21
21
.75
.75
.00
.50
.00
.00
.50
.00
.00
.00
.50
.50
.25
.50
.25
.50
.00
.50
.25
.75
.50
.25
.00
.50
.50
.25
.50
.75
.75
Longview 11
mVsec
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
c.
0.
0.
0.
0.
0.
0.
109
156
213
275
275
256
256
245
213
186
156
131
120
114
104
095
097
097
097
093
095
090
087
082
cfs
3.85
5.49
7.51
9.72
9.72
9.05
9.05
8.66
7.51
6.55
5.49
4.62
4.24
4.04
3.66
3.37
3.47
3.47
3.47
3.27
3.37
3.18
3.08
2.89
Longview if 2
Bank
m^/sec cfs m3/sec
0
0
0
0
0
0
0.019 0.66 0
0.023 0.82 0
0.026 0.92 0
0.028 0.99 0
0.029 1.02 0
0.019 0.67 0
0
0
.033
.033
.033
.065
.041
.039
.035
.041
.035
.039
.030
.026
.024
.016
11
Bank #2
cfs m^/sec cfs
1.
1.
1.
2.
1.
1.
1.
1.
1.
1.
1.
0.
0.
0.
15
15
15
29
46
36
25
46
25
36
04
92
86
58
Note: Runoff values were scaled from figures published by the University of
Cincinnati (1972). Blank spaces indicate no measurements.
219
-------
Table 44. SUSPENDED SOLIDS CONCENTRATIONS
OF THE STORM OF NOVEMBER 9, 1970
BLOODY RUN CATCHMENT
Time,
hr:min:sec Outlet
19:15:00
19:22:30
19:30:00
19:37:30
19:45:00
19:52:30
20:00:00
Concentrations , mg/1
Longview Longview Bank
#1 #2 fl
186
172
154
132
128
Bank
12
148
132
125
98
90
76
Note: Blank spaces indicate no measurements.
Table 45. BIOCHEMICAL OXYGEN DEMAND CONCENTRATIONS
OF THE STORM RUNOFF OF NOVEMBER 9, 1970 -
BLOODY RUN CATCHMENT
Concentrations, mg/1
Time,
hr:min:sec Outlet
18:50:00
18:57:30
19:05:00
19:12:30
19:15:30
19:20:00
19:22:30
19:27:30
19:30:00
19:35:00
19:37:30
19:42:30
19:45:00
19:50:00
19:52:30
19:57:20
20:00:00
Longview
11
85
47
68
108
111
121
102
120
39
115
Longview
#2
27
31
144
99
93
54
65
56
96
88
Bank
11
158
171
138
118
99
Bank
#2
151
99
133
138
118
85
Note: Blank spaces indicate no measurements.
220
-------
Table 46. RAINFALL DATA OF THE STORM OF NOVEMBER 14, 1970 -
BLOODY RUN CATCHMENT
to
Rain intensities
Time,
hr : min
07:25
07:30
07:35
07:40
07:45
07:50
07:55
08:00
08:05
08:10
08:15
08:20
08:25
08:30
08:35
08:40
08:45
08:50
08:55
09:00
09:05
09:10
09:15
09:20
09:25
09:30
09:35
09:40
09:45
09:50
Woodward
raingage
nun/hr
0.0
3.0
3.0
3.0
3.0
0.0
3.0
1.5
1.5
1.5
1.5
3.0
3.0
3.0
3.0
1.5
1.5
6.1
1.5
1.5
1.5
1.5
3.0
3.0
3.0
3.0
6.1
3.0
6.1
1.5
in./hr
0.00
0.12
0.12
0.12
0.12
0.00
0.12
0.06
0.06
0.06
0.06
0.12
0.12
0.12
0.12
0.06
0.06
0.24
0.06
0.06
0.06
0.06
0.12
0.12
0.12
0.12
0.24
0.12
0.24
0.06
Ridge
raingage
mm/hr
0.0
3.0
3.0
3.0
3.0
0.0
3.0
1.5
1.5
3.0
3.0
1.5
1.5
3.0
0.0
0.0
0.0
0.0
0.0
3.0
3.0
in. /hr
0.00
0.12
0.12
0.12
0.12
0.00
0.12
0.06
0.06
0.12
0.12
0.06
0.06
0.12
0.00
0.00
0.00
0.00
0.00
0.12
0.12
Laidlaw
raingage
nun/hr
0.0
2.0
2.0
1.8
1.0
1.3
1.0
3.0
1.5
1.5
1.5
1.5
4.6
1.5
1.5
1.5
2.0
1.0
0.8
1.0
1.0
0.8
1.0
1.0
0.8
1.0
in. /hr
0.00
0.08
0.08
0.07
0.04
0.05
0.04
0.12
0.06
0.06
0.06
0.06
0.18
0.06
0.06
0.06
0.08
0.04
0.03
0.04
0.04
0.03
0.04
0.04
0.03
0.04
Cumulative rain
Woodward
raingage
mm
0.0
0.3
0.5
0.8
1.0
1.0
1.3
1.4
1.5
1.7
1.8
2.0
2.3
2.5
2.8
2.9
3.0
3.6
3.7
3.8
3.9
4.1
4.3
4.6
4.8
5.1
5.6
5.8
6.4
6.5
in.
0.00
0.01
0.02
0.03
0.04
0.04
0.05
0.06
0.06
0.07
0.07
0.08
0.09
0.10
0.11
0.12
0.12
0.14
0.15
0.15
0.16
0.16
0.17
0.18
0.19
0.20
0.22
0.23
0.25
0.26
Ridge
raingage
mm
0.0
0.3
0.5
0.8
1.0
1.0
1.3
1.4
1.5
1.8
2.0
2.2
2.3
2.5
2.5
2.5
2.5
2.5
2.5
2.8
3.0
in.
0.00
0.01
0.02
0.03
0.04
0.04
0.05
0.06
0.06
0.07
0.08
0.09
0.09
0.10
0.10
0.10
0.10
0.10
0.10
0.11
0.12
Laidlaw
raingage
mm
0.0
0.2
0.3
0.5
0.6
0.7
0.8
1.0
1.1
1.3
1.4
1.5
1.9
2.0
2.2
2.3
2.5
2.5
2.6
2.7
2.8
2.8
2,9
3.0
3.1
3.2
in.
0.00
0.01
0.01
0.02
0.02
0.03
0.03
0.04
0.05
0.05
0.06
0.06
0.08
0.08
0.09
0.09
0.10
0.10
0.10
0.11
0.11
0.11
0.11
0.12
0.12
0.12
-------
Table 46 (Continued).
RAINFALL DATA OF THE STORM OF NOVEMBER 14, 1970 -
BLOODY RUN CATCHMENT
NJ
K)
Rain intensities
Time,
hr : min
09:55
10:00
10:05
10:10
10:15
10:20
10:25
10:30
10:35
10:40
10:45
10:50
10:55
11:00
11:05
11:10
11:15
11:20
11:25
11:30
11: 35
11:40
11:45
11:50
11:55
12:00
12:05
12:10
12:15
12:20
Woodward
raincjage
mm/hr
3.0
4.6
3.0
3.0
3.0
3.0
3.0
4.6
1.5
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
0.0
3.0
3.0
0.0
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
3.0
in./hr
0.12
0.18
0.12
0.12
0.12
0.12
0.12
0.18
0.06
0.12
0.12
0.12
0.12
0.12
0.12
0.12
0.12
0.00
0.12
0.12
0.00
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.12
Ridge
raingage
nun/hr
3.0
3.0
0.0
1.5
1.5
1.5
1.5
3.0
3.0
3.0
1.5
1.5
3.0
3.0
3.0
3.0
0.0
3.0
1.5
1.5
1.5
1.5
3.0
1.5
0.0
0.0
1.5
3.0
0.0
0.0
in ,/hr
0.12
0.12
0.00
0.06
0.06
0.06
0.06
0.12
0.12
0.12
0.06
0.06
0.12
0.12
0.12
0.12
0.00
0.12
0.06
0.06
0.06
0.06
0.12
0.06
0.00
0.00
0.06
0.12
0.00
0.00
Laidlaw
raingage
nun/hr
1.0
0.8
1.0
1.0
1.0
1.0
1.0
1.0
3.0
3.0
3.0
0.8
0.8
1.3
1.8
2.0
2.0
1.8
2.0
2.0
1.3
1.3
1.3
1.3
1.3
1.5
0.5
0.5
0.5
0.5
in./hr
0.04
0.03
0.04
0.04
0.04
0.04
0.04
0.04
0.12
0.12
0.12
0.03
0.03
0.05
0.07
0.08
0.08
0.07
0.08
0.08
0.05
0.05
0.05
0.05
0.05
0.06
0.02
0.02
0.02
0.02
Cumulative rain
Woodward
raingage
ram
6.7
7.1
7.4
7.6
7.9
8.1
8.4
8.8
8.9
9.1
9.4
9.7
9.9
10.2
10.4
10.7
10.9
10.9
11.2
11.4
11.4
11.6
11.7
11.8
11.9
12.1
12.2
12.3
12.4
12.7
in.
0.27
0.28
0.29
0.30
0.31
0.32
0.33
0.35
0.35
0.36
0.37
0.38
0.39
0.40
0.41
0.42
0.43
0.43
0.44
0.45
0.45
0.46
0.46
0.47
0.47
0.48
0.48
0.49
0.49
0.50
Ridge
raingage
mm
3.3
3.6
3.6
3.7
3.8
3.9
4.1
4.3
4.6
4.8
5.0
5.1
5.3
5.6
5.8
6.1
6.1
6.4
6.5
6.6
6.7
6.9
7.1
7.2
7.4
7.4
7.4
7.6
7.6
7.6
in .
0.13
0.14
0.14
0.15
0.15
0.16
0.16
0.17
0.18
0.19
0.20
0.20
0.21
0.22
0.23
0.24
0.24
0.25
0.26
0.26
0.27
0.27
0.28
0.29
0.29
0.29
0.29
0.30
0.30
0.30
Laidlaw
raingage
mm
3.2
3.3
3.4
3.5
3.6
3.6
3.7
3.8
4.1
4.3
4.6
4.6
4.7
4.8
5.0
5.1
5.3
5.4
5.6
5.8
5.9
6.0
6.1
6.2
6.3
6.4
6.5
6.5
6.6
6.6
in.
0.13
0.13
0.13
0.14
0.14
0.14
0.15
0.15
0.16
0.17
0.18
0.18
0.19
0.19
0.20
0.20
0.21
0.21
0.22
0.23
0.23
0.24
0.24
0.24
0.25
0.25
0.26
0.26
0.26
0.26
-------
Table 46 (Continued).
N)
NJ
UJ
RAINFALL DATA OF THE STORM OF NOVEMBER 14, 1970 -
BLOODY RUN CATCHMENT
Rain intensities
Time,
hr : min
12:25
12:30
12:35
12:40
12:45
12:50
12:55
13:00
13:05
13:10
13:15
13:20
13:25
13:30
13:35
13:40
13:45
13:50
13:55
14:00
14:05
14:10
14:15
14:20
14:25
14:30
14:35
14:40
14:45
14:50
Woodward
raingage
mm/hr
1.5
1.5
3.0
1.5
1.5
3.0
3.0
1.5
1.5
1.5
4.6
1.5
1.5
1.5
1.5
1.5
0.0
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
in./hr
0.06
0.06
0.12
0.06
0.06
0.12
0.12
0.06
0.06
0.06
0.18
0.06
0.06
0.06
0.06
0.06
0.00
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
Ridge
raingage
mm/hr
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
3.0
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
3.0
3.0
in./hr
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.12
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.12
0.12
Laidlaw
raingage
mm/hr
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.8
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.0
in./hr
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.03
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.00
Cumulative rain
Woodward
raingage
mm
12.8
13.0
13.2
13.3
13.5
13.7
13.7
13.8
14.0
14.1
14.5
14.6
14.7
14.9
15.0
15.1
15.2
15.4
15.5
15.6
15.7
15.9
16.0
16.1
16.3
16.4
16.5
16.6
16.8
16.9
in.
0.51
0.51
0.52
0.53
0.53
0.54
0.54
0.55
0.55
0.56
0.57
0.58
0.58
0.59
0.59
0.60
0.60
0.61
0.61
0.62
0.62
0.63
0.63
0.64
0.64
0.65
0.65
0.66
0.66
0.67
Ridge
raingage
mm
7.6
7.6
7.6
7.6
7.6
7.6
7.6
7.6
7.6
7.6
7.9
8.0
8.1
8.3
8.4
8.5
8.6
8.8
8.9
8.9
8.9
8.9
8.9
8.9
8.9
8.9
8.9
8.9
9.1
9.4
an.
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.31
0.32
0.32
0.33
0.33
0.34
0.34
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.36
0.37
Laidlaw
raingage
mm
6.7
6.7
6.7
6.8
6.8
6.9
6.9
7.0
7.0
7.1
7.1
7.1
7.2
7.2
7.3
7.3
7.3
7.4
7.4
7.5
7.5
in.
0.26
0.26
0.27
0.27
0.27
0.27
0.27
0.27
0.28
0.28
0.28
0.28
0.28
0.28
0.29
0.29
0.29
0.29
0.29
0.29
0.29
-------
Table 46 (Continued).
RAINFALL DATA OF THE STORM OF NOVEMBER 14, 1970 -
BLOODY RUN CATCHMENT
tvj
NJ
*>.
Rain intensities
Time,
hr : min
14:55
15:00
15.05
15:10
15:15
15:20
15:25
15:30
15: 35
15:40
15:45
15:50
15:55
16:00
16:05
16:10
16:15
16:20
16:25
16:30
16:35
16:40
16:45
16:50
16:55
Woodward
raingage
iran/hr
1.5
1.5
1.5
1.5
1.5
1.5
1.0
0.5
1.0
0.5
1.5
0.5
1.0
1.5
1.5
1.5
1.5
1.5
1.3
0.5
0.3
0.3
0.3
0.3
0.0
in./hr
0.06
0.06
0.06
0.06
0.06
0.06
0.04
0.02
0.04
0.02
0.06
0.02
0.04
0.06
0.06
0.06
0.06
0.06
0.05
0.02
0.01
0.01
0.01
0.01
0.00
Cumulative
Ridge Laidlaw Woodward
raingacje raingage raingage
ram/hr
3.0
3.0
3.0
1.5
0.0
0.0
0.0
0.0
0.0
0.0
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
0.0
in,
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
. /hr mm/hr
.12
.12
.12
.06
.00
.00
.00
.00
.00
.00
.06
.06
.06
.06
.06
.06
.06
.06
.06
.06
.00
in./hr mm
17.
17.
17.
17.
17.
17.
17.
17.
17.
17.
18.
18.
18.
18.
18.
18.
18.
18.
18.
18.
19.
19.
19.
19.
19.
0
1
3
4
5
7
8
8
8
9
0
1
2
3
4
5
7
8
9
9
0
0
0
0
0
in.
0.67
0.68
0.68
0.69
0.69
0.70
0.70
0.70
0.70
0.71
0.71
0.71
0.72
0.72
0.73
0.73
0.74
0.74
0.74
0.75
0.75
0.75
0.75
0.75
0.75
rain
Ridge Laidlaw
raingage raingage
mm
9.7
9.9
10.2
10.3
10.4
10.4
10.4
10.4
10.4
10.4
10.4
10.5
10.7
10.8
10.9
11.0
11.2
11.3
11.4
11.6
11.6
in. mm in.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
38
39
40
41
41
41
41
41
41
41
41
42
42
43
43
44
44
45
45
46
46
Note: Intensities represent averages for time interval preceding indicated clock time.
-------
Table 47. RUNOFF DATA OF THE STORM OF NOVEMBER 14, 1970 -
BLOODY RUN CATCHMENT
Runoff
Time
hr :min:sec
07:30
07:37
07:45
07:52
08:00
08:07
08:15
08:22
08:30
08:37
08:45
08:52
09:00
09:07
09:15
09:22
09:30
09:37
09:45
09:52
10:00
10:07
10:15
10:22
10:30
10:37
10:45
10:52
11:00
11:07
11:15
11:22
11:30
11:37
11:45
11:52
12:00
12:07
12:15
12:22
12:30
12:37
12:45
12:52
13:00
13:07
13:15
13:22
13:30
13:37
13:45
13:52
14:00
14:07
14:15
14:22
14:30
14:37
14:45
14:52
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:00
:00
:30
:00
:30
:00
:30
:00
-.30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:00
Outlet
m-Vsec cfs
0.332
0.332
1.174
2.832
6.302
4.282
3.919
4.282
3.540
3.177
2.832
2.435
1.899
2.832
4.282
3.540
5.525
4.282
3.540
3.540
2.832
4.282
6.302
6.302
5.525
3.540
3.177
2.832
2.124
2.124
2.124
2.124
2.832
3.540
2.124
2.124
2.832
2.124
2.124
2.124
2.124
2.124
2.124
2.124
2.124
2.124
2.124
2.124
2.124
2.124
2.124
2.124
11.
11.
41.
100.
222.
151.
138.
151.
125.
112.
100.
85.
67.
100.
151.
125.
195.
151.
125.
125.
100.
151.
222.
222.
195.
125.
112.
100.
75.
75.
75.
75.
100.
125.
75.
75.
100.
75.
75.
75.
75.
75.
75.
75.
75.
75.
75.
76.
75.
75.
75.
75.
71
71
46
00
56
22
41
22
00
20
00
98
07
00
22
00
12
22
00
00
00
22
56
56
12
OC
20
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
Longview #1
m^/sec
0.437
0.828
0.828
0.943
1.450
1.864
2.002
2.301
2.301
2.577
2.715
2.784
2.669
2.669
2.715
2.669
2.577
2.623
2.669
2.669
2.968
2.853
2.922
2.945
3.106
3.405
3.543
3.773
3.819
3.911
3.911
3.773
3.405
3.106
3.106
3.106
3.037
3.037
2.807
2.669
2.623
2.577
2.347
2.186
2.347
2.117
2.002
1.886
1.979
1.979
2.186
2.070
2.002
2.002
1.979
1.979
2.002
Longview #2
cfs ru^/sec
15.
29.
29.
33.
51.
65.
70.
81.
81.
91.
95.
98.
94.
94.
98.
94.
91.
92.
94.
94.
104.
100.
103.
104.
109.
120.
125.
133.
134.
138.
138.
133.
120.
109.
109.
109.
107.
107.
99.
94.
92.
91.
82.
77.
82.
74.
70.
66.
69.
69.
77.
73.
70.
70.
69.
69.
70.
44
25
25
31
19
81
69
25
25
00
88
31
25
25
31
25
00
62
25
25
81
75
19
00
69
25
12
25
88
12
12
25
25
69
69
69
25
25
12
25
62
00
88
19
88
75
69
62
89
89
19
12
69
69
89
89
69
0.170
0.187
0.295
0.315
0.337
0.362
0.367
0.394
0.421
0.394
0.299
0.292
0.288
0.289
0.294
0.306
0.319
0.334
0.351
0.557
0.449
0.476
0.603
0.652
0.621
0.647
0.605
0.605
0.605
0.652
0.428
0.417
0.394
0.384
0.367
0.333
0.333
0.254
0.221
0.215
0.211
0.199
cfs
6.00
6.62
10.42
11.14
11.90
12.77
12.96
13.92
14.88
13.92
10.56
10.32
10.18
10.22
10.37
10.80
11.28
11.81
12.38
19.68
15.84
16.80
21.31
23.04
21.94
22.85
21.36
21.36
21.36
23.04
15.12
14.74
13.92
13.58
12.96
11.76
11.76
8.98
7.82
7.58
7.44
7.01
Bank
m^/sec
0.017
0.025
0.028
0.042
0.065
0.059
0.065
0.068
0.073
0.088
0.073
0.068
0.064
0.066
0.066
0.068
0.073
0.085
0.088
0.094
0.093
0.088
0.110
0.102
0.141
0.152
0.172
0.161
0.155
0.086
0.088
0.085
0.059
0.088
0.088
0.093
0.088
0.088
0.085
0.059
0.045
0.043
0.040
0.031
0.028
0.028
0.028
0.037
0.043
0.041
0.037
0.036
0.034
0.028
0.034
0.037
0.040
0.037
0.040
0.043
#1 Bank #2
cfs m^/sec cfs
0.61
0.88
1.00
1.49
2.29
2.10
2.29
2.39
2.59
3.11
2.59
2.39
2.26
2.32
2.32
2.41
2.59
2.99
3.11
3.32
3.29
3.11
3.90
3.61
4.99
5.37
6.07
5.68
5.48
3.05
3.09
2.99
2.10
3.09
3.09
3.27
3.11
3.09
2.99
2.09
1.59
1.51
1.40
• 1.10
1.00
1.00
1.00
1.30
1.51
1.46
1.31
1.28
1.19
1.00
1.21
1.31
1.40
1.30
1.40
1.52
225
-------
Table 47 (Continued).
RUNOFF DATA OF THE STORM OF
NOVEMBER 14, 1970 - BLOODY
RUN CATCHMENT
Runoff
Time
hr : min :
15:00:
15:07:
15:15:
15:22:
15:30:
15:37:
15:45:
15:52:
16:00:
16:07:
16:15:
16:22:
16:30:
16:37:
16:45:
16:52:
17:00:
17:07:
17:15:
17:22:
17: 30:
17:37:
17:45:
17:52:
18:00:
18:07:
18:15:
18:22:
18:30:
18:37:
18:45:
18:52:
19:00:
Outlet
sec
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
Longview #1
m-vsec crs m
2.124
2.124
2.124
2.832
2.124
2.124
2.124
2.037
2.037
2.003
1.899
1.675
1.675
1.675
1.589
1.364
1.312
1.247
0.898
0.742
0.742
0.691
0.622
0.622
0.604
75.
75.
75.
100.
75.
75.
75.
71.
71.
70.
67.
59.
59.
59.
56.
48.
46.
44.
31.
26.
26.
24.
21.
21.
21.
00
00
00
00
00
00
00
95
95
73
07
15
15
15
10
17
34
02
71
22
22
39
95
95
34
2.
2.
1.
2.
2.
2.
2.
2.
1.
1.
2.
2.
2.
2.
2.
2.
2.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
/sec
002
002
979
002
186
117
094
002
979
933
070
117
347
324
646
301
301
864
864
864
841
815
815
772
749
702
702
657
611
565
518
472
450
cfs
70.69
70.69
69.89
70.69
77.19
74.75
73.94
70.69
69.89
68.25
73.12
74.75
82.88
82.06
93.44
81.25
81.25
65.81
65.81
65.81
65.00
64.19
64.19
62.56
61.75
60.12
60.12
58.50
56.88
55.25
53.62
52.00
51.19
Longview
m3/sec
0.028
0.028
0.031
0.042
0.043
0.037
0.028
0.028
0.028
0.028
0.028
0.028
0.028
0.054
0.054
0.054
0.054
0.023
0.023
0.023
0.023
#2 Bank
cfs m-Vsec
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0.045
0.040
0.034
0.031
.00
.00
.10
.49
.52
.31
.00
.00
.00
.00
.00
.00
.00
.91
.91
.91
.91
.80
.80
.80
.80
#1 Bank #2
cfs nt3/sec cfs
1.59
1.40
1.21
1.11
Note: Runoff values were scaled from figures published by the University of
Cincinnati (1972). Blank spaces indicate no measurements.
226
-------
Table 48. SUSPENDED SOLIDS CONCENTRATIONS OF THE
STORM RUNOFF OF NOVEMBER 14, 1970 -
BLOODY RUN CATCHMENT
Concentrations, mq/1
Time,
hr:min:sec Outlet
11:55:00
12:02:30
12:10:00
12:17:30
12:25:00
12:32:30
12:40:00
12:47:30
12:55:00
13:02:30
13:10:00
13:17:30
13:25:00
Longview Longview Bank
#1 #2 #1
196
216
345
377
325
310
296
272
250
243
237
216
209
Bank
#2
188
216
248
276
264
252
192
160
142
126
110
102
Note: Blank spaces indicate no measurements.
Table 49. BIOCHEMICAL OXYGEN DEMAND CONCENTRATIONS
OF THE STORM RUNOFF OF NOVEMBER 14, 1970 -
BLOODY RUN CATCHMENT
Concentrations, mg/1
Time ,
hrrmin:sec Outlet
11:40:00
11:47:30
11:55:00
12:02:30
12:10:00
12:17:30
12:25:00
12:32:30
12:40:00
12:47:30
12:55:00
13:02:30
13:10:00
13:17:30
13:25:00
Longview
#1
138
66
79
79
66
66
73
86
73
63
69
63
Longview
#2
237
142
89
105
89
89
89
128
227
250
237
Bank
#1
102
85
85
82
95
82
66
92
46
82
76
72
66
Bank
#2
89
79
72
69
69
76
83
99
69
86
79
92
79
Note: Blank spaces indicate no measurements.
227
-------
Table 50. RAINFALL DATA OF THE STORM OF MAY 13, 1971 -
BLOODY RUN CATCHMENT
to
to
co
Rain intensities
Time,
hr:min
03:15
03:20
03:25
03:30
03:35
03:40
03:45
03:50
03:55
04:00
04:05
04:10
04:15
04:20
04:25
04: 30
04:35
04:40
04:45
04:50
04:55
05:00
05:05
05:10
05:15
05:20
05:25
05:30
05:35
05:40
05:45
05:50
Woodward
raingage
mm/hr
0.0
1.5
3.0
0.8
2.3
4.6
3.0
4.6
3.0
7.6
3.0
3.0
1.5
1.5
6.1
4.6
1.5
3.0
6.1
3.0
1.5
3.0
3.0
3.0
4.6
1.5
0.0
0.0
0.0
in . /hr
0.00
0.06
0.12
0.03
0.09
0.18
0.12
0.18
0.12
0.30
0.12
0.12
0.06
0.06
0.24
0.18
0.06
0.12
0.24
0.12
0.06
0.12
0.12
0.12
0.18
0.06
0.00
0.00
0.00
Ridge
raincjage
mm/hr
0.0
1.5
3.0
4.6
4.6
3.0
3.0
1.5
3.0
6.1
3.0
1.5
3.0
3.0
4.6
3.0
3.0
3.0
1.5
1.5
1.5
1.5
1.5
0.0
0.0
0.0
in . /hr
0.00
0.06
0.12
0.18
0.18
0.12
0.12
0.06
0.12
0.24
0.12
0.06
0.12
0.12
0.18
0.12
0.12
0.12
0.06
0.06
0.06
0.06
0.06
0.00
0.00
0.00
Laidlaw
raingage
mm/hr
0.0
0.8
0.8
1.5
1.5
3.0
3.0
0.0
1.5
6.1
1.5
3.0
3.0
1.5
0.0
3.0
4.6
1.5
4.6
3.0
1.5
4.6
1.5
3.0
3.0
0.8
0.8
1.5
0.5
0.5
0.5
0.5
in./hr
0.00
0.03
0.03
0.06
0.06
0.12
0.12
0.00
0.06
0.24
0.06
0.12
0.12
0.06
0.00
0.12
0.18
0.06
0.18
0.12
0.06
0.18
0.06
0.12
0.12
0.03
0.03
0.06
0.02
0.02
0.02
0.02
Cumulative rain
Woodward
raingage
mm
0.0
0.1
0.4
0.4
0.6
1.0
1.3
1.7
1.9
2.5
2.8
3.0
3.2
3.3
3.8
4.2
4.3
4.6
5.1
5.3
5.5
5.7
6.0
6.2
6.6
6.7
6.9
6.9
6.7
in.
0.00
0.01
0.02
0.02
0.03
0.04
0.05
0.07
0.08
0.10
0.11
0.12
0.13
0.13
0.15
0.17
0.17
0.18
0.20
0.21
0.22
0.23
0.24
0.25
0.26
0.27
0.27
0.27
0.27
Ridge
raingage
mm
0.0
0.1
0.4
0.8
1.1
1.4
1.7
1.8
2.0
2.5
2.8
2.9
3.2
3.4
3.8
4.1
4.3
4.6
4.7
4.8
5.0
5.1
5.2
5.2
5.2
5.2
in.
0.00
0.01
0.02
0.03
0.05
0.06
0.07
0.07
0.08
0.10
0.11
0.12
0.13
0.14
0.15
0.16
0.17
0.18
0.19
0.19
0.20
0.20
0.21
0.21
0.21
0.21
Laidlaw
raingage
mm
0.0
0.1
0.1
0.3
0.4
0.6
0.9
0.9
1.0
1.5
1.7
1.9
2.2
2.3
2.3
2.5
2.9
3.0
3.4
3.7
3.8
4.2
4.3
4.6
4.6
4.6
4.7
4.8
4.9
4.9
5.0
5.0
in.
0.00
0.00
0.01
0.01
0.02
0.03
0.04
0.04
0.04
0.06
0.07
0.08
0.09
0.09
0.09
0.10
0.12
0.12
0.14
0.15
0.15
0.17
0.17
0.18
0.18
0.18
0.19
0.19
0.19
0.19
0.20
0.20
-------
Table 50 (Continued).
RAINFALL DATA OF THE STORM OF MAY 13, 1971 -
BLOODY RUN CATCHMENT
Rain intensities
Time,
hr :min
05:55
06:00
06:05
06:10
06:15
06:20
06:25
06: 30
06:35
06:40
06:45
06:50
06:55
07:00
07:05
07:10
07:15
07:20
07:25
07:30
07:35
07:40
07:45
07:50
07:55
08:00
08:05
08:10
08:15
08:20
08:25
08:30
Woodward
raingage
mm/hr
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
6.1
0.0
1.5
3.0
1.5
0.0
0.0
0.0
0.0
0.0
0.0
in./hr
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.24
0.00
0.06
0.12
0.06
0.00
0.00
0.00
0.00
0.00
0.00
Ridge
raingage
mm/hr
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.5
1.5
1.5
1.0
1.0
1.0
1.0
1.0
1.0
in./hr
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.06
0.06
0.06
0.04
0.04
0.04
0.04
0.04
0.04
Laidlaw
raingage
mm/hr
0.5
0.5
0.0
0.0
0.0
0.0
0.0
0.0
0.3
0.3
0.3
0.3
0.3
0.3
0.0
0.0
0.0
0.0
0.0
0.0
0.5
0.5
0.5
1.5
1.5
1.5
0.5
0.5
0.5
0.5
0.5
0.5
in./hr
0.02
0.02
0.00
0.00
0.00
0.00
0.00
0.00
0.01
0.01
0.01
0.01
0.01
0.01
0.00
0.00
0.00
0.00
0.00
0.00
0.02
0.02
0.02
0.06
0.06
0.06
0.02
0.02
0.02
0.02
0.02
0.02
Cumulative rain
Woodward
raingage
mm
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
7.2
7.2
7.4
7.6
7.7
7.7
7.7
7.7
7.7
7.7
7.7
in.
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.29
0.29
0.29
0.30
0.31
0.31
0.31
0.31
0.31
0.31
0.31
Ridge
raingage
mm
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.3
5.5
5.6
5.7
5.8
5.8
5.9
6.0
6.1
in.
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.22
0.22
0.22
0.23
0.23
0.23
0.24
0.24
Laidlaw
raingage
mm
5.0
5.1
5.1
5.1
5.1
5.1
5.1
5.1
5.1
5.1
5.1
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.2
5.3
5.3
5.3
5.5
5.6
5.7
5.8
5.8
5.8
5.9
5.9
6.0
in.
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.22
0.22
0.23
0.23
0.23
0.23
0.23
0.23
0.24
-------
Table 50 (Continued).
RAINFALL DATA OF THE STORM OF MAY 13, 1971 -
BLOODY RUN CATCHMENT
N>
OJ
o
Rain intensities
Time,
hr :min
08:35
08:40
08:45
08:50
08:55
09:00
09:05
09:10
09:15
09:20
09:25
09: 30
09:35
09:40
09:45
09:50
09:55
10:00
10:05
10:10
10:15
10:20
10:25
10: 30
10:35
10:40
10:45
10:50
10:55
Woodward
raingage
mm/hr
1.0
1.0
1.0
1.0
1.0
1.0
1.5
0.0
1.5
1.5
1.5
1.5
0.8
0.8
0.0
0.0
0.0
0.0
0.8
0.8
1.5
1.5
3.0
1.5
3.0
1.5
0.0
1.5
0.0
in./hr
0.04
0.04
0.04
0.04
0.04
0.04
0.06
0.00
0.06
0.06
0.06
0.06
0.03
0.03
0.00
0.00
0.00
0.00
0.03
0.03
0.06
0.06
0.12
0.06
0.12
0.06
0.00
0.06
0.00
Ridge
raingage
mm/hr
0.0
0.0
1.5
0.8
0.8
0.0
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.0
1.0
1.0
3.0
3.0
1.5
1.5
0.0
0.8
0.8
0.0
in./hr
0.00
0.00
0.06
0.03
0.03
0,00
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.04
0.04
0.04
0.12
0.12
0.06
0.06
0.00
0.03
0.03
0.00
Laidlaw
raingage
mm/hr
0.3
0.3
0.3
0.3
0.3
0.3
1.0
1.0
1.0
1.0
1.0
1.5
0.8
0.8
0.8
0.8
0.8
0.8
0.0
0.0
0.0
1.5
0.8
0.8
0.0
in./hr
0.01
0.01
0.01
0.01
0.01
0.01
0.04
0.04
0.04
0.04
0.04
0.06
0.03
0.03
0.03
0.03
0.03
0.03
0.00
0.00
0.00
0.06
0.03
0.03
0.00
Cumulative rain
Woodward
raingage
mm
7.8
7.9
8.0
8.1
8.2
8. 3
8.4
8.4
8.5
8.6
8.8
8.9
9.0
9.0
9.0
9.0
9.0
9.0
9.1
9.1
9.3
9.4
9.7
9.8
10.0
10.2
10.2
10.3
10.3
in .
0.31
0. 31
0.32
0.32
0.32
0.33
0.33
0.33
0.34
0.34
0. 35
0.35
0.35
0.36
0.36
0.36
0. 36
0.36
0.36
0.36
0. 37
0.37
0.38
0. 39
0.40
0.40
0.40
0.41
0.41
Ridge
raingage
mm
6.1
6.1
6.2
6.3
6.4
6.4
6.5
5.6
6.7
6.9
7.0
7.1
7.2
7.4
7.5
7.6
7.7
7.9
8.0
8.0
8.1
8.4
8.6
8.8
8.9
8.9
9.0
9.0
9.0
in.
0.24
0.24
0.25
0.25
0.25
0.25
0.26
0.26
0.27
0.27
0.28
0.28
0.29
0.29
0.30
0.30
0.31
0.31
0.31
0.32
0. 32
0.33
0. 34
0.35
0.35
0.35
0.35
0.36
0.36
Laidlaw
raingage
mm
6.0
6.0
6.0
6.0
6.1
6.1
6.2
6.3
6.4
6.4
6.5
6.6
6.7
6.8
6.8
6.9
7.0
7.0
7.1
7.1
7.1
7.2
7.2
7.3
7.3
in .
0.24
0.24
0.24
0.24
0.24
0.24
0.24
0.25
0.25
0.25
0.26
0.26
0.26
0.27
0.27
0.27
0.27
0.28
0.28
0.28
0.28
0.28
0.28
0.29
0.29
Note: Intensities represent averages for time interval preceding indicated clock time.
-------
Table 51. RUNOFF DATA OF THE STORM OF MAY 13, 1971 -
BLOODY RUN CATCHMENT
Runoff
Time
hr:min:sec
03:07:
03:15:
03:22:
03:30:
03:37:
03:45:
03:52:
04:00:
04:07:
04:15:
04:22:
04:30:
04:37:
04:45:
04:52:
05:00:
05:07:
05:15:
05:22:
05:30:
05:37:
05:45:
05:52:
06:00:
06:07:
06:15:
06:22:
06:30:
06:37:
06:45:
06:52:
07:00:
07:07:
07:15:
07:22:
07:30:
07:37:
07:45:
07:52:
08:00:
08:07:
08:15:
08:22:
08:30:
08:37:
08:45:
08:52:
09:00:
09:07:
09:15:
09:22:
09:30:
09:37:
09:45:
09:52:
10:00:
10:07:
10:15:
10:22
10:30:
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
Outlet
Longview #1
m-Vsec cfs m^/sec
0.345
1.485
3.350
4.748
5.705
5.429
5.525
5.732
5.912
5.912
5.871
5.767
5.491
4.765
3.674
2.383
1.209
0.777
0.622
0.501
0.345
0.345
0.414
0.432
0.501
0.546
0.622
0.673
0.767
0.794
0.822
0.863
0.881
0.967
1.209
1.399
1.485
1.485
1.392
12
52
118
167
201
191
195
202
208
208
207
203
193
168
129
84
42
27
21
17
12
12
14
15
17
19
21
23
27
28
29
30
31
34
42
49
52
52
49
.20
.44
.29
.68
.46
.71
.12
.44
.78
.78
.32
.66
.90
.29
.76
.15
.68
.44
.95
.68
.20
.20
.63
.24
.68
.27
.95
.78
.07
.05
.02
.49
.10
.15
.68
.39
.44
.44
.15
0.078
0.170
0.248
0.368
0.481
0.552
0.609
0.573
0.552
0.609
0.651
0.665
0.651
0.609
0.552
0.481
0.368
0.311
0.269
0.227
0.212
0.198
0.184
0.177
0.170
0.135
0.135
0.135
0.135
0.135
0.135
0.135
0.135
0.135
0.135
0.135
0.163
0.170
0.205
0.227
0.234
0.241
0.241
0.248
0.255
0.262
0.276
0.290
0.290
0.304
0.333
0.347
0.389
0.425
0.375
0.333
0.304
0.290
cfs
2.75
6.00
8.75
13.00
17.00
19.50
21.50
20.25
19.50
21.50
23.00
23.50
23.00
21.50
19.50
17.00
13.00
11.00
9.50
8.00
7.50
7.00
6.50
6.25
6.00
4.75
4.75
4.75
4.75
4.75
4.75
4.75
4.75
4.75
4.75
4.75
5.75
6.00
7.25
8.00
8.25
8.50
8.50
8.75
9.00
9. 25
9.75
10.25
10.25
10.75
11.75
12.25
13.75
15.00
13.25
11.75
10.75
10.25
Longview #2
m-Vsec cfs
0.219
0.354
0.467
0.524
0.524
0.503
0.524
0.545
0.524
0.524
0.524
0.510
0.496
0.476
0.446
0.345
0.326
0.278
0.248
0.212
0.221
0.234
0.255
0.269
0.269
0.269
0.290
0.333
0.347
0.354
0.354
0.354
7.75
12.50
16.50
18.50
18.50
17.75
18.50
19.25
18.50
18.50
18.50
18.00
17.50
16.80
15.75
12.20
11.50
9.80
8.75
7.50
7.80
8.25
9.00
9.50
9.50
9.50
10.25
11.75
12.25
12.50
12.50
12.50
Bank
m3/sec
0.024
0.038
0.076
0.093
0.139
0.135
0.130
0.123
0.119
0.121
0.148
0.126
0.139
0.139
0.113
0.089
0.071
0.096
0.061
0.057
0.051
0.047
0.042
0.040
0.038
0.038
0.038
0.038
0.038
0.038
0.038
0.038
0.038
0.040
0.042
0.050
0.051
0.054
0.054
0.054
0.054
0.057
0.057
0.057
0.057
0.057
#1
cfs
0.83
1.33
2.67
3.30
4.90
4.77
4.60
4.35
4.20
4.28
5.23
4.45
4.90
4.90
4.00
3.15
2.49
3.38
2.15
2.00
1.80
1.65
1.50
1.40
1.33
1.33
1.33
1.33
1.33
1.33
1.33
1.33
1.33
1.40
1.48
1.75
1.80
1.92
1.92
1.92
1.92
2.00
2.00
2.00
2.00
2.00
Bank #2
m3/sec cfs
0.018 0.65
0.023 0.80
0.031 1.10
0.035 1.25
0.048 1.70
0.040 1.40
0.035 1.25
0.044 1.55
0.120 4.25
0.091 3.20
0.068 2.40
0.079 2.80
0.106 3.75
0.035 1.23
231
-------
Table 51 (Cqntinued). RUNOFF DATA OF THE STORM OF
MAY 13, 1971 - BLOODY RUN
CATCHMENT
Runoff
Time Outlet Lgngview #1 Longview #2 3ank #1 Bank #2
hr;min:sec mj/sec cfsm-Vsec cfs m-Vsec cfsmj/seccfs m-Vsec cfs
10:37:
10:45:
10:52:
11:00:
11:07:
11:15:
11:22:
11:30:
11:37:
11:45:
11:52:
12:00:
12:07:
12:15:
12:22:
12:30:
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
1.
1.
0.
0.
0.
0.
0.
0.
392
088
932
760
639
515
483
466
49.
38.
32.
26.
22.
18.
17.
16.
15
41
93
83
56
17
07
46
0.269
0.255
0.248
0.241
0.219
0.205
0.198
0.177
0.170
0.170
0.164
0.164
0.163
0.149
0.142
0.135
9.
9.
8.
8.
7.
7.
7.
6.
6.
6.
5.
5.
5.
5.
5.
4.
50
00
75
50
75
25
00
25
00
00
80
80
75
25
00
75
0.
0.
0.
0.
0.
0.
0.
0.
354
354
333
311
290
269
255
234
12.50
12.50
11.75
11.00
10.25
9.50
9.00
8.25
Note: Runoff values were scaled from figures published by the University of
Cincinnati (1972). Blank spaces indicate no measurements.
232
-------
Table 52. SUSPENDED SOLIDS CONCENTRATIONS OF THE
STORM RUNOFF OF MAY 13, 1970 -
BLOODY RUN CATCHMENT
Concentrations, mg/1
Time,
hr:min:sec
04:05:00
04:12:30
04:20:00
04:27:30
04:35:00
04:42:30
04:50:00
04:57:30
05:05:00
05:12:30
05:20:00
05:27:30
05:35:00
Longview Longview Bank
Outlet #1 #2 #1
259
277
258
146
334
282
214
233
183
66
216
122
276
Bank
#2
Note: Blank spaces indicate no measurements.
Table 53. BIOCHEMICAL OXYGEN DEMAND CONCENTRATIONS
OF THE STORM RUNOFF OF MAY 13, 1971 -
BLOODY RUN CATCHMENT
Concentrations, mg/1
Time,
hr:n\in: sec
04:05:00
04:12:30
04:20:00
04:27:30
04:35:00
04:42:30
04:50:00
04:57: 30
05:05:00
05:12:30
05:20:00
05:27:30
05:35:00
05:42:30
05:50:00
Longview Longview Bank
Outlet #1 #2 #1
195
173
176
118
117
135
150
63
56
58
40
255
253
216
119
Bank
#2
Note: Blank spaces indicate no measurements.
233
-------
N)
OJ
Table 54. RAINFALL DATA OF THE STORM OF AUGUST 25 AND 26, 1971 -
BLOODY RUN CATCHMENT
Rain intensities
Time,
hr :min
19:00
19:05
19:10
19:15
19:20
19:25
19:30
19:35
19:40
19:45
19:50
19:55
20:00
20:05
20:10
20:15
20:20
20:25
20:30
20:35
20:40
20:45
20:50
20:55
21:00
21:05
21:10
21:15
21:20
21:25
Woodward
raingage
mm/hr
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
in. /hr
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Ridge
raingage
mm/hr
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.5
1.5
3.0
3.0
1.5
3.0
1.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
30.5
30.5
in. /hr
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.06
0.06
0.12
0.12
0.06
0.12
0.06
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.20
1.20
Laidlaw
raingage
mm/hr
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.0
1. 3
1.0
1.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
3.0
3.0
3.0
0.0
0.0
in./hr
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.04
0.05
0.04
0.06
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.12
0.12
0.12
0.00
0.00
Cumulative rain
Woodward
raingage
mm
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
in .
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.91
Ridge
raingage
mm
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.6
5.7
6.0
6.2
6.4
6.6
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
9.3
11.8
in.
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.23
0.24
0.25
0.25
0.26
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.37
0.47
Laidlaw
raingage
mm
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
12.0
12.1
12.1
12.3
12.3
12.3
12.3
12.3
12.3
12.3
12.3
12.3
12.3
12.3
12.3
12.5
12.8
13.0
13.0
13.0
in.
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.48
0.48
0.48
0.48
0.48
0.48
0.48
0.48
0.48
0.48
0.48
0.48
0.48
0.48
0.49
0.50
0.51
0.51
0.51
-------
Table 54 (Continued)
RAINFALL DATA OF THE STORM OF AUGUST 25 A1TD 26,
1971 - BLOODY RUN CATCHMENT
NJ
U)
U1
Rain intensities
Time,
hr : min
16:30
16:35
16:40
16:45
16:50
16:55
17:00
17:05
17:10
17:15
17:20
17:25
17:30
17:35
17:40
17:45
17:50
17:55
18:00
18:05
18:10
18:15
18:20
18:25
18:30
18:35
18:40
18:45
18:50
18:55
Woodward
raingage
mm/hr
0.0
15.2
9.1
6.1
9.1
3.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
12.2
15.2
21.3
23.4
30.5
3.0
0.0
in. /hr
0.00
0.60
0.36
0.24
0.36
0.12
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.48
0.60
0.84
0.92
1.20
0.12
0.00
Ridge
raingage
mm/hr
1.5
1.5
3.0
6.1
12.2
12.2
9.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
in . /hr
0.06
0.06
0.12
0.24
0.48
0.48
0.36
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Laid law
raingage
mm/hr
7.6
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
in . /hr
0.30
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Cumulative rain
Woodward
raingage
mm
10.7
11.9
12.7
13.2
14.0
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
15.2
16.5
18.3
20.2
22.8
23.0
23.0
in.
0.42
0.47
0.50
0.52
0.55
0.56
0.56
0.56
0.56
0.56
0.56
0. 56
0.56
0.56
0.56
0.56
0.56
0.56
0.56
0.56
0.56
0.56
0.56
0.60
0.65
0.72
0.80
0.90
0.91
0.91
Ridge
raingage
mm
1.8
1.9
2.2
2.7
3.7
4.7
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
in.
0.07
0.08
0.09
0.11
0.15
0.19
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
Laidlaw
raingage
mm
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
in.
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
-------
Table 54 (Continued).
RAINFALL DATA OF THE STORM OF AUGUST 25 AND 26,
1971 - BLOODY RUN CATCHMENT
M
Rain intensities
Time,
hr :min
14:00
14:05
14:10
14:15
14:20
14:25
14:30
14:35
14:40
14:45
14:50
14:55
15:00
15:05
15:10
15:15
15:20
15:25
15:30
15:35
15:40
15:45
15:50
15:55
16:00
16:05
16:10
16:15
16:20
16:25
Woodward
raingage
mm/hr
0.0
18.3
18.3
39.6
52.8
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
in./hr
0.00
0.72
0.72
1.56
2.04
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Ridge
raingage
mm/hr
0.0
1.5
1.5
1,5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.8
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.3
1.5
in. /hr
0.00
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.07
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.05
0.06
Laidlaw
raingage
mm/hr
0.0
30.5
15.2
9.1
6.1
9.1
6.1
3.0
3.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.0
13.7
12.2
9.1
9.1
7.6
in. /hr
0.00
1.20
0.60
0.36
0.24
0.36
0.24
0.12
0.12
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.04
0.54
0.48
0.36
0.36
0.30
Cumulative rain
Woodward
raingage
mm
0.0
0.0
0.0
1.5
3.0
6.4
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
10.7
in.
0.00
0.00
0.00
0.06
0.12
0.25
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
0.42
Ridge
raingage
mm
0.0
0.1
0.3
0.4
0.5
0.6
0.8
0.9
1.0
1.1
1.3
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.5
1.7
in.
0.00
0.01
0.01
0.02
0.02
0.03
0.03
0.04
0.04
0.05
0.05
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.07
Laidlaw
raingage
mm
0.0
2.5
3.8
4.6
5.1
5.8
6.4
6.6
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.9
8.1
9.1
9.9
10.6
11.3
in.
0.00
0.10
0.15
0.18
0.20
0.23
0.25
0.26
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.32
0.36
0.39
0.42
0.44
-------
Table 54 (Continued)
RAINFALL DATA OF THE STORM OF AUGUST 25 AND 26,
1971 - BLOODY RUN CATCHMENT
N)
Rain intensities
Time,
hr:min
21:30
21:35
21:40
21:45
21:50
21:55
22:00
22:05
22:10
22:15
22:20
22:25
22:30
22:35
22:40
22:45
22:50
22:55
23:00
23:05
23:10
23:15
23:20
23:25
23:30
23:35
23:40
23:45
23:50
23:55
Woodward
raingage
mm/hr
0.0
0.0
0.0
0.0
0.0
0.0
0.0
3.0
3.0
3.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
9.1
0.0
0.0
0.0
0.0
12.2
9.1
in. /hr
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.12
0.12
0.12
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.36
0.00
0.00
0.00
0.00
0.48
0.36
Ridge
raingage
mm/hr
21.3
0.0
0.0
0.0
12.2
12.2
12.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
4.6
4.6
4.6
3.0
1.5
0.0
in./hr
0.84
0.00
0.00
0.00
0.48
0.48
0.48
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.18
0.18
0.18
0.12
0.06
0.00
Laidlaw
raingage
mm/hr
0.0
15.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
9.1
6.1
15.2
6.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
in . /hr
0.00
0.60
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.36
0.24
0.60
0.24
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Cumulative rain
Woodward
raingage
nun
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.3
23.6
23.8
23.8
23.8
23.8
23.8
23.8
23.8
23.8
23.8
23.8
23.8
23.8
23.8
23.8
24.6
24.6
24.6
24.6
24.6
25.6
26.3
in.
0.91
0.91
0.91
0.91
0.91
0.91
0.91
0.92
0.93
0.94
0.94
0.94
0.94
0.94
0.94
0.94
0.94
0.94
0.94
0.94
0.94
0.94
0.94
0.97
0.97
0.97
0.97
0.97
1.01
1.04
Ridge
raingage
mm
13.6
13.6
13.6
13.6
14.6
15.6
16.6
16.5
16.6
16.6
16.6
16.6
16.6
16.6
17.0
17.4
17.8
18.0
18.2
18.2
in.
0.54
0.54
0.54
0.54
0.58
0.62
0.66
0.66
0.66
0.66
0.66
0.66
0.66
0.66
0.67
0.69
0.70
0.71
0.72
0.72
Laidlaw
raingage
mm
13.0
14.3
14.3
14.3
14.3
14.3
14.3
14.3
14.3
14.3
14.3
15.1
15.6
16.8
17.4
17.4
17.4
17.4
17.4
17.4
17.4
17.4
17.4
17.4
17.4
17.4
17.4
17.4
17.4
17.4
in.
0.51
0.56
0.56
0.56
0.56
0.56
0.56
0.56
0.56
0.56
0.56
0.59
0.61
0.66
0.68
0.68
0.68
0.68
0.68
0.68
0.68
0.68
0.68
0.68
0.68
0.68
0.68
0.68
0.68
0.68
intensities represent averages for time inverval preceding indicated clock time.
-------
Table 55. RUNOFF DATA OF THE STORM OF AUGUST 25 AND 26,
1971 - BLOODY RUN CATCHMENT
Runoff
Time
Outlet
Longview #1 Longview #2 Bank #1
hr:min:sec mj/sec cfs mj/sec
13:30:
13:37:
13:45:
13:52:
14:00:
14:07:
14: 15:
14:22:
14: 30:
14:37:
14:45:
14:52:
15:00:
15:07:
15:15:
15:22:
15:30:
15:37:
15:45:
15:52:
16:00:
16:07:
16:15:
16:22:
16:30:
16:37:
16:45:
16:52:
17:00:
17:07:
17:15:
17:22:
17: 30:
17:37:
17: 45:
17:52:
18:00:
18:07:
18:15:
18:22:
18:30:
18:37:
18:45:
18:52:
19:00:
19:07:
19:15:
19:22:
19:30:
19:37:
19:45:
19:52:
20:00:
20:07:
20:15:
20:22:
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
00
30
1.356
21.539
18.661
13.778
8.727
7.242
6.127
4.642
2.135
0.836
0.650
0.557
0.371
0.371
0. 371
0. 371
1. 300
2.618
7.019
8.319
9.228
8.801
7.873
6.610
4.215
2.655
1.114
0.761
0.483
0.483
0.483
2.302
2.878
16.526
19.552
15.449
11.234
9.693
7.242
6.555
4.884
3.547
1.727
1.003
0.743
0.743
0.650
0. 464
47.
760.
659.
486.
308.
255.
216.
163.
75.
29.
22.
19.
13.
13.
13.
13.
45.
92.
247.
293.
325.
310.
278.
233.
148.
93.
39.
26.
17.
17.
17.
81.
101.
583.
690.
545.
396.
342.
255.
231.
172.
125.
60.
35.
2'6.
26.
22.
16.
87
66
02
56
20
74
39
93
41
51
95
67
11
11
11
11
90
46
87
77
90
82
03
44
85
77
34
88
05
05
05
31
64
61
49
57
72
30
74
48
46
25
98
41
23
23
95
39
cfs mVsec cfs m-Vsec cfs
0.
1.
4.
2.
I.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
1.
0.
1.
1.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
1.
2.
4.
1.
1.
0.
0.
0.
0.
0.
0.
0.
204
410
259
430
150
927
801
612
490
427
382
341
282
278
278
278
278
601
261
872
261
154
909
798
779
779
742
649
341
371
430
501
594
402
460
025
410
161
909
779
605
549
501
445
371
7.
49.
150.
85.
40.
32.
28.
21.
17.
15.
13.
12.
9.
9.
9.
9.
9.
21.
44.
30.
44.
40.
32.
28.
27.
27.
26.
22.
12.
13.
15.
17.
20.
49.
86.
142.
49.
41.
32.
27.
21.
19.
17.
15.
13.
0.018 0.65
0.018 0.65
0.026 0.91
0.075 2.64
0.530 18:70
0.000 0.00
21
78
39
81
61
75
30
62
29
07
49
05
96
83
83
83
83
22
54
79
54
74
10
17
51 0.018 0.65
51 0.018 0.65
20 0.075 2.64
93 0.120 4.25
05 0.434 15.34
10 0.040 1.40
20 0.024 0.83
69 0.018 0.65
96 0.018 0.65
52
86
14
78
00
10
51
35
39
69
72
10
Bank
m-Vsec
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.000
.086
.150
.255
.000
.000
.255
.150
.255
.197
.000
.000
.255
.197
.126
.049
.011
#2
cfs
0.00
3.02
5.28
8.99
0.00
0.00
8.99
5.28
8.99
6.96
0.00
0.00
8.99
6.96
4.46
1.73
0.39
238
-------
Table 55 (Continued). RUNOFF DATA OF THE STORM OF AUGUST 25
AND 26, 1971 - BLOODY RUN CATCHMENT
hr
20
20
20
20
21
21
21
21
21
21
21
21
22
22
22
22
22
22
22
22
23
23
23
23
23
23
23
23
24
24
24
24
24
24
24
Time
Outlet
Runoff
Longview #1 Longview #2 Bank #1 Bank #2
:min:sec mj/sec cfs mj/sec cfs m3/sec cfs mj/sec cfs m3/sec cfs
:30
:37
:45
:52
:00
:07
:15
:22
:30
:37
:45
:52
:00
:07
:15
:22
:30
:37
:45
:52
:00
:07
:15
:22
:30
:37
:45
:52
:00
:07
:15
:22
:30
:37
:45
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
:30
:00
0.
0.
0.
0.
0.
0.
0.
0.
8.
7.
6.
6.
6.
6.
6.
5.
2.
2.
5.
8.
8.
7.
4.
3.
1.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
520
650
650
557
427
390
390
390
412
892
610
610
945
945
146
069
859
859
849
727
022
000
698
547
523
891
650
557
464
409
371
371
371
371
371
18.
22.
22.
19.
15.
13.
13.
13.
297.
278.
233.
233.
245.
245.
217.
179.
100.
100.
206.
308.
283.
247.
165.
125.
53.
31.
22.
19.
16.
14.
13.
13.
13.
13.
13.
36
95
95
67
08
77
77
77
05
69
44
44
25
25
05
02
98
98
56
20
28
21
90
25
77
48
95
67
39
43
11
11
11
11
11
Note: Runoff values were scaled from figures published by the University of
Cincinnati (1972). Blank spaces indicate no measurements.
239
-------
Table 56. SUSPENDED SOLIDS CONCENTRATIONS OF THE
STORM RUNOFF OF AUGUST 25, 1971 -
BLOODY RUN CATCHMENT
Concentrations, mg/1
Time,
hr :min: sec
14:45:00
15:07:30
15:22:30
15:30:00
16:45:00
17:07:30
17:30:00
17:37:30
Longview Longview Bank
Outlet #1 #2 #1
276
321
208
170
125
140
106
97
Bank
#2
Note: Blank spaces indicate no measurements.
240
-------
Table 57. BIOCHEMICAL OXYGEN DEMAND CONCENTRATIONS
OF THE STORM RUNOFF OF AUGUST 25, 1971 -
BLOODY RUN CATCHMENT
Concentrations, mg/1
Time,
hr :min: sec
14:30:00
14:37:30
14:45:00
14:52:30
15:00:00
15:07:30
15:15:00
15:22:30
15:30:00
16:30:00
16:37:30
16:45:00
16:52:30
17:00:00
17:07:30
17:15:00
17:22:30
17:30:00
17:37:30
18:22:30
18:30:00
18:37:30
18:45:00
18:52:30
Longview Longview Bank Bank
Outlet #1 #2 #1 \2
113
12
24
11
38
11
8
7
9
33
27
13
30
14
21
4
21
4
4
35
12
6
11
27
Note: Blank spaces indicate no measurements.
241
-------
SECTION VII
TEST RESULTS
Page
Introduction 243
Hypothetical Catchment Data Tests 244
Model Comparison 268
Two-Hour Triangular Rainstorm 269
Hypothetical Pipe Data Tests 272
Model Comparison 296
Two-Hour Triangular Inflow 298
Real Catchment Data Tests 301
Oakdale Avenue Catchment Simulations 301
Bloody Run Catchment Simulations 319
242
-------
INTRODUCTION
The following seven models were tested by computer runs with
the hypothetical catchment and pipe data described in the
previous section:
1. Battelle Urban Wastewater Management Model (BNW)
2. Dorsch Consult Hydrograph-Volume Method (DORSCH)
3. Environmental Protection Agency Stormwater Management
Model (SWMM)
4. Massachusetts Institute of Technology Urban Watershed
Model (MIT)
5. Metropolitan Sanitary District of Greater Chicago
Flow Simulation Program (FSP)
6. SOGREAH Looped Sewer Model (SOGREAH)
7. Water Resources Engineers Stormwater Management
Model (WRE)
The Hydrocomp Simulation Program was also to be included in
the testing, but Hydrocomp International declined to partici-
pate.
Four of the models were also tested by computer runs with real
catchment data. The BNW, FSP, SWMM, and DORSCH models were
tested with data from the Oakdale Avenue catchment in Chicago,
Illinois, and the BNW, FSP, and SWMM models were tested with
data from the Bloody Run catchment in Cincinnati, Ohio. The
proprietary models were not included in this effort due to
their developers doubts about the completeness and accuracy of
the real catchment data.
The BNW model was run on a DEC PDP-9 computer at Battelle-
Northwest in Richland, Washington. The SWMM and FSP were run
on a CDC 6400 computer at Battelie-Columbus, Ohio, by remote
terminal from Battelle-Northwest. This required the conver-
sion of the original IBM versions of these two programs into
CDC versions.
The four proprietary models were run by the respective firms
with data supplied by Battelle-Northwest. The DORSCH model
was run by Dorsch-Consult on a Univac 1108 computer in Munich,
Germany; the MIT model was run by Resource Analysis on an
IBM 370 computer in Boston, Massachusetts; the SOGREAH model
was run by SOGREAH on an IBM 360 computer in Grenoble, France;
243
-------
and the WRE model was run by Water Resources Engineers on a
Univac 1108 computer in San Francisco, California.
The original intent was to run all models on the same computer
to compare running times and costs. This was not possible for
the proprietary models or for the BNW model, which is formu-
lated for a small real-time process computer and would have
required major reprogramming to adapt it to a larger computer.
The test results, however, are still useful for comparing
model sensitivity to parameter variations (using hypothetical
data) and for comparing model accuracy (using real catchment
data). Although running times cannot be compared directly
among all the models, orders of magnitude can be indicated and
fairly reliable cost comparisons can be made.
HYPOTHETICAL CATCHMENT TESTS
Hypothetical catchment data tests were performed for two dif-
ferent catchment sizes, two catchment slopes, two orientations
of each catchment with respect to the direction of surface
flow, five ratios of pervious to impervious areas, two dif-
ferent initial catchment moisture conditions, and four dif-
erent rainstorms, representing a total of 320 data combinations,
The effects of different catchment surface roughness coeffi-
cients and of different time discretizations on computed run-
off were not tested.
A time step of 5 minutes was suggested for the catchment run-
off simulations and was actually used for the BNW, FSP, SWMM,
DORSCH, and WRE models. The SOGREAH model used a time step
of 1 minute. The MIT model sets the time step internally
as a function of catchment characteristics but independent of
rainstorm characteristics. In the tests it ranged from 2 to
16 minutes for the different runs. The time step remains
constant, however, for any particular runoff computation.
The results of the catchment runoff simulations for all seven
models are summarized in Tables 58 to 64, which present peak
runoffs and times for each of the 320 catchment/rainfall com-
binations. The times of peak runoff are not tabulated for the
constant rainstorm since equilibrium runoff conditions were
computed for most data combinations.
It was not possible to plot all computed runoff hydrographs,
but plots are presented in Figures 31 to 42 for the runoff
from the 2-hr triangular storm with initially dry catchment
moisture conditions and the direction of flow parallel to the
short length of the rectangular catchments. The plots show
the effect on catchment runoff of changes in catchment slope
and imperviousness.
244
-------
Table 58a.
PEAK RUNOFF FROM HYPOTHETICAL CATCHMENTS FOR TWO-HOUR
CONSTANT RAINSTORM (cfs)
Ul
3
O
+J •" -H 4J
- c £ > c
V 0 -P ^ 0>
DU O O1 V U
0^ c an
rH J) « 4J g (B
WO. >J >H MQ.
0
25
316 50
75
0.1 100
0
25
158 50
75
100
0
25
316 50
75
10.0 100
0
25
158 50
75
100
0
25
1000 50
75
0.1 100
0
25
500 50
75
100
0
25
1000 50
75
10.0 100
0
25
500 50
75
100
Catchment
number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Dry initial condition
SWMM
0.23
0.50
0.76
0.99
1.15
0.36
0.60
0.82
1.00
1.16
0.56
0.72
0.87
1.01
1.16
0.58
0.72
0.87
1.01
1.16
0.89
3.75
6.55
9.21
10.91
1.61
4.41
7.14
9.66
11.48
4.41
6.54
8.46
10.11
11.57
5.34
7.06
8.64
10.13
11.57
BNH
0.58
0.72
0.87
1.01
1.16
0.58
0.72
0.87
1.01
1.16
0.58
0.73
0.87
1.02
1.16
0.58
0.73
0.87
1.02
1.16
5.10
6.63
8.24
9.89
11.58
5.77
7.22
8.67
10.13
11.58
5.83
7.28
8.73
10.18
11.62
5.83
7.28
8.73
10.18
11.62
PSP
0.34
0.34
0.34
0.34
0.85
0.17
0.17
0.17
0.17
0.84
1.09
1.09
1.09
1.09
0.86
1.06
1.06
1.06
1.06
0.86
0.52
1.93
4.11
6.27
8.30
1.09
2.47
4.62
6.75
8.34
9.69
9.63
9.40
8.98
8.37
10. 37
10.10
9.61
9.03
a. 34
DOR
0.2
0.4
0.7
0.9
1.2
0.3
0.5
0.7
0.9
1.2
0.5
0.7
0.8
1.0
1.2
0.6
0.7
0.9
1.0
1.2
0.7
3.4
6.1
8.8
11.5
1.4
3.9
6.5
9.0
11.6
4.0
5.9
7.8
9.7
11.6
5.1
6.7
8.3
10.0
11.6
MIT
0.29
0.50
0.72
0.92
1.15
0.46
0.63
0.80
0.97
1.14
0.57
0.72
0.87
1.02
1.16
0.57
0.73
0.88
1.03
1.18
0.93
3.52
6.17
8.83
11.49
1.74
4.16
6.61
9.05
11.49
5.24
6.78
8.33
9.88
11.46
5.69
7.15
8.64
10.13
11.61
SOG
0.57
0.71
0.85
1.02
1.17
0.57
0.71
0.85
1.02
1.17
0.57
0.71
0.88
1.02
1.17
0.57
0.71
0.88
1.02
1.17
5.05
6.78
8.41
9.99
11.58
5.33
6.96
8.51
10.07
11.58
5.72
7.20
8.65
10.10
11.58
5.72
7.20
8.65
10.10
11.58
WRE
0.23
0.50
0.76
0.99
1.16
0.36
0.60
0.82
1.01
1.16
0.56
0.72
0.87
1.01
1.16
0.58
0.72
0.87
1.01
1.16
0.89
3.75
6.54
9.09
10.85
1.61
4.41
7.14
9.66
11.47
4.41
6.54
8.46
10.11
11.58
5.34
7.06
8.64
10.13
11.58
SWMM
0.30
0.55
0.79
1.00
1.16
0.43
0.65
0.84
1.01
1.16
0.57
0.72
0.87
1.01
1.16
0.58
0.72
0.87
1.01
1.16
1.24
4.08
6.83
9.29
10.91
2.17
4.89
7.49
9.82
11.48
4.99
6.88
8.59
10.12
11.57
5.60
7.17
8.67
10.13
11.57
Wet initial condition
BNW
0.58
0.72
0.87
1.01
1.16
0.58
0.72
0.87
1.01
1.16
0.58
0.73
0.87
1.02
1.16
0.58
0.73
0.87
1.02
1.16
5.79
7.24
8.68
10.13
11.58
5.79
7.24
8.68
10.13
11.58
5.83
7.28
8.73
10.18
11.62
5.83
7.28
8.73
10.18
11.62
FSP
0.34
0.34
0.34
0.34
0.85
0.17
0.17
0.17
0.17
0.84
1.09
1.09
1.09
1.09
0.86
1.06
1.06
1.06
1.06
0.86
0.52
1.93
4.11
6.27
8.30
1.09
2.47
4.62
6.75
8.34
9.69
9.63
9.40
8.98
8.37
10.37
10.10
9.61
9.03
8.34
DOR
0.4
0.6
0.8
1.0
1.2
0.5
0.7
0.8
1.0
1.2
0.6
0.7
0.9
1.0
1.2
0.6
0.7
0.9
1.0
1.2
2.3
4.6
6.9
9.2
11.5
3.6
5.6
7.6
9.6
11.6
5.6
7.1
8.6
10.1
11.6
5.8
7.2
8.7
10.1
11.6
MIT
0.37
0.56
0.76
0.95
1.15
0.52
0.67
0.83
0.99
1.14
0.58
0.72
0.87
1.02
1.16
0.58
0.73
0.88
1.03
1.18
1.02
3.58
6.22
8.86
11.49
2.14
4.46
6.81
9.15
11.49
5.66
7.10
8.54
9.99
11.46
5.76
7.18
8.68
10.15
11.61
SOG
0.57
0.71
0.88
1.02
1.17
0.57
0.71
0.88
1.02
1.17
0.57
0.71
0.88
1.02
1.17
0.57
0.71
0.88
1.02
1.17
5.76
7.20
8.65
10.14
11.58
5.76
7.20
8.65
10.14
11.58
5.76
7.20
8.65
10.14
11.58
5.76
7.20
8.65
10.14
11.58
WRE
0. 30
0.55
0.79
1.00
1.16
0.43
0.65
0.84
1.01
1.16
0.58
0.72
0.87
1.01
1.16
0.58
0.72
0.87
1.01
1.16
1.24
4.08
6.83
9.29
10.92
2.17
4.89
7.50
9.83
11.48
4.99
6.88
8.59
10.12
11.58
5.60
7.17
8.67
10.13
11.58
-------
Table 58b. PEAK RUNOFF FROM HYPOTHETICAL CATCHMENTS FOR TWO-HOUR
CONSTANT RAINSTORM (m3/sec)
NJ
*>.
a-,
3
O
•P - -H 4J
c ..c > c
0> 01 +J M * OJ
CX U tit 01 W U
oh c a. ra n
rH 0) 0) € 0> 0>
w a. j g H c a
0
25
96.4 50
75
0.1 100
0
25
48.2 50
75
100
0
25
96.4 50
75
10.0 100
0
25
48.2 50
75
100
0
25
304.8 50
75
0.1 100
0
25
152.4 50
75
100
0
25
304.8 50
75
10.0 100
0
25
152.4 50
75
100
Catchment
number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Dry initial condition
SWMM
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
007
014
022
028
033
010
017
023
028
033
016
020
025
029
033
016
020
025
029
033
625
106
185
261
309
046
125
202
274
325
125
185
240
286
328
151
200
245
287
328
BNW
0.016
0.020
0.025
0.029
0.033
0.016
0.020
0.025
0.029
0.033
0.016
0.021
0.025
0.029
0.033
0.016
0.021
0.025
0.029
0.033
0.144
0.188
0.233
0.280
0.328
0.163
0.204
0.246
0.287
0.328
0.165
0.206
0.247
0.288
0.329
0.165
0.206
0.247
0.288
0.329
PSP
0.010
0.010
0.010
0.010
0.024
0.005
0.005
0.005
0.005
0.024
0.031
0.031
0.031
0.031
0.024
0.030
0.030
0.030
0.030
0.024
0.015
0.055
0.116
0.178
0.235
0.031
0.070
0.131
0.191
0.236
0.274
0.273
0.266
0.254
0.237
0.294
0.286
0.272
0.256
0.236
DOR
0.006
0.011
0.020
0.025
0.034
0.008
0.014
0.020
0.025
0.034
0.014
0.020
0.023
0.028
0.034
0.017
0.020
0.025
0.028
0.034
0.020
0.096
0.173
0.249
0.326
0.040
0.110
0.184
0.255
0.329
0.113
0.167
0.221
0.275
0.329
0.144
0.190
0.235
0.283
0.329
MIT
0.008
0.014
0.020
0.026
0.033
0.013
0.018
0.023
0.027
0.032
0.016
0.020
0.025
0.029
0.033
0.016
0.021
0.025
0.029
0.033
0.026
0.100
0.175
0.250
0.325
0.049
0.118
0.187
0.256
0.325
0.148
0.192
0.236
0.280
0.325
0.161
0.202
0.245
0.287
0.329
SOG
0.016
0.020
0.024
0.029
0.033
0.016
0.020
0.024
0.029
0.033
0.016
0.020
0.025
0.029
0.033
0.016
0.020
0.025
0.029
0.033
0.143
0.192
0.238
0.283
0.328
O.isi
0.197
0.241
0.285
0.328
0.162
0.204
0.245
0.286
0.328
0.162
0.204
0.245
0.286
0.328
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
u
0
0
0
0
0
0
0
0
0
0
0
0
0
0
WRE
.007
.014
.022
.028
.033
.010
.017
.023
.029
.033
.016
.020
.025
.029
.033
.016
.020
.025
.029
.033
.025
.106
.185
.257
.307
.046
.125
.202
.274
.325
.125
.185
.240
.286
.328
.151
.200
.245
.287
.328
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
SWMM
.008
.016
.022
.028
.033
.012
.018
.024
.029
.033
.016
.020
.025
.029
.033
.016
.020
.025
.029
.033
.035
.116
.193
.263
.309
.061
.138
.212
.278
.325
.141
.195
.243
.287
.328
.159
.203
.246
.287
.328
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
BMW
.016
.020
.025
.029
.033
.016
.020
.025
.029
.033
.016
.021
.025
.029
.033
.016
.021
.025
.029
.033
.164
.205
.246
.287
.328
.164
.205
.246
.287
.328
.165
.206
.247
.288
.329
.165
.206
.247
.288
.329
Wet initial condition
FSP
0.010
0.010
0.010
0.010
0.024
0.005
0.005
0.005
0.005
0.024
0.031
0.031
,0.031
0.031
0.024
0.030
0.030
0.030
0.030
0.024
0.015
0.055
0.116
0.178
0.235
0.031
0.070
0.131
0.191
0.236
0.274
0.273
0.266
0.254
0.237
0.294
0.286
0.272
0.256
0.236
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
DOR
.011
.017
.023
.028
.034
.014
.020
.023
.028
.034
.017
.020
.025
.028
.034
.017
.020
.025
.028
.034
.065
.130
.195
.261
.326
.102
.159
.215
.272
.329
.159
.201
.244
.286
.329
.164
.204
.246
.286
.329
MIT
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.010
.016
.022
.027
.033
.015
.019
.024
.028
.032
.016
.020
.025
.029
.033
.016
.021
.025
.029
.033
.029
.101
.176
.251
.325
.061
.126
.193
.259
.325
.160
.201
.242
.283
.325
.163
.203
.246
.287
.329
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
SOG
.016
.020
.025
.029
.033
.016
.020
.025
.019
.033
.016
.020
.025
.029
.033
.016
.020
.025
.029
.033
.163
.204
.245
.287
.328
.163
.204
.245
.287
.328
.163
.204
.245
.287
.328
.163
.204
.245
.287
.328
WRE
0.008
0.016
0.022
0.028
0.033
0.012
O'.OIS
0.024
0.029
0.033
0.016
0.020
0.025
0.029
0.033
0.016
0.020
0.025
0.029
0.033
0.035
0.116
0.193
0.263
0.309
0.061
0.138
0.212
0.278
0.325
0.141
0.195
0.243
0.287
0.328
0.159
0.203
0.246
0.287
0.328
-------
Table 59a.
PEAK RUNOFF FROM HYPOTHETICAL CATCHMENTS FOR
ONE-HOUR TRIANGULAR RAINSTORM (cfs)
c
0
•U - -2 4J
41 41 4J S §
P< V O> Q) O
ou c o, IH
•-( 4)
-------
Table 59b.
PEAK RUNOFF FROM HYPOTHETICAL CATCHMENTS FOR
ONE-HOUR TRIANGULAR RAINSTORM (m3/sec)
00
3
O
4-» * -H -p
C S > C
Ot 01 4-> M ^ 0)
ft u en cu en u
O ^ C Qj W ^i
^H 01 O E O 0)
W ft j e w c a*
0
25
96.4 50
75
0.1 100
0
25
48.2 50
75
100
0
25
96.4 50
75
10.0 100
0
25
48.2 50
75
100
0
25
304.8 50
75
0.1 100
0
25
152.4 50
75
100
0
25
304.8 50
75
10.0 100
0
25
152.4 50
75
100
Catchment
number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
SWMM
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
u
0
0
1
1
.016
.039
.063
.083
.092
.027
.047
.073
.096
.106
.066
.080
.097
.114
.121
.083
.091
.107
.117
.122
.058
. 282
.447
. 554
.586
.109
. 342
.558
.729
.801
. 368
. 549
.796
.006
.115
. 547
.700
.894
.098
. 185
BNW
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
u.
0.
0,
0.
0,
0,
0.
0,
0,
0.
0,
0.
1.
1
1.
u,
0,
1,
1.
067
073
081
089
,097
084
091
099
106
113
092
099
,106
113
.120
092
099
,106
,113
,120
.342
, 395
.448
501
, 554
, 534
, 606
,679
.752
,825
.918
.990
.060
.131
.202
.918
.990
.060
.131
,202
Dry initial condition
FSP
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0 .
0.
0.
0.
0.
0.
0.
0.
u.
0.
0.
0.
0.
0.
0.
0.
0.
0.
u.
0.
0.
0.
0.
0.
0.
0.
0.
0.
Oil
Oil
Oil
Oil
041
005
005
005
005
035
092
092
092
092
041
091
091
091
091
041
016
074
163
252
343
033
090
179
268
358
822
753
635
500
361
878
789
649
502
358
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
u
0
0
0
1
0
0
0
0
1
DOR
.020
.037
.059
.082
.105
.031
.045
.065
.088
.113
. 062
.074
.082
.102
.119
.076
. 082
.091
.108
.122
.076
.246
.433
.623
. 810
. 139
.314
.530
.753
.980
. 399
. 515
.697
.926
.175
.544
.632
.776
.977
.195
MIT
0.
0.
0.
0.
0.
0.
0.
0.
0.
0,
0,
0.
0,
0.
0.
0,
0.
0,
0,
0,
0
0.
0,
0,
0,
0.
0.
0,
0,
1.
0
0
0,
0,
1,
0,
0,
1.
1,
1,
018
035
,061
086
.112
,034
,043
.067
,094
,120
.082
,088
, 097
,108
.120
.092
097
.104
.112
.120
.065
.251
. 448
.646
.844
.103
.300
.535
.773
. 010
.510
.572
.735
.965
.197
. 680
.744
.031
.024
.200
SOG
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
1.
1.
1.
1.
0.
1.
1.
1.
1.
070
080
089
099
109
075
084
093
103
112
099
106
113
121
128
099
107
114
121
129
533
631
733
845
931
593
694
791
890
990
960
031
108
183
258
972
045
119
193
263
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
u
0
0
1
1
0
0
0
1
1
WRE
.017
.039
.063
.083
.091
.028
.047
.073
. 096
.106
.066
.080
. 097
.114
.121
.083
.092
.107
.117
.122
. 062
.280
.441
. 546
. 585
.115
.341
.553
.721
.788
.381
.549
.796
.006
.110
. 547
.700
.894
.098
.185
Wet initial condition
SWMM
0.
0.
0.
0.
0.
0.
0.
0.
0.
o,
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
o.
0.
0.
0.
1.
1,
0.
0.
0.
1.
1.
020
042
067
086
092
033
052
078
098
106
072
086
102
115
121
088
097
109
117
122
073
296
461
565
586
135
366
581
746
801
433
617
845
036
114
621
771
951
120
If? 5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Q
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
BNW
.081
.085
.089
.093
.098
.097
.101
.105
.109
.104
.108
.112
.116
.120
.104
.108
.112
.116
.120,
.443
.474
.504
.534
.564
.676
.715
.755
.795
.834
.038
.080
.121
.161
,20.2
.038
.080
.121
.161
.202
FSP
0.011
0.011
0.011
0.011
0.041
0.005
0.005
0.005
0.005
0.035
0.092
0.092
0.092
0. 092
0.041
0.091
0.091
0.091
0.091
0.041
0.016
0.074
0.163
0.252
0.343
0.033
0.090
0.179
0.268
0.358
0.822
0.753
0.635
0.500
0.361
0.878
0.789
0.649
0.502
0.358
DOR
0.
0.
0.
0.
0.
0.
0 .
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
1.
1.
0.
0.
0.
1.
1.
037
048
068
088
108
051
062
079
096
113
088
093
102
110
119
096
102
108
113
122
150
303
476
651
824
261
411
592
790
988
640
728
847
005
175
801
867
957
076
195
MIT
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
1
0
0
0
1
1
.021
.037
.062
. 087
.112
.040
.048
.069
.095
.120
.090
. 097
.104
.111
.120
.103
.106
.110
.114
.,120
. 074
.257
.452
.648
.844
.129
.316
.544
.777
.010
.596
.641
.776
.984
.197
.777
.831
.923
.055
.200
SOG
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
. 091
.096
.100
.104
.109
.095
.099
.104
. 108
.112
.112
. 116
.120
.124
.128
.112
.116
.121
.125
.129
.762
.806
.850
.893
.936
.819
.863
.906
.954
.994
.091
.132
.174
.216
.258
.099
.141
.182
.224
.263
WRE
0.021
0.042
0.670
0.086
0.092
0.034
0.053
0.078
0.099
0. 106
0.073
0. 086
0. 102
0.115
0.121
0.088
0.098
0. 109
0. 116
0.122
0.077
0. 29h
0.461
0 . 5 6 f,
0. 598
0. 142
0.361,
0.381
0.74i
0.801
0.44:
0.617
0. 84
1 . '"> ' •
1.11.;
0. ' J
0. 7
0. "
1 . 1
1.1-
-------
Table 60a. PEAK RUNOFF FROM HYPOTHETICAL CATCHMENTS FOR
TWO-HOUR TRIANGULAR RAINSTORM (cfs)
Slope,
percent
0.1
10.0
0.1
10.0
11
c
n
3
O
-* *>
.C > C
•W HO)
Cn 01 0
c an
a -u E o
P *u M o,
0
25
316 50
75
100
0
25
158 50
75
100
0
25
316 50
75
100
0
25
158 50
75
100
0
25
1000 50
75
100
0
25
500 50
75
100
0
25
1000 50
75
100
0
25
500 50
75
100
Catchment
number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Dry initial condition
SWMM
0.31
0.69
1.18
1.63
1.90
0.50
0.84
1.32
1.79
2.07
1.08
1.36
1.70
2.02
2.21
1.31
1.56
1.83
2.07
2.23
1.18
5.54
9.45
12.48
14.21
" 2.15
6.30
10.99
14.95
17.31
6.59
9.79
14,23
18.66
21.16
9.15
12.09
15.99
19.57
21.80
BNW
1.25
1.44
1.63
1.82
2.02
1.40
1.59
1.78
1.97
2.16
1.47
1.66
1.85
2.04
2.22
1.47
1.66
1.85
2.04
2.22
7.84
9.76
11.70
13.65
15.59
10.97
12.93
14.89
16.85
18.93
14.75
16.62
18.49
20. 36
22.23
14. 75
16.62
18.49
20.36
22.23
FSP
1.87
1.87
1.87
1.87
1.04
1.88
1.88
1.88
1.88
1.03
1.94
1.94
1.94
1.94
1.05
1.90
1.90
1.90
1.90
1.05
0.54
2.16
4.66
7.17
9.65
1.14
2.73
5.21
7.70
9.80
17.22
16.07
14.05
11.89
9.81
18.41
16.85
14.41
11.97
9.80
DOR
0.3
0.6
1.1
1.6
2.1
0.5
0.8
1.2
1.7
2.1
1.0
1.2
1.4
1.8
2.2
1.1
1.3
1.6
1.8
2.2
1.3
4.9
9.1
13.2
17.5
2.3
5.7
10.3
14.9
19.7
6.3
8.6
12.1
16.7
21. 8
8.4
10.4
13.1
17.2
22.1
MIT
0.46
0.71
1.14
1.60
2.08
0.73
0.89
1.23
1.69
2.18
1.33
1.52
1.71
1.95
2.19
1.49
1.67
1.84
2.02
2.22
1.26
5.16
9.40
13.65
17.89
2.82
6.21
10.81
15.46
20.15
9.87
11.23
13.76
17.81
22.17
12. 45
14.04
15.98
18.79
22.16
SOG
1.10
1.34
1.59
1.84
2.08
1.17
1.38
1.62
1.87
2.12
1.52
1.70
1.91
2.08
2.30
1.52
1.70
1.91
2.08
2.30
8.72
11.27
13.81
16.46
19.14
9.54
12.01
14.51
17.13
19.81
14.59
16.60
18.54
20.55
22.57
14.83
16.78
18.72
20.70
22.67
WRE
0.31
0.70
1.18
1.62
1.89
0.50
0.84
1.32
1.79
2.07
1.09
1.36
1.70
2.02
2.21
1.31
1.56
1.83
2.07
2.23
1.18
5.52
9.36
12.32
13.95
2.15
6.30
10.95
14.84
17.15
6.59
9.79
14.28
18.66
21.15
9.15
12.09
15.99
19.57
21.81
SWMM
0.40
0.79
1.26
1.68
1.90
0.63
0.98
1.44
1.85
2.07
1.23
1.50
1.79
2.04
2.21
1.43
1.63
1.88
2.07
2.23
1.59"
5.90
9.80
12.77
14.21
2.84
6.96
11.58
15.40
17.31
8.03
11.28
15.53
19.19
21.15
10.73
13.59
17.05
20.04
21.81
Wet initial condition
BNW
1.44
1.59
1.73
1.87
2.02
1.58
1.72
1.87
2.01
2.16
1.64
1.79
1.93
2.08
2.22
1.64
1.79
1.93
2.08
2.22
9.99
11.41
12.84
14.26
15.69
13.14
14.59
16.03
17.48
18.93
16.44
17.88
19.33
20.78
22.23
16.44
17.88
19.33
20.78
22.23
FSP
1.87
1.87
1.87
1.87
1.04
1.88
1.88
1.88
1.88
1.03
1.94
1.94
1.94
1.94
1.05
1.90
1.90
1.90
1.90
1.05
0.54
2.16
4.66
7.17
9.65
1.14
2.73
5.21
7.70
9.80
17.22
16.07
14.05
11.89
9.81
18.41
16.85
14.41
11.97
9.80
DOR
0.7
0.9
1.3
1.7
2.1
0.9
1.2
1.5
1.8
2.1
1.4
1.6
1.8
2.0
2.2
1.5
1.7
1.9
2.1
2.2
3.0
6.3
10.0
13.8
17.6
5.0
8.0
11.7
15.7
19.8
11.0
13.1
15.7
18.5
21.8
13.2
15.1
17.1
19.6
22.1
MIT
0.50
0.74
1.15
1.61
2.08
0.81
0.96
1.27
1.70
2.18
1.44
1.59
1.77
1.99
2.21
1.57
1.72
1.88
2.05
2.22
' 1.44
5.27
9.48
13.68
17.89
3.13
6.41
10.93
15.51
20.14
10.62
11.90
14.28
18.04
22.17
13.32
14.81
16.62
19. 17
22.16
SOG
1.48
1.63
1.77
1.94
2.08
1.52
1.66
1.80
1.98
2.12
1.70
1.84
1.98
2.15
2.30
1.70
1.84
2.01
2.15
2.30
12.96
14.51
16.10
17.66
19.18
13.63
15.22
16.78
18.29
19.81
16.70
18.15
19.63
21.08
22.57
16.81
18.26
19.74
21.19
22.67
WRE
0.40
0.79
1.27
1.68
1.90
0.63
0.98
1.44
1.85
2.07
1.24
1.50
1.79
2.05
2.21
1.43
1.64
1.88
2.08
2.23
1.59
5.91
9.80
12.77
14.21
2.84
6.96
11.58
15.40
17.32
8.03
11.29
15.54
19.19
21.16
10.73
13.57
17.05
20.04
21.81
-------
Table 6Ob.
PEAK RUNOFF FROM HYPOTHETICAL CATCHMENTS FOR
TWO-HOUR TRIANGULAR RAINSTORM (m3/sec)
ro
en
o
•p
c c~
0)0) -P
ft 0 CP
O 1-t C
r-i 0) OJ
03 a j g
96.4
0.1
48. 2
96.4
10.0
48.2
304.8
0.1
152.4
304.8
10.0
152.4
Imperviou
ness ,
percent
0
25
50
75
100
0
25
50
75
100
0
25
50
75
100
0
25
50
75
100
0
25
50
75
100
0
25
50
75
100
0
25
50
75
100
0
25
50
75
100
Catchment
number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Dry initial condition
SWMM
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
009
020
033
046
054
014
024
037
051
059
031
039
048
057
063
037
044
052
059
063
033
157
268
353
402
061
178
311
423
490
187
277
404
528
599
259
342
453
554
617
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
u
0
0
0
0
BNW
.035
.041
.046
.052
.057
.040
.045
.050
.056
.061
. 042
. 047
.052
.058
.063
. 042
. 047
.052
.058
.063
.222
.276
.331
. 387
.442
.311
.366
. 422
.477
.536
. 418
.471
.524
.577
.630
.418
.471
.524
.577
.630
FSP
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
u
0
0
0
0
0
0
0
0
0
0
0
0
0
0
u
0
0
0
0
.053
.053
.053
.053
.029
.053
.053
.053
.053
.029
.055
.055
. 055
.055
.030
.054
.054
.054
.054
.030
.015
.061
.132
.203
.273
.032
.077
.148
.218
.278
.488
.455
.398
.337
.278
.521
.477
.408
.339
.278
DOR
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
008
017
031
045
059
014
023
034
048
059
028
034
040
051
062
031
037
045
051
062
037
139
258
374
496
065
161
292
422
558
178
244
343
473
617
238
295
371
487
626
MIT
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
013
020
032
045
059
021
025
035
048
062
038
043
048
055
062
042
047
052
057
063
036
146
266
387
507
080
176
306
438
571
280
318
390
504
628
353
398
453
532
628
SOG
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.031
.038
.045
.052
.059
.033
.039
.046
.053
.060
.043
.048
.054
.059
.065
. 043
.048
.054
. 059
.065
.247
.319
.476
.466
.542
.270
.340
.411
.485
.561
.413
.470
.525
.582
.639
.420
.475
.530
.586
.642
WRE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
,0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.009
.020
.033
.046
.054
.014
.024
.037
.051
.059
.031
.039
.048
.057
.063
. 037
.044
.052
.059
.063
.033
.156
.265
.349
.395
.061
.173
.310
.420
.486
.187
.277
. 404
.528
.599
.259
.342
.453
.554
.618
SWMM
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.011
.022
.036
.048
.054
.018
.028
.041
.052
.059
.035
.042
.051
.058
.063
.040
.046
.053
. 059
.063
.045
.167
.278
.362
.402
.080
.197
.328
.436
.490
.227
.319
.440
.543
.599
.304
.385
.483
.568
.618
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
BNW
.041
.045
.049
.053
.057
.045
.049
.053
.057
.061
.046
.051
.055
.059
.063
. 046
.051
.055
.059
.063
.283
.323
.364
.404
.444
.372
.413
.454
.495
.536
.466
.506
.547
.588
.630
.466
.506
.547
.588
.630
Wet initial condition
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
FSP
.053
.053
.053
.053
.029
.053
.053
.053
.053
.029
.055
.055
.055
.055
.030
.054
.054
.054
.054
.030
.015
.061
.132
.203
.273
.032
.077
.148
.218
.278
.488
.455
.398
.337
.278
.521
.477
.408
.339
.278
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
u
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
DOR
.020
.025
.037
.048
.059
.025
. 034
.042
.051
.059
.040
.045
.051
.057
.062
.042
. 048
.054
.059
.062
.085
.178
.283
.391
.498
'.1*2
.227
.331
.445
.561
.312
.371
.445
.524
.617
. 374
.428
.484
.555
.626
MIT
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
u
0
0
0
0
.014
.021
.033
.046
.059
.023
.027
.036
.048
.062
.041
.045
.050
.056
.063
.044
.049
.053
.058
.063
.041
.149
.268
. 387
.507
. 089
.182
.310
.439
.570
.301
.337
.404
.511
.628
.377
.419
.471
.543
.628
SOG
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
u
0
0
0
0
.042
. 046
.050
.055
.059
.043
. 047
.051
.056
.060
.048
.052
.056
.061
.065
.048
.052
.057
.061
.065
.367
.411
.456
. 500
.543
. 386
.431
.475
.518
.561
.473
.514
.556
.597
.639
.476
.517
.559
.600
.642
WRE
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0
0.
0,
0,
0,
0
0.
0.
0,
0.
0.
0
0.
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.011
062
036
.048
.054
.018
.028
.041
.052
. 059
.03
.042
.051
.058
.063
.040
.046
. 053
.059
.063
.045
.167
.278
. 362
.402
.080
.197
. 328
. 436
. 491
.227
. 320
.440
. 543
. 599
. 304
. 384
.483
. 568
. 618
-------
Table 61a.
PEAK RUNOFF FROM HYPOTHETICAL CATCHMENTS FOR
FOUR-HOUR TRIANGULAR STORM (cfs)
K)
Ul
3
O
4-> * -H 4J
- c .c > c
V Q) ±> ^0)
£X U tyi (DO
on c an
r-l JJ HO)
CO QJ J 4-1 H(i
0
25
316 50
75
0.1 100
0
25
158 50
75
100
0
25
316 50
75
10.0 100
0
25
158 50
75
100
0
25
1000 50
75
0.1 100
0
25
500 50
75
100
0
25
1000 50
75
10.0 100
0
25
500 50
75
100
Catchment
number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Dry initial conditions
SWMM
0.06
0.29
0.56
0.82
1.04
0.10
0.31
0.58
0.85
1.09
0.26
0.44
0.67
0.92
1.13
0.33
0.51
0.72
0.95
1.14
0.20
2.72
5.06
7.10
8.77
0.38
2.84
5.44
7.85
9.94
1.36
3.38
5.98
8.70
11.08
2.05
3.99
6.35
8.99
11.24
BNW
0.46
0.62
0.77
0.93
1.08
0.50
0.66
0.81
0.96
1.11
0.52
0.67
0.82
0.98
1.13
0.52
0.67
0.82
0.98
1.13
3.20
4.81
6.43
8.06
9.66
4.23
5.76
7.33
8.91
10.51
5.20
6.72
8.25
9.77
11. 30
5.20
6.72
8.25
9.77
11.30
FSP
0.32
0.32
0.32
0.32
0.73
0.17
0.17
0.17
0.17
0.71
1.06
1.06
1.06
1.06
0.73
1.04
1.04
1.04
1.04
0.73
0.53
1.66
3.46
5.26
6.92
1.10
2.17
3.94
5.70
6.95
9.43
9.10
8.44
7.65
6.95
10.11
9.55
8.64
7.71
6.95
DOR
0.0
0.3
0.5
0.8
1.1
0.1
0.3
0.6
0.8
1.1
0.2
0.3
0.6
0.8
1.1
0.2
0.4
0. 6
0.9
1.1
0.1
2.5
5.0
7.4
9.9
0.3
2.7
5.3
8.0
10.7
0.9
2.8
5.6
8.4
11.2
' 1.4"
3.0
5.6
8.5
11.3
MIT
0.15
0.33
0.58
0.84
1.09
0.25
0.40
0.62
0.86
1.11
0.48
0.63
0.79
0.96
1.14
0.52
0.67
0.83
0.98
1.14
0.47
2.80
5.29
7.77
10.26
0.96
3.09
5.62
8.17
10.73
3.33
4.76
6.59
8.87
11.22
4.34
5.77
7.44
9.38
11.41
SOG
0.25
0.42
0.64
0. 85
1.10
0.25
0.46
0.64
1.10
0.57
0.39
0.57
0.71
0.88
1.17
0.39
0.57
0.71
0.88
1.17
1.70
3.81
5.86
8.02
10. 38
1.94
3.99
6.00
8.16
10.56
3.64
5.26
6.89
8.58
11.41
' 3.74"
5.33
6.96
8.62
11.41
WRE
0.06
0.29
0.56
0.82
1.04
0.10
0.31
0.58
0.85
1.09
0.26
0.45
0.67
0.92
1.14
0.33
0.52
0.72
0.95
1.14
0.20
2.72
5.04
7.05
8.68
0.38
2.84
5.43
7.83
9,89
1.36
3.38
5.98
8.70
11.09
2.05
3.99
6.35
8.99
11.24
SWMM
0.11
0.34
0.61
0.86
1.04
0.19
0.40
0.66
0.91
1.09
0.39
0.58
0.79
0.98
1.13
0.47
0.64
0.82
0.99
1.14
0.44
2.91
5.26
7.28
8.77
0.80
3.20
5.77
8.15
9.94
2.42
4.50
6.97
9.34
11.08
3.34
5.30
7.56
9.61
11.24
Wet initial conditions
BNW
0.50
0.65
0.79
0.94
1.08
0.54
0.68
0.83
0.97
1.11
0.55
0.70
0.84
0.99
1.13
0.55
0.70
0.84
0.99
1.13
3.92
5.36
6.81
8.26
9.71
4.72
6.17
7.62
9.07
10.51
5.51
6.96
8.40
9.85
11.30
5.51
6.96
8. 40
9.85
11.30
FSP
0. 32
0.32
0.32
0.32
0.73
0.17
0.17
0.17
0.17
0.71
1.06
1.06
1.06
1.06
0.73
1.04
1.04
1.04
1.04
0.73
0.53
1.66
3.46
5.26
6.92
1.10
2.17
3.94
5.70
6.95
9.43
9.10
8.44
7.65
6.95
10.11
9.55
8.64
7.71
6.95
DOR
0.2
0.4
0.6
0.8
1.1
0.3
0.5
0.7
0.9
1.1
0.5
0.6
0.8
1.0
1.1
0.5
0.7
0.8
1.0
1.1
0.8
3.0
5.3
7.6
10.0
1.4
3.5
5.8
8.2
10.7
3.4
5.0
7.0
9.1
11.2
4.2
5.8
7.5
9.3
11.3
MIT
0.15
0.34
0.58
0.84
1.09
0,26
0.41
0.62
0.87
1.11
0.48
0.63
0.79
0.96
1.14
"0,52
0.67
0.82
0.98
1.14
0.47
2.80
5.29
7.77
10.26
0.97
3.10
5.63
8.18
10.73
3.39
4.82
6.64
8.90
11.22
4.38
5.81
7.49
9.41
11.41
SOG
0.49
0.64
7.77
0.95
1.10
0.49
0.64
0.81
0.95
1.10
0.57
0.71
0.85
0.99
1.17
0.57
0.71
0.85
0.99
1.17
4.24
5.83
7. 35
8.90
10.38
4.49
6.04
7.59
9.08
10.56
5.54
6.99
8.48
9.92
11.41
5.58
7.03
8.51
9.96
11.41
WRE
0.12
0.35
0.61
0.86
1.05
0. 19
0.40
0.66
0.91
1.09
0.39
0.58
0.79
0.98
1.14
0.47
0.64
0.82
0.99
1.14
0.44
2.91
5.26
7.28
8.77
0.80
3.20
5.77
8.15
9.94
2.42
4.51
6.98
9.34
11.09
3.34
5.30
7.56
9.61
11.24
-------
Table 61b.
PEAK RUNOFF FROM HYPOTHETICAL CATCHMENTS FOR
FOUR-HOUR TRIANGULAR STORM (m3/sec)
NJ
Ul
NJ
Slope
percent
0.1
10.0
0.1
10.0
0
-H 4J
JS > C
-4J H * Q>
C Q.
-------
Table 62. TIMES OF PEAK RUNOFF FROM HYPOTHETICAL CATCHMENTS
FOR ONE-HOUR TRIANGULAR RAINSTORM (minutes)
Ul
LO
o
-P - -H 4J
- C J3 > C
01 Q> -P M Q)
a o 01
-------
Table 63. TIMES OF PEAK RUNOFF FROM HYPOTHETICAL CATCHMENTS
FOR TWO-HOUR TRIANGULAR STORM (minutes)
Ul
Slope ,
percent
0. 1
10.0
0.1
10.0
0)
c
w
a
o
•H *J
J= > C
jj i^
tn
-------
Table 64. TIMES OF PEAK RUNOFF FROM HYPOTHETICAL CATCHMENTS
FOR FOUR-HOUR TRIANGULAR RAINSTORM (minutes)
Ul
U1
0)
a
01
D
o
4-1 * -H 4-»
- C J= > C
(U o
o t4 c an
»-i
-------
1 SWHM
2 MIT
3 SOGREBH
4 WE
B
9.00
IB. 00
n.ee
i2.ee
ia.ee
TIME,
HOUR5
15.90
ie.ee
ir.ee
ie.ee
1 SVHM
2 BNW
3 FSP
OORSCH
a.ae
». ee
11. ea
i2.ee
13.99 14.99
TIME, HOURS
13.99
ie.ee
i7.ee
ia.ee
Figure 31. Runoff for Two-Hour Triangular Rainstorm - Small
Hypothetical Catchment, 48 m (158 ft) Long, 0.1%
Slope, 0% Imperviousness (Catchment #6)
256
-------
9.00
10.00
11.00 12.00
19.00 It.00
TIME, HOURS
1 SVMM
2 HIT
3 SOGRERH
4 WE
«--*
is. 00
18.00
17.00
18.00
9.00
ie.ro
14.00
HOURS
1 SVHH
2 BNW
3 FSP
4 DORSCH
a-
§
Is
is. 00
16,00
17.00
-o
3
o
8-
I
•?
8
18.00
Figure 32. Runoff for Two-Hour Triangular Rainstorm - Small
Hypothetical Catchment, 48 m (158 ft) Long, 0.1%
Slope, 50% Imperviousness (Catchment #8)
257
-------
9.00
1 SVMM
2 MIT
3 SOGREBH
4 VRE
10.00
11.00
12.00
.3.00 14.00
TIME, HOURS
t—
15.00
16.00
3D
m
o
•p
8=
17.00 16.00
1 SVMM
2 BNV
3 FSP
4 DORSCH
12.00
13.00 14.00
TIME. HOURS
15.00
16.00
17.00
33
rn
n
u>
I—I
o
16.00
Figure 33.
Runoff for Two-Hour Triangular Rainstorm - Small
Hypothetical Catchment, 48 m (158 ft) Long, 0.1%
Slope, 100% Imperviousness (Catchment #10)
258
-------
1 SWMM
2 MIT
3 SOSREflH
4 VRE
L.s
LU
cs
cc
§«.
CO-
•o
LU
CO
.83
8...
-f—
18.88
O
g
9.88
12.08
. HOUR
S*"
15.00 16.08 17.00 18.08
1 SVHM
2 BNV
3 FSP
4 DORSCH
9.08
10.08
11.08
12.80
13.80 14.88
TIME, HOURS
15.80
16.00
17.00
m
o
la.oo
Figure 34.
Runoff for Two-Hour Triangular Rainstorm - Small
Hypothetical Catchment, 48 m (158 ft) Long, 10%
Slope, 0% Imperviousness (Catchment #16)
259
-------
cs
oc
C3
8..
•o
UJ
co
.aS
1 SVMM
2 MIT
3 SOGREflH
4 WRE
—i
ie.ee
§
ffl
s.ee
ie.ee
n.ee
ia.ee id.ee
TIME. HOURS
is.ee
ir.ee
ie.ee
1 SVMM
2 BNV
3 FSP
tDORSCH
g--
i2.ee
is.«a i4.ee
TIME. HOURS
is.ee
ie.ee
17.
S
o
m
18. M
Figure 35. Runoff for Two-Hour Triangular Rainstorm - Small
Hypothetical Catchment, 48 m (158 ft) Long, 10%
Slope, 50% Imperviousness (Catchment #18)
260
-------
_.8
LU
(0
i»..aS
8. _S
•*-
9.00
1 SVHH
2 HIT
3 S06REAH
4 VRE
s
10.00 11.00
—i
15.00
16.00 17.M
18. M
1 SVHH
2 BNV
3 FSP
4 DORSCH
9.00
Figure 36. Runoff for Two-Hour Triangular Rainstorm - Small
Hypothetical Catchment, 48 m (158 ft) Long, 10%
Slope, 100% Imperviousness (Catchment #20)
261
-------
SWUM
2 MIT
3 SOGREflH
VRE
17.00
18.89
17.00
16.00
Figure 37. Runoff for Two-Hour Triangular Rainstorm - Large
Hypothetical Catchment, 152 m (500 ft) Long, 0.1%
Slope, 0% Imperviousness (Catchment #26)
262
-------
1 SWMM
2 MIT
3 SOCREftH
4 VRE
9.88
11.88
i2.ea
T1IME?, HOUfiS*
i5.ee ie.ee ir.ee ie.ee
9.80
19.88 11.88 12.88
I9ME?. HOURS8
is.ee 16.88 i7.ee ie.ee
Figure 38. Runoff for Two-Hour Triangular Rainstorm - Large
Hypothetical Catchment, 152 m (500 ft) Long, 0.1%
Slope, 50% Imperviousness (Catchment #28)
263
-------
9.88
10.08
15.00
1 SWMM
2 MIT
3 SOGREflH
4 VRE
16.00
i
g i«="t3
i- »"""!
17.00
3
-
18.00
15.00
1 SWMM
2 BNW
3 FSP
U DORSCH
-o
33
m
o
33
t—i
O
5--?"*
'
16.00
17.00
16.00
Figure 39. Runoff for Two-Hour Triangular Rainstorm - Large
Hypothetical Catchment, 152 m (500 ft) Long, 0.1%
Slope, 100% Imperviousness (Catchment #30)
264
-------
i£S.
on.
UJ
..SI
..So
1 SWMM
2 MIT
3 SOGRERH
4 VRE
T1-
ft'
8
3D
m
n
9.00 10.00
11.00 12.00
. Hou
15. M
16. M
17. M
18. M
1 SWMM
2 BNW
3 FSP
4 OORSCH
S
12.00
13.00 14.M
TIME, HOURS
15.00
16.00
17.00
18.00
Figure 40. Runoff for Two-Hour Triangular Rainstorm - Large
Hypothetical Catchment, 152 m (500 ft) Long, 10%
Slope, 0% Imperviousness (Catchment #36)
265
-------
1 SVMM
2 MIT
3 SOGRERH
4 VRE
S3"
g
m
o
3D
12.00
13.00
TIME,
14.00
HOURS
—i
15.00
—I
16.00
17.00 16.00
1 SVMM
2 BMW
3 FSP
OORSCH
9.00
17.00
18.00
Figure 41. Runoff for Two-Hour Triangular Rainstorm - Large
Hypothetical Catchment, 152 m (500 ft) Long, 10%
Slope, 50% Imperviousness (Catchment #38)
266
-------
9.019
1 SWMM
2 MIT
3 SOGRERH
4 VRE
3
X
3
-o
O
1—4
•f~°
15
—I
I—I
O
V.
ie.ee
ii.ee
i3.ee n.ee
TIME. HOURS
is.ee
16.1
17.
ie.ee
0.0.
LU
CS
..01
•o
LU
CO
..So
S
9. an
1 SWMM
2 BNV
3 FSP
4 DORSCH
S
ie.ee
11.ea
12.00
13.00 14.00
TIME, HOURS
15.00
16.00
3
m
o
•J"
85
3D
17.00 18.00
Figure 42. Runoff for Two-Hour Triangular Rainstorm - Large
Hypothetical Catchment, 152 m C500 ft) Long, 10%
Slope, 100% Imperviousness (Catchment #40)
267
-------
Model Comparison
Comparable runoff hydrographs are computed by the SWMM, DORSCH,
MIT, and WRE models for most catchment data combinations and
for many catchment data combinations those computed by the BNW
and SOGREAH models are comparable. Peak runoffs computed by
the BNW and SOGREAH models are up to several times higher than
those by the SWMM, DORSCH, MIT, and WRE models, and the dif-
ferences between the peak runoff values and times computed by
these two groups of models increase with increasing catchment
size and decreasing catchment slope, imperviousness and ini-
tial moisture condition. The six models compute comparable
runoff hydrographs for most fully impervious conditions. The
runoff hydrographs computed by the FSP are different from
these six models for most catchment data combinations.
The results of the SWMM, DORSCH, MIT, and WRE models are sim-
ilar since all use the Horton equation for infiltration and
the kinematic wave equation for overland flow. Infiltration
is computed from overland flow depth and consequently is
affected by the runoff delay and storage of the catchment
surface. For the large catchment, the DORSCH and MIT models
vary slightly from the SWMM and WRE models, particularly for
the fully pervious conditions, which may be caused by dif-
ferent solution techniques for the infiltration/overland flow
computations and by differences in the retention storage formu-
lations.
The results of the BNW and SOGREAH models are surprisingly
similar, although the BNW model uses the Holtan equation for
infiltration and the unit hydrograph method for overland flow
and the SOGREAH model uses the Horton equation for infiltration
and the Muskingum method for overland flow. Both models com-
pute infiltration from rainfall directly rather than the
actual depth of water on the catchment surface. This and
the different overland flow routing methods may explain
the differences in computed runoff hydrographs between the
two groups. Although the fully impervious cases do not vary
significantly, for some fully pervious data combinations
the peak runoffs predicted by the BNW and SOGREAH models are
over 5 times greater than those predicted by the SWMM, DORSCH,
MIT, and WRE models.
The FSP defines initial moisture conditions internally, so
consequently differences between dry and wet initial catch-
ment moisture conditions cannot be considered. Due to pro-
gram constraints on numerical values of partial results of
the catchment runoff computations, consideration of certain
combinations of catchment size, shape, slope, and pervious-
ness is limited. Consequently, for the small catchment data
268
-------
combinations, the percent imperviousness has no influence on
the computed peak runoff for the partially to fully pervious
catchments, the peak runoff from the short catchment is lower
than from the long catchment and the runoff from the steep
slope is higher from the pervious than from the impervious
areas. For the large catchment data combinations, the peak
runoff is lower from the fully impervious area than from the
fully pervious area. Only the peak runoff values for the
large catchment with the flat slope are similar to the other
models; and these values are lower than the other model values.
It appears, therefore, that caution should be used in applying
the model to small catchments (i.e., with drainage areas of
0.5 ha [1 acre] or less). Criteria could probably be developed
for combinations of catchment size, slope, length, and per-
viousness which would define the applicability of the model.
Examination of the entire computer output indicates that the
initial moisture condition has a definite effect on the shape
of the computed runoff hydrographs, even for cases in which
the peak runoff is not affected. For the dry initial con-
ditions, the peak runoff occurs later and higher rainfall
losses during the early part of the rainfall result in lower
runoff values until the catchment is saturated and the runoff
approaches the values of the wet initial conditions.
Evaluation of model sensitivity to variations in catchment
characteristics indicates that catchment slope, shape, and
initial moisture conditions have no effect on the computed
peak runoff for all fully impervious cases. Initial catch-
ment moisture conditions become more significant as the per-
viousness and overland flow time increase (i.e., with lower
slopes and longer catchments). The catchment length becomes
more significant with higher perviousness and lower initial
moisture condition. The effect of perviousness is significant
for all cases, with differences in peak runoffs between fully
pervious and fully impervious catchments being the greatest
for the long and flat catchments.
Two-Hour Triangular Rainstorm
The runoff computed by each of the seven tested models is
plotted for twelve catchment data combinations in Figures 31
to 42. The models were separated into two groups for plotting
purposes to prevent obscuring of model differences by too many
overlapping lines. Each plot includes the runoff computed by
the SWMM and three other models.
The plotted runoff is for the 2-hr triangular storm which has
a peak rainfall intensity of 50.8 mm/hr (2 in./hr). The first
six figures show runoff from a 0.465 ha (1.15 acre) rectan-
gular catchment and the second six figures from a 4.65 ha
269
-------
(11.5 acre) rectangular catchment. The catchment length in
the direction of surface flow is 48.2 m (158 ft) for the
small and 152 m (500 ft) for the large catchment. The catch-
ment length perpendicular to the direction of surface flow is
96.4 m (316 ft) for the small and 305 m (1000 ft) for the
large catchment. A Manning's roughness coefficient of 0.25
is assumed for the pervious area and 0.025 for the impervious
area of each catchment. Initially dry catchment moisture
conditions are assumed. For pervious areas, the maximum
infiltration rate is 50.8 mm/hr (2.0 in./hr), the minimum
infiltration rate is 12.7 mm/hr (0.5 in./hr), and the infil-
tration decay rate is 0.001 sec"-'- as defined by Horton's
infiltration equation. The retention storage capacity for
pervious areas is 5.1 mm (0.20 in.) and for impervious areas
1.3 mm (0.05 in.). The plotted examples are for different
combinations of catchment slope (0.1 and 10 percent) and
impervious areas (0, 50, and 100 percent).
Differences in the mathematical formulations for infiltration
produced considerable variation among the models in the com-
puted runoff for the catchments with 0 percent imperviousness
(Figures 31, 34, 37, and 40). The differences are particularly
great for the 0.1 percent slope (Figures 31 and 37). For both
slopes, runoff computed by the BNW and SOGREAH models is
considerably higher than for the other models. One reason
appears to be that Horton's equation, as used by most models,
neglects catchment moisture conditions in computing potential
infiltration. When the ground becomes rapidly saturated,
Horton's equation overestimates infiltration and underestimates
surface runoff. For steeper slopes where runoff occurs more
rapidly or for low intensity rain this effect is less pro-
nounced, since less water is available for infiltration.
Although Holtan's equation, as used by the BNW model, accounts
for changes in soil moisture, it introduces a different ap-
proximation by computing potential infiltration from rainfall,
rather than the depth of water on the catchment. It there-
fore underestimates infiltration for flat slopes where runoff
is sufficiently slow, and rainfall occurring during one time
step continues to contribute to infiltration during succeeding
time steps.
The FSP assumes that a constant fraction of the rain falling
on the pervious areas of sewered catchments runs off during
the same time step; it neglects catchment slope, shape, and
roughness. For the FSP simulations presented here, however,
nonsewered catchment runoff was specified, which computes
losses from rainfall with an empirical equation accounting
for soil moisture changes and evaporation and considers catch-
ment shape and slope. For the flat slope (Figures 31 and 37) ,
270
-------
the FSP computes an extremely low and slow response and the
runoff hydrograph does not recede during the 6-hour simulation
period.
Differences in the computed results are introduced also by the
overland flow routing procedures. The BNW model uses a unit
hydrograph approach; the SOGREAH model uses the Muskingum
method; the SWMM, DORSCH, MIT, and WRE models use kinematic
wave formulations; and the FSP uses a linear storage routing
which considers catchment shape and slope but neglects surface
roughness.
The effect of these differences can be seen by comparing the
results of the runoff computations for the 100 percent im-
pervious areas, since for these runs rainfall losses were
considered negligible and the computed differences are pri-
marily the result of differences in the overland flow formu-
lations. As Figures 33, 36, 39, and 42 show, the results of
all models except the FSP are quite comparable for the steep
slope (Figures 33 and 36) and show only small differences for
the flat slope (Figures 39 and 42). The FSP assumes that a
constant fraction of the overland flow storage on nonsewered
areas runs off during each time step. The resulting runoff
hydrograph is much flatter and longer than the other model
hydrographs. Since the FSP formulation neglects catchment
shape, slope, and surface roughness for impervious areas, the
computed runoff hydrographs for the flat and steep slopes are
the same.
The combined effects of the formulations for infiltration and
overland flow is illustrated in Figures 32, 35, 38, and 41 for
50 percent imperviousness. Again, comparable runoff is com-
puted by the BNW and SOGREAH models on the one hand and the
SWMM, DORSCH, MIT, and WRE models on the other hand. The dif-
ferences in computed runoff between the two groups, both in
magnitude and timing, are smaller than for the fully pervious
case and larger than for the fully impervious case. The peak
runoff computed by the FSP is less than half that of the other
models for the small flat catchment. The PSP produces more
comparable runoff hydrographs for the other cases, but the
computed runoff volume is slightly larger, and the computed
peaks are slightly higher and later for the small steep and
large flat catchment and average for the steep large catch-
ment.
The selected examples accentuate model differences. As can
be seen in a later section, many of these differences are
damped in actual catchment applications as a result of the
smoothing effect of more random rainfall sequences and the
routing over many small subcatchments of various sizes, slopes
and surface characteristics.
271
-------
HYPOTHETICAL PIPE DATA TESTS
Hypothetical pipe data tests were performed for two different
pipe diameters, three invert slopes, two types of upstream
and downstream boundary conditions, four inflow hydrographs,
and three inflow quality graphs, representing a total of 48
data combinations. The effect of different pipe roughness
coefficients and different time discretizations on computed
pipe outflow hydrographs and quality graphs was not tested.
A time step of 5 minutes was suggested for the pipe flow and
water quality routing simulations. This time step was actually
used by the BNW, FSP, SWMM, and MIT models. The DORSCH model
used a time step of 2.5 minutes for the 1-hr triangular inflow
and 5-minute time steps for the other three inflows. The
SOGREAH model used a time step of 5 minutes for the constant
inflow; for the other three inflows, the time steps varied
according to changes in flow, with 5-minute steps at the
beginning and end of the runoff gradually decreasing to
1 minute near the peaks of the hydrographs.
For these six models the length of time step is selected only
on the basis of accuracy, while for the WRE model, it is
limited by numerical stability criteria. Consequently, dif-
ferent time steps were used by the WRE model for the dif-
ferent data combinations but the time step was held constant
for any particular routing computation. Different time steps
were used for flow and water quality routing, which were
computed by separate computer runs and have different stability
criteria. The time steps for the flow routing ranged from 12
seconds for the large pipe with the steep slope to 60 seconds
for the small pipe with the flat slope. The time step for
the water quality routing varied from 24 seconds to 120 sec-
onds .
The results of the pipe routing simulations of all seven models
are summarized in Tables 65 to 71. These present magnitudes
and times of peak outflows, weir overflows and outflow con-
centrations for each of the 48 pipe/inflow combinations. For
cases with upstream storage and downstream diversion structures,
the tabulated peak outflow represents the sum of the weir and
orifice discharges. The times of the peak outflows and out-
flow concentrations are not tabulated for the constant con-
tinuous inflow and inflow concentrations. Variations from the
constant values for these cases are the result of numerical
instabilities which are generally oscillatory in nature, and
consequently model comparisons are meaningful between the
magnitudes, but not the times, of the peaks.
It was not possible to plot all computed outflow hydrographs
and quality graphs; however, plots are presented in Figures
43 to 66 for the outflow hydrographs and quality graphs from
272
-------
Table 65a.
PEAK OUTFLOWS FROM HYPOTHETICAL PIPES
(cfs)
4J
- c
a) a>
CL D
0 Z
•H n
O O 0)
r-H ^ ,Q
u-t 'b "e
C >) 3
M & C
•5
£.
-\
1
2
0
O
1
JL
O
^
0
0) -^
0> 10
id h
^ QJ
O T3 >
-P C -H
in id 13
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
NO
Yes
No
Yes
No
Yes
No
Yes
No
Yes
Diameter =
SWMM
5.94
*
3.63
3.63
4.75
4.65
5.27
5.42
20.66
*
16.86
*
17.78
*
18.22
*
67.12
*
55.71
*
57.43
*
58.26
*
BNW
5.93
5.93
**
**
5.50
5.50
5.69
5.71
18.77
18.77
**
**
17.06
17.06
17.92
17.92
59. 35
50.54
* *
**
55.99
50.65
57.41
50. 73
FSP
5.94
***
**
**
3.47
***
4.47
***
18.77
***
**
**
17.57
* **
18.17
***
59.36
***
**
**
59.36
***
59.36
***
DOR
5.9
6.0
3.5
3.4
4.5
3.8
5.4
4.0
18. 8
18.8
15.4
14.7
16.8
16.2
17.6
17.2
59.4
59.4
53.7
48.5
55.9
49.6
57.8
49.6
2 ft
MIT
5.94
5.94
3.60
3.44
4.60
4.53
5.24
5.21
19; 51
18.77
16.88
16.46
17.82
17.50
18.30
18.11
59.35
55.24
55.73
51.00
57.41
50.52
58.37
50.33
Diameter =
SOG
5.93
5.93
3.88
3.57
4.77
4.56
5.32
5.23
18.75
18.75
17.30
16.70
18.01
17.34
18.26
17.83
59.32
59.32
59.96
52.26
58.12
53.96
58.48
55.47
WRE
5.94
5.93
3.03
2.02
4.34
3.24
5.12
4.44
18.77
18.28
16.43
12.30
17.49
14.80
18.10
16.29
59. 35
48.86
56.56
33.24
57.14
39.91
58.70
45.94
SWMM
708
706
502
505
595
593
636
655
2481
2485
2080
2076
2158
2153
2190
2187
7411
*
6666
*
6861
*
6946
*
BNW
705
705
**
**
640
640
670
670
2231
2231
**
* *
2107
2107
2169
2169
7054
3114
**
**
6860
3103
6946
3109
FSP
706
***
**
**
665
* * *
683
***
2231
***
**
**
2231
***
2231
***
7056
***
**
**
7056
***
7056
* **
= 12 ft
DOR
705
705
570
505
614
572
654
635
2231
1879
2042
1869
2103
1878
2164
1881
7054
2866
6683
2863
6868
2867
6958
2861
MIT
717
705
535
443
617
560
652
630
'2418'
2231
2088
1839
2157
1989
2195
2094
7399
2888
6660
2785
6861
2786
6958
2778
SOG
705
705
631
522
670
609
685
659
2230
2230
2146
1828
2186
1999
2200
2226
7053
6049
6902
5646
6978
6036
7000
6234
WRE
705
705
570
404
638
533
672
620
2231
1088
2141
1614
2182
1524
2204
1606
7024
2845
6594
2822
6656
2836
6987
2844
Notes: * Value not computed because overflowing storage tank terminates model output.
** Value not computed because model.cannot read and interpolate one-hour triangular inflow hydrograph.
*** Value not computed because model cannot simulate diversions.
-------
Table 65b. PEAK OUTFLOWS FROM HYPOTHETICAL PIPES
to
-p
" C
01 0)
QJ U
o u
en a
0.05
0.5
5.0
.c
a
n)
M
3 Oi M
o o a)
u-) T3 E
c >i 3
H C C
i
j.
2
3
±
3
4
2
3
4
rage
jrsion
O "O >
C/] IB t3
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
(m /sec)
Diameter = 0
SWMM
0.168
It
0.103
0.103
0.135
0.132
0.149
0.153
0.585
*
0.477
*
0.504
*
0.516-
*
1.901
*
1.578
*
1.626
ft
1.650
*
BNW
0.168
0.168
**
* *
0.156
0.156
0.161
0.162
0.532
0.532
ft *
* *
0.483
0.483
0.507
0.507
1.681
1.431
**
**
1.586
1.434
1.626
1.437
FSP
0.168
***
* *
* *
0.098
***
0.127
***
0.532
***
**
* *
0.498
***
0.515
***
1.681
* **
ft *
* *
1.681
***
1.681
***
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
DOR
.167
.170
.099
.096
.127
.108
.153
.113
.532
.532
.436
.416
.476
.459
.498
.487
.682
.682
.521
.374
.583
.405
.637
.405
.61 m
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
MIT
.168
.168
.102
.097
.130
.128
.148
.148
.553
.532
.478
.466
.505
.496
.518
.513
.681
.564
.578
.444
.626
.431
.653
.425
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
SOG
.168
.168
.110
.101
.135
.129
.151
.148
.531
.531
.490
.473
.510
.491
.517
.505
.68
.680
.698
.480
.646
.528
.656
.571
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
0
1
1
1
1
WRE
.168
.168
.086
.057
.123
.092
.145
.126
.531
.517
.465
.348
.495
.419
.512
.461
.680
.383
.601
.941
.617
.129
.661
.300
SWMM
20
20
14
14
16
16
18
18
70
70
58
58
61
61
62
61
209
*
188
*
194
*
196
ft
.1
.0
.2
.3
.9
.8
.0
.5
.3
.4
.9
.8
.1
.0
.0
.9
.9
.8
.3
.7
Diameter = 3
BNW
20.0
20.0
* *
ft *
18.1
18.1
19.0
19.0
63.2
63.2
A *
* *
59.7
59.7
61.4
61.4
199.8
88.2
**
ft *
194.3
87.9
196.7
88.0
FSP
20.0
* ft *
ft *
**
18.8
***
19.3
** *
63.2
* **
*ft
**
63.2
* * *
63.2
** *
199 .8
***
**
* *
199.8
***
199.8
ft **
. 66 m
DOR
20
20
16
14
17
16
18
18
63
53
57
52
59
53
61
53
199
81
189
81
194
81
197
81
.0
.0
.1
.3
.4
.2
.5
.0
.2
.2
.8
.9
.6
,2
.3
. 3
.a
.2
.3
.1
.5
.2
.1
.0
MIT
20.3
20.0
15.2
12.5
17.5
15.9
18.5
17.8
68.5
63.2
59.1
52.1
61.1
56.3
62.2
59.3
209.5
81.8
188.6
78.9
194.3
78.9
197.1
78.7
SOG
20
20
17
14
19
17
19
18
63
63
60
51
61
56
62
63
199
171
195
159
197
170
198
176
.0
.0
.9
.8
.0
.2
.4
.7
.2
.2
.8
.8
.9
.6
.3
.0
. V
.3
.5
.9
.6
.9
.2
.5
WRE
20.0
20.0
16.1
11.4
18.1
15.1
19.0
17.5
63.1 '
30.8
60.6
45.7
61.8
43.1
62.4
45.4
198. 8
80.5
186.6
79.9
188.4
80.3
197.7
80.5
Notes: * Value not computed because overflowing storage tank terminates model output.
** Value not computed because model cannot read and interpolate one-hour triangular inflow hydrograph.
*** Value not computed because model cannot simulate diversions.
-------
Table 66a. PEAK OVERFLOWS FROM HYPOTHETICAL PIPES
Ul
Slope,
percent
0.05
0.5
5.0
flow
Jrograph
nber
c >i 9
H x; ct-
1
2
3
4
1
2
3
4
1
2
3
4
(cfs)
Diameter = 2 ft
SWMM
*
0.34
1.00
1.63
*
*
*
*
*
*
*
*
BNW
1.19
**
1.83
1.98
13.16
**
11.63
12. 42
42. 79
* *
42.88
42.95
FSP DOR
*
*
*
*
*
*
*
*
*
*
*i
*4
2.0
0.1
0.2
0.2
9.9
* 7.8
* 8.6
* 9.3
* 31.9
* 26.8
'* 27.4
'* 27.5
MIT
1.62
0.00
0.56
1.07
11.25
9.52
10.30
10.75
36.96
35.44
35.08
34.94
SOG
2.65
0.46
1.17
1.66
12.36
10.38
10.84
11.19
40.82
34.82
36.02
37.11
WRE
2.12
0.00
0.00
1.04
18.20
7.21
8.17
9.87
47.73
23.07
26.46
34.18
SWMM
3
81
124
158
30
26
28
29
*
*
*
*
Diameter
BNW
593
**
282
306
1686
**
1576
1631
2509
**
2491
2496
FSP
***
***
***
***
***
***
***
***
* * *
***
***
***
= 12 ft
DOR
319
158
210
259
1033
1026
1034
1039
1595
1595
1596
1596
MIT
279
82
170
223
1424
1130
1243
1322
1917
1840
1841
1835
SOG
342
192
261
301
1448
1166
1285
1442
4076
3791
4062
4118
WRE
336
98
197
266
2650
1136
1273
1406
2686
2520
2659
2697
Notes: * Value not computed because overflowing storage tank terminates model output.
** Value not computed because model cannot read and interpolate one-hour triangular inflow hydrograph.
*** Value not computed because model cannot simulate diversions.
-------
Table 66b. PEAK OVERFLOWS FROM HYPOTHETICAL PIPES
Slope,
percent
0.05
0.5
5.0
£,
Cu
rO
H
3 CT> H
O 0 O
•H M XI
c >i 3
H n n -..
SWMM BMW
1 * 0.034
2 0.010 **
3 0.028 0.052
4 0.046 0.056
1
2
3
4
1
2
3
4 '
0.373
**
0.329
0.352
1.212
**
1.214
k 1.216
Diameter =
FSP
***
***
***
***
* * *
***
***
***
***
***
***
***
(m /sec)
O^ej. m Diameter = 3.66 m
DOR MIT SOG WRE SWMM BMW FSP DOR MIT SOG WRE
0.057 0.046 0.075 0.060 0.1 16.8 *** 9.0 7.9 9.7 9.5
0.003 0.000 0.011 0.000 2.3 ** ** 4.5 2.3 5.4 2.8
0.006 0.016 0.033 0.000 3.5 8.0 * 5.9 4.8 7.4 5.6
0.006 0.030 0.047 0.029 4.5 8.7 * 7.3 6.3 8.5 7.5
0.280 0.319 0.350 0.516 0.8 47.7 * 29.3 40.3 41.0 75.0
0.221 0.270 0.294 0.204 0.7 ** * 29.1 32.0 33.0 32.1
0.244 0.292 0.307 0.231 0.8 44.6 * 29.3 35.2 36.4 36.0
0.263 0.304 0.317 0.279 0.8 46.2 * 29.4 37.4 40.8 39.8
0.903 1.047 1.156 1.351 * 71.1 * 45.2 54.3 115.4 76.0
0.759 1.004 0.986 0.653 * ** * * 45.2 52.1 107.4 71.3
0.776 0.993 1.020 0.749 * 70.5 *** 45.2 52.1 115.0 75.2
0.779 0.990 1.051 0.967 * 70.7 *** 45.2 52.0 116.6 76.3
Notes: * Value not computed because overflowing storage tank terminates model output.
** Value not computed because model cannot read and interpolate one-hour triangular inflow hydrograph.
*** Value not computed because model cannot simulate diversions.
-------
Table 67. TIMES OF PEAK OUTFLOWS FROM HYPOTHETICAL PIPES
Slope
percent
0.05
0.5
5.0
Inflow
hydrograph
number
2
3
4
2
3
4
2
3
4
Storage
and
diversion
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
Diameter
SWMM
60
60
120
125
180
175
55
*
85
*
145
*
40
*
70
*
130
*
BNW
**
**
120
115
180
175
**
**
80
80
140
140
**
**
65
65
125
135
FSP
**
***
190
***
250
***
** '
**»
125
***
125
***
**
***
115
***
175
***
DOR
80
80
115
105
175
165
45
50
80
80
135
135
35
35
65
70
125
115
V"!
= 2 ft
MIT
90
90
120
125
180
185
50
50
80
80
140
140
35
35
65
60
125
110
1-1-I1U !_C
:oi
Diameter
SOG
78
84
105
109
165
170
47
49
77
82
138
141
36
38
66
70
126
131
WRE
80
116
106
142
166
202
" 45
60
75
93
135
155
36
51
63
97
125
157
SWMM
50
50
80
80
145
135
40 '
40
70
70
130
130
35
*
65
*
125
*
BNW
**
**
80
80
140
140
**
**
70
70
125
130
**
**
60
65
120
120
FSP
**
***
120
***
180
***
**
***
115
***
115
***
**
***
115
***
175
***
= 12 ft
DOR
45
45
75
75
135
130
35
35
65
60
123
105
30
35
60
60
120
110
MIT
50
55
80
85
135
145
' 35 "
40
65
70
125
130
30
40
60
25-100
120
60-200
SOG
40
42
69
72
130
132
35
36
65
67
125
121
32
37
62
69
122
118
WRE
40
52
68
84
130
140
35
41
65
93
125
177
33
33
63
63
123
123
Notes: * Value not computed because overflowing storage tank terminates model output.
** Value not computed because model cannot read and interpolate one-hour triangular inflow hydrograph.
*** Value not computed because model cannot simulate diversions.
24-50 Constant peak outflow for indicated period.
-------
NJ
^J
co
Table 68. EXTREME OUTFLOW CONCENTRATIONS OF SMALL
HYPOTHETICAL PIPES (mg/£)
4J
0) 0)
a. o
rH 01
(0 Vj
M
4J C -H
in n) -a
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
Maximum for
constant
inflow concentration
S'WMM
99
*
100
102
101
104
100
101
105
*
103
*
101
*
101
*
106
*
106
*
107
*
107
*
BNW
100
100
**
**
100
100
100
100
100
100
**
**
100
100
100
100
100
100
**
**
100
100
100
100
SOG
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
WRE
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
Maximum for
upright triangular
inflow concentration
SWMM
85
*
67
67
77
77
88
88
91
*
86
*
92
*
96
*
96
*
95
*
97
*
99
*
BNW
91
91
**
**
92
92
96
96
90
90
**
* *
90
90
95
95
94
94
**
* *
94
94
97
97
SOG
87
85
53
50
75
73
88
87
90
90
84
82
92
91
97
96
93
92
97
96
99
98
99
99
WRE
66
66
55
51
71
66
84
78
87
81
83
72
92
78
96
86
96
72
94
70
96
75
98
81
Minimum for
inverted triangular
inflow concentration
SWMM
15
*
***
***
25
25
14
14
10
*
2
*
9
*
5
*
4
*
7
*
4
*
2
*
BNW
9
9
**
**
8
8
4
4
10
10
**
**
10
10
5
5
6
6
**
**
6
6
3
3
SOG
13
15
47
50
25
28
12
13
10
10
16
18
8
9
4
4
7
8
3
4
2
2
1
1
WRE
34
34
45
49
29
34
16
22
13
19
17
28
9
22
4
14
4
28
7
30
4
25
2
19
Notes:
* Value not computed because overflowing storage tank terminates model output.
** Value not computed because model cannot read and interpolate one-hour triangular inflow hydrograph.
*** Value not computed.
-------
M
--4
vo
Table 69. EXTREME OUTFLOW CONCENTRATIONS OF LARGE
HYPOTHETICAL PIPES (mg/£)
ilope,
>ercent
W M«
0.05
0.5
5.0
inflow
lydrograph
t umber
•-« ,*-« ^
1
2
4
•t
1
X
0
J
1
X
•>
J
Itorage
tnd
liver si on
uj ig TJ
No
yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
Maximum for constant
inflow concentration
SWMM
107
110
103
108
101
101
100
100
104
106
104
122
105
122
106
122
103
99
108
*
106
*
106
*
BNW
100
100
**
**
100
100
100
100
100
100
**
**
100
100
100
100
100
100
**
**
100
100
100
100
SOG
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
WRE
100
100
100
100
100
100
100
100
100
***
100
100
100
100
100
100
100
100
100
100
100
100
100
100
» J
Maximum for
upright triangular
inflow concentration
SWMM
96
96
87
87
93
93
96
96
96
96
95
94
97
97
99
99
98
*
97
*
98
*
99
*
BNW
90
90
**
**
90
90
95
95
94
94
**
**
94
94
97
97
97
97
**
**
97
97
99
99
SOG
91
90
89
84
94
92
98
96
94
92
98
95
99
98
99
99
97
95
98
98
99
99
99
99
WRE
86
82
85
70
92
82
96
90
97
***
95
80
97
87
98
92
91
70
97
79
98
87
99
92
Minimum for
inverted triangular
inflow concentration
SWMM
6
6
14
14
8
8
4
4
4
4
7
7
4
4
2
2
3
*
4
*
3
*
1
*
BNW
10
10
**
**
10
10
5
5
6
6
**
**
6
6
3
3
3
3
*
*
3
3
2
2
SOG
9
11
11
16
6
8
2
4
6
8
3
5
1
2
1
1
4
5
2
2
1
1
1
1
WRE
14
18
17
30
9
18
4
10
3
***
6
20
3
13
1
8
9
30
3
21
2
13
1
8
Notes: * Value not computed because overflowing storage tank terminates model output.
** Value not computed because model cannot read and interpolate one-hour triangular inflow hydrograph.
*** Value not computed.
-------
Table 70. TIMES OF EXTREME OUTFLOW CONCENTRATIONS
OF SMALL HYPOTHETICAL PIPES (minutes)
0) Q)
a o
O M
rH Q)
U3 Pi
0.05
0.5
5.0
t-LI
18
? DI H
O O (1)
r"1 ^ •§
C >i H
w fi C
2
3
4
2
3
4
2
3
4
}_i
o
D -H
Oi W
td M
M 0)
o -a >
4-> C -H
CO C3 T3
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
For maximum outflow
concentration of
upright triangular
inflow concentration
SWMM
120
120
145
145
200
200
60
*
90
A
150
*
45
it
75
*
135
BNW
**
* *
120
120
180
180
**
**
80
80
140
140
* *
**
65
65
125
125
SOG
100
110
125
135
182
192
52
54
81
83
140
143
37
37
67
67
126
128
WRE
84
140
114
162
174
216
45
65
79
101
140
166
37
57
65
97
127
169
For minimum outflow
concentration of
inverted triangular
inflow concentration
SWMM
* **
** *
135
135
195
195
60
*
40
*
150
*
45
*
75
*
135
*
BNW
**
**
120
120
180
180
* *
* *
80
80
140
140
**
**
65
65
125
125
SOG
100
110
125
135
182
192
52
54
81
83
140
143
37
37
67
67
126
128
WRE
84
140
114
162
174
216
45
65
79
101
140
166
37
57
65
97
127
169
Notes: * Value not computed because overflowing storage tank terminates model output.
** Value not computed because model cannot read and interpolate one-hour
triangular inflow hydrograph.
*** Value not computed.
Table 71. TIMES OF EXTREME OUTFLOW CONCENTRATIONS
OF LARGE HYPOTHETICAL PIPES (minutes)
Slope,
percent
0.05
0.5
5fO
Inflow
hydrograp
number
2
3
4
2
3
4
2
3
4
Storage
and
diversion
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
For maximum outflow
concentration of
upright triangular
inflow concentration
SWMM
55
55
85
85
145
145
45 "
45
75
75
135
135
40
*
70
*
130
BNW
* *
**
80
80
140
140
**
**
75
75
125
125
**
60
60
120
120
SOG
46
54
75
83
135
143
36
39
66
69
126
128
32
33
62
63
122
124
WRE
48
66
76
96
136
155
36
47
66
83
125
149
33
42
63
75
121
137
For minimum outflow
concentration of
inverted triangular
inflow concentration
SWMM
55
55
85
85
145
145
45
45
75
75
135
135
40
*
70
*
130
*
BNW
* *
**
80
80
140
140
**
* *
65
65
125
125
**
**
60
60
120
120
SOG
46
54
75
83
135
143
36
39
66
69
126
128
32
33
62
63
122
124
WRE
45
66
76
96
135
155
36
47
66
83
125
149
33
42
63
75
121
137
Notes: * Value not computed because overflowing storage tank terminates model output.
** Value not computed because model cannot read and interpolate one-hour
triangular inflow hydrograph.
*** Value not computed.
280
-------
5+"!
en
u_.
os.
..SI
1
9.M
10. M
- INFLOW
1 SWMM
2 HIT
3 SOGREflH
4 WRE
16.00
17.00
16.00
£*
h-d--
1 SVMM
2 BNV
3 FSP
4 DOfiSCH
9.00 10.00 11.00 12.00 13. W 11.00 IS.00 16.00 17.00 18.00
Figure 43. Outflows for Two-Hour Triangular Inflow -
Small Hypothetical Pipe, Free Inflow and
Outflow, 0.05% Slope
281
-------
s
•*•*
\
- INFLOW
1 SVHN
2 MIT
3 SOSREflH
4 VRE
9.W 10.00 11.00 12.00
.3.00 14.00
"" " HOURS
15.00
16.00
17.
18.00
- INFLOW
1 SVNM
2 BNW
3 FSP
4 DORSCH
-i r
13.88 14.00
TIME. HOURS
Figure 44.
Outflows for Two-Hour Triangular Inflow -
Small Hypothetical Pipe, Free Inflow and
Outflow, 0.5% Slope
282
-------
9.88
18.88
- INFLOW
1 SVNM
2 HIT
3 SOGREflH
4 VRE
11.00
12.00
HOUR
RS'
15.00
16.00
17.00
16.00
- INFLOW
1 SVMH
2 BNW
3 FSP
-------
- INFLOW
1 SWMN
2 MIT
3 S06RERH
4 WRE
o
1.00 10.00
11.00
12.00
13.00 14.fi
TIME. HOURS
15.00
16.00
17.00
18.
- INFLOW
1 SWMM
2 BNW
3 FSP
4 DORSCH
9.00
10.00
11.00
12.00
13.00 14.00
TIME. HOURS
15.00
16.00
17.00
18.00
Figure 46.
Outflows for Two-Hour Triangular Inflow -
Large Hypothetical Pipe, Free Inflow and
Outflow, 0.05% Slope
284
-------
- INFLOW
1 SVHM
2 MIT
3 SOCREflH
4 VRE
11.88 12.00 13.00 11.00 15.00 16.00 17.00 18.00
TIME, HOURS
9.00
10.00
-*-•—I-
- INFLOW
1 SVMM
2 BNV
3 FSP
4 OORSCH
10.00 11.00 12.00 13.00 14.00 15.00 16.00 17.00
TIME, HOURS
Figure 47. Outflows for Two-Hour Triangular Inflow -
Large Hypothetical Pipe, Free Inflow and
Outflow, 0.5 % Slope
18.00
285
-------
•*-•—i-a—i-a—i-a—t-a
- INFLOW
1 SVMM
2 MIT
3 SOGREftH
4 WE
9.a
ie.ee
n.ee
i2.ee
is.ee
TIME,
it.ee
HOURS
is.ee
ie.ee
i7.ee
is.ee
- INFLOW
1 SWMM
2 BNV
3 FSP
4 DOflSCH
9.84
ie.»e
11. ae
i2.ee
i3.N
TIME.
.
HOURS
i5.ee
ie.ee
i7.ee
18.
Figure 48. Outflows for Two-Hour Triangular Inflow -
Large Hypothetical Pipe, Free Inflow and
Outflow, 5% Slope
286
-------
8
"
o
:8
3R-
£
- INFLOW
1 SVNN
2 BNV
3 SOGREflH
1 I '
10.00
8.00
Figure 49.
11.00
—i
15. M
—I
16.00
17.M
18.98
Outflow Concentrations for Constant Inflow
Concentrations with Two-Hour Triangular
Inflow - Small Hypothetical Pipe, Free
Inflow and Outflow, 0.05% Slope
5i
8-
- INFLOW
1 SUNN
2 BNV
3 SOGREflH
8.00 10.00
Figure 50.
11.00
12.00
13.00 11.00 15.00 16.00 17.00
TIME, HOURS
Outflow Concentrations for Constant Inflow
Concentrations with Two-Hour Triangular
Inflow - Small Hypothetical Pipe, Free
Inflow and Outflow, 0.5% Slope
18.00
287
-------
ts,
cc
CCs
s
- INFLOW
1 SWMM
2 BNV
3 SOSREflH
R-
—I
11.88
—I
12.09
—1
15.80
—I
16.88
9.88
18.00
Hours'8
17.W
18.
Figure 51.
Outflow Concentrations for Constant Inflow
Concentrations with Two-Hour Triangular
Inflow - Small Hypothetical Pipe, Free
Inflow and Outflow, 5% Slope
f
- INFLOW
1 SWMM
2 BNW
3 SOSREflH
.
JEt
O
o
s.eo
10.08
11. ae
12.88
Figure 52.
13.88 14. B8
TIME. HOURS
15.00
16.00
17.00
18.00
Outflow Concentrations for Constant Inflow
Concentrations with Two-Hour Triangular
Inflow - Large Hypothetical Pipe, Free
Inflow and Outflow, 0.05% Slope
288
-------
o
gs-
o
o
o
s-
-»*-
- INFLOW
1 SVMM
2 BNV
3 SOGREflH
9.00
10.09
11.00
12.00
Figure 53-
13.00 11.00
TIME, HOURS
15.00
16.00
17.00
18.00
Outflow Concentrations for Constant Inflow
Concentrations with Two-Hour Triangular
Inflow - Large Hypothetical Pipe, Free
Inflow and Outflow, 0.5% Slope
C9
o
•—*
en
o
£_)
- INFLOV
1 SVMM
2 BNV
3 SOGREflH
9.00
10.00
11.00
12.00
13.00 14.00
TIME, HOURS
15.00
16.00
17.00
18.00
Figure 54. Outflow Concentrations for Constant Inflow
Concentrations with Two-Hour Triangular
Inflow - Large Hypothetical Pipe, Free
Inflow and Outflow, 5% Slope
289
-------
9.M
- INFLOW
1 SVfflM
2 BMW
3 SOCREflH
ie.88
ii.m
12.88
13.M 14.88
TIME, HOURS
15.M
16.M
17.88
16.00
Figure 55. Outflow Concentrations for Triangular Inflow
Concentrations with Two-Hour Triangular
Inflow - Small Hypothetical Pipe, Free
Inflow and Outflow, 0.05% Slope
o
-------
.r>.
Z1-
O
5s-
o
o
8
R-
- INFLOW
1 SWMM
2 BNV
3 SOCREflH
9.M
11.00
12. M
15.88
16. N
17.90
Figure 57.
TIME. HOURS'"
Outflow Concentrations for Triangular Inflow
Concentrations with Two-Hour Triangular
Inflow - Small Hypothetical Pipe, Free
Inflow and Outflow, 5% Slope
16.
tsa
ZR"~
o
I—I
cc
£•
Ss-
8
8
R-
- INFLOW
1 SVHM
2 BNV
3 SOGREflH
9.00
11.00
12,00
n3ME*. HOURS"
15.8
16,1
17.1
16.00
Figure 58.
Outflow Concentrations for Triangular Inflow
Concentrations with Two-Hour Triangular
Inflow - Large Hypothetical Pipe, Free
Inflow and Outflow, 0.05% Slope
291
-------
§
58-
o
o
- INFLOW
1 SWMM
2 BNV
3 SOCREflH
9.119
12.98
i3.ee i«.a
TIME. HOURS
is.ee
16.90
17.09
18.00
Figure 59,
Outflow Concentrations for Triangular Inflow
Concentrations with Two-Hour Triangular
Inflow - Large Hypothetical Pipe, Free
Inflow and Outflow, 0.5% Slope
•£?*
r
- INFLOW
1 SWMM
2 BNW
3 SOGRERH
9.00
10.00
11.00
12.00
13.00 14.00
TIME. HOURS
15.00
16.00
17. ee
18.00
Figure 60,
Outflow Concentrations for Triangular Inflow
Concentrations with Two-Hour Triangular
Inflow - Large Hypothetical Pipe, Free
Inflow and Outflow, 5% Slope
292
-------
- INFLOW
1 SWHM
2 BNV
3 SOGREAH
9.00
10. M
18.00
Figure 61.
Outflow Concentrations for Inverted Trian-
gular Inflow Concentrations with Two-Hour
Triangular Inflow - Small Hypothetical
Pipe, Free Inflow and Outflow, 0.05% Slope
- INFLOW
1 SVMM
2 BNV
3 SOGREflH
9.M
10.00
11.00
16.00
17.00
16.00
Figure 62.
Outflow Concentrations for Inverted Trian-
gular Inflow Concentrations with Two-Hour
Triangular Inflow - Small Hypothetical
Pipe, Free Inflow and Outflow, 0.5% Slope
293
-------
- INFLOW
1 SWMM
2 BNV
3 SOGREflH
9.88
11.88
12.88
13.88
TIME.
it.ee
HOURS
is.ea
ie.ee
i7.ee
is.ee
Figure 63
Outflow Concentrations for Inverted Trian-
gular Inflow Concentrations with Two-Hour
Triangular Inflow - Small Hypothetical
Pipe, Free Inflow and Outflow, 5% Slope
- INFLOW
1 SWMM
2 BNV
3 SOGREflH
9.88
ie.ee
ii.ee
iz.ee
ia.ee it.ee
TIME, HOURS
is.ee
ie.ee
17.M
i8.ee
Figure 64.
Outflow Concentrations for Inverted Trian-
gular Inflow Concentrations with Two-Hour
Triangular Inflow - Large Hypothetical
Pipe, Free Inflow and Outflow, 0.05% Slope
294
-------
- INFLOW
1 SUMM
2 BNV
3 SOGREAH
9.00
ia.ua
11.89
12.00
—i 1
TIME*, HOURS9"
—i
15.88
16.M
—1
17.00
16.00
Figure 65.
Outflow Concentrations for Inverted Trian-
gular Inflow Concentrations with Two-Hour
Triangular Inflow - Large Hypothetical
Pipe, Free Inflow and Outflow, 0.5% Slope
- INFLOW
1 SWMH
2 BNV
3 SOGREflH
9.00
10.00
11.00
12.00
13.00 14.00
TIME. HOURS
—i
15.00
~I
16.00
17.8
18.00
Figure 66.
Outflow Concentrations for Inverted Trian-
gular Inflow Concentrations with Two-Hour
Triangular Inflow - Large Hypothetical
Pipe, Free Inflow and Outflow, 5% Slope
295
-------
the 2-hr triangular inflow and all three inflow qualities for
the free inflow and outflow conditions. Outflow hydrographs
are plotted for all seven tested models and outflow concen-
tration graphs are plotted for the five models which include
water quality simulations (SWMM, BNW, DORSCH, SOGREAH, and
WRE). The results of the water quality routing by the DORSCH
and WRE models, however, were received too late to be incor-
porated and evaluated in this section. They are presented in
Appendix E as submitted by these two firms.
As indicated in the tables, output is not listed for all data
combinations due to various model limitations. The SWMM
terminates execution and the routed hydrograph is not printed
if the storage tank overflows. This occurs for most inflows
into the small pipe and for the steep large pipe for the
second boundary condition.
The FSP model does not include diversion formulations and con-
sequently could not simulate the pipes with the upstream
storage and downstream diversion structure.
The BNW and FSP models could not simulate the 1-hr triangular
inflow data combinations. To read inflow hydrographs for the
pipe flow routing directly without computing them from rain-
fall, the data can be provided only as hourly dry-weather flow
and concentration values, which are then interpolated linearly
by the models for smaller time steps. Consequently, the 1-hr
triangular inflow could not be read since it has a peak at
the 1/2 hr. The linear interpolation for time steps of less
than 1 hr was added to the FSP by Battelle in order to perform
the tests.
Model Comparison
Comparable outflow hydrographs are computed for the free in-
flow and outflow conditions by all models except the FSP which
shows considerable differences from the other models as a
result of its linear storage routing scheme (Tables 65 and
67). No significant patterns can be detected either from
inspection of the complete outflow hydrographs or from the
magnitudes and times of the peak outflows between the SWMM,
BNW, DORSCH, MIT, SOGREAH, and WRE models, which would in-
dicate that the models which solve the dynamic wave equations
(DORSCH, SOGREAH, and WRE) show similar results while the models
which solve the kinematic wave equation (SWMM, BNW, MIT) show
different results. It appears that the numerical solution tech-
niques employed by the models introduce enough numerical dis-
persion to obscure differences in the flow phenomena considered
296
-------
by the dynamic and kinematic wave equation for the simple flow
conditions defined for the first boundary condition. Greater
differences between the kinematic and dynamic wave solution
could be expected, however, in complex networks with loops and
significant backwater and flow reversal.
Although no definite patterns of relative model performance are
evident, the differences among model results are generally
greatest for the small flat pipe and decrease with increasing
pipe diameter and slope. Up to 25 percent differences in the
magnitude and 15 minutes in the time of the peak outflow can
be observed for the flat pipes, while the corresponding dif-
ferences are generally less than 15 percent and 5 minutes for
the steep pipes.
An exception is the FSP model, which computes much lower and
later (over 1 hr) peaks for the small flat pipe and comparable
peaks generally more than 45 minutes later for most other pipe
data combinations. Only the 4-hr triangular inflows into the
medium slope pipes produce comparable peak times.
Considerably greater differences among the models occur for the
cases with upstream storage and downstream diversion (Tables
65, 66, and 67). The differences in the total outflow hydro-
graphs among models are comparable to those for the free inflow
and outflow cases as long as the pipe does not surcharge and
the storage tank does not overflow.
The discharge from a full upstream storage tank into the pipe,
assuming free surface flow in the pipe, is 1.484 m3/sec (52.40
cfs) for the small pipe and 87.24 m3/sec (3080.5 cfs) for the
large pipe if the pipe axis intersects the bottom of the tank.
The values are 1.421 m3/sec (50.17 cfs) and 78.64 m3/sec (2776.7
cfs), respectively, if the pipe invert intersects the bottom
of the tank.
Surcharging occurs when the inflow to the diversion structure
exceeds the maximum combined discharge capacity of the orifice
and weir under free-surface, near-full pipe flow conditions.
This is 0.264 m3/sec (9.33 cfs) for the small pipe and 23.32
m3/sec (823.3 cfs) for the large pipe as computed from the
standard orifice and weir equations, neglecting the effect of
the velocity of approach. This implies that both the small
and large pipes are expected to surcharge for the medium and
steep slopes, since the peak inflows are several times these
values.
Considerable differences exist among the models, however, in
the diversion even if the total outflows are similar (Table
66). Since all but the SWMM use similar weir and orifice
297
-------
equations for the diversion computations, the differences can
be explained only by differences in computing the upstream
heads for the weir and orifice and interfacing of the routing
with the diversion equations. Sufficient information is not
available to explain differences in the proprietary models.
The SWMM model terminates execution if it computes an over-
flowing storage tank. The BNW, DORSCH, MIT, and WRE models do
not terminate execution but assume free orifice flow from the
upstream tank into the pipe and neglect the effect of the sur-
charging on the orifice discharge. The SOGREAH model con-
siders the entire system as surcharged and computes much
higher inflow from the tank into the pipe and (consequently
much higher downstream outflow). This results in peak out-
flows which vary with the inflow hydrograph for the SOGREAH
model, but the same peak outflows regardless of hydrograph
shape for the other five models for the same slope and diame-
ter. Differences in the times of the peak discharges between
the models are generally less than 15 minutes and do not seem
to be affected by surcharging.
Comparable routed water quality concentrations are computed by
the BNW and SOGREAH models (Tables 68, 69, 70, and 71). As
usual, the differences between model results are greater for
small pipes and low slopes. The BNW shows earlier and higher
maxima and lower minima than the SWMM and SOGREAH models due
to its characteristic solution of the kinematic wave equation
for the flow routing and the use of the kinematic wave celer-
ity, rather than flow velocity, for pollutant routing. The
differences become smaller as the pipe diameter and slope in-
crease .
Two-Hour Triangular Inflow
The outflow hydrographs computed by each of the seven tested
models are plotted for six pipe data combinations in Figures
43 to 48. The models were separated into two groups for plot-
ting the outflow hydrographs to prevent too many overlapping
lines from obscuring model differences. Each plot includes
the outflow computed by the SWMM and three other models. The
corresponding outflow concentrations computed by the SWMM, BNW,
and SOGREAH models are plotted in Figures 49 to 66.
The plotted outflow is for the 2-hr triangular inflow which
has a peak flow rate of 90 percent of full pipe flow as com-
puted by Manning's equation. A constant flow rate of 10 per-
cent of the peak inflow rate (9 percent of full pipe flow)
precedes and follows the constant inflow. Three conservative
inflow water quality constituents were specified for each in-
flow hydrograph: a constant continuous concentration of 100
298
-------
mg/1, a triangular concentration distribution with 100 mg/1
maximum concentration and 0 mg/1 before and after the tri-
angular distribution, and inverted triangular concentration
distribution with an 0 mg/1 minimum concentration and 100 mg/1
before and after the triangular distribution.
The plots are for 0.61 m (2 ft) and 3.66 m (12 ft) diameter
circular pipes, each 3048 m (10,000 ft) long with a Manning's
roughness coefficient of 0.01 and with 0.05, 0.5, and 5 per-
cent slopes. Free upstream inflow and downstream outflow are
assumed for the selected examples. The plots consequently
show the effects of differences in pipe diameter and slope on
the routed hydrographs and water quality graphs.
The SWMM, FSP, and MIT models are not formulated to start the
simulation with nonzero initial flow conditions in the pipe,
consequently the outflow hydrographs begin with a value of
zero flow, rather than the constant 10 percent of the peak
flow which was specified for the period preceding the tri-
angular inflow. The simulation was started several time steps
prior to the beginning of the triangular hydrographs for all
models to compute initial conditions in the pipes for the
initially constant inflows.
The overall shape of the computed outflow hydrographs, in-
cluding the magnitudes and times of the peak outflows, are
quite similar for all models except the FSP. The linear
storage routing scheme of the FSP produces outflow hydrographs
with long time lags between the beginning of the rising por-
tion of the inflow hydrograph and the first outflow. For
the small pipe, the outflow hydrograph rises and falls very
slowly, resulting in a 25 percent lower and 1 hr later
peak than the other models (Figure 43). As the slope in-
creases, the computed outflow hydrographs rise and fall more
rapidly. For the medium slope, the shape and peak of the
outflow hydrograph are similar to the other models but the
peak occurs about 45 minutes later (Figure 44). For the steep
slope, a very steeply rising outflow hydrograph reaches a con-
stant outflow equal to the maximum inflow for a short time and
then drops very rapidly following cessation of the triangular
inflow (Figure 45).
For the large flat pipe, the hydrograph shape is similar to
the other models, the peak discharge is approximately the
same as for the SOGREAH model, which is about 5 percent to 10
percent higher than the other models, but it occurs about 40
to 50 minutes later than all other models (Figure 46). For
the medium and steep slope, a sharply rising and falling out-
flow hydrograph is computed with a fairly constant outflow
equal to the maximum inflow for a short period (Figures 47
299
-------
and 48). In large steep pipes, the linear storage routing
scheme apparently stores the inflow for some time before any
outflow occurs and then dumps it at a high rate until the
inflow ceases.
The outflow hydrographs of the remaining six models are very
similar in shape and in the magnitude and time of the peak
discharge. Differences in the magnitude of the peak discharge
among these models for the plotted data combinations are less
than 20 percent for the flat slope and less than 5 percent for
the steep slope. The differences are greatest for the flat
slope and decrease as the slope increases. Differences in
the times of the peak discharges are less than 15 minutes for
the flat slope and less than 5 minutes for the steep slope.
This indicates that both the kinematic wave and dynamic wave
formulations can be expected to compute similar routed hydro-
graphs for flows ranging from sub- to supercritical conditions,
provided backwater effects, surcharging, and flow reversal do
not occur or are insignificant.
No consistent pattern in the differences of performance is
apparent for the DORSCH, SOGREAH, and WRE models, which use
the dynamic wave equations, or for the SWMM, BNW, and MIT
models, which use the kinematic wave equation for the conduit
flow routing. Numerical dispersion caused by the different
numerical solution techniques obscures differences in the
basic routing equations for the first boundary condition.
Plots of outflow concentrations are shown only for the SWMM,
BNW, and SOGREAH models. Concentration plots for the DORSCH
and WRE models were received too late to be incorporated with
the other plots. They are shown in Appendix E. The other
tested models do not include water quality formulations. All
plotted outflow concentrations are the result of routing the
specified inflow concentrations with the 2-hr triangular
inflow hydrographs.
The BNW and SOGREAH models route the constant inflow concen-
tration without modification for both pipe sizes and all three
slopes (Figures 49 to 54). The SWMM assumes a zero initial
condition and consequently computes a rising limb which reaches
the constant concentration value after the start of the inflow
hydrograph. The lag corresponds to the travel time through
the pipe. The computed outflow concentration then fluctuates
about the constant concentration value until they coincide
several hours after the beginning of the triangular inflow.
Similarly shaped outflow concentration graphs are computed by
the SWMM, BNW, and SOGREAH model for the triangular inflow
concentration for the medium and steep slopes (Figures 55 to
300
-------
60). The differences increase, however, with decreasing pipe
size and slope. The differences are still small for the
large flat pipe but become significant for the small flat
slope. The BNW model computes an earlier peak with a higher
maximum for the upright triangular concentration and a lower
minimum for the inverted triangular concentration than do the
SWMM and SOGREAH models, since its mass routing uses the
kinematic wave celerity rather than the water flow velocity
to facilitate interfacing with the real-time control optimi-
zation of the model. The results show, however, that the ef-
fect of this approximation is insignificant for large pipes,
such as trunk and interceptor sewers for which the model was
designed.
The SWMM shows the same phenomenon with the routed inverted
triangular concentrations as with the routed constant con-
centration (Figures 61 to 66). The computed outflow concen-
trations start first with zero rather than 100 mg/1, then rise
for some time until they reach a peak and finally follow the
shape of the inverted concentration graphs. This implies
that for practical applications, the user has to estimate the
longest flow travel time from an upstream inflow point to the
downstream outflow point and initiate the simulation of a
corresponding time period earlier to initialize the flows and
concentrations in the system, and not use the values computed
for this initial period.
REAL CATCHMENT DATA TESTS
Real catchment data tests were performed with data from the
Oakdale catchment in Chicago, Illinois and the Bloody Run
catchment in Cincinnati, Ohio. Four runoff events of the
Oakdale catchment were simulated. The initial testing raised
certain doubts with respect to the completeness and accuracy
of the Bloody Run data, and consequently tests were completed
for only two of the four storms reported in Section VI.
Oakdale Avenue Catchment Simulations
The Oakdale Avenue catchment is located in an urban area about
6 miles northwest of downtown Chicago, Illinois. It has a
drainage area of 5.22 ha (12.9 acres, approximately 2-1/2
blocks long by 1 block wide) and consists entirely of residen-
tial lots and adjoining streets.
The DORSCH model simulations were performed by Drosch Consult
and the SWMM, FSP, and BNW model simulations by Battelle.
The same spatial discretization of catchment and sewer elements
was used by all four models. Runoff was routed directly from
the catchment into the sewers without routing it separately
301
-------
through the gutters except the Dorsch model. The same em-
pirical model coefficients were used by all models for pheno-
mena being modeled by the same equations.
The maximum infiltration, the minimum infiltration, and the
decay rate of infiltration were assumed to be 63.5 mm/hr
(2.50 in./hr), 11.4 mm/hr (0.45 in./hr), and 0.00115 sec"1,
respectively. The overall depths of retention storage on the
pervious and the impervious areas were assumed to be 5.08 mm
(0.20 in.) and 2.03 mm (0.08 in.), respectively. For storms
which had to be simulated in two parts, the initial infil-
tration rate for the second part was set equal to the minimum
infiltration rate.
The rainstorms on the following four dates were selected to
test the catchment runoff and sewer routing formulations of
the four models: May 19, 1959; July 2, 1960; July 26, 1960;
and August 2, 1963. These rainstorms represent a typical
range of possible combinations of rainfall intensities and
durations.
The model results are summarized in Table 72, which lists the
magnitudes and times of the peak discharges for each storm.
Figures 67 to 82 show comparisons between the measured runoff
and the runoff computed by the BNW, SWMM, FSP, and DORSCH
models. Each computed hydrograph was plotted in a separate
figure to better show the variation from the measured runoff.
Plotting of all computed runoff hydrographs for a given storm
in the same figure may provide better comparisons among models,
but preliminary plots showed that the lines would be too close
together to adequately distinguish among the different model
hydrographs. Runoff periods lasting longer than 2 hours and
15 minutes are plotted on more than one figure, with a 15-
minute overlap between successive figures.
The measured rainfall and runoff data were reported at 1-
minute time intervals. The same interval was chosen for the
SWMM and DORSCH model simulations. Due to model limitations,
5-minute time intervals were used for the BNW model and FSP.
The BNW model is restricted to a minimum time step of 2
minutes and a maximum of 56 time steps. The 5-minute time
interval was selected to reduce the need for dividing a long
runoff period into too many segments for the simulation. The
FSP requires input data and simulation for a minimum of one
day and is restricted to a minimum time step of 5 minutes.
Figures 67 to 82 indicate that the SWMM, BNW, and DORSCH
models can be expected to produce satisfactory runoff hydro-
graphs in most cases for small catchments similar to the
302
-------
Oakdale Avenue catchment. The FSP, however, does not produce
satisfactory results, which confirms the model developers'
original intent to use the model only for the continuous simu-
lation of runoff from large, mostly unsewered catchments
(greater than 1.3 km2 or 0.5 mi2) using 1-hr time steps. FSP
formulations are not adequate to accurately simulate runoff
from small sewered areas requiring short time steps. The
model's assumption of immediate runoff from sewered areas pro-
duces peaks which are generally too high and occur too early.
The assumption that all rain falling on impervious areas and
a constant fraction falling on pervious areas becomes runoff
generally produces also a higher volume of runoff than measured.
The use of 5-minute time steps for the BNW model results in
smoothing of the peaks and valleys which appear in the measured
values. Exceptions are the second peaks of the July 2, 1960
(Figure 72) and August 2, 1963 (Figure 80) storms which show
computed peaks and runoff volumes higher than the measured
values. This appears to be the result of the model's lack of
formulations for catchment moisture balance between storms.
The model does not compute the recovery of depression storage
and infiltration capacity during dry periods, and consequently
computes insufficient rainfall losses for the second runoff
period of successive storms.
Similar overestimates of the second peaks and runoff volumes
are observed for the SWMM for the August 2, 1963 storm (Figure
79) for the same reasons. The second peak and runoff volume
of the storm of July 2, 1960 (Figure 71) are underestimated,
however. This storm had to be split into two simulation per-
iods since it was too long for a single run. The underestim-
ate occurs although the infiltration value was set to the
minimum for the second period.
Dorsch Consult simulated only the major runoff periods of
each storm and split longer runoff periods into separate simu-
lation periods. This generally produces satisfactory results,
with the exception of overestimating the second peak and run-
off volume of the storm of August 2, 1963 (Figure 82). This
is probably caused by uncertain initial moisture conditions
at the beginning of the second runoff period, since the model
does not simulate a catchment moisture balance during dry
periods (with the exception of the recovery of depression
storage on pervious areas).
The numerical model testing indicates that equally satisfac-
tory results can be obtained for the SWMM, DORSCH, and BNW
models for small catchments and sewerage systems where back-
water and surcharging conditions are nonexistent or negligible.
Difficulties arise with these three models as a result of
303
-------
Table 72. RUNOFF COMPARISONS FOR OAKDALE STORMS
Peak
Date No.
5/19/59 1
7/02/60 1
2
3
7/26/60 1
U> ,
0 2
3
8/02/63 1
2
Observed
7
4
17
2
4
2
4
5
.25
.60
.40
*
.50
.30
.90
.85
.95
Peak
discharge,
SWMM
7.
3.
15.
11.
2.
3.
2.
4.
7.
77
89
46
23
01
00
44
43
18
BNW
5.
3.
21.
12.
1.
2.
3.
3.
6.
90
45
74
47
81
88
21
32
87
cfs
FS
11.
7.
14.
9.
6.
3.
3.
7.
8.
P
27
34
50
80
00
87
48
31
54
DOR
8.1
4.3
17.7
* *
**
3.3
3.2
5.5
1.0
Time of
Observed
17
15
161
*
12
212
262
18
90
peak discharge, minutes
SWMM
17
15
165
192
10
212
263
18
90
BNW
20
15
160
185
10
210
265
20
90
FSP
15
15
160
185
5
210
260
15
90
DOR
15
13
167
**
* *
212
263
18
81
Observed
0
0
0
0
0
0
0
0
.21
.13
.49
*
.07
.12
.08
.14
.17
Peak discharge.
SWMM
0
0
0
0
0
0
0
0
0
.22
.11
.44
.32
.06
.08
.07
.13
.20
BNW
0
0
0
0
0
0
0
0
0
.17
.10
.62
.35
.05
.08
.09
.09
.19
m /sec
FSP
0.32
0.21
0.41
0.28
0.17
0.11
0.10
0.21
0.24
DOR
0.23
0.12
0.50
**
**
0.09
0.09
0.16
0.03
Notes: * No observation
** Not computed
-------
8 3
111] UU U U Ull liliUU U UUUUUUU
l.M 1.23
IfME, HOURS
2.M
2.25
Comparison of Measured and Computed Runoff for
the Storm of May 19, 1959 - Oakdale Avenue
Catchment - EPA Storm Water Management Model
- KERSURED RUNOFF
2 BNV
a.M
.29
Figure 68
Comparison of Measured and Computed Runoff
the Storm of May 19, 1959 - Oakdale Avenue
Catchment - Battelle Urban Wastewater
Management Model
305
-------
uuuu u uuuuuuu u
- MEftSURED RUNOFF
3 FSP
2.29
Comparison of Measured and Computed Runoff for
the Storm of May 19, 1959 - Oakdale Avenue
Catchment - Chicago Flow Simulation Program
lili UUUU U UUUUUUU
- MEflSURED RUNOFF
DORSCH
I.M
2.M
2.29
Figure 70,
Comparison of Measured and Computed Runoff for
the Storm of May 19, 1959 - Oakdale Avenue
Catchment - Dorsch Hydrograph Volume Method
306
-------
uuuuuuo u
TTinr
- MERSURED RUNOFF
1 SVMM
is
5--S3
-o
3D
m
o
0.00
T^ME. HOURS
25
1.50 1.75 2.00 2.25
uuu uuuu u
- MERSURED RUNOFF
1 SWMM
2.25
2.59
2.75
9.00 9.25
flME. HOURS
9.50
9.75
t.00
1.25
Figure 71.
Comparison of Measured and Computed Runoff for
the Storm of July 2, 1960 - Oakdale Avenue
Catchment - EPA Stormwater Management Model
307
-------
UUUUUUU U
U UUU
MEflSURED RUNOFF
2 BNW
58--
m
o
JO
l.M
.25
1.11 1.2
TIME. HOURS
1.58
1.75
2.99 2,29
- MEflSURED RUNOFF
2 BNW
2.8J
2.23
2.5?
2.75
3.OT 3.25
TfME. HOURS
3,59
3.75
4 25
Figure 72,
Comparison of Measured and Computed Runoff for
the Storm of July 2, 1960 - Oakdale Avenue Catch-
ment - Battelle Urban Wastewater Management Model
308
-------
r
O.M
uuuuuuu u
U UUULA
- NERSURED RUNOFF
3 FSP
1.79
2.M
a- -e
2.29
innni u
- MERSURED RUNOFF
3 FSP
2.N
2.25
2.50
2.75
, HOUi
3.9ft
9.75
1.W
*i
»—i
o
U.25
Figure 73. Comparison of Measured and Computed Runoff for
the Storm of July 2, 1960 - Oakdale Avenue
Catchment - Chicago Flow Simulation Program
309
-------
MERSURED RUNOFF
DORSCH
T*(ME. HOUR'S23
2.M
2.25
\1
UUU UUUU IT
8
- MERSURED RUNOFF
1 DORSCH
2.08
2.25
2.50
2.75
3.50
9.75
4.B8
I
s
fi"S~
§ *~
8
4.25
3.25
HOURS
Figure 74. Comparison of Measured and computed Runoff for
the Storm of July 2, 1960 - Oakdale Avenue
Catchment - Dorsch Hydrograph Method
310
-------
nr
i.M
.25
RUNOFF
1 SWMH
8
1.75
2.M
o
1
2.25
LU
.IN
•u
..s3
2.M
inriiu liinnnj ILJIIU inn i u u u o o u
- ,vf.R3'JRED RUNOFF
1 SWMH
. HOUfif
3.73
4.M
t.25
Figure 75a. Comparison of Measured and Comouted Runoff for
the Storm of July 26, 1960 - Oakdale Avenue
Catchment - EPA Stormwater Management Model
311
-------
8
0
t—«
a
U UULJUU U U U U U
.8
•CJ
UJ
g
•
~ • ^v
^F^7 \&r+*~^_
8
U U U UU U U *
- MERSURED RUNOFF a_
1 SVMM g
mf *
Sw j8
3D
P-
3
s
o
I.M
4.25 4.59
4.75
5.25 5.59 5.75 6.90
, HOURS
6.25
Figure 75b. Comparison of Measured and Computed Runoff for
the Storm of July 26, 1960 - Oakdale Avenue
Catchment - EPA Stormwater Management Model
8
^~"
8>
UJ
cc
COn'-
Q
R
rJ~
i -i- •_
co 58
*3 g-
g
-fe !i!_
y
W^^^ *
.00 .25 .50 .75 1.00 1.25 1.50 1.75 2.00 2
8
_JO
PRECIPITI
MI 4.ae
i
3
3
"a«
*z
J°
"a
.25
Figure 76a. Comparison of Measured and Computed Runoff for
the Storm of July 26, 1960 - Oakdale Avenue Catch-
ment - Battelle Urban Wastewater Management Model
312
-------
8
UUULJ UUU UUUUUUUUI I U U U U U U UU
- MEflSURED RUNOFF
2 BMW
.
1
.s3
2.N
2.23
1.25
iruuuuLr Lrir u u u
8.25
fift. HOUfif
Figure 76b. Comparison of Measured and Computed Runoff for
the Storm of July 26, 1960 - Oakdale Avenue Catch-
ment - Battelle Urban Wastewater Management Model
313
-------
"AWED RUNOFF
3 FSP
8
8.88 .23
.75
TIME, HOURS3
1.90
I
1.73
2.M
2.23
- MEflSURED RUNOFF
3 FSP
8
r9fME, HOURS'
t.2S
Figure 77a. Comparison of Measured and Computed Runoff for
the Storm of July 26, 1960 - Oakdale Avenue
Catchment - Chicago Flow Simulation Program
314
-------
CO
£
0 liUULJU LTDU U U I U U UU U U
.. NERSURED RUNOFF
3 FSP
--N
•o
..aS
s
s
o
i
4-p"
•9
8.25
Figure 77b. Comparison of Measured and Computed Runoff for
the Storm of July 26, 1960 - Oakdale Avenue
Catchment - Chicago Flow Simulation Program
UUUU UUU UUULJUUUUI U U U U U U
- MEASURED RUNOFF
4 OORSCH
2.M
2.25
2.79
T9fME. HOURf
9.99
8.79
t.N
4.29
Figure 78a. Comparison of Measured and Computed Runoff for
the Storm of July 26, 1960 - Oakdale Avenue
Catchment - Dorsch Hydrograph Method
315
-------
85.
U UUUUU O U U U D U U UU U IT
•o
_.SD
RUNOFF
4 DORSCH
S--
8
3
8
:
i
|t5~
i.M
1.25
Figure 78b. Comparison of Measured and Computed Runoff for
the Storm of July 26, 1960 - Oakdale Avenue
Catchment - Dorsch Hydrograph Method
8s-.,
U 8
- rteHSURED RUNOFF g
1 SYMM g
o
a.w
i
.23
.39
I
.75
KM 1.25
TIME. HOURS
1.39
1.73
2.88
2.25
Figure 79,
Comparison of Measured and Computed Runoff for
the Storm of August 2, 1963 - Oakdale Avenue
Catchment - EPA Stormwater Management Model
316
-------
_ MEflSURED RUNOFF
2 BNW
0.M
.»
.79
TfME. HOURS'
1.91
1.79
2.M
2.29
Figure 80.
Comparison of Measured and Computed Runoff for
the Storm of August 2, 1963 - Oakdale Avenue
Catchment - Battelle Urban Wastewater Manage-
ment Model
TlME, HOUR'S
1.79
2.M
2.25
Figure 81
Comparison of Measured and Computed Runoff for
the Storm of August 2, 1963 - Oakdale Avenue
Catchment - Chicago Flow Simulation Program
317
-------
V
LJ - MLH5JRCD RUNOFF
4 DORSCH 8
8
a.M
.73
T^I'ME. HOURS25
l.M
1.75
2.M
2.29
Figure 82.
Comparison of Measured and Computed Runoff for
the Storm of August 2, 1963 - Oakdale Avenue
Catchment - Dorsch Hydrograph Volume Method
318
-------
approximations in the computation of catchment moisture con-
ditions and uncertainties with respect to initial catchment
moisture conditions, particularly for long intermittent storm
periods.
Among these four models, the DORSCH model would be most appli-
cable for simulating backwater, downstream flow control, sur-
charging and pressure flow. The SWMM or BNW model could be
the choice if these phenomena were not important. The BNW
model has considerable flexibility in that it can model only
selected phenomena, if desired, and can suppress flow routing,
water quality computations, real-time control optimization,
and design optimization as specified by the user. The BNW
model, however, does not simulate water quality from land use,
unit treatment processes, or receiving water flow and quality,
and has not been tested as extensively as the SWMM.
The FSP is suited primarily for the continuous simulation of
large nonsewered catchments. Its general applicability may
be limited, however, by considerable simplification of the
catchment hydrology and channel flow routing and by the need
for modifications of model coefficients which are internal
to the computer program.
Bloody Run Catchment Simulations
The Bloody Run catchment is located in the northwest section
of Cincinnati, Ohio. It has a drainage area of 964 ha (2,380
acres) consisting of rolling terrain with commercial and in-
dustrial sections in the valleys and residential districts
on the ridges. Approximately 55 percent of the area is
residential, 22 percent open land and parks, and the rest
commercial and industrial.
Simulations with Bloody Run catchment data were performed by
Battelle with the SWMM, FSP, and BNW models. The same spatial
discretization of catchment and sewer elements was used by all
three models. Runoff was routed directly from the catchment
into the sewers rather than separately through the gutters.
The same empirical model coefficients were used by all three
models for phenomena being modeled by the same equations.
Comparable values were selected for the Horton equation (in
SWMM) and Holtan equation (BNW model). For the FSP, related
values are fixed internally by the program.
For dry initial catchment moisture conditions, the maximum
infiltration, the minimum infiltration, and the decay rate of
infiltration were assumed to be 63.5 mm/hr (2.50 in./hr),
11.4 mm/hr (0.45 in./hr), and 0.00115 sec"1, respectively.
Retention storage depths were assumed to be 4.67 mm (0.184 in.)
319
-------
for pervious and 1.57 mm (0.062 in.) for impervious areas.
For wet initial moisture conditions, a constant infiltration
rate of 0.3 mm/hr (0.01 in./hr) was assumed and the available
depth of retention storage was set at 0.3 mm (0.01 in.) for
both pervious and impervious areas. These values were selected
on the basis of previous runs with the SWMM performed by the
University of Cincinnati and preliminary runs performed by
Battelle.
Default values were used for the water quality model coeffi-
cients since the available water quality measurements were
inadequate to calibrate the SWMM and BNW models. The FSP
does not simulate water quality.
Preliminary runs indicated that the Bloody Run data may not
be sufficiently complete and accurate to yield reliable tests
of the models. Information on initial moisture conditions,
spatial variations in infiltration characteristics in the
catchment, and accuracy of the rainfall, runoff, and water
quality measurements were unavailable. The sewer discharge
was computed from pressure measurements using Manning's equa-
tion without establishing stage-discharge relationships or
verifying the assumed Manning's roughness coefficient with
simultaneous stage and velocity measurements during different
flow periods. The four upstream sewer sampling stations were
located very short distances upstream of major sewer junctions;
the measured stage in one sewer could therefore be affected
by backwater caused by the other branch, making the assump-
tion of uniform flow conditions for the discharge computation
incorrect for these conditions. Water quality measurements
were made only during short periods during the storms and
the runoff and water quality were tabulated only for those
periods. The values of the remaining portions of the runoff
hydrographs had to be obtained from plotted hydrographs,
since the original tables were not available.
For these reasons, only the storms of November 9, 1970, and
August 25, 1971, were simulated. The SWMM and BNW model
simulations were run with both dry and wet initial catchment
moisture conditions to demonstrate their effects on computed
runoff. The FSP was run only once for each storm, since it
sets initial catchment moisture conditions internally. The
model results are summarized in Table 73, which lists the
magnitudes and times of the peak discharges for each storm
at the five Bloody Run gaging stations. The water quality
data and simulations were not considered sufficiently reli-
able to warrant tabular comparisons.
Figures 83 to 111 show comparisons between the measured run-
off and the runoff computed by the SWMM, FSP, and BNW models.
320
-------
Table 73a. RUNOFF COMPARISONS FOR BLOODY RUN STORMS
tvj
Monitoring Peak
Date Station No.
11/09/70 Outlet 1
2
Longview 11 1
2
Longview #2 1
2
Bank #1 1
2
Bank #2 1
2
8/25/71 Outlet 1
2
3
4
Longview #1 1
2
3
4
Longview #2 1
2
3
4
Bank #1 1
2
3
4
Bank 12 1
2
3
4
Peak discharge, cfs
Observed
120.00
*
9.72
*
1.02
*
2.29
*
*
*
760.66
325.90
690.49
297.05
*
*
*
*
150. 39
44.54
142. 14
*
18. 70
15.34
*
*
8.99
8.99
8.99
*
SWMM
Dry
98.06
75.11
61.97
47.88
38.29
23.57
22.13
15.45
6.90
5.07
522.73
168.20
376.96
249.90
413.61
102.22
293.79
43.25
140.42
100.38
98.98
220.18
169.94
35.10
107.32
7.26
50.57
10.75
35.55
2.21
Wet
143.32
115.54
80.34
71.79
55.00
34.74
28.36
24.33
8.75
7.97
669.93
267.11
513.62
322.49
519.42
146.38
385.31
69.43
174.85
133.16
133.32
282.94
204.14
48.52
143.58
10.97
59.92
16.96
46.93
4.59
BNW
Dry
84.82
64.62
31.48
21.96
51.19
45.94
4.00
2.56
11.21
7.35
549.94
228.42
611.28
266.09
328.58
103.58
386.47
31.70
250.77
127.67
258.35
262.45
40.73
12.59
53.76
3.47
130.13
38.24
150.45
10.36
Wet
128.63
64.62
.51.45
21.96
68.22
45.94
6.56
2.56
17.67
7.35
1039.29
253.70
611.28
266.09
577.00
125.46
386.47
31.70
402.50
130.68
258.35
262.45
80.62
14.16
53.76
3.47
229.04
41.54
150.45
10.36
Time of peak
FSP Observed
175.88
103.17
62.58
48.47
86.26
66.32
29.92
19.23
13.69
7.60
761.99
282.99
613.99
141.97
569.46
145.57
403.09
45.39
556.87
170.21
380.77
159.18
281.42
63.07
176.13
20.25
117.41
31.03
70.06
7.67
67.5
*
60
*
75
*
22.5
*
it
*
68
210
315
600
*
*
*
*
75
195
323
*
30
270
*
*
90
188
330
*
SWMM
Dry
95
145
80
125
75
130
70
125
70
125
85
235
335
505
75
210
325
500
75
225
325
490
75
205
325
540
70
210
320
535
Wet
90
135
80
125
75
130
70
125
70
125
85
230
335
500
75
210
325
500
75
225
325
490
75
205
325
540
70
210
320
535
discharge , minutes
BNW
Dry
105
170
95
165
100
155
85
160
85
160
80
220
330
495
75
210
325
540
75
210
320
490
75
205
320
530
70
205
320
535
Wet
75
170
70
165
65
155
65
160
60
160
75
215
330
495
75
195
325
540
70
210
320
490
70
205
320
530
70
205
320
535
FSP
70
105
55
85
60
85
45
85
45
85
85
215
330
495
70
205
320
530
70
205
320
490
70
195
320
530
70
190
320
530
Note: * No observation
-------
Table 73b. RUNOFF COMPARISONS FOR BLOODY RUN STORMS
u>
t\5
Monitoring Peak
Date Station No.
11/09/70 Outlet 1
2
Longview #1 1
2
Longview #2 1
2
Bank #1 1
2
Bank #2 1
2
S/25/71 Outlet 1
2
3
4
Longview #1 1
2
3
4
Longview #2 1
2
3
4
Bank 11 1
2
3
4
Bank #2 1
?.
3
4
Peak discharge, m /sec
Observed
3.40
*
0.28
*
0.03
*
0.06
*
*
*
21.54
9.23
19.55
8.41
*
*
*
*
4.26
1.26
4.03
*
0.53
0.43
*
*
0.25
0.25
0.25
*
Dry
2.78
2.13
1.75
1.36
1.08
0.6-7
0.63
0.44
0.20
0.14
14.80
4.76
10.68
7.08
11.71
2.89
8.32
1.22
3.98
2.84
2.80
6.24
4.81
0.99
3.04
0.21
1.43
0.30
1.01
0.06
SWMM
Wet
4.06
3.27
2.28
2.03
1.56
0.98
0.80
0.69
0.25
0.23
18.97
7.56
14.55
9.13
14.71
4.15
10.91
1.97
4.95
3.77
3.78
8.01
5.78
1.37
4.07
0.31
1.70
0.48
1.33
0.13
BNW
Dry
2.40
1.83
0.89
0.62
1.45
1.30
0.11
0.07
0.32
0.21
15.57
6.47
17.31
7.54
9.31
2.93
10.94
0.90
7.10
3.62
7.32
7.43
1.15
0.36
1.52
0.10
3.69
1.08
4.26
0.29
Wet
3.64
1.83
1.46
0.62
1.93
1.30
0.19
0.07
0.50
0.21
29.43
7.18
17.31
7.54
16.34
3.55
10.94
0.90
11.40
3.70
7.32
7.43
2.28
0.40
1.52
0.10
6.49
1.18
4.26
0.29
FSP
4.98
2.92
1.77
1.37
2.44
1.88
0.85
0.54
0.39
0.22
21.58
8.01
17.39
4.02
16.13
4.12
11.42
1.29
15.77
4.82
10.78
4.51
7.97
1.79
4.99
0.57
3.33
0.88
1.98
0.22
Note: * No observation
-------
Measured and computed biochemical oxygen demand and suspended
solids concentrations for the SWMM and BNW models are com-
pared in Figures 112 to 122. Plots of computed runoff hydro-
graphs are shown for all five gaging stations, so that all
models could be compared regardless of whether measurements
existed at each station or not. Plots of the computed water
quality are shown for the Outlet station and only those
upstream stations which had measured water quality data.
This was considered sufficient to indicate the difficulty of
simulating wastewater quality with the SWMM and BNW models.
The measured rainfall data were reported at 5-minute intervals
and the measured runoff and water quality data at 7.5-minute
intervals. Five-minute time steps were selected for all
model simulations.
All three models predict considerably higher runoff than
measured for the storm of November 9, 1970, at the Bank #2,
Longview #1, and Longview #2 stations, and the differences
between models are significant (Table 73). For the Outlet
station, however, the measured runoff lies between the runoff
predicted by the SWMM and the BNW models for the dry and wet
initial catchment moisture condition, and the FSP over-
estimates the measured runoff by a much smaller percentage
than for the upstream stations.
The sum of the Longview #1 and Longview #2 runoff should be
almost as high as the Outlet runoff. As shown by Table 73
and Figures 91 to 97, the sum of the measured runoff at
Longview #1 and #2 for the storm of November 9, 1970, is less
than 10 percent of the runoff at the Outlet. It is highly
improbable that the missing 90 percent of the runoff entered
the sewers between these stations. The runoff predicted by
the models, however, appears to be in the approximate ratio
of the drainage areas of these stations.
It is interesting to note that no significant difference
exists in the times of the peak runoff values computed by the
SWMM for dry and wet initial conditions, although the magni-
tudes of the peaks differ considerably.
The BNW model predicts the first peak from 15 to 25 minutes
later than the SWMM for the dry initial condition and from
5 to 10 minutes earlier for the wet initial condition. The
BNW model predicts the same times for the second peaks
regardless of initial moisture condition, but they are from
25 to 40 minutes later than the second peaks computed by the
SWMM. The plots for this storm show also that the BNW model
computes saturated catchment moisture conditions after only
about 1 hour of storm runoff, while over 6 hours are required
by the SWMM.
323
-------
The FSP model predicts the correct time for the first peak at
the Outlet, but the predicted value is considerably higher
than the measured value. Both the FSP and BNW models predict
a second peak, which is only slightly visible in the SWMM
prediction and does not exist in the measured data. This
seems to indicate that the catchment did not become saturated
and that the second small rainfall peak did not have a large
effect on the runoff hydrograph.
Inspection of Figures 95 and 96 indicates that a better fit
could probably be obtained between measured and computed run-
off by adjusting model coefficients. This would not provide
better information with regard to model accuracy, however,
considering the uncertainties in the measured data accuracy,
particularly at the upstream stations.
Similar problems occur for the storm of August 25, 1971, which
consists of several intermittent rainfall bursts and associatec
short runoff periods. Again, the measured runoff at the Bank
#1 and #2 stations is considerably lower than the runoff com-
puted by any model. The SWMM model compares more favorably
with the Longview #2 measurements (Figure 107), but then
underestimates the runoff at the Outlet (Figure 110) for both
dry and wet initial conditions. The BNW model considerably
overestimates the runoff at the Longview #2 station (Figure
108) but its values compare more favorably with the measured
values at the Outlet station (Figure 111). The FSP model
predicts the runoff at the Outlet quite well (Figure 112)
although its values are considerably higher than the measured
values at Longview #2 (Figure 109). The models agree surpri-
singly in predicting the times of the four major peaks of
this storm (Table 73).
The models cannot predict the measured water quality for the
selected Bloody Run storms (Figures 113 to 122). The SWMM
and BNW model predictions disagree significantly with each
other and with the measured values. The BNW model predictions
for both suspended solids and biochemical oxygen demand are
considerably higher than the SWMM predictions. The polluto-
graphs are roughly mirror images (upside down) of the runoff
hydrographs, although this is more apparent for the BNW model
(due to its higher values) than for the SWMM. The measured
concentrations, where available, generally lie between the
BNW and SWMM predictions, but their duration is too short to
draw valid conclusions about model performance.
324
-------
- BflNK NO. 1 HERS.
1 SVMM - DRY
2 SVHM - WET
17.88
is. M
19. W
20.M
HOURS
23.B«
21.99
23.W
26. M
Figure 83. Comparison of Measured and Computed Runoff at
the Bank #1 Station for the Storm of
November 9, 1970 - Blood Run Catchment -
EPA Stormwater Management Model
325
-------
UJ
u>
cc
_
UJ
CO
i..R
- BANK NO. 1 HERS.
3 BNW - DRY
4 BMW - WET
—i
28. aa
—i
23.ee
—i
zs.oe
17.
—i
ie.ee
ig.ee
2i.ee
TIME,
22.ee
HOURS
2t.ee
26.ee
Figure 84.
Comparison of Measured and Computed Runoff at
the Bank #1 Station for the Storm of
November 9, 1970 - Bloody Run Catchment -
Battelle Urban Wastewater Management Model
- BflNK NO.
e FSP
1 NEflS.
ts
en
17.08
16.80
i9.ee
20.00
21.00 22.98
TIME. HOURS
23.ee
24.B8
25.00
26.00
Figure 85,
Comparison of Measured and Computed Runoff at
the Bank #1 Station for the Storm of
November 9, 1970 - Bloody Run Catchment -
Chicago Flow Simulation Program
326
-------
1 SWMM - DRY
2 SVMM - WET
17.88
18.88
19.98
28.99
23.88
21.00
2S.00
Figure 86.
TIME. HOL
Computed Runoff at the Bank #2
Station for the Storm of November 9, 1970
Bloody Run Catchment - EPA Stormwater
Management Model
26.00
3 BNW - DRY
4 BNW - WET
17.00
25.00
26.00
Figure 87.
Computed Runoff at the Bank #2
Station for the Storm of November 9, 1970
Bloody Run Catchment - Battelle Urban
Wastewater Management Model
327
-------
en
u_-
ur>.
LU
CS
cn
-.3
«s FSP
•o
LU
CO
.83
§
—i
is.ee
1
i9.ro
1
20.ee
1
23.ee
1
2t.ee
17.08
2i.ee
TIME.
22.ee
HOURS
25.ee
26.ee
Figure 88.
Computed Runoff at the Bank #2
Station for the Storm of November 9r 1970 -
Bloody Run Catchment - Chicago Flow Simula-
tion Program
CS
DC
- LONGVIEV NO.
1 SVHM - DRY
2 SWMM - WET
i7.ee
is.ee
i9.ee
ze.ee
zi.ee
TIME.
22.ee
HOURS
23.ee
2t.ee
25.ee
26.ee
Figure 89.
Comparison of Measured and Computed Runoff at
the Longview #1 Station for the Storm of
November 9, 1970 - Bloody Run Catchment -
EPA Stormwater Management Model
328
-------
s
- LONGVIEV NO. 1
3 BNV - DRY
4 BNV - VET
21.00 22.00
TIME. HOURS
23.80
24.00
25.08
26.00
Comparison of Measured and Computed Runoff at
the Longview #1 Station for the Storm of
November 9, 1970 - Bloody Run Catchment -
Battelle Urban Wastewater Management Model
- LONGVIEW NO. 1
e FSP
UJ
C9
OC
•*(_>
UJ
cn
17.00
18.00
19.00
20.00
21.00 22.00
TIME. HOURS
29.00
24.00
25.00
26.00
Figure 91.
Comparison of Measured and Computed Runoff at
the Longview #1 Station for the Storm of
November 9, 1970 - Bloody Run Catchment -
Chicago Flow Simulation Program
329
-------
- LONGVIEW NO.
1 SWMM - DRY
2 SWMM - VET
uj
ts
S
—i
i8.ee
—T—
is. e
—T
2e.ee
—i 1
zi.ee 22.ee
TIME. HOURS
—i
23.ee
—T
25.ee
17. C
24.ee
26.ee
Figure 92.
Comparison of Measured and Computed Runoff at
the Longview 12 Station for the Storm of
November 9, 1970 - Bloody Run Catchment - EPA
Stormwater Management Model
- LONGVIEW NO.
3 BNW - DRY
4 BNW - WET
—i 1
21.98 22.ee
TIME. HOURS
is.ee
-\
I9.«e
2e.ee
23.ee
2i.ee
2s.ee
26.ee
Figure 93.
Comparison of Measured and Computed Runoff at
the Longview #2 Station for the Storm of
November 9, 1970 - Bloody Run Catchment -
Battelle Urban Wastewater Management Model
330
-------
UJ
CD
OC
a
UJ
(0
- LONSVIEV NO. 2
e FSP
—I
23.00
—!
24.00
—T
25.88
17.00
18.88
19.00
20.00
Figure 94.
21.00 22.00
TIME, HOURS
26.00
Comparison of Measured and Computed Runoff at
the Longview #2 Station for the Storm of
November 9, 1970 - Bloody Run Catchment -
Chicago Flow Simulation Program
- OUTLET - MEflS.
1 SVMM - DRY
2 SWMH - WET
17.00
16.00
19.00
20.00
22.00
HOURS
23.00
24.00
23.00
26.00
Figure 95.
Comparison of Measured and Computed Runoff at
the Outlet Station for the Storm of November
9, 1970 - Bloody Run Catchment - EPA Stormwater
Management Model
331
-------
17.00
- OUTLET - MEftS.
3 BNV - DRY
4 BNV - WET
—i
16.00
19.00
—I
20.00
21.00 22.8
TIME. HOURS
23.00
—1
21.00
—1
25.00
26.00
Figure 96.
Comparison of Measured and Computed Runoff at
the Outlet Station for the Storm of November
9, 1970 - Bloody Run Catchment - Battelle Urban
Wastewater Management Model
- OUTLET - MEfiS.
a FSP
17.00
18.00
19.00
20.00
21.00 22.00
TIME. HOURS
23.00
21.00
25.00
26.00
Figure 97.
Comparison of Measured and Computed Runoff at
the Outlet Station for the Storm of November
9, 1970 - Bloody Run Catchment - Chicago Flow
Simulation Program
332
-------
- BANK NO. 1 MEflS
1 SWHM - DRY
2 SWHM - WET
14.00
15.00
16.00
17.00
Figure 98.
18.00 19.00
TIME. HOURS
20.00
21.00
22.00
23.00
Comparison of Measured and Computed Runoff at
the Bank #1 Station for the Storm of August 25,
1971 - Bloody Run Catchment - EPA Stormwater
Management Model
14.00
- BRNK NO. 1 HERS.
3 BNV - DRY
4 BNW - WET
15.00
17.00
TIME". HOUR!'
20.00
21.00
22.00
23.00
Figure 99.
Comparison of Measured and Computed Runoff at
the Bank #1 Station for the Storm of August 25,
1971 - Bloody Run Catchment - Battelle Urban
Wastewater Management Model
333
-------
14.00
- BflNK NO. 1 MEflS.
o FSP
is.ee
-1——
ie.ee
i7.ee
Figure 100.
ie.ee ia.ee
TIME, HOURS
ze.ee
ai.ee
zz.ee
23.ee
Comparison of Measured and Computed Runoff at
the Bank #1 Station for the Storm of August
25, 1971 - Bloody Run Catchment - Chicago Flow
Simulation Program
U_sj
Ss
=*<_>
LU
en
.8.3
NO. 2 MEflS.
1 SWUM - DRY
2 SWMM - VET
it.ee
is.ee
ie.ee
i7.ee
ie.ee ia.ee
TIME, HOURS
ae.ee
2i.ee
22.ee
23.ee
Figure 101.
Comparison of Measured and Computed Runoff at
the Bank #2 Station for the Storm of August
25, 1971 - Bloody Run Catchment - EPA Stormwater
Management Model
334
-------
14.00
- BflNK NO. 2 HERS.
3 BMW - DRY
4 BNV - VET
15.00
,
16.00
17.00
Figure 102.
TIM* HOURS'8*
20.00
21.00
22.00
23.00
Comparison of Measured and Computed Runoff at
the Bank #2 Station for the Storm of August
25, 1971 - Bloody Run Catchment - Battelle
Urban Wastewater Management Model
38..
UJ
&•
I—I
a
S
si
- BflNK NO. 2 HERS.
9 FSP
14.00
15.00
16.00
17.00
TIME. HOURS
L9.00
20.00
21.00
22.00
23.00
Figure 103. Comparison of Measured and Computed Runoff at
the Bank #2 Station for the Storm of August
25, 1971 - Bloody Run Catchment - Chicago Flow
Simulation Program
335
-------
1 SWMM - DRY
2 SWMM - WET
14. e»
15.88
Figure 104.
TIME,
22.89
23. M
Computed Runoff at the Longview #1
Station for the Storm of August 25, 1971
Bloody Run Catchment - EPA Stormwater
Management Model
3 BNW - DRY
4 BMW - WET
14.8»
15.00
16.88
17.,
19.00
HOURS
20.00
21.00
—T
22.00
23.1
Figure 105.
Computed Runoff at the Longview #1 Station
for the Storm of August 25, 1971 - Bloody
Run Catchment - Battelle Urban Wastewater
Management Model
336
-------
14.00
e FSP
15.00
16.00
17.00
is. oe
HOURS
2B.ro
21.88
22. 00
23.00
Figure 106. Computed Runoff at the Longview #1 Station
for the Storm of August 25, 1971 - Bloody
Run Catchment - Chicago Flow Simulation
Program
- LONGVIEV 2 MEflS.
1 SWMM - DRY
2 SVMM - WET
H.ee
is.ee
is.ee
17.
ie.ee is.ee
TIME, HOURS
20.ee
2i.ee
22.00
29.ee
Figure 107.
Comparison of Measured and Computed Runoff at
the Longview #2 Station for the Storm of
August 25, 1971 - Bloody Run Catchment - EPA
Stormwater Management Model
337
-------
14.00
- LONGVIEV 2 MEflS.
3 BNW - DRY
4 BMW - VET
15.00
16.00 19.00
TIME, HOURS
Figure 108.
Comparison of Measured and Computed Runoff at
the Longview #2 Station for the Storm of
August 25, 1971 - Bloody Run Catchment -
Battelle Urban Wastewater Management Model
- LONGVIEW 2 MEflS
o FSP
14.00
15.00
16.00
17.00
18.00 19.00
TIME, HOURS
20.00
21.00
22.00
23.00
Figure 109.
Comparison of Measured and Computed Runoff at
the Longview #2 Station for the Storm of
August 25, 1971 - Bloody Run Catchment -
Chicago Flow Simulation Program
338
-------
- OUTLET - MEflS.
1 SWMH - DRY
2 SWUM - WET
14. M
15.00
22.80
29. M
Figure 110.
Comparison of Measured and Computed Runoff at
the Outlet Station for the Storm of August
25, 1971 - Bloody Run Catchment - EPA
Stormwater Management Model
- OUTLET - MEflS.
3 BMW - DRY
4 BNW - WET
14.80
15.00
19.00
HOURS
Figure 111.
Comparison of Measured and Computed Runoff at
the Outlet Station for the Storm of August
25, 1971 - Bloody Run Catchment - Battelle
Urban Wastewater Management Model
339
-------
14.00
15.00
16.00
17.00
18.00 19.00
TIME. HOURS
20.00
21.00
22.00
29.00
Figure 112.
Comparison of Measured and Computed Runoff at
the Outlet Station for the Storm of August
25, 1971 - Bloody Run Catchment - Chicago
Flow Simulation Program
8
a-
cs
- BflNK NO. 1
1 SWMM - DRY
2 SWIM - WET
3 BMW - DRY
4 BMW - WET
24.00
25.00
26.00
Figure 113.
Comparison of Measured and Computed Suspended
Solids Concentrations at the Bank #1 Station
for the Storm Runoff of November 9, 1970 -
Bloody Run Catchment
340
-------
- BANK NO. 2
1 SWHM - DRY
2 SWUM - WET
3 BNV - DRY
4 BMW - VET
24.88
25.88
26.M
Figure 114.
Comparison of Measured and Computed Suspended
Solids Concentrations at the Bank #2 Station
for the Storm Runoff of November 9, 1970 -
Bloody Run Catchment
1 SWMM - DRY
2 SVHH - WET
3 BNV - DRY
4 BMW - WET
Figure 115.
Computed Suspended Solids Concentrations
at the Outlet Station for the Storm Runoff
of November 9, 1970 - Bloody Run Catchment
341
-------
1 SVMH - DRY
2 SVMM - VET
3 BMW - DRY
4 BNW - WET
16.00
T*
19.00
20.00
21.00 22.00
TIME. HOURS
i"
29.00
—1
21.00
25.00
26.00
Figure 116.
Computed Biochemical Oxygen Demand Concen-
trations at the Bank #1 Station for the Storm
Runoff of November 9, 1970 - Bloody Run Catchment
1 SVMM - DRY
2 SVMM - VET
3 BNV - DRY
BNV - VET
17.00
16.00
19.00
20.00
21.00 22.
TIME, HOURS
22.00
23.00
20.00
25.00
26.00
Figure 117.
Computed Biochemical Oxycren Demand
Concentrations at the Bank #2 Station for
the Storm Runoff of November 9, 1970 -
Bloody Run Catchment
342
-------
17.00
1 SVMM - DRY
2 SWHM - VET
3 BNW - DRY
4 BMW - WET
18.89
19.98
24.00
25.00
Figure 118.
Computed Biochemical Oxygen Demand
Concentrations at the Outlet Station for
the Storm Runoff of November 9, 1970 -
Bloody Run Catchment
26.00
1 SVMM - DRY
2 SVMM - VET
3 BNV - DRY
4 BNV - VET
a 14.00
21.09
22.00
23.00
Figure 119. Computed Suspended Solids Concentrations at the
Bank #1 Station for the Storm Runoff of August 25,
1971 - Bloody Run Catchment
343
-------
- OUTLET - MEflS.
1 SWMM - DRY
2 SWMM - WET
3 BNW - DRY
4 BNV - WET
18.W .
TIME. HOURS
29.88
2i.ee
22.ee
2s.ee
Figure 120.
Comparison of Measured and Computed Suspended
Solids Concentrations at the Outlet Station
for the Storm Runoff of August 25, 1971 -
Bloody Run Catchment
1 SWMM - DRY
2 SWMM - WET
3 BNW - DRY
ft BNW - WET
ie.ee
ir.ee
ie.ee is.ee
TIME. HOURS
2e.ee
2i.ee
22.ee
23.ee
Figure 121.
Computed Biochemical Oxygen Demand Concentrations
at the Bank #1 Station for the Storm Runoff of
August 25, 1971 - Bloody Run Catchment
344
-------
14.00
15.00
16.00
17.00
o.9 19.00
[ME. HOURS
20.00
21.00
22.00
23.00
Figure 122. Comparison of Measured and Computed Biochemical
Oxygen Demand Concentrations at the Outlet Station
for the Storm Runoff of August 25, 1971 -
Bloody Run Catchment
345
-------
SECTION VIII
COSTS OF COMPUTER APPLICATIONS
CONTENTS
Page
Introduction 347
Input/Output Features of Tested Models 348
Environmental Protection Agency Stormwater
Management Model 348
Battelle Urban Wastewater Management Model 343
Chicago Flow Simulation Program 349
Dorsch Consult Hydro graph-Volume Method 350
Massachusetts Institute of Technology
Urban Watershed Model 350
SOGREAH Looped Sewer Model 350
Water Resources Engineer Stormwater
Management Model 350
Computer Times and Costs of Test Runs 350
Computer Processing Time 351
Computer Processing Costs . 353
Summary 356
346
-------
INTRODUCTION
The cost of applying any of the reviewed models depends on the
objectives of model use and the specific location of applica-
tion. Objectives may include preliminary planning of new sys-
tems, evaluation of existing system performance, design of new
system components, and real-time control of an existing or
planned system.
The costs of implementing a model for any of these objectives
are highly site specific. They depend upon the size of the
system to be modeled, whether small subcatchments or only the
major trunk and interceptors have to be simulated, and whether
only flow or both flow and quality have to be considered. The
costs also depend upon the complexity of the system, its inter-
connections, special facilities (such as diversions, pumps,
siphons, tide gates, storage reservoirs, and treatment plants),
the nature of the runoff events, and the importance of specific
water quality parameters.
The availability of data and their form will greatly influence
costs. Some cities maintain very efficient files of sewerage
system plans and specifications and have monitored rainfall,
runoff and water quality. In other cases, extensive field sur-
veys and new monitoring programs may have to be implemented to
collect sufficient data to characterize the catchments, sewerage
system components, and hydrologic and water quality aspects.
The cost of running a program on a computer and performing com-
puter simulations may be small in comparison to the costs of
problem definition, data collection, and interpretation of the
results. Only for very small catchments and simple problems
may computer costs become a major item.
Significant differences can be expected, nevertheless, in the
implementation and application of different computer programs,
depending on their complexity and the available computer sys-
tem. In general, these costs will increase with the number of
phenomena being modeled, the number of options in a program,
the size of the system, and the length of the time period to be
simulated. The costs will decrease with the clarity of the
input data arrangement, the adequacy of data error diagnostics,
the efficiency of the numerical program algorithms, and the
flexibility, completeness, and format of the desired computer
output.
347
-------
INPUT/OUTPUT FEATURES OF TESTED MODELS
Environmental Protection Agency Stormwater Management Model
The SWMM, being the most comprehensive of the tested models,
may be the most expensive of the generally available models to
implement and apply, provided all of its features are needed.
Implementation is difficult because discrepancies exist between
the model documents and the computer program and the documenta-
tion does not clearly separate the model's theoretical basis,
testing and input data instructions. The user's manual is dif-
ficult to follow and not sufficiently clear to prevent misin-
terpretations of data definitions. Limits in numerical values
are not indicated for variables which cause numerical problems
if their value is not within a certain range. The model does
not include sufficient error diagnostics.
The printout of hydrographs and pollutographs is limited to 20
sewerage system elements, which may not be adequate for large
systems. Repeated simulations of the same system are required
if printout is needed for more elements. The tables of hydro-
graphs and pollutographs do not associate clock times with the
discharge and pollutant concentrations or mass values. Their
arrangement in blocks by system element, rather than columns,
makes it difficult to obtain visual comparisons of tabulated
values for selected times.
Battelle Urban Wastewater Management Model
The catchment runoff and sewer flow and water quality routing
formulations of the BNW model are fairly simple. The complete
model, however, is rather complex since it includes mathematical
optimization for real-time control and for design. Implementa-
tion costs are expected to be high since the model is programmed
for a small process computer and would require major reprogram-
ming for applications to other computers. Documentation for
the BNW model is only in the draft stage. The user's manual is
separate from documentation of model testing and theoretical
formulations; some variables are not defined sufficiently,
however, to be understood without special instructions. The
input data are arranged into logical groups, but the program
does not have sufficient data error diagnostics to prevent false
starts.
Stage, velocities, and discharge can be printed automatically
for all conduit elements but discharge and pollutant concentra-
tions have to be retrieved by light pen action on a cathode ray
tube separately for each desired junction or diversion struc-
ture, which is time consuming. This is offset, however, by the
low cost of the small computer. The model is highly flexible,
348
-------
however, in that output can be limited to only the elements of
interest, but output can also be obtained for all system ele-
ments if desired. The stage, velocity, and discharge in sewers
are printed in columns as functions of time and easy to read,
but they are tabulated at irregular time intervals. Hydrographs
and pollutographs are printed at constant time intervals for
junctions and diversion structures, with only the beginning
time of the hydrograph or pollutograph indicated on the print-
out. The characteristic solution of the flow routing results
for different sewerage system elements, making comparisons some-
what difficult. Plots can be obtained on an electrostatic
printer, however, for any hydrograph and pollutograph and sev-
eral graphs can be overlaid for easy comparison. A plot of the
system schematic is a useful feature.
Contracting with Watermation, Inc., may be advantageous since
the firm has improved and programmed the BNW model for routine
applications using an IBM 360.
Chicago Flow Simulation Program
The FSP does not include water quality simulation and most model
coefficients are set internally. It is consequently fairly
easy to implement the model and to prepare the input data. The
user's instructions are quite clear and the input data are well
arranged. Limiting parameter values are not given. For large
areas, the specification of the channel network by x-y coordi-
nates has certain advantages over other methods of defining
element connectivity.
Depth, flow, and storage are printed for each channel or con-
duit. The arrangement of the output, however, does not identify
the sewer elements or the clock time. The user must therefore
refer to the input data, which are not listed by the program
automatically, to identify each line of the printout. Each
line of computer printout contains the time step number and
values of stage, discharge, and storage for only one element
and one time step, which produces unnecessarily long computer
printouts. The printout is arranged so that the stage, flow
and storage can be seen easily at all elements for a given time
step, but the complete hydrograph at a single element is not
printed and is difficult to extract. Output is limited to 20
channel elements. Part of the printout related to the channel
network configuration is not labeled.
The four proprietary models are generally applied by the model
developers for interested clients, although they may be re-
leased under certain contractual arrangements. Sufficient in-
formation was not available in time to evaluate input data
arrangements, consequently only output features are summarized.
349
-------
Dorsch Consult Hydrograph-Volume Method
The DORSCH model printout is very well organized. This is the
only model which prints both the depth and discharge separately
for each of the three types of catchment surfaces. Clock time,
stage, dry-weather and combined flow are printed in clearly-
marked tables, facilitating inspection of channel stage and
hydrographs. The user must memorize abbreviations used in the
summary tables for output interpretation.
Massachusetts Institute of Technology Urban Watershed Model
The MIT model prints clock time, stage, velocities and discharge
in columnar form for each sewerage system element, which is
easy to read and to interpret. A useful feature is a line
printer plot of a labeled schematic of the modeled system. A
separate line printer plotting program is used to plot hydro-
graphs .
SOGREAH Looped Sewer Model
The SOGREAH model prints one catchment runoff hydrograph per
page, clearly labeling the clock time for all runoff values.
Stage, discharge and concentrations at sewerage network ele-
ments are printed concurrently for the entire system for one
value of time making it easy to obtain an overview for the
entire network for a given time but difficult to extract hydro-
graphs for a particular element. A separate plotter program is
used for this purpose.
Water Resources Engineer Stormwater Management Model
The WRE model output is very well organized. Separate tables
are printed for junctions and conduits. The junction tables
list clock time and water surface elevation and depth while
the conduit tables list clock time, discharge and velocity.
Separate tables list clock time, discharge and concentration
for each pollutant at selected junctions. Line printer plots
of stage, discharge, and concentrations are also available.
COMPUTER TIMES AND COSTS OF TEST RUNS
Comparisons of computer processing time and costs are provided
for the hypothetical data tests performed with the SWMM, BNW,
FSP, DORSCH, MIT, SOGREAH and WRE models. These tests are
equivalent to the simulation of four runoff events, each of
six hours' average duration for a watershed containing 80 sub-
catchments, 37 kilometers (23 miles) of conduit, 6 diversion
structures and 6 storage basins. Three pollutants were routed
with each runoff hydrograph for the models simulating water
quality (Table 74).
350
-------
Table 74. SUMMARY OF HYPOTHETICAL DATA TESTS
4 Runoff events
6 Hour average duration
80 Catchments
37 Kilometers of pipe (23 miles)
6 Diversion structures
6 Storage basins
3 Pollutants
Computer Processing Time
The computer processing time required for these tests is listed
for the seven models in Table 75. Due to the proprietary nature
of four of the models and the special requirements of the BNW
model, it was not possible to run all models on the same com-
puter to obtain good running-time comparisons. The table nev-
ertheless presents useful information for comparison of at
least those models which were run on similar computers. Since
not all models performed all hypothetical data tests, some of
the listed running times are estimates based on the assumption
that the same number of data combinations were performed by all
models.
Computer running times for the pollutant routing are not listed
for the FSP and MIT models since they do not include water qual-
ity formulations. Computer running times for the pollutant
routing by the DORSCH model were not available. For the SOGREAH
and WRE models it was possible to list the times required for
the flow and pollutant routing separately since these models
performed separate computer runs for them. For the SWMM and
BNW models, the flow and pollutant routing is performed in the
same run; consequently only the total running time for both can
be listed.
The computer processing times of the FSP, DORSCH, MIT, SWMM,
SOGREAH and WRE models for the catchment runoff computations
are quite comparable, although they were performed on different
computers. The SWMM version used for these tests performed
water quality computations, although they were not needed, and
consequently performed more computations than the other models.
A new SWMM version allows the suppression of water quality
351
-------
u>
Table 75. COMPUTER PROCESSING TIME FOR HYPOTHETICAL
DATA TESTS (minutes)
Flow only
Model
Computer
Runoff
Flow routing
Pollutant routing
Flow and pollutant routing
Total
FSP
CDC
6400
29
18
-
-
47
DORSCH
UNIVAC
1108 3
15
40
-
-
55
MIT
IBM
70/195
25
32
-
-
57
Flow and quality
BMW*
PDF
9
300
-
-
624
924
SWMM*
CDC
6400
38
-
-
81
119
SOGREAH WRE
IBM UNIVAC
360/65 1108
8 14
23 26
17 9
40 35
48 49
Note: *With plotting.
-------
computations, which would result in shorter running time for
the hypothetical catchment tests.
The FSP, DORSCH, MIT, WRE and SOGREAH models show comparable
running times for the flow routing, and the SWMM, WRE and
SOGREAH models are comparable for the combined flow and pollu-
tant routing. The BNW model running times are much longer
because of the slower execution speed of the PDP-9.
Computer Processing Costs
Processing cost, a more meaningful comparison than processing
time, is listed in Table 76. The FSP and SWMM were run on a
CDC 6400 computer at a cost of U.S. $640/hr, the MIT model on
an IBM 370/195 computer at a cost of U.S. $860/hr, the WRE
model on a UNIVAC 1108 computer at a cost of U.S. $750/hr, and
the BNW model on a PDP-9 computer at a cost of U.S. $35/hr.
Sufficient information was not available for these models to
estimate computer running time and cost as a function of num-
ber of sewerage system elements and number of time steps. Test
runs with the WRE surface runoff transport model performed by
Water Resources Engineers indicated nearly identical costs for
the CDC 6600, IBM 360/65 and UNIVAC 1108 computers.
The DORSCH model was run on a UNIVAC 1108 computer at a cost
of U.S. $600/hr. Dorsch Consult provided the following in-
formation to estimate the cost of applying the DORSCH model:
Computer running time for flow routing = 0.02 to 0.07 sec
x number of sewerage system elements x number of time
steps; 0.02 sec for sewerage systems with few diversions,
weirs, special structures, and backwater effects; 0.07
sec for sewerage systems with loops and extensive back-
water effects throughout the entire network; 0.05 sec for
average configurations.
Input data preparation: 0.25 to 0.60 hr per sewerage sys-
tem element for evaluating existing systems and 0.35 to
0.60 hr per sewerage system element for evaluating system
improvements depending on the availability and quality of
sewerage system plans and data.
Dorsch Consult estimates that the run time of a CDC 6600 com-
puter would be 55.5 percent of the run time on a UNIVAC 1108.
The SOGREAH model was run on an IBM 360/65 computer at a cost
of U.S. $900/hr. SOGREAH provided the following information
to estimate the computer cost for applying the SOGREAH model:
353
-------
Table 76. COMPUTER COSTS FOR HYPOTHETICAL DATA TESTS
(dollars)
00
Ul
Flow only
Model
Computer
Cost per hour
Runoff
Flow routing
Pollutant routing
Flow and pollutant routing
Total
FSP
CDC
6400
640
310
190
-
-
500
DORSCH
UN I VAC
1108
600
150
400
-
-
550
MIT
IBM
370/195
860
360
460
-
-
820
Flow and
BNW*
POP
9
35
175
-
-
365
540
SWMM*
CDC
6400
640
405
-
-
865
1270
quality
SOGREAH
IBM
360/65
900
120
345
255
600
720
WRE
UN I VAC
1108
750
170
325
110
435
610
Note: *With plotting.
-------
Computer running time for flow routing = 0.002 sec
x number of sewerage system elements x number of time
steps + 0.00012 sec x (number of sewerage system
elements) .
The costs of the catchment runoff computations are comparable
for the DORSCH, BNW, SOGREAH and WRE models. The cost of the
SWMM catchment simulations could be reduced with the new version
by suppressing the catchment water quality simulations. It is
not clear why the FSP and MIT model runs of the catchment simu-
lations would cost two to three times more than the other models.
The actual cost of the MIT catchment simulations was less, since
only fully pervious and fully impervious catchments were simu-
lated and the runoff for the various combinations of pervious
and impervious catchments was computed from these in proportion
to the percent imperviousness. The listed cost would be repre-
sentative, however, for running all 320 catchment data combina-
tions.
The FSP shows the lowest cost for flow routing due to the simple
linear routing scheme. Comparable costs are shown for the DORSCH,
MIT, WRE, and SOGREAH models. The MIT cost is the highest of
these four, although it uses the simplest routing scheme; the
cost difference, however, may not be significant.
For the combined flow and pollutant routing, the BNW model shows
the lowest cost, primarily because it runs on the inexpensive
PDP-9 computer. Surprisingly, the SOGREAH and WRE models are
less expensive than the SWMM model although they solve the full
dynamic wave equations and the SWMM solves the simpler kinematic
wave equation.
These comparisons indicate that the tested models feature effi-
cient numerical solution algorithms for the full dynamic wave
equation which are competitive with the more approximate kine-
matic wave equation. The tests also indicate that no signifi-
cant differences exist in the computer running costs of models
which use either an explicit (WRE model) or implicit (DORSCH
and SOGREAH models) finite difference solution of the dynamic
wave equation. Preliminary runs by the model developers
indicate, however, that computer running times several times
longer than necessary may result if the time step is chosen
shorter than necessary with respect to the time and space
variability of the modeled phenomena. Explicit solutions
generally require much smaller computational time steps than
implicit solutions due to stringent numerical stability con-
ditions, but fewer iterations are required for the solution
at any one time step for the explicit than the implicit solu-
tions. For example, to obtain the same accuracy for a particu-
lar application, the implicit scheme may be able to use time
355
-------
steps which are ten times longer than the explicit scheme. On
the other hand, the explicit scheme may need only four itera-
tions to converge on a solution at a particular time step, while
the implicit scheme may need as many as 30 iterations. Whether
one scheme is more efficient than the other depends on the
physical characteristics of the channel system and flow phe-
nomena being modeled. No general criteria have been developed.
SUMMARY
It should be pointed out that these computer processing costs
can be used only as guidelines. Relative running times and
costs for the models may be quite different for real catchments
as a result of special features which permit the identification
of typical catchment elements and reduce duplication of data
input and simulations for similar subcatchments and sewerage
system components. The BNW, MIT and WRE models have features
of this type.
At the beginning of the model comparison, it was planned to
run all models selected for the numerical testing on the same
computer to provide a common base for comparing computer pro-
cessing time and cost. Subsequently, the FSP and SWMM were
converted to run on the CDC 6400 computer of Battelle-Columbus,
since an IBM computer was not readily available to Battelle-
Northwest at that time. Conversion of the BNW model, however,
from the small PDP-9 computer to the CDC 6400 was not performed
due to expected high cost. In addition, the four proprietary
models had to be run on the computers being used by the respec-
tive firms since the programs were not released.
The cost comparisons are still realistic, however, since the
potential user would run a particular model on the computer
for which the model is written unless he is willing to pay for
the conversion cost. The costs in Table 76 are consequently
valid comparisons of computer costs for running the simple
hypothetical data tests. Additional numerical tests simulat-
ing large sewerage networks of varying complexity would be
required to obtain a more comprehensive comparison of computer
costs for running the different models, to evaluate the effect
on computer processing costs of model differences in input
data arrangement for complex networks, of economies in comput-
ing hydrologic phenomena for typical subcatchments only rather
than every subcatchment, and of different network flow routing
algorithms.
356
-------
SECTION IX
DISCUSSION
CONTENTS
Page
Introduction 358
Data 358
Models 359
357
-------
INTRODUCTION
Several observations can be made as a result of the preceding
model reviews and numerical testing. It is hoped that they may
provide some guidance with respect to future model development
and implementation.
DATA
Although highly sophisticated mathematical models exist for the
simulation of water flow and quality in urban drainage systems,
their verification and application has been greatly hindered by
the lack of reliable and comprehensive data on physical charac-
teristics of urban catchments, rainfall runoff, and water quality.
Past data collection programs have generally been designed to
provide answers to specific problems or to develop relationships
of limited scope, rather than to provide a general body of infor-
mation such as is needed to assess the comprehensive models
reviewed in this study. Quite often, reliable rainfall and run-
off data are collected but data are insufficient or unavailable
to describe other important meteorological variables and catch-
ment moisture conditions at the beginning of rainfall and during
the rainstorm. Quite commonly, the physical dimensions of the
sewerage system have not been described adequately, such as
length, areas, slopes, and roughness characteristics of the run-
off surfaces; sizes, slopes and materials of conduits and open
channels; and configurations and dimensions of special control
structures. Expensive programs would be needed to obtain these
measurements and in some cases, the watershed characteristics
may have changed sufficiently since the rainfall and runoff data
were collected to make post-facto measurements meaningless.
This lack of comprehensive data has forced model developers to
test portions of their models on data for different watersheds.
This requires replacing unavailable data with assumptions, and
consequently the tests cannot be considered as conclusive as if
all needed model data had been available for the same catchment.
Very rarely is the accuracy of the measured data documented.
Data accuracy can be estimated if descriptions of the instru-
mentation and measurement procedures are available, but this is
still less than satisfactory. In one case it was found that
portions of the reportedly observed runoff and water quality data
were not measured but interpolated from discontinuous measurements,
In another case, runoff was computed from water pressure measure-
ments with Manning's equation without attempts to calibrate the
equation (Manning's n) with measured depth and velocity measure-
ments. In computing the discharge, uniform flow conditions were
assumed where backwater conditions may have existed for certain
358
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flow conditions, particularly where the measuring stations were
a short distance upstream of major trunk sewer junctions.
A fair amount of reliable runoff data is now available, but reli-
able water quality data are hard to find. Particularly lacking
is information which would permit definitive conclusions or corre-
lations between catchment land uses and water quality.
MODELS
This review of eighteen sewerage system simulation models and
testing of seven of them indicates that it is extremely difficult
to select the best model for a particular application. Some models
have been designed for specific objectives not considered by
others, and consequently they would be preferred if the user has
the same objectives in mind. Some proprietary models have features
which appear superior to the publicly available models, but a user
may prefer to run his own model and consequently has to be satis-
fied with a model that does not exactly meet his requirements.
Quite often it is found that the model does not perform exactly
as claimed by the model developers or that certain features which
appeared to be working for the developer are not adequate for the
needs of a new user. The user should therefore expect to perform
some model modifications and improvements. Most models that are
actively used are consequently in a continuous state of develop-
ment by both the original developers and by various users. As a
result, several versions of the same model may exist and the new
user has the added problem of making a selection from different
versions of the same model.
Because of this continuing development work, model documentation
is rarely up-to-date and the user is faced with reconciling dif-
ferences among the model descriptions, user's manuals, and the
actual computer program. Sometimes the model reports describe
features which were planned for a model which to the model user's
surprise were never implemented in the computer program he receives,
The numerical testing of the models indicates that a direct rela-
tionship between model complexity and its cost of implementation
and application exists with respect to the number of major phe-
nomena which are modeled. Efficient solution algorithms, however,
may reduce this difference significantly. This is true particu-
larly for proprietary models due to their need to stay competitive.
A model which simulates many special sewerage system facilities
will be more complex in structure and require more data and com-
puter storage than a model that computes only runoff from a single
catchment without routing flows or which does only flow routing
in a simple converging network without computing runoff from pre-
cipitation and land use.
359
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The simulation of water quality adds considerable complexity to
a model, even if it routes only conservative substances. The
complexity increases substantially if both storm and dry-weather
water quality is computed from land use characteristics. Addi-
tional complexities are -added if wastewater treatment and receiv-
ing water flow and quality are being modeled.
To reduce this complexity, it would be desirable to have a series
of models which are interfaced by common input and output, that
can be run independently provided the required data are available,
or that can be run in any desired sequence. This would allow
model implementation in stages, reduce implementation cost and
computer storage requirements, and facilitate acceptance of the
models. A series of models, rather than one large comprehensive
model, would reduce the need to compromise in specific submodel
formulations, a course which is often required to save computer
space.
Such model series already exist, but some streamlining and improve-
ment of components is needed to facilitate their use, either
independently or in any sequence. An example is the EPA's Storm-
water Management Model, which simulates storm and dry-weather run-
off and water quality from catchments, routes them through complex
sewerage networks, simulates storage and various treatment pro-
cesses, and computes the effects of sewerage system effluents on
receiving water quality. The model needs several improvements,
however, before it becomes sufficiently general to model all
important phenomena and to allow arbitrary sequencing of major
model components. Needed improvements, for instance, would be
the simulation of catchment moisture balance between rainstorms
to provide continuous simulation capability, the addition of
snowmelt and evapotranspiration, the simulation of backwater,
flow reversal and surcharging, a more accurate formulation for
storage and flow diversion facilities, the simulation of main
treatment plants, and the interfacing with more comprehensive
receiving water quality models for river basins, including
estuaries and deep lakes and impoundments.
The testing of seven models indicates that approximations in
mathematical formulations to simplify their solution do not neces-
sarily reduce computer processing times, as shown by comparisons
in the flow routing between models using different numerical
schemes for solving the kinematic and dynamic wave equations.
Solutions of more complex and comprehensive equations can appar-
ently be more efficient than attempts to approximate comprehensive
phenomena with simplified equations. The testing and review of
the models indicates also that the flow and water quality routing,
although complex for looping and converging and diverging branch
systems with special structures, are the best understood phenomena
and that the selection of a particular mathematical formulation
360
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and numerical solution technique is governed only by the prefer-
ence and needs of the model developer and user. Considerable
uncertainties exist, however, in the modeling of catchment phe-
nomena, both the flow and water quality of storm and dry-weather
runoff. The definition of adequate formulations for soil infil-
tration, the filling of depression storage, evapotranspiration,
groundwater seepage and soil moisture are extremely difficult
considering the heterogeneity of catchment land uses, geometry,
vegetation, and soils. The adequacy of catchment water quality
computations from catchment land use and runoff hais not been
sufficiently demonstrated. Although various models have shown
good agreement between measured and computed catchment runoff
water quality, the comparisons have been too limited to assign
confidence limits to predictions for catchments without measure-
ments .
Another problem is related to the calibration of the more com-
prehensive models, that is the determination of the best values
of empirical model coefficients. Traditionally, much hard work
is required to obtain a best fit between measured and computed
runoff (and water quality, if modeled), and generally the model
user must rely on his experience and intuition to adjust model
coefficients in an optimal manner. Automatic optimization
schemes would be needed to obtain optimal values of coefficients
and to indicate confidence limits to be expected in model appli-
cations for predictions.
In summary, the reviewed models provide very useful tools
to the engineer and planner for assessing, designing, planning
and controlling storm and combined sewerage systems. It is
extremely important, however, that the potential model user study
the formulations of the models, their limitations and approxima-
tions, if he is to use the models in an appropriate manner. It
is hoped that this review will aid him in assessing model capa-
bilities and limitations and thus to select models most suited
for his purposes.
361
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SECTION X
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ments dans les Reseaux d'Assainissement Urbains, Programme
Hydrologiques. Societe Grenobloise d1Etudes et
d1Applications Hydrauliques, Grenoble, France, October
1973c.
373
-------
SOGREAH. Mathematical Flow Simulation Model for Urban
Sewerage Systems, Caredas Program. Societe Grenobloise
d'Etudes et d'Applications Hydrauliques, Grenoble, France,
Partial Draft Report, April 1973. Translated from French
by David Vetrano, December 1973d.
SOGREAH. Looped Sewer Model. Societe Grenobloise
d1Etudes et d1Applications Hydrauliques, Grenoble,
France, Unpublished Manuscript, 1973e.
Stall, J. B., and M. L. Terstriep. Storm Sewer Design—
An Evaluation of the RRL Method. U.S. Environmental
Protection Agency Report EPA-R2-068, October 1972.
Surkan, A. J. HYDRA: Dynamic Model for Urban Hydrologic
Systems. University of Nebraska, Lincoln, Department
of Computer Science, to U.S. Office of Water Resources
Research, July 1973.
Surkan, A. J., and P. Kelton. Binary Tree Model Simula-
tion of the Behavior of Urban Hydrologic Systems. Inter-
national Journal of Systems Science Preprint, 1974.
Systems Control. Sewerplan. Systems Control, Inc.,
Palo Alto, California, Urban Systems Application Series
No. 2, Promotional Folder, December 1972.
Tang, W. H., L. W. Mays, and B. C. Yen. Optimal Risk-
Based Design of Storm Sewer Networks. Journal of the
Environmental Engineering Division, American Society
of Civil Engineers, 101(EE3) :381-398, Proc. Paper 11360,
June 1975.
Terstriep, M. L., and J. B. Stall. Urban Runoff by Road
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Division, American Society of Civil Engineers, 95(HY6):
1809-1834, Proc. Paper 6878, November 1969. Discussions:
96 (HY4)-.1100-1102, April 1970; 96 (HY7) : 1625-1631, July
1970; 96(HY9):1879-1880, September 1970. Closure:
97(HY4) .-574-579, April 1971.
Terstriep, M. L., and J. B. Stall. The Illinois Urban
Drainage Area Simulator. Illinois State Water Survey,
Bulletin 58, 1974.
Tholin, A. L., and C. J. Keifer. The Hydrology of
Urban Runoff. Journal of the Sanitary Engineering
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47-106, Proc. Paper 1984, March 1959. Discussions:
85(HY8):119, August 1959; 85(SA5):37-51, September
1959. Closure: 86(SA2):112, March 1960.
374
-------
Tucker, L. S. Oakdale Gaging Installation, Chicago—
Instrumentation and Data. American Society of Civil
Engineers, Urban Water Resources Research Program,
Technical Memorandum No. 2, August 1968.
Tucker, L. S. Control of Combined Sewer Overflows in
Minneapolis-St. Paul. Colorado State University, Fort
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Water Intelligance Systems Project Technical Report No.
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University of Cincinnati. Urban Runoff Characteristics.
U.S. Environmental Protection Agency Report 11024 DQU
10/70, October 1970.
University of Cincinnati. Urban Runoff Characteristics:
Volume I— Analytical Studies, Volume II—Field Data.
U.S. Environmental Protection Agency Draft Report 11024
DQU 10/72, October 1972.
U.S. Corps of Engineers. Snow Hydrology, Summary Report
of the Snow Investigations. North Pacific Division,
Portland, Oregon, June 1956.
U.S. Corps of Engineers. Runoff from Snowmelt.
Washington, D. C., Manual EM-1110-2-1406, January 1960.
U.S. Corps of Engineers. HEC-3, Reservoir System
Analysis. U.S. Army Engineer District, Sacramento,
California, Hydrologic Engineering Center Computer Pro-
gram 23-X6-L253, December 1968.
U.S. Corps of Engineers. HEC-1, Flood Hydrograph
Package. U.S. Army Engineer District, Sacramento,
California, Hydrologic Engineering Center Computer Pro-
gram' 23-X6-L270, March 1969.
U.S. Corps of Engineers. Urban Runoff: Storage, Treatment
and Overflow Model "STORM". U.S. Army, Davis, California
Hydrologic Engineering Center Computer Program 723-S8-
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Waddel, W. W., R. G. Baca, C. R. Cole, A. Brandstetter,
and K. D. Feigner. A Dynamic Hydraulic and Water Quality
Model for River Basins. Paper Presented at National
Water Resources Engineering Meeting, American Society of
Civil Engineers, Washington, D. C., January 1973.
375
-------
Walsh, S., and L. C. Brown. Least Cost Method for Sewer
Design. Journal of the Environmental Engineering Divi-
sion, American Society of Civil Engineers, 99(EE3):333-
345, Proc. Paper 9796, June 1973.
Watkins, L. H. The Design of Urban Sewer Systems.
Department of Scientific and Industrial Research, London,
England, Road Research Technical Paper 55, 1962.
Watt, W. E. QUURM - Queen's University Urban Runoff Model.
Queen's University at Kingston, Canada, Department of Civil
Engineering, Unpublished Manuscript, May 1975.
Williams, J. R., and R. W. Hann. HYMO: Problem-Oriented
Computer Language for Hydrologic Modeling. U.S. Agri-
cultural Research Service, Report ARS-S-9, Mary 1973.
Wood, E. F., B. M. Harley, and F. E. Perkins. Opera-
tional Characteristics of a Numerical Solution for the
Simulation of Open Channel Flow. Massachusetts Institute
of Technology, Cambridge, Ralph M. Parsons Laboratory
for Water Resources and Hydrodynamics, Report No. 150,
June 1972.
Yen, B. C. Methodologies for Flow Prediction in Urban
Storm Drainage Systems. University of Illinois, Urbana-
Champaign, Water Resources Center, Research Report No. 72,
September 1973a.
Yen, B. C. Open-Channel Flow Equations Revisited. Jour-
nal of the Engineering Mechanics Division, American
Society of Civil Engineers, 99(EMS) :979-1009, Proc.
Paper 10073, October 1973b.
Yevjevich, V., and A. H. Barnes. Flood Routing through
Storm Drains. Colorado State University, Fort Collins,
Hydrology Papers 43, 44, 45, and 46, November 1970.
Young, C. P., and J. Prudhoe. The Estimation of Flood
Flows From Natural Catchments. Department of the
Environment, Transport and Road Research Laboratory,
Crowthorne, Berkshire, England, TRRL Report LR 565,
1973.
376
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SECTION XI
GLOSSARY
Advective transport - mass transport resulting from average
velocity component of flow only, neglecting turbulent dis-
persion and molecular diffusion.
Backwater - the increased depth of water upstream from a
dam or obstruction in a stream channel due to the existence
of such obstruction, and the raising by it of the water
level some distance upstream.
Binary - the representation of a numerical quantity by use
of the two digits 0^ and !_.
Bit - abbreviation of binary digit: smallest possible unit
of computer storage.
BOD - biochemical oxygen demand, a standard test used in
assessing wastewater strength; the quantity of oxygen used
in the biological-chemical oxidation of organic matter in
a specified time under standard conditions.
Branch network - network with tree type structure without
closed loops.
Byte - a sequence of adjacent binary digits operated as a
unit.
Catchment - the area tributary to a lake, stream or drain;
also called drainage area, catchment area, watershed.
Closed conduit - any closed artificial or natural duct for
conveying liquids or possibly other fluids.
Coliform - bacteria found in intestines of,mammals,
therefore used as an indication of the pollution level of
a sample or body of water.
Combined sewer - a sewer receiving both intercepted surface
runoff and municipal sewage.
377
-------
Conservative pollutant,.- pollutant whose total mass does
not change in the system under consideration.
Core - computer storage area where binary data is represented
by the direction of the magnetic field in each unit of an
array of tiny donut-shaped rings (generally).
Crown - the ceiling, top, of highest portion of the internal
cross section of a closed conduit.
Dispersion - the mixing of a pollutant with a large volume
of water in a stream or other body of water.
Diversion structure - a structure that may be closed to
divert flow from the channel in which it is located to some
other channel; also called regulator.
DO - dissolved oxygen, the amount of gaseous oxygen dissolved
into a liquid sample.
Dry-weather flow - the flow of wastewater in a combined
sewer during dry weather; such flow consists mainly of waste-
water, with no stormwater included.
Dynamic regulator - a regulator which automatically makes
adjustments in control settings by responding to water
levels in the combined sewer or interceptor.
Dynamic wave - open channel flow defined as a function of
water depth, water surface slope, advective acceleration and
local acceleration.
Evapotranspiration - water withdrawn from soil by evaporation
and plant transpiration; also called consumptive use.
First flush - heavy load of material, previously settled in
sewers, which is washed along by the initial flow resulting
from a storm.
Fixed regulator - a regulator which has no moving parts.
Froude number - a numerical quantity used as an index to
characterize the type of flow in a hydraulic structure that
has the force of gravity (as the only force producing motion)
acting in conjunction with the resisting force of inertia;
it is equal to the square of a characteristic velocity (the
mean, surface, or maximum velocity) of the system, divided
by the product of a characteristic linear dimension, such as
diameter or depth, and the gravity constant or acceleration
due to gravity - all expressed in consistent units so that
the combinations will be dimensionless; the number is used
in open-channel flow studies or in cases in which the free
surface plays an essential role in influencing motion.
378
-------
Hydrograph - a graph showing the discharge of water with
respect to time for a given point for open-channel or closed
conduit.
Hyetograph - a graph showing average rainfall, rainfall
intensities or volume over specified areas with respect to
time.
Infiltration - the entrance of water into the soil or other
porous material through the interstices or pores of a soil
or other porous medium; the water entering a sewer system
and service connections from the ground, through such means
as, but no limited to, defective pipes, pipe joints, connec-
tions, or manhole walls. Infiltration does not include,
and is distinguished from, inflow.
Inflow - water discharged into a sewer system and service
connections from such sources as roof gutters, cellars,
yard and area drains, foundation drains, cooling water
discharges, drains from springs and swampy areas, manhole
covers, cross-connections from storm sewers and combined
sewers, catchbasins, stormwaters, surface waters, street
washwaters or drainages.
Inline storage or treatment - storage or treatment of waste-
water within the sewer network.
Interceptor sewer - a sewer that generally receives most
dry-weather flow and a portion of the combined flow from
a number of transverse combined sewers and conveys such
waters to a point for treatment.
Interface - a common boundary between parts of a computer
system.
Invert - the floor, bottom or lowest portion of the internal
cross section of a closed conduit; used particularly with
reference to aqueducts, sewers, tunnels, and drains.
Inverted siphon - a pipeline crossing a depression or
passing under a structure and having a reversal in grade
on a portion of the line, thus creating a V- or U-shaped
section of conduit; the line is under positive pressure
from inlet to outlet and should not be confused with a
siphon; also called depressed sewer.
Kinematic wave - open-channel flow defined as a function of
water depth alone, neglecting the effects of the water
surface slope, advective and local acceleration on wave
celerity.
379
-------
Leaping weir - a leaping weir is formed by a gap in the
invert of a sewer; dry-weather flow falls through the gap to
an intercepter, high flow with increased velocity leaps the
gap and continues in the sewer, generally to an overflow
outlet.
Looped network - channel and conduit network containing
closed loops.
- chemical symbol for ammonia and nitrate in
solution1.
Non-conservative pollutant - a pollutant whose total mass in
the system under consideration changes as a result of decay
or chemical-biological reactions.
Overflow storage or treatment - storage or treatment of
overflow from high flow periods outside the sewer network.
Overland flow - the flow of water over the ground surface
before it becomes channelized.
Perpendicular weir - a regulator whose weir crest is
perpendicular to the direction of flow.
Plug flow - the passage of liquid through a chamber such
that all increments of liquid move only in the direction
of flow and at equal velocity.
POT"* - chemical symbol for phosphate in solution.
Pressure flow - full pipe flow with energy gradient or
hydraulic gradeline above conduit crown.
Rainfall excess - that part of a rain of a given storm
which falls at intensities exceeding the infiltration
capacity and is thus available for direct runoff.
Rational method - a method of estimating the runoff in a
drainage basin at a specific point and time by means of
the rational runoff formula; for each drainage area, the
rainfall rate under a stated intensity-duration'relation-
ship, the fraction that will appear as runoff, and the
basin area above the specific point are estimated; their
product is the flow; this method is used to estimate
storm runoff in urban areas and flood flows in streams.
380
-------
Real-time control - control of a system by using computers
and timing such that the speed of response to the input
information is fast enough to effectively influence the
performance of that system; in a combined sewerage system,
regulation of wastewater flows during rainstorms by changing
regulator gate openings and weir heights to minimize over-
flows .
Regulator - a structure which controls the amount of sewage
entering an interceptor by storing in a trunk line or
diverting some portion of the flow to an outfall.
Retention - the prevention of runoff from entering the sewer
system by storing on a surface area or in a storage basin.
Routing - computing the downstream outflow hydrograph of an
open channel from known values of upstream inflow.
Sanitary sewer - a sewer that carries liquid and water-
carried wastes from residences, commercial buildings, indus-
trial plants, and institutions, together with relatively
low quantities of ground, storm, and surface waters that
are not admitted intentionally.
Scour - the action of a flowing liquid as it lifts and
carries away the material on the sides or bottom of a water-
way, conduit, or pipeline.
Sedimentation - the process of subsidence and deposition of
suspended matter carried by water, wastewater, or other
liquids, by gravity; it is usually accomplished by reducing
the velocity of the liquid below the point at which it can
transport the suspended material; also called settling.
Settleable solids - That matter in wastewater which will not
stay in suspension during a preselected settling period, such
as one hour, but either settles to the bottom or floats to
the top; in the Imhoff cone test, the volume of matter that
settles to the bottom of the cone in one hour.
Sewer - a pipe or conduit generally closed, but normally not
flowing full, for carrying sewage or other waste liquids.
Sewerage - system of piping, with appurtenances, for
collecting and conveying wastewaters from source to discharge.
381
-------
Sidespill weir - a regulator which is essentially a long
slot cut into the side of a sewer; normal dry-weather flow
continues through the sewer while the increased depth during
a storm will allow excessive flows to exit through the slot
to some alternate point as an overflow.
Stage - the elevation of a water surface above its minimum
or above or below an established low-water plane or datum
of reference.
Static regulator - a regulator which is either fixed or can
be adjusted only by manual actions of a human operator.
Storm sewer - a sewer that carries intercepted surface
runoff, street wash and other surface drainage, but
excludes domestic sewage and industrial wastes.
Surface runoff - precipitation that falls onto the surfaces
of roofs, streets, ground, etc., and is not absorbed or
retained by that surface, thereby collecting and running
off.
Surcharge - the flow condition occurring in closed conduits
when the hydraulic grade line is, above the conduit crown;
or the transition from open channel to pressure flow.
Suspended solids - Solids that either float on the surface
of, or are in suspension in, water, wastewater, or other
liquids, and which are largely removable by laboratory
filtering; the quantity of material removed from wastewater
in a laboratory test, as prescribed in "Standard Methods
for the Examination of Water and Wastewater" and referred
to as nonfilterable residue.
Synthetic unit hydrograph - a unit hydrograph developed
for an ungaged drainage area, based on known physical
characteristics of the basin.
Thiessen polygon - the points of location of raingages on a
map are joined by straight lines and their perpendicular
bisector drawn; the polygon formed around each raingage
station by these perpendiculars is called, after its
originator, a Thiessen polygon; the drainage area within a
polygon is assumed to receive the same precipitation as the
raingage at the center of the polygon.
Trunk sewer - a sewer that receives many tributary branches
and serves a large territory.
382
-------
Unit hydrograph - the hydrograph of storm runoff at a given
point on a given stream which will result from an isolated
rainfall excess of unit duration occurring over the
contributing drainage area and resulting in a unit of
runoff; also called unitgraph.
Unit treatment process - component of wastewater treatment
facility, e.g., screens, trickling filter, etc.
Wastewater - the spent water of a community, including
domestic,industrial and commercial water carrying solids
plus storm or other water sources; replacing the term
sewage.
Wave - a rise in open-channel flow to a crest in response
to runoff generated by precipitation and its subsequent
recession after the cessation of precipitation; the crest
moves downstream at a velocity (wave celerity) different
from the velocity of flow.
Wave ce1 e rity - the velocity of propagation of a wave
through a fluid medium relative to the undisturbed velocity
of the fluid through which the disturbance is propagated.
Word - a set of 16 or more bits stored and transferred as
a unit by the computer.
383
-------
SECTION XII
APPENDICES
Page
A List of Sources of Computer Programs 385
B English to Metric Units Conversion Table 393
C Mathematical Formulations of Tested Models 394
D Mathematical Symbols for Tested Models 463
E Additional Model Test Results 475
F Selected Computer Input and Output 509 and Vol. 2
384
-------
APPENDIX A
LIST OF SOURCES OF COMPUTER PROGRAMS
Battelle Urban Wastewater Management Model
Dr. Albin Brandstetter
Research Associate
Environmental Management Section
Battelle-Northwest
P. 0. Box 999
Richland, Washington 99352
Telephone (509) 946-2412
For IBM version:
Mr. David J. Anderson
Vice President
Watermation, Inc.
2304 University Avenue
St. Paul, Minnesota 55114
Telephone (216) 687-0220
Mr. Kenneth A. Pew
Chief, Control Systems Group
Department of Public Utilities
City of Cleveland
3090 Broadway Avenue
Cleveland, Ohio 44115
Telephone (216) 641-6000
British Road Research Laboratory Model
Mr. Harry C. Torno, P. E.
Staff Engineer
Environmental Protection Agency
Office of Research and Development
Municipal Pollution Control Division
Washington, D. C. 20460
Telephone (202) 426-8553
385
-------
Chicago Flow Simulation Model
Mr. Richard Lanyon, P. E.
Supervising Engineer of Flood Control
Mr. Frank Kudrna
Engineer of Flood Control
Metropolitan Sanitary District of Greater Chicago
100 East Erie Street
Chicago, Illinois 60611
Telephone (312) 751-5600
Chicago Hydrograph Method and Chicago Runoff and Pollution Model
Mr. Louis Koncza
Acting Chief Engineer
City of Chicago Department of Public Works
Bureau of Engineering
320 North Clark Street
Chicago, Illinois 60610
Telephone (312) 744-3544
CH2M-Hill Wastewater Collection System Analysis Model
Dr. Allen L. Davis
CH2M-Hill
1600 S. W. Western Boulevard
P. 0. Box 428
Corvallis, Oregon 97330
Telephone (503) 752-4271
Colorado State University Urban Runoff Modeling
Hydrologic and hydraulic modeling:
Dr. V. Yevjevich
Professor
Telephone (303) 491-8651
Dr. A. H. Barnes
Associate Professor
Telephone (303) 491-6767 or (303) 491-8640
Department of Civil Engineering
Colorado State University
Fort Collins, Colorado 80521
386
-------
Real-time control investigations:
Dr. Neil S. Grigg
Associate Professor
Telephone (303) 491-8649
Department of Civil Engineering
Colorado State University
Fort Collins, Colorado 80521
Corps of Engineers STORM Model
Mr. Jesse Abbott
Research Hydraulic Engineer
The Hydraulic Engineering Center
Sacramento District
Corps of Engineers
609 Second Street
Davis, California 95616
Telephone (916) 449-2329 or (916) 449-3286
Dorsch Consult Hydrograph-Volume Method and Quantity-Quality
Simulation Program
Mr. Helmut R. Dorsch
Managing Partner
Dorsch Consult
Ingenieurgesellschaft GmbH
D-8000 Munchen 21
Postfach 210243
Elsenheimerstrasse 63
Germany
Telephone (089) 5797-1
Mr. Fritz Mevius, P. E.
Chief Engineer
Dorsch Consult, Ltd.
Consulting Engineers
45 Richmond St. West
Suite 1203
Toronto 110, Ontario
Canada M5H 1Z2
Telephone (416) 368-7030 or (416) 368-7039
387
-------
Environmental Protection Agency Stormwater Management Model
Mr. Harry C. Torno, P. E.
Staff Engineer
Environmental Protection Agency
Office of Research and Development
Municipal Pollution Control Division
Washington, D. C. 20460
Telephone (202) 426-8553
Dr. Wayne C. Huber
Associate Professor
Department of Environmental Engineering
University of Florida
Gainesville, Florida
Telephone (904) 392-0846
Hydrocomp Simulation Program
Dr. Norman Crawford
President
Hydrocomp International, Inc.
1502 Page Mill Road
Palo Alto, California 90430
Telephone (415) 493-5522
Illinois State Water Survey Urban Drainage Simulator
Mr. John B. Stall
Head, Hydrology Section
Telephone (217) 333-2210
Mr. Michael L. Terstriep
Associate Engineer
Telephone (217) 333-4959
Illinois State Water Survey
Box 232
Urbana, Illinois 61801
388
-------
Massachusetts Institute of Technology Urban Watershed Model
Dr. Brendan M. Harley
President
Resource Analysis, Inc.
1050 Massachusetts Avenue
Cambridge, Massachusetts 02138
Telephone (617) 354-1922
Minneapolis-St. Paul Urban Runoff Model
Mr. David J. Anderson
Vice President
Watermation, Inc.
2304 University Avenue
St. Paul, Minnesota 55114
Telephone (216) 687-0220
Norwegian Institute for Water Research Sewerage System Models
Mr. Oddvar G. Lindholm
Norwegian Institute for Water Research
Gaustadalleen 25
P. 0. Box 260 Blindern
Oslo 3
Norway
Telephone 23 52 80 or 46 69 60
Queen's University Urban Runoff Model
Dr. W. E. Watt
Professor
Department of Civil Engineering
Ellis Hall
Queen's University
Kingston
Canada K7L 3N6
Telephone (613) 547-6184
389
-------
Seattle Computer Augmented Treatment and Disposal System
Mr. Curtis P. Leiser
Manager of Computer Services
Municipality of Metropolitan Seattle
410 West Harrison Street
Seattle, Washington 98199
Telephone (206) 284-5100
Mr. Stuart M. Alexander
Associate
R. W. Beck and Associates
200 Tower Building
Seattle, Washington 98102
Telephone (206) 622-5000
SOGREAH Looped Sewer Model
Mr. G. Chevereau or Dr. Jean Cunge
SOGREAH Ingenieurs Conseils
BP 172
Centre De Tri/38042
Grenoble Cedrex
France
Telephone (76) 09.80.22
SOGREAH, Inc.
375 Park Avenue
New York, New York 10022
Telephone (212) 758-8333
Lasalle Hydraulic Laboratory
0250 St. Patrick Street
Lasalle, Province of Quebec
Canada
Telephone (514) 366-2970 or (514) 366-2464
University of Cincinnati Urban Runoff Model
Dr. Constantine N. Papadakis
Hydraulic Engineer
Department of Civil Engineering
University of Michigan
Ann Arbor, Michigan 48104
Telephone (313) 764-4280 or (313) 764-4303
390
-------
Dr. Herbert C. Preul
Professor
University of Cincinnati
Department of Civil and Environmental Engineering
Cincinnati, Ohio 45221 l
Telephone (513) 475-2634 or (513) 475-3648
University of Illinois Storm Sewer System Simulation Model
Dr. Yen Te Chow
Professor
Telephone (217) 333-0107
Dr . Ben C. Yen
Associate Professor
Telephone (217) 333-4934
Department of Civil Engineering
University of Illinois
Urbana, Illinois 61801
University of Massachusetts Combined Sewer Control Simulation
Model
Dr. Donald D. Adrian
Professor
Department of Civil Engineering
University of Massachusetts
Amherst, Massachusetts 01002
Telephone (413) 545-2508
University of Nebraska Urban Hydrologic Simulator
Dr. Alvin J. Surkan
Department of Computer Science
University of Nebraska
Lincoln, Nebraska 68508
Water Resources Engineers Storm Water Management Model
Dr. Larry Roesner
Principal Engineer
Water Resources Engineers, Inc.
710 South Broadway
Walnut Creek, California 94596
Telephone (415) 933-4500
391
-------
Mr. Harold Coffee
Civil Engineer
Department of Public Works
City of San Francisco
770 Golden Gate Avenue
San Francisco, California 94102
Telephone (415) 558-2131
Mr. T. Clark Lyons
F. H. Kocks KG
Hiiro Hamburg
D-2000 Hamburg 76
Pappelallee 28
Germany
Telephone (0411) 20 69 42
Wilsey and Ham Urban Watershed Model
Mr. James H. Iverson
Director of Systems Analysis
Wilsey and Kara
1035 East Hillsdale Boulevard
Foster City, California 94404
Telephone (415) 349-2151
392
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APPENDIX B
ENGLISH TO METRIC UNITS CONVERSION TABLE
English unit
acre
acre-foot
cubic foot
cubic feet per second
cubic inch
cubic yard
degree Fahrenheit
feet per minute
feet per second
foot (feet)
gallon (s) (U.S. liquid)
gallons per minute
inch (es)
inches per hour
million gallons per day
mile
miles per hour
pound (s)
square foot
square inch
square mile
square yard
ton (short)
yard
Abbr.
acre
acre-ft
ft3
cfs
in3
yd3
•F
fpm
fps
ft
gal.
gpm
in.
in./hr
mgd
mi
mph
Ib
ft2
in2
mi2
yd2
ton
yd
Multiplier
0.4047
1,233.5
28.32
0.02832
16.39
0.7646
(°P-32)/1.8
0.005080
0.3048
0.3048
3.785
0.06309
2.540
2.540
0.04381
1.609
1.609
0.4536
0.09290
6.452
2.590
0.8361
0.9072
0.9144
Abbr.
ha
m3
1
m3/sec
cm3
m3
«C
m/sec
m/sec
m
1
I/sec
cm
cm/hr
mVsec
km
km/hr
kg
m2
cm2
km2
m2
metric ton
m
Metric unit
hectare
cubic meter
liter
cubic meters per second
cubic centimeter
cubic meter
degree Celsius
meters per second
meters per second
meter (s)
liter (s)
liters per second
centimeter
centimeters per hour
cubic meters per second
kilometer
kilometers per hour
kilogram
square meter
square centimeter
square kilometer
square meter
metric ton
meter
CONVERSIONS OF CONCENTRATION X DISCHARGE TO MASS FLOW RATE
Define:
C = pollutant concentration
Q = wastewater discharge
M = pollutant mass flow rate
Then :
Mtlb/hrJ = 0.224 741 x C[mg/l] x Q[cfs]
M[kg/hr] = 0.1Q1 941 x C[mg/l] x Q[cfs]
M[lb/hr] = 7.936 641 x C[mg/l] x Q[m3/sec]
M[kg/hr] = 3.600 000 x C[mg/l] x Q[m3/sec]
393
-------
APPENDIX C
MATHEMATICAL FORMULATIONS OF TESTED MODELS
CONTENTS
Page
Introduction 397
Battelle Urban Wastewater Management Model 397
Summary 397
Watershed Representation 398
Losses on Impervious Areas 398
Losses on Pervious Areas 399
Stormwater Runoff 401
Dry-Weather Runoff 402
Combined Catchment Runoff 402
Conduit Flow Routing 404
Diversion Structures 407
Storage Facilities 411
Water Quality 411
Chicago Flow Simulation Program 412
Summary 412
Watershed Representation 412
Snowmelt 413
Runoff from Pervious Areas of Nonsewered
Catchments 414
Runoff from Impervious Areas of Nonsewered
Catchments 416
394
-------
CONTENTS (Continued)
Paqe
Runoff from Pervious and Impervious Areas of
Sewered Catchments
Channel and Conduit Flow Routing .......... 417
Storage Facilities ................. 419
Dorsch Consult Hydrograph-Volume Method ......... 419
Summary ...................... 419
Catchment Surface Runoff .............. 420
Channel and Conduit Flow Routing .......... 421
Environmental Protection Agency Stormwater Management
Model .......................... 423
Summary ...................... 423
Watershed Representation .............. 424
Stormwater Runoff ................. 424
Gutter Flows .................... 426
Dry-Weather Runoff ................. 427
Infiltration into Sewers .............. 428
Channel and Conduit Flow Routing .......... 429
Diversion Structures ................ 433
Pumping Stations .................. 434
Storage Facilities ................. 434
Water Quality ................... 435
Massachusetts Institute of Technology Urban Watershed
Model ....................... ... 442
Summary ...................... 442
395
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CONTENTS (Continued)
Page
Watershed Representation 442
Stormwater Runoff 442
Conduit and Open Channel Flow Routing 444
SOGREAH Looped Sewer Model 447
Summary 447
Catchment Runoff 447
Conduit and Open Channel Flow Routing 450
Water Resources Engineers Stormwater Management
Model 451
Summary 451
Watershed Representation 451
Catchment Runoff 452
Conduit and Open Channel Flow Routing 453
Flow Control Devices 457
Water Quality 459
396
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INTRODUCTION
Brief descriptions and the principal equations are presented
for each of the seven models which were tested with hypothet-
ical and real catchment data. The descriptions are intended
primarily as a quick reference to the main equations and
assumptions of each model, so the reader will not have to
wade through a maze of theoretical developments and derivations
to gain a basic understanding of the models' capabilities.
The original model documentation should be consulted, however,
for detailed derivations and justifications of model assump-
tions.
Equations are given for the catchment and sewerage system flow
and water quality computations if available in model docu-
ments. The inclusion of equations for other model features,
such as receiving water flow and quality simulation, and real-
time and design optimization was beyond the scope of this
s tudy.
Complete mathematical formulations were not available for some
proprietary models. Consequently only the available equations
are presented, and the potential user is advised to contact
the model developer for additional details.
Consistent nomenclature is used for the equations of all models
to facilitate model comparisons. The selected mathematical
symbols and their definitions are listed in Appendix D. They
are also defined following their first occurrence in each model
description.
BATTELLE URBAN WASTEWATER MANAGEMENT MODEL
Summary
The Battelle Urban Wastewater Management Model (Brandstetter
et al., 1973) is intended primarily for the simulation of
major sewer system components, such as trunk and interceptor
sewers, regulators, overflow storage facilities, and treat-
ment plants. It provides a means of evaluating the time-
varying performance of a planned or existing sewerage system
under a variety of rainfall conditions, considering both the
time and spatial variations of rainfall rates without requir-
ing the simulation of every small sewer, manhole, etc., in the
system. Stormwater and sanitary runoff and quality of major
catchment areas are computed using hydrologic lumping tech-
niques to arrive at hydrographs and quality graphs at major
regulators and at junctions of major trunks and interceptors.
The runoff is then routed through trunk and interceptor
sewers to the treatment plant. The model is limited to the
simulation of single runoff events.
397
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The model can simulate up to seven conservative wastewater
quality parameters. Quality reactions, with the exception of
changes at treatment facilities, are not modeled. The model
determines the required diversion at control regulators during
real-time rainstorm events in order to minimize wastewater dis-
charges to receiving waters. The model can also be used for
design and planning studies. It computes sizes and costs of
structural sewer system modifications (such as sewers, storage
and treatment facilities) which will result in the least-cost
combination of alternatives for improving system performance.
Watershed Representation
Catchments are represented by their areas and the length of the
main drainage channel; catchment shape does not enter the
computations. Overland flow and flow routing in gutters and
minor channels are lumped into a single computation. The
model includes provisions to compute runoff from only major
catchments and to increase the computed runoff in proportion
to drainage area to account for runoff from adjacent small
catchments not modeled separately. Cumulative rainfall can be
provided at irregular time intervals for several raingages.
Weighted rainfall intensities are computed for each subcatch-
ment by the Thiessen polygon method.
Losses on Impervious Areas
Rainfall losses on impervious areas are assumed to depend on
the rainfall, the antecedent moisture condition, the accumu-
lated losses, and three coefficients. The accumulated loss
represents the amount of moisture retained on the impervious
surfaces and intercepted by trees. The first coefficient
represents the accumulated loss which must be reached before
any runoff will occur. Once the initial loss has been satis-
fied, the additional loss at each time step is assumed to
decrease exponentially. The accumulated loss until the begin-
ning of a time step is given by
V. at beginning of rain
Vi = * (1)
V. + f. thereafter
i i
where
V. = antecedent moisture condition, in.
f. = rainfall loss on impervious area during
1 interval At, in.
i ii
V.,V. = accumulated loss at beginning and end of time
1 1 interval At, in.
398
-------
The loss during the time interval At is then computed from
(2)
rt if v! < h.
fi = '
r a exp[- b v^ if V. > h.
where
h. = minimum accumulated loss which must be reached
before runoff will occur, in.
a,b = impervious loss rate coefficients
r = rainfall during time interval At, in.
The rainfall excess from the impervious area during the time
interval At is then given by
r. = rt - f± (3)
where
r. = rainfall excess on impervious areas during time
1 interval At, in.
Losses on Pervious Areas
Rainfall losses from the pervious areas are assumed to depend
on the rainfall, the antecedent moisture condition, the accu-
mulated losses, the infiltration rate under dry conditions,
the equilibrium infiltration rate, the total available mois-
ture storage capacity in the soil, and a rate coefficient. As
before, an initial loss must be satisfied before any runoff
can occur. The accumulated loss until the beginning of a time
step is given by
P (4)
V^ at beginning of rain
V =\
P
•V + f thereafter
P P
where
V = antecedent moisture condition, in.
P
f = rainfall loss on pervious area during time
p interval At, in.
i n
V ,V = accumulated loss at beginning and end of time
" interval At, in.
399
-------
The loss is then determined from
f =.
P
^ if V. < h or r. > f
t i - p t
f if V. > h and r > f
i p t
(5)
where
h =- minimum accumulated loss which must be satisfied
p before runoff will occur, in.
f = potential infiltration on pervious area during
time interval At, in.
The potential loss is approximated by the Holtan infiltration
equation as modified by Huggins and Monke:
f =
or
s - V
(f _ f ) E I
Uo V \ s / J"60
if v > s
e 60 p -
< s
(6)
where
f = equilibrium infiltration rate, in./hr
f = infiltration rate under dry conditions, in./hr
a = pervious infiltration rate coefficient
s = total available soil moisture storage capacity, in.
At = constant time interval, minutes
The rainfall excess from the pervious area during the time
interval At is then given by
where
r = r. - f
p t p
r = rainfall excess on pervious area during time
P interval At, in.
(7)
400
-------
Stormwater Runoff
The combined rainfall excess of the catchment from both per-
vious and impervious areas during the time interval At is
given by
rp (8)
where
r = rainfall excess on catchment during time
interval At, in.
p. = fraction of impervious area of catchment
drainage area, percent/100
Storm runoff is computed for each modeled catchment using
the unit-hydrograph method. Triangular unit-hydrographs are
derived from catchment characteristics (including catchment
length, average catchment slope, and type of soil and soil
cover) using the formulas of the U.S. Soil Conservation
Service:
0.8f/ \ )
L llOOO/c - 10) + 1
t = — ^ TT-T- -
31.67 S°'5
c
0.7
(9)
t, = 2.67 t (10)
b p
U - -1
P " tb (11)
where
c = SCS soil cover complex number
L = Length of main runoff channel, ft
C
S = average slope of catchment, percent
t = time to peak of unit hydrograph, minutes
t, = base time of unit hydrograph, minutes
-1
U = peak ordinate of unit hydrograph, minutes
401
-------
The rainfall excess is then convoluted with the unit hydro
graph to derive the stormwater runoff hydrograph:
m+1
Uj
At
where
m = length of memory of catchment (mAt = t, )
b
qk = catchment stormwater runoff during k-th time
interval, in.
U. = unit hydrograph ordinate, minutes'
rk-i+l = rainfa11 excess during (k-j+l)-th time
J interval, in.
The total stormwater runoff from a catchment at the end of
the k-th time interval is then
qs = 1.008
= 60.48
(13)
where
A = drainage area of catchment, acres
(_.
q = catchment stormwater runoff, cfs
o
Dry-Weather Runoff
Dry-weather flow rates are estimated from measurements in the
modeled catchments or similar areas. Average dry-weather flows
for each catchment are multiplied by hourly, daily, and sea-
sonal factors to obtain hourly dry-weather flow rates for a
given day of the week and season. The average flow and ad-
justment factors are specified by input data for each catch-
ment. The hourly values are then interpolated linearly to
obtain dry-weather flow rates at the selected time intervals
corresponding to the stormwater runoff hydrographs.
Combined Catchment Runoff
The storm runoff and dry-weather flow hydrographs are then
added to obtain the combined catchment runoff hydrograph:
402
-------
qc = qd + qg (14)
where
q, = dry-weather runoff from catchment, cfs
q = combined dry-weather and stormwater runoff
from catchment, cfs
This combined hydrograph is then reduced by the overflows
from small upstream regulators not modeled separately. The
mathematical formulation is based on the clipping action of
regulators on the peaks of the hydrograph:
qc =
qc if qc < a qd
(15)
aD + 8 (q -a q.q) if q > oc q,
O U C- U
where
a = regulator clipping factor
3 = overflow reduction factor, < 1
q, = average dry-weather runoff rate, cfs
*
q = combined dry-weather and stormwater runoff from
0 catchment, reduced by upstream overflows not
modeled separately, cfs
The overflow reduction factor is approximated by
n
AC - £ A'
B = — jpi—- (16)
c
where
n = number of upstream regulators not modeled
separately
A. = combined drainage areas tributary to regulators
-* not modeled separately, acres
A = drainage area of modeled catchment, acres
403
-------
To reduce data requirements and computational effort, only
major catchments are modeled in the Detail described above.
The runoff from smaller catchments is lumped into the runoff
from the adjacent major catchments in proportion to their
drainage areas:
Qc = k q* (17)
where
k = catchment lumping factor
Q = combined dry-weather and stormwater runoff
from catchment, increased by runoff from
adjacent catchments not modeled separately, cfs
The lumping factor is approximated by
A + / A.
c -
k =
where
n = number of adjacent catchments not modeled
separately
A. = drainage areas of adjacent catchments not
-1 modeled separately, acres
A = drainage area of modeled catchment, acres
C
Conduit Flow Routing
The Battelle model is formulated for flow routing in circular
closed conduits only. The flow routing uses a characteristic
solution of the kinematic wave equation, which is defined by
the
continuity equation:
SQ 6A -. ( -i n \
•7-=- + 7— = o ij.yj
and Manning's equation:
Q . 1^49 A R2/3 1/2 = 1,49 A5/3 -2/3 gl/2 (2Q)
w n n
404
-------
where
Q = discharge, cfs
2
A = cross-sectional area, ft
x = distance, ft
t = time, sec
n = Manning's roughness coefficient
P = wetted perimeter, ft
R = A/P = hydraulic radius, ft
S = invert slope, ft/ft
The following geometric relationships for circular pipes are
introduced into the kinematic wave equation:
A = e
Y = I (1- cos |) (22)
cos £=!- 2Y/D (23)
2
9=2 cos'1 (1- 2 ) (24)
P = e (25)
R = = (1- _) (26)
where
Y = depth of water, ft
9 = angle of pipe center with water surface,
radians, 0 < 9 < 2ir
d = diameter, ft
This results in the following formulation of the kinematic
wave equation for circular pipes:
405
-------
continuity equation:
where
c = sl/2 D2/3
F(8) = (1- Sig-1)2/3 (3-5 cos 6 + 2
and Manning's equation:
Q = c' 6 (1- sin_e}5/3 (3Q)
where
c. = S D8/3
The characteristic form of Equation (27) is
•|£ = c F(6) (32)
This equation is then solved by finite differences in the
form
At = c-fw (33)
where
At = travel time of kinematic wave through conduit
reach, sec
Ax = length of conduit reach, ft
The flow routing for a pipe reach starts with the upstream
inflow hydrograph, specified at constant time intervals.
Assuming uniform flow conditions, the angle 6 is computed by
the method of bisection from Equation 30. Equation 33 then
gives the kinematic wave travel time to the downstream end
of the pipe reach. Since this results in a hydrograph speci-
fied at irregular time intervals, it is interpolated linearly
at constant time intervals to obtain the inflow hydrograph
for the next downstream pipe reach.
406
-------
This formulation neglects downstream flow control and cannot
compute backwater, flow reversal, and surcharging. Warning
statements are printed by the computer program if the computed
flow depth exceeds 93 percent of the diameter.
Diversion Structures
The diversion equations are based on standard weir and ori-
fice discharge equations and neglect downstream effects on
the regulator discharge.
The discharge over a weir is assumed to follow the relation-
ship
Qw= i
O if Y < h
* w a (34)
c L (Y-h ) if Y > h
WWW W
where
Q = weir discharge, cfs
c = weir discharge coefficient
w
Y = depth of flow above sewer invert upstream
of weir, ft
h = height of weir crest above sewer invert, ft
Vv
L = length of weir crest, ft
vt
a = weir equation exponent
The discharge through an orifice is assumed to follow the
relationship
0 if Y < h
" ° (35)
where
CoAo 29-h/2-h) if Y
Q = orifice discharge, cfs
2
A = area of flow through the orifice, ft
407
-------
c = orifice discharge coefficient
2
g = gravitational acceleration, 32.2 ft/sec
Y = depth of flow above sewer invert upstream of
orifice, ft
h = height of orifice invert above sewer invert, ft
height of orifice opening if orifice submerged, ft
h =•
" depth of flow above orifice invert if orifice
not submerged, ft
For a diversion structure with an orifice dry-weather outlet
immediately upstream of a combined overflow weir, Equations
34 and 35 are solved simultaneously with the equation of
continuity:
Q = QQ + Qw (36)
where
Q = inflow rate to the diversion structure, cfs
Equations 34 to 36 have the three unknown variables: Y, Q ,
and Q . Elimination of H and Q results in the diversion °
equation
Q2 h \a
Q - Q - c L W0 0 + 7^- + h -hi =0 (37)
0 W W2g cV 2 o w 1
\ o o /
for Y > h .
w
This equation can be solved for Q in terms of the known
inflow Q. Since the equation canSot be solved explicitly
for Q , it is determined in the computer program by the
metho9 of bisection.
Three types of orifice shapes are modeled at present:
1. rectangular (a rectangular gate sliding over a
rectangular opening),
2. segment of a circle (a rectangular gate sliding
over a circular opening), and
408
-------
3. crescent (a circular gate sliding over a circular
opening).
The area of the orifice A is determined by the orifice opening
if the depth of water is °deeper than the top of the orifice,
or by the depth of water itself if it is below the top of the
orifice.
The area of the rectangular opening is simply
where
A = W h (38)
° o g
W = width of rectangular orifice, ft
The area of a segment of a circle is
D2
A = -§• (0 - sin 9) (39)
O o
where
D = diameter of circular orifice, ft
o
® = angle formed by center of circle and chord
formed by top of gate or water surface, radians,
0 < 6 < 27r
The angle 6 is computed from
0 if h < 0
2ir if h > D (40)
g o
h
4 arctan p _? otherwise
This relationship is valid for all values of h between 0
and D (or all angles of 6 between 0 and 2ir) . "
The leaping weir consists of an opening in tha invert of the
combined sewer. Intercepted flow drops through the opening
to enter the dry-weather outlet. At high flow rates, a por-
tion of the flow leaps across the opening and continues to
the stormwater outlet. At present it is assumed that no
409
-------
overflow occurs until the flow in the pipe reaches the capacity
of the sanitary outlet as given by the orifice equation
Qmin = co Ao
where
Y = normal depth of flow in combined sewer, ft
h = depth of invert of sanitary outlet below invert
0 of combined sewer, ft
Q . = minimum combined flow rate for overflow to occur,
and the remaining variables are defined as before.
The normal depth Y for the combined inflow Q to the leaping
weir is computed from Manning's equation as described else-
where. A is taken as the smaller of the areas of the sani-
tary outlet or combined invert opening.
The intercepted flow is then computed from
Q if Q < Q min
(42)
Qw=<
- Qmin if Q > Qmin
where
Q = intercepted flow through sanitary outlet, cfs
From continuity,
where
QQ = Q - Qw (43)
Q = combined overflow, cfs
This is a very crude approximation of the leaping weir flow
diversion and probably results in overestimates of the inter-
cepted flows. It neglects the velocity of approach of the
combined flow and the geometry of the opening in the combined
sewer invert.
410
-------
Control regulators encompass all types of diversion struc-
tures which have controllable gates and/or weirs that can be
adjusted continuously or at periodic intervals to divert the
incoming combined flow to the diversion structure. The per-
cent diversion, that is the fraction of the inflow that is to
be intercepted by the sanitary sewer, is determined by the
control optimization. The real-time control optimization
determines the amount of flow division at each control regu-
lator for each time interval, so that the total mass of pol-
lutant overflow from the entire sewerage system during a
storm is minimized.
Storage Facilities
A storage facility can be specified anywhere on the overflow
outlet of a diversion structure. In-line storage facilities
are not simulated. Only the inflow and cumulative storage
volume are computed. The real-time control optimization
determines the optimal allocation of available storage space
during the inflow period of a rainstorm but neglects the
optimal emptying of the facility during or after the rain-
storm.
Water Quality
Up to seven arbitrary conservative water quality constituents
can be simulated. The quality of the dry-weather flow is
specified by input data defining average concentrations and
24 hourly, seven daily, and up to six seasonal adjustment
factors. The average value is multiplied by the hourly, daily,
and seasonal adjustment factors to obtain a value for a given
hour of a weekday and season, and then interpolated linearly
between the values at the beginning and end of the hour to
obtain the concentration for a given time step.
The stormwater quality is computed from the storm runoff by
the linear regression equation
M =
O for q < O
~
3 ~ (44)
Kl + K2qs + K3Vs f°r
where
K,,K9,K_ = empirical coefficients
-L & j
q = stormwater runoff rate per unit catchment
area at time t, cfs/acre
411
-------
vs -/V(t)dt
= cumulative volume of storm runoff per unit area
from beginning of runoff until time t, ft3/acre
M = pollutant mass flow rate per unit area at time
t, Ib/hr/acre
The coefficient values have to be determined for each modeled
pollutant by regression between measured storm runoff and
quality.
The mass flow rate of each pollutant for the dry-weather and
stormwater runoff are then added to obtain the combined in-
flow at each inlet. Mass flow routing in the sewers is
accomplished by simple advection according to the kinematic
wave travel time computed by Equation 33. Although this
moves the pollutants faster than the actual mass travel time,
this assumption was necessary to facilitate the optimization
scheme for real-time control of overflow regulators. A
pseudo-dispersion is attained by averaging consecutive mass
flow rate values at the end of each sewer reach. At regu-
lators, the mass flow rates are divided in proportion to the
flow diversion. In storage facilities, the mass of each
pollutant is simply accumulated. No other computations,
such as chemical reactions or interactions, are performed.
Wastewater treatment is computed independently for each pol-
lutant by linear interpolation of tables relating discharge,
concentration and percent removal of a pollutant.
CHICAGO FLOW SIMULATION PROGRAM
Summary
The Chicago Flow Simulation Program is intended primarily for
the simulation of large catchments consisting of both sewered
and nonsewered areas (Lanyon and Jackson, 1972 and 1974). It
simulates the time-varying runoff in combined sewerage systems
and nonurban drainage basins consisting of several catchments
and a converging branch sewer and open channel network. The
flow routing formulation for natural channels includes provi-
sions for flow and storage in flood plains. The model can
perform continuous simulation using hourly or shorter time
steps. Water quality, real-time control, and design features
are not included.
Watershed Representation
The watershed being modeled is defined by a system of open
channel and closed conduit reaches. It is suggested that the
412
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reach network of natural streams be defined by permanent and
intermittent streams shown by blue lines on a USGS 7-1/2 min-
ute quadrangle map. All forks in the channel network are
considered ends of reaches and the maximum length of any
single reach is restricted to 3 km (2 mi).
The model simulates a maximum of two upstream reaches to be
connected directly to one downstream reach. Reaches are
defined by the x and y coordinates of the upstream and down-
stream ends of open channels or closed conduits. The model
was designed for catchments larger than 5 km^ (2 mi ).
Snowmelt
Snowmelt is computed by a method of the U.S. Bureau of Recla-
mation from precipitation, daily average air temperature and
daily average wind velocity. The snowmelt computations assume
a linear relationship between snowpack depth and accumulated
water content:
s = 147.4 - 0.474pw
(45)
where
s = snowpack depth in percent of initial depth
p = accumulated water content in percent of initial
water content
It is assumed that drainage from the snow occurs only after
the snowpack has reached a specified threshold density. The
conditions of the snowpack at the adopted threshold density
can be computed by the following three equations derived from
Equation 45:
Pwt ' 147'4dPt/(Pso
syt = 147'4dso/(pso
(46)
(47)
st
* °'678 (p
so
(48)
where
•wt
threshold accumulated water content in percent
of initial water content
Yt
= threshold depth in percent of initial depth
413
-------
p = density of initial dry snowpack in percent
s o
p = threshold density of compacted wet snowpack
P in percent
p . = threshold density of dry snow in compacted wet
snowpack in percent
The procedure requires knowledge of the initial snow depth and
density. For succeeding time steps, the precipitation in
inches of water or inches of snow and its density must be
known. The potential snowmelt during each time step is com-
puted by the empirical relationships
s = (0.029 + 0.0084k u + 0.007r,)(T - 32) + 0.09 (49)
m odd.
for open or partly forested areas (mean canopy cover less than
80 percent), and
s = (0.074 + 0.007r,)(T - 32) + 0.05 (50)
m Q a
for heavily forested areas (mean canopy cover more than 80
percent),
where
s = total daily snowmelt, in.
k = empirical coefficient reflecting the relative
° exposure of the basin to wind
u = mean wind velocity at the 50-foot level, mph
r, = total daily precipitation, in.
T = mean daily air temperature of saturated air at
a the 10-foot level, °F
Runoff from Pervious Areas of Nonsewered Catchments
Infiltration losses on pervious areas of nonsewered catch-
ments are computed at 15-minute intervals by an empirical
function of rainfall or snowmelt, catchment shape, and soil
moisture:
Kn A r.
f - 1 P t
*j ~ 4 L s (51)
J c
414
-------
where
f . = the 15-minute infiltration, in.
r. = hourly rainfall, in.
A = pervious drainage area, acres
KI = empirical coefficient
L = length of open channel reach of catchment, ft
C
s = soil moisture, in.
The change in soil moisture due to evapotranspiration and deep
percolation is assumed to be proportional to the air tempera-
ture and the available soil moisture:
s" = f. + s1
T - 50 ]
K (1 + -S-- ) (52)
where
T = average daily air temperature, °F
cl
K
2/K3 = empirical coefficients
s1,s" = soil moisture at beginning and end of 15-minute
time step, in.
The total hourly infiltration is the sum of the four 15-minute
infiltrations:
(53)
where
f = hourly infiltration, in.
Linear storage routing is used to compute overland flow on the
pervious areas of nonsewered catchments. The surface runoff
is assumed to be proportional to the overland flow storage,
ground slope, and flow distance and independent of the surface
characteristics (roughness) :
415
-------
where
L
q = K, V S ~
Mp 4 p c A
^ P
q = hourly surface runoff from perv'.ous area of
" nonsewered catchment, in.
K
. = empirical coefficient
V = overland flow storage on pervious areas of
" nonsewered catchment, in.
S = ground surface slope of catchment, ft/ft
v_-
The overland flow storage at every time step is defined by
V" = v1 + r - f - q
P P t p Mp
where
V',V" = overland flow storage on pervious areas of non-
^ " sewered catchment at beginning and end of hour, in.
Runoff from Impervious Areas of Nonsewered Catchments
No moisture losses are computed for impervious areas of non-
sewered catchments. The surface runoff is assumed to be a
fraction of the overland flow storage neglecting catchment
shape, slope, and roughness:
qi = K5 Vi (56)
where
q. = hourly surface runoff from impervious area of
1 nonsewered catchment, in.
KR = empirical coefficient
V. = overland flow storage on impervious areas of
1 nonsewered catchment, in.
The storage on the impervious surface at every time step is
computed from
V'.' = V! + r. - q. (57)
i i t ^i
416
-------
where
V! ,V'.' = overland flow storage on impervious areas of
nonsewered catchment at beginning and end of
hour, in.
Runoff from Pervious and Impervious Areas of Sewered Catchments
The model assumes that for sewered catchments all of the rain-
fall or snowmelt on impervious areas and a constant fraction
of the rainfall or snowmelt on pervious areas becomes surface
runoff during the same hour:
qs = 3630 rt(Ai + 0.3A ) (58)
where
q = hourly surface runoff rate from impervious and
s pervious area of sewered catchment, ft^
A. = impervious area of catchment, acres
This formulation neglects the effects of catchment shape, slope,
and roughness on the surface runoff.
Wastewater inflow to the sewers is computed by
qd - qj Pc (59)
where
q, = hourly dry-weather or sanitary wastewater in-
flow to sewer reach, ft^
q. = wastewater flow during j-th hour of day,
^ ft3/hr/capita
P = catchment population
Channel and Conduit Flow Routing
The model assumes a nonsewered catchment drained by an open
channel if Manning's roughness coefficient is greater than
0.019 and a sewered catchment drained by a closed conduit if
Manning's roughness coefficient is less than 0.019. It con-
sequently does not simulate flows in open channels draining
sewered areas or in closed conduits draining nonsewered areas.
The total inflow (from a nonsewered catchment) into the up-
stream end of an open channel reach is given by
417
-------
I = 3600Q + 3630 (q A + q.A.) (60)
tr Sr -^ ^"
where
I = total hourly inflow into upstream end of open -.
channel reach crossing nonsewered catchment, ft
Q = inflow into upstream end of open channel reach
from upstream reach, cfs
The total inflow from a sewered catchment into the upstream
end of a sewer reach is given by
I = 3600Q 4- qd + qg (61)
where
I = total hourly inflow into upstream end of sewer
reach crossing sewered catchment, ft3
Q = inflow to upstream end of sewer reach from
upstream sewer reach, cfs
The flow routing is formulated for trapezoidal open channels
and flood plains of trapezoidal cross section and for circular
closed conduits using a storage routing technique. The change
in channel or conduit storage is computed from
V" = V + I - Q (62)
where
V ,V" = volume stored in reach at beginning and end of
hour , f t-3
I = total hourly inflow into upstream end of reach, ft
Q = total hourly outflow from downstream end of
reach, ft^
The channel or conduit discharge is defined by Manning's
equation :
where
418
-------
Q* = discharge in channel or conduit, cfs
n = Manning's roughness coefficient
o
A = cross-sectional area of flow, ft
P = wetted perimeter, ft
S = slope of channel or conduit invert, ft/ft
The outflow from the channel or conduit reach is then simply
Q = 3600Q* (64)
Appropriate geometric relationships are defined for the cross-
sectional area of flow and for the wetted perimeter of trape-
zoidal channels and flood plains. For circular closed con-
duits, it is assumed that the discharge varies linearly with
the depth of flow. If the depth of flow is computed to be
greater than the pipe diameter (i.e., the pipe surcharges)
then the model assumes a discharge equal to full pipe flow
under free surface flow conditions. Geometric relationships
also define the volume of water stored in the reach for both
open channels, flood plains and closed conduits.
Storage Facilities
A storage facility can be specified anywhere at the end of a
channel or pipe reach. The model formulation assumes that all
inflow exceeding a specified maximum outflow value is stored.
If water is stored and the inflow falls below the maximum out-
flow value, the outflow is set equal to the maximum outfall
value until the storage volume is reduced to zero. Thereafter
the outflow is set equal to the inflow if the inflow becomes
less than the maximum specified outflow value.
DORSCH CONSULT HYDROGRAPH-VOLUME METHOD
Summary
The Dorsch Consult Hydrograph-Volume Method simulates the
time-varying runoff in combined sewerage systems consisting
of several catchments and a converging branch and looping
sewer and open channel network (Ritter and Warg, 1971; Koniger
and Klym, 1972; Koniger et al., 1972; Klym et al., 1972;
Mevius, 1973; Dorsch Consult, 1973; and Klym, 1975). The flow
routing is based on a simplified solution of the full dynamic
wave equations and simulates backwater, surcharging, and
pressure flow, but not flow reversal. The model simulates
diversion structures and storage basins. The model is limited
to the simulation of single runoff events. Water quality,
real-time control, and design features are not included.
419
-------
Catchment Surface Runoff
Either measured rainfall or design rainfall intensities com-
puted by regression analysis of measured rainfall are pro-
vided as input data. The hyetographs may be defined by dis-
crete rainfall intensities at constant or variable intervals
or be various depth-duration frequency formulas, e.g., the
Eltinge formula.
Storm runoff from urban watersheds is computed separately for
pervious and impervious surfaces using the kinematic wave
equation:
continuity equation:
9t 3A
c
and Manning's equation:
3q = -H-i- <65>
where
y = water depth, m
r = rainfall intensity, m/sec
f = infiltration intensity, m/sec
2
A = surface area of the catchment, m
C
q = catchment storm runoff, m /sec
5
n = Manning's roughness coefficient
S = catchment slope, m/m
L = catchment length, m
(_.
e = evapotranspiration, m/sec
h = depression storage, m
420
-------
Both equations are solved iteratively.
Infiltration and the filling and emptying of surface depressions
are simulated separately for roofs, streets and for pervious
surfaces subject to both infiltration and depression storages.
The infiltration rate, for instance, is only reached when the
given depth is supplied by precipitation and/or surface stor-
age. As the surface depression depths differ greatly, runoff
begins when the shallowest depressions are filled. After
rainfall ceases, the puddles on impervious surfaces are re-
duced by evaporation and those on pervious surfaces slowly
drain through infiltration. The individual tributary areas
are characterized by combinations of the above three surface
types. The hydrographs of the three surface types are super-
imposed according to the relative portion of each surface to
obtain the tributary area hydrograph.
Channel and Conduit Flow Routing
Flow routing in closed conduits and open channels of various
cross sections is accomplished by an implicit finite differ-
ence solution of the dynamic wave equations for unsteady
gradually varied open channel flow (St. Venant equations) :
momentum equation:
+ 55 + +
continuity equation:
IS + IT - °c (67)
where
2
A = cross-sectional area of flow, m
g = acceleration due to gravity, m/sec
v = average velocity of flow, m/sec
S = energy slope, m/m
S = invert slope, m/m
v = average velocity of tributary inflow, m/sec
421
-------
Q = tributary inflow at the sewer inlet, m /sec
\^r
a = angle between the flow through the sewer inlet and
the flow in the sewer
Q = flow rate in the sewer, m /sec
Y = depth of flow in the sewer, m
These two equations describe the flow process in one network
element, such as a sewer section, stormwater overflow structure,
or retention basin. The energy slope Se is calculated using
the customary Manning or Prandtl-Colebrook equations. All
additional losses, for example through manholes, unclean sewers,
bends and curves, etc., are included in the friction factor.
Principles of mass and energy conservation are used to obtain
the necessary equations for solving the flow conditions at
sewer junctions. The simplest nodal point used in the program
is one inflow and one outflow, and the maximum case consists of
three inflowing and two outflowing sewers.
The equations for the simplest nodal point (one inflow, one
outflow) are as follows:
continuity equation:
Oil = Qo2 <68>
energy equation:
2 2
v. v ~
Z... + Y., + ^~ > Z „ + Y „ 4- £±- (69)
il il 2g — o2 o2 2g
backwater constraint:
Z.n+Y.1>Z_+Y0 (70)
il il ~~ o2 o2
The equations programmed for the most complex case (three
inflows, two outflows) are:
continuity equation:
j=3 j=5
I "u - I
^OJ
j=4
422
-------
energy equation:
j —
I
j = 5
,Z,, + Y,, + ^/Q^ > £ lz. + Y_, + ^- yQ_, (72)
j=4
backwater constraint:
min (Z. . + Y. .) >. max (Z . + Y .) (73)
where
Z = elevation of channel or conduit invert, m
i = subscript designating inflow variable
o = subscript designating outflow variable
1,2,3,4,5 = number of inflow or outflow
The system of equations is solved by an iterative method. It
starts with estimated flow depths to calculate unknown dis-
charges in the downstream direction and then the corresponding
depths in the upstream direction. The entire procedure is
repeated with the help of convergence formulations until the
convergence criteria are fulfilled. Normally not more than
30 iterations are necessary to obtain convergence.
ENVIRONMENTAL PROTECTION AGENCY STORMWATER MANAGEMENT MODEL
Summary
The U.S. Environmental Protection Agency's Stormwater Manage-
ment Model is one of the most comprehensive mathematical models
available for the simulation of storm and combined sewerage
systems. It computes the combined storm and sanitary runoff
from several catchments and routes the flows through a converg-
ing branch sewer network (Metcalf & Eddy et al., 1971). Flow
diversion structures can be modeled and storage can be simu-
lated for both inline and overflow retention basins. An
additional feature is a receiving water model which includes
nonsteady formulations of hydrodynamics and mass transport
for two-dimensional (vertically mixed) water bodies receiving
sewerage system effluents.
Both dry-weather and stormwater quality are computed for sus-
pended and settleable solids, biochemical and chemical oxygen
demand, coliform bacteria, phosphorus, nitrogen, and oil and
grease for each modeled catchment and routed through the
-------
sewerage system. Mathematical formulations which simulate
various combinations of overflow treatment processes for one
treatment facility are included to evaluate the effectiveness
of overflow treatment. The model does not include real-time
control and design features. The model is limited to the simu-
lation of single runoff events and inline treatment cannot be
simulated. Cost functions are built into the program to com-
pute the cost of overflow storage and treatment.
Watershed Representation
The watershed being modeled is conceptually represented by a
network of hydraulic elements (i.e., catchments, gutters and
pipes) . A catchment is envisioned as a unit of uniform water-
shed characteristics, such as surface cover and ground slope.
Each catchment is defined by area, width, ground slope, the
detention depth requirements, the roughness factor (such as
Manning's coefficient), and the coefficients describing the
infiltration loss by Horton ' s equation. Gutters and pipes
are characterized by the Manning's coefficient, length, invert
slope, and geometric description of the network.
Stormwater Runoff
Each catchment is split into pervious areas and impervious areas
with and without surface detention for runoff computations from
rainfall. Instant runoff is assumed from impervious areas with-
out detention, no infiltration is computed on impervious areas
with detention, and the full computations outlined below are
used for pervious areas.
For pervious areas and impervious areas with detention, the
depth of overland flow is computed by
+ rt At (74)
where
y',y" = overland flow depth of the catchment at
beginning and end of time interval At, ft
r = rainfall intensity during time interval At, ft/sec
At = time interval, sec
The potential infiltration rate on pervious areas is computed
by Horton 's exponential function:
f = fe +
-------
where
f = potential infiltration at time t, ft/sec
f = inintial infiltration rate, ft/sec
f = equilibrium infiltration rate, ft/sec
e = base of natural logarithm
k = constant based on soil and vegetation, sec
An intermediate water depth, yt, after accounting for infiltra-
tion, is given by
yt = y' - f At (76)
If the value of y^ in the catchment is larger than the avail-
able detention depth, overland flow is computed using Manning's
equation:
(77,
and
qs = vc Wc(yt - h) (78)
where
v = velocity of overland flow, fps
n = Manning's roughness coefficient
S = ground slope of catchment, ft/ft
c
W = width of subcatchment , ft
c
q = stormwater runoff from catchment, cfs
O
h = detention depth, ft
The water depth in the subcatchment resulting from the rainfall,
infiltration, and outflow after time interval At is:
y" = y1 - ^ At (79)
425
-------
where
2
A = surface area of the catchment, ft
(_*
Gutter Flows
The depth of water in a gutter resulting from the inflow and
outflow is computed as follows. The rate of inflow into a
gutter, q,-, is the summation of the tributary subcatchments'
outflow, qs, and the flow rate of the immediate upstream gutter,
i , so that
The water depth at the upstream end of the gutter after time
interval At is
Yg = Yg + At
where
Y',Y" = water depth in the gutter at beginning and end
g g of time step At, ft
A = mean water surface area between the depths
Yg and Yg' ft
The outflow from the gutter is computed using Manning's equa
tion:
v = !ii! R2/3 sl/2
g n g g
and
where
q = V A (83)
Mg g g
V = gutter flow velocity, fps
R = hydraulic radius, ft
S = gutter invert slope, ft/ft
2
A = cross-sectional area of gutter at Y , ft
q = outflow from gutter, cfs
426
-------
The water depth at the downstream end of the gutter resulting
from the inflow and outflow after time interval At is
Y" = Y1 + (i - q ) ^ (84)
g g g Mg AS
Flows that reach the point of concern are added to produce a
hydrograph ordinate for each succeeding time period until the
complete hydrograph is computed.
Dry-Weather Runoff
The quantity and quality of dry-weather flow (sanitary runoff)
is estimated from three data categories: drainage basin data,
subarea data, and decision and adjustment parameters. The
dry-weather flow from commercial and industrial areas is esti-
mated from water use values. The dry-weather flow from resi-
dential areas is computed from regression equations.
For metered dwelling units with public sewer:
q, = 206 + 3.47 V - 1.30 P (85)
d m w
where
q, = average annual dry-weather runoff,
gpd/dwelling unit
V = market value of the dwelling unit, thousands
m of dollars
P = sum of water and sewerage charges
For flat rate dwelling units and apartments with public sewers;
q, = 28.9 + 4.39 V + 33.6 P (86)
d. m u
where
P = number of persons per dwelling unit
For metered dwelling units with septic tanks:
qd = 30.2 + 39.5 PU (87)
427
-------
Infiltration into Sewers
Infiltration into sewers is assumed to be a part of the dry-
weather flow but it is computed separately. The effect of
infiltration upon quality is assumed negligible, unless the
water is known to be contaminated by passage through soils
with significant soluble impurities (of the type being modeled)
Quantitatively, infiltration is assumed to include moisture
from miscellaneous sources causing a base dry-weather inflow,
frozen residual moisture, antecedent precipitation, and high
groundwater . If the groundwater table is below the sewer
invert, infiltration is defined by
qf = fd + fr + fs (88)
where
qf = total infiltration, cfs
f, = dry-weather infiltration, cfs
f = wet-weather infiltration - f,, cfs
f = melting residual ice and snow infiltration, cfs
is
f = groundwater infiltration, cfs
If the groundwater table rises above the sewer invert, the
groundwater infiltration predominates and is determined by
the regression equation
£ ' " B (89)
where
G = groundwater elevation above sewer invert, ft
a . = coefficient for j-th term in equation
B. = power to which ¥„. is raised in j-th term
] (e.g., 0,1,2,1/2 for j = 0,1,2, and 3,
respectively)
The wet-weather infiltration is estimated from antecedent pre-
cipitation using the following linear relationship
fr = a + a0 r0 + al rl + ... ag rg (90)
428
-------
where
fr = QS - fd - Qd
a = coefficient to rainfall for n days prior to
n estimate, n = 0,1,....9
r = precipitation on n days prior to estimate, in.
Q, = daily average sewer flow excluding surface
runoff, gpm
Q, = sewage flow, gpm
Residual melting ice and frost infiltration is determined by
fs =
0.0 if the day under study is not in the
melting period; that is, the number of
degree days does not exceed 750
where
s = residual moisture peak contribution, cfs
N. = day on which infiltration estimate is desired
N, = day on which melting period begins; that is,
number of degree days exceeding 750
N = day on which melting period ends
After the total infiltration, q^, has been computed, this flow
must be apportioned throughout the designated study area. The
opportunity factor, F, which represents the relative number
and length of openings susceptible to infiltration, determines
the criterion for apportionment:
Z/ j • j. \ / number of \
conduit / JQints in \ (92)
conduits \Perimeter/ ^ch conduit^
Channel and Conduit Flow Routing
Flows are routed in open channels and closed conduits by the
kinematic wave equation:
429
-------
continuity equation:
and Manning's equation:
Q = Ldi A R2/3 sl/2 (94
where
Y = depth, ft
x = longitudinal distance, ft
t = time, sec
2
g = gravitational acceleration, ft/sec
S = invert slope, ft/ft
Q = flow rate, cfs
2
A = flow area, ft
R = hydraulic radius, ft
n = Manning's roughness coefficient
Normalizing the above equation by the full-flow values of Q,
A, and R gives
Q - A
Of " A R 2/3 '
± Af Kf
This formulation neglects backwater effects, which may be
appreciable for low slopes. To improve the predictions but
retain the kinematic wave formulation's simplicity, the
terms of the dynamic wave equation are used in defining the
friction slope for the full-flow computation:
Qf = ±nJ^ Af V" (S ' *Z ~ £ & (96)
r n r r ox g dx
where
430
-------
v = flow velocity, fps
This system of equations is solved by an iterative finite
difference scheme.
The cross-sectional areas of various conduit shapes are de-
fined by the following equations
circular:
A = irD2/4 (97)
rectangular:
A = H W (98)
egg-shaped:
A = 0.5105 H2 (99)
horseshoe:
A = 0.829 H2 (100)
gothic:
A = 0.655 H2 (101)
catenary:
A = 0.703 H2 (102)
semi-elliptic:
A = 0.785 H2 (103)
basket-handle:
A = 0.786 H2 (104)
semi-circular:
A = 1.27 H2 (105)
modified basket-handle:
A = W (H + 7TW/8) (106)
5
rectangular with triangular bottom:
A = W (H - Ht/2) (107)
431
-------
rectangular with round bottom:
A = H W + D.2 (0 - sin0)/8 (108)
S 1
0=2 sin~1(W/Di) (109)
where
2
A = cross-sectional area, ft
D = diameter, ft
H = height, ft
W = width, ft
H = side height, ft
S
H = height of triangle, ft
D. = invert diameter, ft
0 = angle formed by center of circle with chord
intersecting circle, radians
Surcharging is approximated by storing water exceeding the
full pipe flow capacity in the next upstream manhole. No
further upstream propagation of the surcharging is computed.
The program execution terminates if the storage capacity of
the manhole is exceeded.
Backwater is approximated by routing a portion of the flow
normally through the conduit and allocating the rest to stor-
age by specifying a storage element. The flow division is
computed by
Q-L = Q \P (HO)
and
Q2 = Q - Q1 (HI)
where
Q.. = flow directly into storage, cfs
Q = flow routed through conduit, cfs
432
-------
Q = inflow to backwater element, cfs
p = ratio of current to maximum storage volume in
the downstream storage element
Diversion Structures
Three types of flow diversion structures are modeled. The
formulations neglect downstream effects on the flow division
The flow diversion by the first type specifies that a diver-
sion occurs only if a given inflow is exceeded. At that
point, the nondiverted flow remains constant and the surplus
is diverted:
Q0 = Q
Q =0.0
o max
w max
if Q < Q_ (112)
if Q >
max
where
Q = inflow to diversion structure, cfs
Q = undiverted flow, cfs
Q = diverted flow, cfs
w
Q = maximum undiverted flow, cfs (provided as input
max data)
The same relationship is assumed for a cunnette type flow
divider, except that the value of Qmax is computed internally
as a function of the sewer size, assuming that the full flow
capacity of the divider pipe is one-half of the main sewer.
Equation 112 is used to define the continuity relationships
between inflow and outflow of weir diversion structures, but
the diverted flow is computed from the weir formula and a
linear flow-depth relationship:
Q = c L H1'5 (113)
w w w w
433
-------
Y = (Q - Q ) (Y - Y )/(! - Q ) (114)
w max max w ' max max v-»- -<••*;
where
c = weir discharge coefficient
L = weir length, ft
Y = depth of flow above weir crest, ft
Y = water depth at maximum flow, ft
IflclX
Q = maximum undiverted flow, cfs
I = maximum inflow to structure, cfs
max
Values for variables in the above list have to be provided as
input data.
Pumping Stations
Lift stations are assumed to operate when wet well volume
reaches a designated value which actuates a single, constant-
discharge pump. Pumping continues until the wet well is
emptied. Flooding caused when wet well capacity is exceeded
is not considered.
Storage Facilities
Flows are routed through storage facilities by solving the
continuity equation in conjunction with a weir or orifice
equation for the outlet of the storage facility:
continuity equation:
0.5 (I1 + I") At = 0.5 (Q1 + Q") At + (V" - V) (115)
where
I1, I" = inflow at beginning and end of time interval
At, cfs
Q1 ,Q" = outflow at beginning and end of time interval
At, cfs
V ,V" = stored volume at beginning and end of time
interval At, ft3
434
-------
At = time interval, sec
orifice equation:
Q = c A /64.4 Y(116)
o o o o
where
Y = water depth above orifice centerline, ft
A = orifice area, ft
c = coefficient of discharge
weir equation:
Q = 3.33 L Y1/5 (117)
w w w
where
L = length of weir, ft
Y = depth of flow above weir crest, ft
Water Quality
The modeled water quality constituents are BOD, COD, sus-
pended solids, settleable solids, coliforms, phosphorus,
nitrogen, and oil and grease. Average daily values and the
quality of dry-weather flow are either computed from measured
values or from average per capita values. Hourly variations
in the dry-weather flow quality are computed by adjusting the
daily average values using hourly variation factors.
The stormwater quality computations consider the quantity of
pollutants on each subcatchment before the storm event and
the rate of their removal during the storm. The pounds of
pollutant washed off in any time interval, At, are assumed to
be proportional to the pounds remaining on the ground. It is
further assumed that a uniform rate of 1/2 in./hr would wash
away 90 percent of the pollutant in 1 hr. This leads to the
equation
M - M = M (1 - e~4'46 qst) (118)
o o
435
-------
where
>
M = pollutants on surfaces which produce runoff in
0 a subcatchment at beginning of runoff, Ib
M = pollutants on surfaces at time t, Ib
t = time, hr
q = runoff rate, in./nr
Concentrations of pollutants washed away from the subcatch
ment are expressed as
M -M
- qV
s o
C = pollutant concentration in mg/1
A = catchment drainage area, acres
At = time interval, minutes
How much dirt and dust accumulates on the ground before
the start of a storm depends upon the sweeping efficiency
and the cleaning frequency. The equivalent number of days
of accumulation, N , is computed by
,
Ne - - (120)
where
N, = number of dry days before storm event
N = number of days between cleaning frequency
The pounds of dust and dirt on the ground before the start
of the storm, M , are given by
a
N
M, = N m, [1 + (1-E )+...+ d-E ) 6] (121)
ct c ci c c
436
-------
where
m
i, = dust and dirt accumulation rate/subarea
E = efficiency of street cleanings
c
Pollutant concentrations in the sewer are initialized by
the quality of the wastewater inflows diluted by infiltra-
tion, which is assumed to contain no pollutants. These
pollutants are then routed through the sewer system, with
accounting for decay during transit. The model is based
on the assumptions that mixing within each sewer element
in the system is instantaneous and complete and the non-
conservative pollutants decay according to a first-order
reaction.
i
f
The general equation of the model representing continuity
of mass is as follows:
pounds in pounds in
element at = element at
new time-step old time-step
+ pounds _ pounds
entering leaving -
pounds
decayed or +
generated
pounds entering
or leaving from
source or sink
(122)
Using the finite difference scheme, the final computer model for
routing pollutants is in the form
-n+1
n
Vn+l[lt + (K1+K2> 1+ (Qout)n+l
(Cin
(123)
437
-------
where
C = concentration of pollutant in element, Ib/ft
3
V = volume in element, ft
n = time- step number
Q = flow rate, cfs
K, = decay rate or oxygen utilization rate, sec
_ 1
K = growth rate or reaeration rate, sec
C = maximum growth or oxygen saturation value,
m mg/1
At = time increment, sec
Sediment deposition and scum in the sewer considers the
particle diameter in suspension corresponding to the velo
city in the sewer conduit:
(124)
(124)
where
d = particle diameter, ft
R = hydraulic radius , ft
S = conduit invert slope, ft/ft
k = Shield's k as criterion for deposition and
resuspension
g = specific gravity of the sediment
438
-------
The amount of settled sediment to the beginning of the time
step is
M1 = M' + Fa (T, + T~ + T,) At (125)
S S S X ^ J
The amount of suspended sediment transported during the time
step is
[(1-F ) (T,+T +T-)] (1-F ) M'
C = - O + — - - (126)
s Qin
The amount of settled sediment at the end of the time step is
M" = Fs M^ . (127)
where
C = concentration of suspended solids, Ib/ft
S
M", M' = amount of settled sediment, at start and end
of time step At, Ib
F = fraction of sediment in suspension with
s diameter greater than or equal to the
critical particle diameter
Sedimentation, scour and water quality reactions are not simu-
lated in storage facilities. The pollutant loads are traced
and redistributed using complete mixing or plug flow options.
Nine unit treatment processes at or near a sewer outfall can be
modeled in any combination. Storage, either alone or combined
with sedimentation, may be used to reduce the hydraulic capacity
of the treatment units and is included in the model . The
removal efficiency of each unit treatment process is defined
by internal empirical equations for each pollutant. Only a
few physical dimensions of the treatment facilities have to
be provided as input data.
For dissolved air flotation the average removal of suspended
solids is given by
0.06 C
AC = 0.656 + —,„„ - 0.40
s
Q - 300
2000
(128)
where
2
Q = overflow rate, gpm/ft /day
439
-------
The above equation is applicable if the overflow rate is at
least 300 gpm/ft /day and the removal efficiency is not less
than 0.30 nor more than 0.76. If chemicals are added, the
removal of suspended solids will be given by
0.06C /n_innn\
AC = 0.656 + -- 0.40Q°00 (129)
20,000 - Q
"1 \ 100,000
where
AC = suspended solids removed, ppm
C = suspended solids in inflow, ppm
k, = 1 if chemicals are added or 0 if not added
2
Q = overflow rate, gpm/ft /day
The amount of chemicals added is defined as 12 mg/1.
The rate of BOD removal is computed by
°'05 cb /o - 1000 \
ACb = °'59 + 100 °'36 ( 7000 )+ °-°2 ^ + °'15 ^ U30)
where
AC, = BOD removal, ppm
C, = BOD concentration, ppm
k, = 1 if chemicals are added or 0 if not added
k2 = 1 if chlorine is added or 0 if not added
The model restricts the BOD removal to not less than 0.18 and
not more than 0.60. The amount of chlorine is defined as
10 mg/1 if the BOD of the influent is 130 or less and as
15 mg/1 if it is more.
If the dissolved air flotation process is preceded by fine
screens, a different removal efficiency is applied to the fine
screen effluent. It is assumed that fine screens remove 27
percent of the suspended solids and 22 percent of the BOD.
The equations used in case of fine screen effluent are
440
-------
AC = 0.528 + ',„» S - 0.486 (Q ~n^°°
+ 1 37
j..j/
AC, = 0.475 +
D
190
20,000 - Q
100,000
0.05 <1
/Q - 1000\
\ 7000 j
100
+ 0.026 k, + 0.195 k.
- 1000
7000
b i i w » ^ -^ -^ r\. r*
The capacity of a microstrainer is given by
169
F. + 1.8
where
C = capacity, gpm/ft submerged area
F. = filterability index
The removal of suspended solids is given by
10,000 F^
where
F =
c
m
400 \ 0.5
A = catchment drainage area, acres
(131)
(132)
(133)
(134)
The factor FC allows for the effect of comminution and dis-
integration of the solids during flow in the sewers. It has
a maximum value of 1.0. The model restricts the capacity to
40 gpm/ft of submerged area regardless of the solids con-
centration.
The following equations are used for estimating the removal of
BOD by a microstrainer
ACb =
- 10.0 if
>. 27 ppm
ACfo =17.0 Cb/27.0 if
< 27 ppm
(135)
(136)
441
-------
MASSACHUSETTS INSTITUTE OF TECHNOLOGY URBAN WATERSHED MODEL
Summary
The Massachusetts Institute of Technology (MIT) Urban Watershed
Model (MITCAT) simulates the time-varying runoff of several
catchments and a converging sewer and open channel network,
including loops and converging and diverging branches (Harley
et al., 1970). The model can simulate only single runoff events,
Water quality and real-time control features are not included.
A separate model includes design features to compute the sizes
and costs of sewers, storage and treatment facilities which
will result in the least-cost combination of alternatives for
the elimination of untreated overflows and the reduction of
flooding and surcharging (Kirshen et al., 1972),
The original model was developed at MIT for the U.S. Office of
Water Resources Research but the model has been modified by
Resource Analysis, Inc., for its routine application (Schaake
et al., 1973) .
Watershed Representation
The model replaces the natural complexities with a number of
simple elements such as overland flow planes, stream segments,
pipe lengths, etc. A suitable combination of these simple
elements is assumed sufficient to model the behavior of an
entire catchment. Two basic runoff elements were chosen.
Flow distribution over the surface of the catchment is modeled
as planes of overland flow. The inputs to an overland flow
plane can be spatially uniform lateral inflow from rainfall,
lateral outflow to infiltration, and upstream inflow from
adjacent overland flow segments. Flow from the overland flow
planes is collected by streamflow segments as lateral inflow
and then passed downstream to other stream segments. The term
stream is used in a generic sense and may include any open or
closed form of conveyance.
Stormwater Runoff
Several alternative representations of infiltration are avail-
able in the MIT catchment model. These are
1. Horton's equation
2. Holtan's method
3. U.S. Soil Conservation Service method
4. Runoff coefficient method
442
-------
The runoff coefficient method assumes that the potential infil-
tration f(t) at time t is a portion of the rainfall rate r(t)
at that time:
f(t) = B(t) r(t) (137)
where 3(t) depends on the antecedent precipitation volume V
calculated over the past N days and the rainfall depth during
the storm up to time t:
B(t) = 1 - exp
a V^ + /_ r(t) dt
r
(138)
where a is determined from observed volumes of rainfall and
runoff or from past experience in the region.
Each of the methods permits initial infiltration rates to
depend on some measure of antecedent soil moisture and to vary
with time during the storm.
These methods are applied differently to the input rainfall.
For methods 3 and 4 the infiltration is subtracted from the
rainfall to obtain an effective rainfall which is then input
to the catchment element. For methods 1 and 2 the original
rainfall is applied directly to the catchment and then the
infiltrated portion is subtracted within the routing through
the element.
The kinematic wave equation is used for overland flow routing:
= (r - f)/43200 (139)
q = a ym c (140)
\^f
where
y = depth of overland flow, ft
q = rate of flow per catchment element width, cfs/ft
t = time, sec
x = distance in direction of flow, ft
r = rainfall intensity, in./hr
f = infiltration rate, in./ hr
443
-------
a ,m = empirical coefficients dependent on surface
geometry and roughness
Runoff occurs only if the rainfall intensity exceeds the poten-
tial infiltration rate.
The coefficients a and m for overland flow are defined by
Manning's equation? c
as
and
where
mc = 5/3 (143)
n = Manning's roughness coefficient for catchment
° element
S = overland surface slope of catchment element, ft/ft
C
Conduit and Open Channel Flow Routing
The kinematic wave equation is also used for flow routing in
conduits and open channels. The kinematic wave equation for
open channel segments is
- Q = a Ams (145)
s
where
2
A = cross-sectional area of flow, ft
Q = discharge rate, cfs
q = lateral inflow rate of overland flow, cfs/ft
a ,m = empirical coefficients
444
-------
The coefficients a- and m for a triangular open channel are
defined by Manning's equation:
Q =
1.182
n
2/3
A4/3 S1/2
(146)
as
a =i^2
s n
ms = 4/3
2/3
l/2
(147)
where
n = Manning's roughness coefficient of stream
segment
S = invert slope of stream segment, ft/ft
z = W/(2Y)
W = width of water surface, ft
Y = water depth, ft
The routing procedure used to represent pipe flow is an
adaptation of the flow routing methods developed for EPA'S
Stormwater Management Model. The model has the capability
of routing through all common sewer conduit shapes. The
solution procedure follows the basic kinematic wave approach
used in other routing elements. The problem of flow routing
is basically one of determining the downstream conditions
(flow and area) in a conduit, given the upstream conditions
and the conditions at the previous time step:
continuity equation
at
and Mannings equation:
n
AR2/3 s 1/2
e
(149)
(150)
445
-------
where
n = Manning's roughness coefficient
R = hydraulic radius, ft
S = energy slope, ft/ft
In order to improve the accuracy of results at low slopes,
additional dynamic terms for the water surface and velocity
head slopes are included in the slope term of Manning's
equation. The energy slope is computed as follows:
'.-*-£-!£ <»»
where
S = invert slope, ft/ft
Y = depth of flow, ft
v = flow velocity, fps
2
g = gravitational constant, ft/sec
A normalized continuity equation in finite difference form
using the dimensionless area a and the dimensionless flow
rate ¥ is
¥ + F^a + F2 = 0 (152)
where F^ and F2 are variables that may be computed at any
time step from the known upstream conditions and the condi-
tions in the previous time step. Equations 150 and 152 may
then be solved for a and ^ by determining the intersection
of the straight line -Fiot-F2 with the normalized flow area
relationship developed from Manning's equation. Since a
represents the ratio of the cross-sectional area A of flow
to the full-flow area and Y represents the ratio of the flow
Q to the full flow value, the current time step values of A
and Q are directly determined from a and ¥.
Thus, the kinematic wave approach allows simple finite
difference solutions of the unsteady flow equations governing
typical sewer flow. In this form all disturbances propagate
only in the downstream direction. As a result, precise simu-
lation of transient backwater conditions is not possible.
Backwater effects are included for flow routing in a given
conduit element by means of an iterative flow averaging
446
-------
scheme. However, since upstream conduits are routed indepen-
dently of those downstream a continuous backwater profile is
not simulated. Backwater effects due to ponding as a result
of a flow control structure can be simulated more directly
by a combination of conduit routing and in-system storage.
Pressure-flow conditions are not modeled in this flow routing
procedure. Surcharging is represented to an extent, however,
by storing flows in excess of the full flow capacity at an
upstream manhole (an assumed upstream manhole is associated
with every pipe element) until sewer capacity exists to
accept the stored volume.
SOGREAH LOOPED SEWER MODEL
Summary
The Looped Sewer Model of the French consulting firm Societe
Grenobloise d'Etudes et d1Applications Hydrauliques (SOGREAH)
simulates the time-varying runoff of combined sewerage systems
consisting of several catchments and a sewer and open channel
network including loops and converging and diverging branches
(SOGREAH, 1973 - 5 reports). The model includes formulations
for most hydraulic phenomena encountered in closed conduit
and open channel networks. The flow routing solves the
dynamic wave equations coupled with equations for special
sewer system facilities, such as diversion structures, pumping
stations, inverted siphons, and retention basins. The solu-
tion considers both upstream and downstream boundary conditions,
backwater, surcharging, pressure flow, and flow reversal.
The model appears to be limited to the simulation of single
runoff events. Water quality, real-time control and design
features are not included. This is a proprietary model and
not all details of the model formulations are available. The
firm has North American branch offices in New York City and
Lasalle, Quebec, Canada.
Catchment Runoff
Dry-weather flow data for each inlet are input in the form of
hydrograph values at constant time intervals. Storm runoff
is computed from hyetographs provided as input or from design
storms on the basis of frequency of occurrence and catchment
characteristics. Options exist to use two different methods
to compute design storms.
Using the first method, the maximum rainfall is computed by
the formula:
447
-------
rmax = r Ac
where
r = maximum rainfall of frequency F, m /sec
max
r = average rainfall intensity of selected
duration and frequency, m/sec
A = catchment drainage area, ha
c
Using the second method, the maximum catchment rainfall is
computed by a formula suggested by Caquot:
r = Sa pb AC (154)
max c ^i c vj-j-*/
where
S = slope of main drainage channel, percent
\^r
p. = fraction of total drainage area which is
impervious
a,b,c = universal empirical coefficients independent
of location
Using either method, the maximum rainfall is transformed into
a design rainfall hyetograph by
r = a t (155)
where
r = rainfall intensity at time t, m /sec
a, 3 = empirical coefficients
The empirical coefficients in this equation are determined by
regression analysis of measured rainfall and runoff data.
Either measured or design hyetographs are then transformed
into rainfall excess hyetographs by the rational formula or
Horton's equation. The runoff coefficient of the rational
formula can be computed with the equation
c1 = 0.14 + 0.65 p. + 0.05 S (156)
1 C
448
-------
Overland flow routing is accomplished by the Muskingum method:
Q" = C;L I1 + c2 I" + c3 Q1 (157)
where
Q1 ,Q" = catchment runoff at the beginning and end of
a time step, respectively, m^
I1, I" = rainfall excess or upstream inflow at beginning
and end of time step, m /sec
c,,Cp,c^ = Muskingum routing coefficients
The Muskingum routing coefficients are defined by
c = 2 KX + At
Cl 2K (1 - X) + At
At - 2 KX
C2 2K (1 - X) + At
= 2K (1 - X) - At .
C3 2K (1 - X) + At UbU'
where
At = time step, sec
X = 0.2 (empirical coefficient)
K = lag time , sec
A first approximation of the lag time is computed with an
equation suggested by Schaake and Geyer which considers
physical catchment characteristics:
1.40 L-24
K =
where
_0.16 0.26
c Pi
L = length of main drainage channel, m
This value is adjusted if rainfall and runoff measurements
are available. If measurements are not available, the Caquot
adaptation of the rational formula is used:
449
-------
K = d Se Af rg (162)
c c max V-LD^;
where
d,e,f,g = empirical coefficients and r is defined
by Equation 154. max
Conduit and Open Channel Flow Routing
Flow routing in conduits and open channels is accomplished by
an implicit finite difference solution of the full dynamic
wave equations for nonsteady gradually varied open channel
flow (St. Venant equations):
continuity equation:
dA
dt
dQ
~
momentum equation:
1
g
dv
dt
dv
dY
dx
QlQ
K2
= 0
(163)
(164)
equation at the network nodes:
£Q = 0 (165)
where
v = mean velocity in a section, m/sec
Y = water stage, m
2
A = cross-sectional area, m
Q = vA = discharge, m /sec
K = conveyance factor
The length of the computational time steps can be varied
throughout the simulated period to save computation time.
Longer time steps are used during periods of small changes
in flow and shorter time steps for fast rising or falling
hydrographs.
The program can simulate unsteady flow in any looped and
branching network of sewers. The only limits are imposed by
the computer equipment. Each sewer is divided into a certain
450
-------
number of computational points where discharges (and/or veloc-
ities) and water stages are computed. Any common structure
can be simulated, including weirs, lateral weirs, gates
(automatic and time dependent), storage basins linked with
a sewer by gates or weirs, siphons, pumping stations (pumping
water from one sewer to another), and local head losses. As
the program is written, nearly any other structure (such as
an inflatable weir) can be introduced with a minimum loss of
time. The following sewer cross sections are provided for:
circular, oval, trapezoidal, and arbitrary (defined as a
function of depth). The formulation computes backwater and
surcharging due to any structure or to any cross-sectional
variation.
WATER RESOURCES ENGINEERS STORMWATER MANAGEMENT MODEL
Summary
The Stormwater Management Model of Water Resources Engineers,
Inc. (WRE) is a modified version of the Stormwater Management
Model of the U.S. Environmental Protection Agency. It simu-
lates the time-varying combined storm and sanitary runoff and
wastewater quality of several catchments and a sewer and open
channel network including loops and converging and diverging
branches (Shubinski and Roesner, 1973).
The flow routing procedure is based on the dynamic wave
equations which consider backwater, flow reversal and both
upstream and downstream flow control. A special formulation
is built in for the solution of surcharging and pressure
flow. The solution is coupled with the hydraulic equations
for flow control and diversion structures considering both
upstream and downstream flow conditions. The model simulates
overflow storage basins but not in-line storage facilities.
Both dry-weather and Stormwater quality are computed for six
constituents: suspended solids, settleable solids, biochemical
oxygen demand, nitrogen, phosphorus, and oil and grease. The
pollutants are routed through the sewer system but treatment
processes are not modeled. The model does not include real-
time control and design features and is limited to the simu-
lation of single runoff events. A separate model for simu-
lating both flow and quality in receiving waters is available
(Chen and Orlob, 1972).
Watershed Representation
The model takes into account typical characteristics of urban
drainage systems and permits modeling of large areas without
a lot of detailed, geometric data. The collection system is
451
-------
divided into blocks; each block in a catchment is considered
to have similar average characteristics and to be an average
distance from the low point. This simulates the hydrograph
for both rising and falling limbs more accurately than does
lumping all blocks into one large catchment. This technique
also permits a reasonably large area to be represented as
only two elements: a block-sized overland flow element, and
an average length collection element. The overland flow por-
tion is further subdivided into pervious and impervious parts.
The user is required to specify only a single element with
basic geometric information. The computer will break this
down into pervious, impervious and collection elements and
provide the required linkages. For example, dry-weather flows
are assigned to the collection element, while infiltration is
applied mainly to the pervious area.
Catchment Runoff
Dry-weather flow is input as average values which are then
adjusted internally for fluctuations during the day and week.
Storm runoff is computed from rainfall data.
Infiltration is computed by the Horton formula:
— Ir-t-
f = fe +
-------
Manning's equation:
1 49 1/2 iv' + v" \5/3
^c = ^ Sc Wc -*- - h <168>
where
At = time step
Y"fY1 = overland flow depth at beginning and end of
time step
h = maximum depth of detention storage
r = rainfall during At
f = infiltration to groundwater during At
i = inflow from upstream catchment
(_*
q = outflow from catchment
c
q, = other flow sources (e.g., dry-weather flow)
A = surface area of the catchment element
c
n = Manning's roughness coefficient
W = width of the catchment element
c
The continuity and Manning's equations are solved simulta-
neously by a Newton-Raphson method which handles the nonlin-
ear ity involved.
Conduit and Open Channel Flow Routing
The flow routing requires geometric definition of the net-
work and operating rules for pumps and flow diverters. Such
items as the flow across weirs or through orifices, the flow
split in looping systems, surcharge conditions, and backwater
are handled automatically by the model and need not be pre-
specified.
The conduit system is represented by a series of links (pipes)
which are joined at nodes. Any shape cross section can be
incorporated into the computer program; at present it simulates
453
-------
rectangular, circular, horseshoe, basket-handle or eggshape
pipes and trapezoidal open channels.
Conduit and open channel flow routing is accomplished by an
explicit finite difference solution of the dynamic wave equa
tions for nonsteady gradually varied open channel flow (St.
Venant equations). The momentum equation is
+ 2v j£ + v ^ - gA —- (169)
where
Q = discharge
v = velocity
A = cross-sectional area of the flow
Y - hydraulic head
S = friction slope
x = distance along conduit
t = time
The friction slope is expressed as
Se = 7/3 Q'V' U70)
gAR
where
/ n \2
k = g (irfe) (171)
R = hydraulic radius
g = gravitational acceleration
n = Manning's roughness coefficient
The following finite difference form of the momentum equation
is used:
454
-------
/3Q
v.
- A
"AF
t-At
- 2
2
' A
(172)
The term c j— represents the entrance and exit losses in the
conduit. " The coefficients c^ and 02 are input values,
while subscripts i and j refer to the nodal values at the
ends of the link. The barred symbols for R, v, and A indicate
a weighted average along the link, e.g.,
Rt - 1/4 (R.
R.)t
(173)
where the subscript m refers to the midpoint of the link.
The continuity equation for a node is written directly in
finite difference form:
3Y\ EQt
at/. ~
(174)
st
where
£Q = algebraic sum of all conduit flows, inflows and
outflows at the node at time t
A = water surface area associated with the node at
sr time t
When all of the pipes entering a node are at maximum flow, the
node is said to be surcharged. The usual form of the con-
tinuity equation is not strictly applicable in this case,
because no additional storage is available at the node. Con-
tinuity then becomes
ZQt = 0
(175)
and the earlier form is indeterminate. The exact change in
hydraulic head cannot be determined directly; the situation
is now a dynamic version of the traditional pipe network
problem. However, an approximate, first-order correction
455
-------
based on the Hardy Cross method can be computed. The Hardy
Cross head correction for a node is
AY = (176)
V (il\
L \ Y'
where
AY = change in nodal head for one iteration
Q = flow in a line entering the node
Y = pressure drop along that line
£ = summation over all lines entering node
Successive application of Equation 176 to the nodes of the
pipe network leads to the satisfaction of the continuity
Equation 175. A derivation similar to that used to obtain
Equation 176, but using the dynamic equation of motion, yields
- ZQt
where K = constant, usually taken as 0.25 to introduce some
underrelaxation in the system. Note that A is the cross-
sectional area of the links; the term
K
is a measure of the capacity of the system to absorb excess
flow. It is a kind of equivalent surface area. For a sur-
charged node, the calculations are carried out using the
above equation, which is identical in form to Equation 174.
Equations 172 and 174 are numerically integrated by a modified
Euler method which yields a completely explicit approach.
The momentum equation is applied to each link and the continuity
equation to each node, entirely without implicit coupling.
Explicit methods involve fairly simple arithmetic and require
little storage space compared to implicit methods, but they
are generally less stable and often require very short time
steps. Experience showed that a severe stability relation-
ship is required for the solution technique of this model:
456
-------
c A
(178)
where c = constant determined by experience, usually about
0.10. When c = 0.10 in the above equation, the rise in water
surface during At should not exceed 0.10 of the depth avail-
able in the pipe. This criterion is approximate and must be
approached with caution.
The solution of the dynamic wave equation considers special
conditions which may exist all or part of the time in a sewer,
First, the invert elevations of pipes which join at a node
may be different; sewers are frequently built with invert
discontinuities. Second, critical depth may occur in the
conduit. Third, normal depth may control.
may be dry .
Flow Control Devices
Finally, the pipe
Weir diversions provide relief to the sanitary system during
periods of storm runoff. Flow over a weir is computed by
the equation
where
c = weir discharge coefficient
L = weir length
Yt
Y = driving head on the weir
v = approach velocity
a = weir exponent; 3/2 for transverse weirs,
5/3 for sideflow weirs
Normally, the driving head on the weir is given by
Y = Yn - h
w 1 w
(180)
where
YI = water depth upstream of weir
h = height of weir crest above invert
457
-------
However, several other existing conditions can modify the
situation. If the downstream water depth also exceeds the
weir crest height, the weir is submerged, and the flow com-
puted by the above weir formula is corrected by applying the
following equation:
0.385
* / i „ - h_
Q = Q
w vw
where
*
QW = submerged weir discharge
¥„ = water depth downstream of weir
If the upstream pipe is surcharged, the weir will behave like
an orifice and the flow is computed by the equation
Q - c* L (Y - Y ) j2gY + v2 (182)
w w w \ max c / \ ^ w
where
*
c = discharge coefficient for submerged case
Y = maximum flow depth
max
For all of the above cases, the direction of flow may be
reversed under certain conditions. This does not affect the
equations, except that Y^ and Y are switched.
An orifice is usually installed as a dropout to divert sani-
tary sewage out of the storm system to an interceptor and to
limit the flow of stormwater into the sanitary system. Flow
through an orifice is computed by
where
Q = c A J§Y~ (183)
o o ov^ o
c = discharge coefficient
A = cross-sectional area of orifice
o
Y = driving head on the orifice
458
-------
The driving head is usually the depth of flow in the upstream
pipe, Y]_. For a few installations, when the orifice is side
flowing instead of a dropout, the head difference Y^ ~ Y2 may
control. The variables Y are defined identically for orifices
and for weirs, and backflow can occur.
A pump is represented conceptually as an off-line storage
node (the wet well) from which the contents are pumped to
another node according to a programmed rule curve. One, two,
or three stage pumping is permitted, and the turning on and
off of the pumps is computed automatically.
The program simulates weir outfalls and free outfalls with or
without tide gates. The characteristics of the weir outfall
were described above. For truly free outfall, the water sur-
face at the free outfall is taken as critical or normal depth,
whichever is less. If backwater exists, the receiving water
elevation is taken as the water surface value at the outfall.
Water Quality
The following six water quality constituents are modeled:
suspended solids, settleable solids, biochemical oxygen demand
(BOD), total nitrogen, phosphorus, and oil and grease. Al-
though this list could be modified within the form of the
existing model, the present arrangement is ordered and linked
to some extent. For example, BOD is produced both in dis-
solved form and as a percentage of the weights of suspended
and settleable solids. Hence, the calculations in the program
depend to a small degree on the order of the constituents.
The six water quality constituents are computed for three
sources within the watershed: dry-weather flow, catchbasin
washout and surface runoff.
Both flow and mass emission rate of the sanitary sewage are
input as average values. Built-in program functions vary
the average value to account for time and land use differences.
The following land uses are presently included in the program:
single-family residential, multiple-family residential, com-
mercial, industrial, and open (or park). If the system con-
sists of storm sewers only, all dry-weather flow contributions
are omitted.
Catchbasins collect and store pollutants during dry weather,
flushing rather rapidly in the early hours of a storm. The
washout of material from the catchbasins is computed by
459
-------
M I 1.6 V
AMC = At V1 " e C / (184>
where
AM = mass emission rate from catchbasins, mass/unit
time
M = total mass in catchbasins at beginning of time
interval
Q = flow through catchbasins (runoff from pervious
and impervious areas)
V = total catchbasin volume
c
Surface runoff of pollutants is treated much the same as
catchbasin washout:
AM = ^ (l - e '4'6 q At) (185)
where
AM = mass emission rate from the watershed
q = outflow per unit area
M = mass available at time t
Auxiliary computations account for the efficiency of the
street cleaning process and other minor variations.
Most water quality constituents move in the sewer system by
advective transport. The differential equation which des-
cribes this process is usually in one of two forms. In terms
of mass rate of change
= QC (186)
where
M = mass
C = concentration
460
-------
In terms of concentration rate of change
l£=_C3v3C ,
3t V 8t V 3X U87)
where
v = flow velocity
V = volume
These equations are completely interchangeable; some aspects
of both are used in the numerical solution.
The finite difference form for the concentration change in a
conduit is
AC. AC
t^-^-T (188)
where
L = length of conduit
AC = change in concentration along the conduit
AC. = change in nodal concentration, due only to
-* advection in a single conduit
This equation is applied to each conduit entering a node,
provided the flow in that conduit is into the node. The con-
centration at the node does not take into account events which
occur downstream.
Combining the conduit computations at a node, and adding the
effects of volume change, source-sink contributions, pumps,
weirs, and orifices produce the total change in concentration
at the node:
AC . C . AV. AC . AC.
t^^QnAr1^-^1 (189)
n u s
where
V. = nodal volume
461
-------
£ = summation over all upstream conduits
a = ^Q
n u
Q = flow in conduit
n
£ - summation of all source-sinks, pumps, etc.
o
The latter term in the above equation is computed by a mass
balance technique.
The time history of concentration at all nodes can be ob-
tained by sucessfully integrating Equation 189 through time
in a single step for each time step:
AC. (t+At) = C.(t) +(^-)t At (190)
J —J \ /
The integration step, At, must be restricted so that
L
At <
v
(191)
for each conduit, or an unstable solution may occur. In
practice, this restraint can be violated occasionally with-
out causing the solution to become unstable, although some
error will be introduced. The model contains a trap to guard
against this occurrence.
Scour, deposition, and decay are not considered during routing.
462
-------
APPENDIX D
MATHEMATICAL SYMBOLS FOR TESTED MODELS
VARIABLES AND COEFFICIENTS
Symbol Definition
a angle between sewer flow and inflow or coefficient
g coefficient
6 partial differential
A difference
9 angle between center of circle and chord intersecting
circle
TT ratio of circumference to diameter of circle
p density of initial dry snowpack in percent of water
density
p . threshold density of compacted wet snowpack in per-
p cent of water density
p . threshold density of dry snow in compacted wet snow-
pack in percent of water density
ip coefficient
a coefficient
A cross-sectional area of channel flow
*
A normalized area
A catchment drainage area
\^r
Af cross-sectional area of conduit flowing full
A cross-sectional area of gutter flow
463
-------
VARIABLES AND COEFFICIENTS (Continued)
Symbol Definition
A. impervious catchment drainage area
A pervious catchment drainage area
A water surface area
s
b coefficient
c coefficient
c1 coefficient
c orifice discharge coefficient
c weir discharge coefficient
C water quality concentration
C, biochemical oxygen demand
C capacity of micro-strainer
C suspended solids concentration
•3
d particle diameter
D channel diameter
D. invert diameter of rectangular conduit with round
bottom
D orifice diameter
e coefficient, base of natural logarithm,
evapotranspiration
E efficiency of street cleaning
f coefficient, infiltration
f saturated infiltration capacity of soil
464
-------
VARIABLES AND COEFFICIENTS (Continued)
S ymbo 1 Definition
f, dry-weather infiltration into sewers
f equilibrium infiltration rate into soil under satu-
rated conditions
f groundwater infiltration into sewers
f. rainfall loss on impervious areas
f. rainfall loss or infiltration into soil during j-th
•^ time interval
f initial potential infiltration into soil
f rainfall loss on pervious areas or infiltration into
" soil
f storm water infiltration into sewers
f ice and snowmelt infiltration into sewers
o
f. rainfall loss or infiltration into soil during time
interval At
F factor, function, or ratio
g coefficient, gravitational acceleration
g,, specific gravity of sediments
S
h height or depth
h height of diversion gate or orifice opening
h. catchment detention depth on impervious areas
h height of orifice invert above or depth of orifice
invert below channel invert
h catchment detention depth on pervious areas
h weir height
465
-------
VARIABLES AND COEFFICIENTS (Continued)
Symbol Definition
H height of noncircular conduit
HS side height of modified basket handle or rectangular
conduit with round bottom
H. height of triangle of rectangular conduit with tri-
angular bottom
i combined inflow to catchment
o
i inflow to gutter
I inflow to channel or storage
k coefficient
k , k.,, . . coefficients
K channel conveyance coefficient or Muskingum routing
coefficient
K , K, ,.. coefficients
L channel length
L catchment length
L length of weir crest
m coefficient
m overland flow coefficient
(—•
ITU dust and dirt accumulation rate
a
m channel flow coefficient
o
M mass
M pollutant mass in catch basin
M, mass of dirt and dust
466
-------
VARIABLES AND COEFFICIENTS (Continued)
Symbol Definition
M mass of settled sediments
s
M market value
n number of items
n channel roughness coefficient, English units
N number of day or days
N, day at beginning of time period
N number of days between street cleaning
Nd number of dry days before storm event
N day at end of time period, equivalent number of days
of catchment pollutant accumulation
N. specific day
p percent or fraction
p. percent or fraction of catchment surface which is
impervious
p percent or fraction of catchment surface which is
pervious
p accumulated water content of snow in percent of
initial water content
p . threshold accumulated water content of snow in per-
cent of initial water content
P hydraulic radius
P catchment population
W
P number of persons per dwelling unit
P sewer and water charge
w 3
467
-------
VARIABLES AND COEFFICIENTS (Continued)
Symbol Definition
q discharge per unit width or unit area
q combined runoff from catchment
O
q, dry-weather or sanitary runoff from catchment
q.e infiltration into sewers
q. runoff from impervious area of catchment
q. runoff during j-th time step
q runoff from pervious area of catchment
q storm water runoff from catchment
5
Q channel flow or outflow from downstream end of
channel or from storage
Q combined catchment runoff entering sewer inlets,
catchbasin throughflow
Q.p full conduit flow
Q gutter flow
Q orifice discharge
Q weir discharge
r instantaneous rainfall intensity
r, daily precipitation
r rainfall excess
e
r. rainfall excess on impervious area
r rainfall excess on pervious area
r. rainfall during time interval At
468
-------
VARIABLES AND COEFFICIENTS (Continued)
Symbol Definition
R hydraulic radius
R^ hydraulic radius of conduit flowing full
R hydraulic radius of gutter
s soil moisture content or capacity
s snowmelt
s snowpack depth in percent of initial depth
s . threshold depth of snowpack in percent of initial
yr depth
S channel invert slope
S ground surface slope of catchment
c
S energy slope
S gutter invert slope
t time
t, base time or duration of hyetograph or hydrograph
t time of concentration of overland flow
t end of time period
t n-th time interval or time value
t beginning of time period
t time from beginning to peak of hyetograph or hydro-
graph
T temperature
T air temperature
469
-------
VARIABLES AND COEFFICIENTS (Continued)
Symbol Definition
u wind velocity
U unit hydrograph ordinate
U peak ordinate of unit hydrograph
v channel flow velocity
v overland flow velocity
v gutter flow velocity
V volume of water stored in channel or storage
V catchbasin volume
C>
V. overland flow storage or cumulative rainfall loss on
impervious area
V market value
V overland flow storage or cumulative rainfall loss on
" pervious area
V antecedent precipitation volume
V cumulative storm water runoff from catchment
s
W channel width
W catchment width
c
W orifice width
W width of water surface at depth y
x distance
X Muskingum routing coefficient
470
-------
VARIABLES AND COEFFICIENTS (Continued)
Symbol Definition
y overland flow depth
y. overland flow depth on impervious area
y overland flow depth on pervious
Y depth of water in channel or storage
Y depth of water in gutter
Y depth of groundwater above sewer invert
YO depth of water above orifice center line
Y depth of water above weir crest
z geometric channel ratio
Z elevation above reference plane
471
-------
SUBSCRIPTS
Symbol
Definition
d
e
f
F
g
gw
i
j
k
m
max
min
n
o
P
r
s
t
base, biochemical oxygen demand, beginning of time
period
capacity, catchment, cleaning, hydrograph concen-
tration time
decay, dirt and dust, dry-weather
end of time period, equilibrium, excess
full
return frequency
gate, gutter
groundwater
i-th item, impervious, inflow, invert
j-th item
k-th item
snowmelt
maximum
minimum
n-th item
initial, orifice, outflow
peak, pervious, snowpack
rain
sediment, side, snow, suspended solids
threshold, triangle, average during time interval At
472
-------
SUBSCRIPTS (Continued)
Symbol Definition
u per unit
w water, weir
y depth
473
-------
SUPERSCRIPTS
Symbol Definition
average
normalized, adjusted
at beginning of time interval
at end of time interval
474
-------
APPENDIX E
ADDITIONAL MODEL TEST RESULTS
Two requests were mailed to model developers to comment on the
draft report:
1. Request to review model comparison Tables 1 to 5,
dated June 17, 1974.
2. Request to review sections of rough draft of final
report, dated May 9, 1975.
The final report includes revisions based on the responses of
the model developers. Following are new model test results
which were received too late to be incorporated in the main
body of the report. They were provided by Dorsch Consult and
Water Resources Engineers and are included without editing by
Battelle-Northwest or the Environmental Protection Agency.
475
-------
DORSCH CONSULT
INGENIEURGESELLSCHAFT MBH
DORSCH CONSULT Ingenieurges. mOH 8 Miinchen 21 Postfach 210243
Mr. Albin Brandstetter
Research Associate,
Environmental Management Section
Battelle Pacific Northwest Laboratories
Richland, Washington 99352
USA
Ihre Nachricht Ihr Unsere Nachncht Unser Munchen 28.5. IT/5
vom Ze.chen vom Zeichen
GEG/ck
Dear Sir,
In reply to your telex please find enclosed a brief description of
the Dorsch Consult "QQS-MODEL" and of its capabilities. Test runs
according to your requirements are under way and will be mailed within
one week.
Please note that the Dorsch Consult "QQS-MODEL" is a model on
its own not connected with the"Hydrograph - Volume - Method of
Dorsch Consult.
Sincerely yours
* "/
W.F. Geiger, P. Eng.
DORSCH CONSULT Ingenieurgesellschaft mbH - 8 Munchen 21 - Posttach 2102 43 Sitz der Gesellschaft: Munchen - HRB 42 898
ElsenheimerstraBe 63 - Telefon5797-1 ^,-7 Geschaftsfiihrende Gesellschafter
Durchwahl ^O/ Regierungsbaumeister Xaver Dorsch. Minislenaldireklor a. D.
Telex dors 05-212862 - Telegramme dorschconsult Munchen Diol -Ing Dieter Dorsch - Dipl.-tno. Helmut Oorsch
Dresdner Bank Munchen. Promenadeplatz, Konto Nr 3086070. BLZ 70080000 Geschaftsfuhrer Dipl -Ing Hermann Krebs
Postscheckkonto Munchen 116919-809 Dipl-Ing Giinter Riedel - Dipl -Kfm Werner Schleber
476
-------
DORSCH CONSULT QUANTITY - QUALITY - SIMULATION (QQS)
Summary
The Dorsch Consult QQS-MODEL (Geiger, 1975) allows for continuous simulation
of four conservative water quality parameters. Runoff and its pollution from
catchment areas, characterized as residential, commercial, industrial or mixed
areas, are calculated by an unit hydrograph method, modified for the calculation
of water quality. Flow routing through the network is based on the dynamic wave
equations. Statistical analysis of the results provides annual and monthly frequency
and duration curves for flows and pollutants at any node of the network. Still,
single event simulation is possible providing pollutographs and hydrographs at
any node of the network.
The model is generally applicable to any urban drainage basin and to any pollutant.
The input has been established for the pollution indicating parameters BOD and
settleable solids. Presently efforts are being made to complete the input sets for
COD, suspended solids, bacteria coli and if possible for nutrients and chloride.
The Dorsch Consult QQS-MODEL includes the following features:
1. continueous simulation or single event simulation;
2. dry-weather flow and quality of several catchments;
3. three rain records;
4. stormwater runoff and quality from pervious and
impervious areas of several catchments;
5. routing of combined wastewater flow and quality in
a network of loops and converging and diverging branches;
6. various closed conduit and open channel cross-sections,
but linearized partial filling curves;
7. backwater, upstream and downstream flow and quality
control, surcharging and pressure flow;
477
-------
8. weirs and diversion structures considering both upstream and
downstream flow conditions;
9. pumping stations;
10. retention storage basins;
11. wastewater quality improvement at treatment
plants and overflow treatment facilities; and
12. statistical analysis of results.
The model does not include the following features:
1. snow accumulation and melt;
2. flow reversal;
3. detailed flow and quality routing in gutters;
4. realtime control;
5. sedimentation and scour in channels;
6. wastewater quality decay, reactions and inter-
actions in sewers and receiving waters;
7. design; and
8. costs.
478
-------
Methods
The surface runoff from small catchment areas including the flow process through
underlying small sewers, such as street sewers and laterals is obtained by means
of the unit hydrograph method which is modified, however, for the qualitative
part. The combined consideration of surface runoff and flow in small sewers and
the use of a systemized network, each segment of which can be composed by
several sewer elements totaling a length of up to 500 m, result in a tremendous
reduction of network nodes. The assumption of linearity of the runoff process,
being sufficiently valid for small catchment areas, could not be employed for
the flow routing through the system of trunk and interceptor sewers, the flow be-
haviour of which may be formed by backwater effects and interaction of branching
points, retention facilities and overflow structures. Thus, flow routing is based
on the dynamic wave equations. This combination provides the necessary accuracy
and still allows for continuous long-time simulation. The hydrographs and their
flow velocities obtained by the hydraulic calculations form the basis for the
pollutant transport within the network.
In case of outfalls the hydrographs and pollutographs resulting from the network
calculations form the loading of the receiving waters. These loadings are applied
at the nodes of a receiving water system. They are superimposed and routed through
this system according to the same principles applied in the sewer network. Quality
reactions and interactions in receiving waters, due to their complexity, have to
be treated in a separate model.
The results are the continuous time-dependent pollutant loadings of receiving
waters. Various properties are subjected to linear and logarithmic regression analysis.
Two-dimensional frequency distributions are formed for the three pairs of variables
showing the best correlations and for any other combination of variables given by
input. All results are printed in block form together with their relevant statistics
as well as in computer generated graphs.
479
-------
In principle at each node of the sewer and receiving water network a statistical
analysis of hydrographs and pollutographs can be produced. Usually only a
selection of the possibilities given below are desired, mainly for outfalls,
retention facilities and treatment plants. Annual and monthly frequency and
durations curves of
by-passed flows
intercepted flows
receiving water flows
used storage capacities
effluent pollutant loads or concentrations
intercepted pollutant loads or concentrations
receiving water pollutant loads or concentrations
retained pollutant loads
can be evaluated.
All parts of the model have been verified checking quality against measurements
taken in Augsburg, Munich and Stuttgart, Germany, and quantity against
the Dorsch Consult HVM-Method and measurements, (Geiger, 1975). The model
presently is applied to Augsburg, Germany (360,000 inhabitants). Completion of
this project is scheduled for Sept. 1975.
480
-------
Computer Program
The computer program consists of three main programs which are run sequen-
tially. Model documentation does not describe details of the computer
program. This is a proprietary model developed by the engineering consult-
ing firm Dorsch Consult Ingenieurgesellschaft mbH of Munich, Germany. The
model may be released under certain use and distribution restrictions. A
user's manual is available upon request.
The complete program package is written in Standard-Fortran IV and consists
of nearly 30,000 statements. Usable core storage of 400 K-bytes and a
configuration with fast external mass storage are required. The package
is presently installed in a Univac 1108 computer. The program, however,
can be used on all BATCH processing systems with Fortran IV - compilers.
For single event simulation program output includes both tables and plots
of discharges and water quality (mass rates) for any nodal point of the
sewerage system and receiving water network. Flow velocities are not
printed. For continuous simulation principal output is tables of statis-
tical analysis and graphs of frequency and durations curves.
481
-------
Hypothetical Pipe Tests
Comparison runs were performed for the hypothetical pipes described in
Section VI.
Results of the flow and quality routing for the Two-Hour Triangular Inflow
using the Dorsch Consult QQS-MODEL are presented in Figures 1 to 24.
Simulations used five minutes time steps. Fluctuations are apparent at
the beginning and at the end of the triangular quality graphs. Later
improvements in the flow routing portion of the model eliminated these
fluctuations. In general the results are very similar to the SWMM-Model
results for conditions without backwater. Slightly lower minimum concen-
tration and later arrival time are computed for the 0.05% slope.
Reference
Geiger, F. W. "Urban Runoff Pollution Derived from Long-Time Simulation."
Presented at the National Symposium on Urban Hydrology and
Sediment Control, Lexington, Kentucky, July 28-31, 1975.
482
-------
Table 1. SUPPLEMENT TO COMPARISON OF MODEL FEATURES
(Tables 2 to 5 in main text)
COMPARISON OF HYDROLOGIC FEATURES OF MODELS (Table 2 in main text)
DORSCH CONSULT
QQS - MODEL
MULTIPLE
CATCHMENT
INFLOWS
YES
DRY -WEATHER
FLOW
DIURNAL PATTERN
COMPUTED FROM
LAND USE
SUBCATCHMENT
PRECIPITATION
ONE HYETOGRAPH*
PER SUBC., MAX.
THREE PREC. REC.
PER CALC. AREA
EVAPORATION
NONLINEAR
FUNCTION OF
AIR TEMPERATURE
SNOW ACCUMUL.
AND MELT
IN PREPARATION
GROUNDWATER
SIMULATION
NO
GUTTER FLOW
NO
OO
OJ
COMPARISON OF HYDRAULIC FEATURES OF MODELS (Table 3 in main text)
DORSCH CONSULT
QQS - MODEL
INFILTRATION ON
IMPERVIOUS AREAS
NO
OTHER RAINFALL
LOSSES ON
IMPERVIOUS AREAS
INITIAL LOSS*
BEFORE RUNOFF
BEGINS
STORM RUNOFF
FROM IMPERVIOUS
AREAS
UNIT HYDRO-
GRAPH
INFILTRATION
ON PERVIOUS
AREAS
CONSTANT
LOSS RATE
OTHER RAINFALL
LOSSES ON
PERVIOUS AREAS
INITIAL LOSS*
BEFORE RUNOFF
BEGINS
STORM RUNOFF
FROM PERVIOUS
AREAS
UNIT HYDRO-
GRAPH
WATER BALANCE
BETWEEN STORMS
RECOVERY OF
DEPRESSION STORAGE
DUE TO
EVAPORATION
DORSCH CONSULT
QQS - MODEL
OPEN CHANNEL
NETWORK
CONV. AND D1V.
BRANCH NETWORK
FREE SURFACE
FLOW
DYNAMIC WAVE EQU.
IMPLICIT FINITE DIFF.
SOL., MANNING OR
PRANDTL EQU.
BACKWATER
EFFECTS
YES
FLOW REVERSAL
NO
SURCHARGING
AND
PRESSURE FLOW
YES
DIFFERENT PIPE
CROSS-SECTIONS
VAR. STAND. PLUS
ARBITR. SHAPES, BUT
LINEARIZED PARTIAL
FILLING CURVES
INFILTRATION INTO
SEWERS OR OPEN
CHANNELS
NO
DORSCH CONSULT
QQS - MODEL
DIFFERENT
DIVERSION
STRUCTURES
WEIR, DIVERGING
PIPE BRANCHES
DIVERSION
COMPUTATION
WEIR EQU. CON-
SIDERING UPSTREAM
AND DOWNSTREAM
CONDITIONS
PUMPING STATIONS
PUMPING CAPACITY
CURVE
STORAGE
FACILITIES
YES
STORAGE
COMPUTATION
FUNCTION OF
SHAPE, INFLOW AND
OUTFLOW,
CONTINUITY EQU.
COMPUTES AND
PRINTS STAGE
HYDROGRAPHS
FOR EACH SEWER
SYSTEM ELEMENT
PRINT OPTIONAL
COMPUTES AND
PRINTS
FLOW VELOCITIES
COMPUTED FOR EACH
SEWER SYSTEM
ELEMENT, BUT NO
PRINTS
» PROVIDED AS INPUT DATA
-------
Table 1. SUPPLEMENT TO COMPARISON OF MODEL FEATURES (CONTD.)
(Tables 2 to 5 in main text)
COMPARISON OF WATER QUALITY FEATURES OF MODELS (Table 4 in moin text)
DORSCH CONSULT
QQS - MODEL
QUALITY
CONSTITUENTS
4 ARBITRARY
CONSERVATIVE
CONSTITUENTS
DRY-WEATHER
QUALITY
DIURNAL PATTERNS
CALCULATED FROM
LAND USE
STORM RUNOFF
QUALITY
NONLINEAR FUNCT.
OF CATCHM. CHAR.,
POLL. ACCUMUL.
AND RUNOFF
QUALITY
INTERACTIONS ON
CATCHMENTS
NO
QUALITY ROUTING
IN CHANNELS
ADVECTION WITH
PARTIAL MIXING
BETWEEN SUCCESSIVE
TIME STEPS
SEDIMENTATION AND
SCOUR IN CHANNELS
NO
QUALITY REACTIONS
IN CHANNELS
NO
CO
DORSCH CONSULT
QQS - MODEL
QUALITY ROUTING
THROUGH STORAGE
PLUG FLOW
QUALITY
REACTIONS IN
STORAGE
NO
TREATMENT
FACILITIES
TABULAR
FUNCTION OF
FLOW AND
CONCENTRATION
QUALITY
INTERACTIONS
DURING TREATMENT
NO
QUALITY .BALANCE
BETWEEN STORMS
FUNCTION OF POL-
LUTANT ACCUMULAT-
ION AND STREET
SWEEPING
RECEIVING WATER
FLOW SIMULATION
YES
RECEIVING WATER
QUALITY
SIMULATION
YES, BUT NO
QUALITY
REACTIONS AND
INTERACTIONS
COMPARISON OF MISCELLANEOUS FEATURES OF MODELS (Table -5 In main text)
DORSCH CONSULT
QQS - MODEL
CONTINUOUS
SIMULATION
YES
TIME INTERVAL
CONSTANT
INTERVALS IN
MINUTES
MIN. AND MAX.
TIME PERIOD FOR
SIMULATION
NO MIN., ,
MAX. 2 x 10
TIME STEPS
ALLOWS INPUT
OF INITIAL
CONDITIONS
YES
DESIGN
COMPUTATIONS
NO
REAL-TIME
CONTROL
NO
TESTED ON URBAN
DATA AND APPLIED
TO REAL PROBLEMS
LIMITED TESTING
AND APPLICATIONS
DORSCH CONSULT
QQS - MODEL
ERROR MESSAGES
EXTENSIVE, PLUS
SEPARATE DATA
CHECKING
PROGRAM
PRINCIPAL
PRINTED OUTPUT
TABLES OF
STATISTICAL
ANALYSIS
PRINCIPAL
GRAPHIC
OUTPUT
FREQUENCY AND
DURATION CURVES
UNITS OF
MEASUREMENT
METRIC
COMPUTER VERSIONS
AND CORE STORAGE
REQUIREMENT
UNIVAC 1108,
400 K BYTES
COMPUTER
k LANGUAGE
FORTRAN IV,
18 000 STATE-
MENTS
COMPUTER
PROGRAM
AVAILABLE
UNDER USE
AGREEMENT
* PROVIDED AS INPUT DATA
-------
8
LO
u_
U
LLJ
O
U
to
5
u
LU
1/1
— DORSCH - QQS
— INFLOW
18
Figure 1:
TIME, HOURS
Outflow for Two-Hour Triangular Inflow - Small Hypothetical Pipe,
Free Inflow and Outflow, 0.05 % Slope
— DORSCH - QQS
— INFLOW
11
12
I I T
13 K 15
TIME, HOURS
16
i
17
18
Figure 2:
Outflow for Two-Hour Triangular Inflow - Small Hypothetical Pipe,
Free Inflow and Outflow, 0.5 % Slope
485
-------
— DORSCH - QQS
— INFLOW
i i i
13 14 15
TIME, HOURS
16
17
18
Figure 3: Outflow for Two-Hour Triangular Inflow - Small Hypothetical Pipe,
Free Inflow and Outflow, 5 % Slope
— DORSCH - QQS
— INFLOW
13 14 15
TIME, HOURS
i
16
17
18
Figure 4:
Outflow for Two-Hour Triangular Inflow - Large Hypothetical Pipe,
Free Inflow and Outflow, 0.05 % Slope
486
-------
— DORSCH - QQS
— 'NFLOW
Figure 5:
I I i I i
13 14 15 16 17
TIME, HOURS
18
Outflow for Two-Hour Triangular Inflow - Large Hypothetical Pipe,
Free Inflow and Outflow, 0.5 % Slope
— DORSCH - QQS
— INFLOW
10
13 14 15
TIME, HOURS
16
17
18
Figure 6: Outflow for Two-Hour Triangular Inflow - Large Hypothetical Pipe,
Free Inflow and Outflow, 5 % Slope
487
-------
8
O
— DORSCH - QQS
— INFLOW
O
8
U
O
o
ci
10
r
11
12 13 V,
TIME, HOURS
i
15
i
16
17
18
Figure 7: Outflow Concentration for Constant Inflow Concentration with
Two-Hour Triangular Inflow - Small Hypothetical Pipe, Free
Inflow and Outflow, 0.05 % Slope
— DORSCH - QQS
— INFLOW
o -
Z 8
*- I
LU
U
o
o
o
10
i
11
12 13 U 15
TIME, HOURS
16
17
18
Figure 8: Outflow Concentration for Triangular Inflow Concentration with
Two-Hour Triangular Inflow - Small Hypothetical Pipe, Free In-
flow and Outflow, 0.05 % Slope
488
-------
— DORSCH - QQS
— INFLOW
13 U 15
TIME, HOURS
Figure 9: Outflow Concentration for Inverted Triangular Inflow Concentra-
tion with Two-Hour Triangular Inflow - Small Hypothetical Pipe,
Free Inflow and Outflow, 0.05 % Slope
o
*8
z a
LU
U
§:
3
o
A
A
— DORSCH - QQS
— INFLOW
10 11 12 13 v. 15
TIME, HOURS
16
17
18
Figure 10: Outflow Concentration for Constant Inflow Concentration with
Two-Hour Triangular Inflow - Small Hypothetical Pipe, Free
Inflow and Outflow, 0.5 % Slope
489
-------
O
8
g
I
Z
LLJ
U
S
8
o
— DORSCH - QQS
— INFLOW
15
16
—i—
17
TIME, HOURS
18
Figure 11:
Outflow Concentration for Triangular Inflow Concentration with
Two-Hour Triangular Inflow - Small Hypothetical Pipe, Free In-
flow and Outflow, 0.5 % Slope
— DORSCH - QQS
— INFLOW
-V
16
—r-
17
15
18
TIME, HOURS
Figure 12:
Outflow Concentration for Inverted Triangular Inflow Concentra-
tion with Two-Hour Triangular Inflow - Small Hypothetical Pipe,
Free Inflow and Outflow, 0.5 % Slope
490
-------
O
8
(J
Z
U
8
a
A
A
— DORSCH - QQS
— INFLOW
10
12 13 16 15
TIME, HOURS
16
17
18
Figure 13: Outflow Concentration for Constant Inflow Concentration with
Two-Hour Triangular Inflow - Small Hypothetical Pipe, Free
Inflow and Outflow, 5 °/o Slope
P
£8
R
s
U
o
§
— DORSCH - QQS
— INFLOW
10 11 12 13 14 15
TIME, HOURS
16
17
18
Figure 14: Outflow Concentration for Triangular Inflow Concentration with
Two-Hour Triangular Inflow - Small Hypothetical Pipe, Free In-
flow and Outflow, 5 % Slope
491
-------
A
— DORSCH - QQS
— INFLOW
13 u 15
TIME, HOURS
16
17
18
Figure 15:
Outflow Concentration for Inverted Triangular Inflow Concentra-
tion with Two-Hour Triangular Inflow - Small Hypothetical Pipe,
Free Inflow and Outflow, 5 % Slope
8
o
z
o
8
8
LU
(J
-------
o
~Z. in
O "
LU
U
Z o
O Cl-
X in
U
-------
8
z
O
8
u
zs
O *
(I ^>
i i i r r
10 11 12 13 U 15
TIME, HOURS
16
17
18
Figure 19: Outflow Concentration for Constant Inflow Concentration with
Two-Hour Triangular Inflow - Large Hypothetical Pipe, Free
Inflow and Outflow, 0.5 % Slope
O
8
O
O
7&-
/ LO
O ^
is
LU
u
O
8
O
— DORSCH - QQS
— INFLOW
11
12
i i i i
13 14 15 16
TIME, HOURS
17
18
Figure 20: Outflow Concentration for Triangular Inflow Concentration with
Two-Hour Triangular Inflow - Large Hypothetical Pipe, Free In-
flow and Outflow, 0.5 % Slope
494
-------
— DORSCH - QQS
— 1NFLOW
10
Figure 21:
11
13 14 15
TIME, HOURS
16
\
17
18
Outflow Concentration for Inverted Triangular Inflow Concentra-
tion with Two-Hour Triangular Inflow - Large Hypothetical Pipe,
Free Inflow and Outflow, 0.5 % Slope
I
Z §
"
s
u
08
8
d
— DORSCH - QQS
— INFLOW
10 11 12 13 14 15
TIME, HOURS
16
17
18
Figure 22: Outflow Concentration for Constant Inflow Concentration with
Two-Hour Triangular Inflow - Large Hypothetical Pipe, Free
Inflow and Outflow, 5 % Slope
495
-------
O 8
2 "
£8
O £
LU
U
8
8
— DORSCH - QQS
— INFLOW
i r i i i
13 14 15 16 17
TIME, HOURS
18
Figure 23:
Outflow Concentration for Triangular Inflow Concentration with
Two-Hour Triangular Inflow - Large Hypothetical Pipe, Free In-
flow and Outflow, 5 °/o Slope
— DORSCH - QQS
— INFLOW
13 14 15
TIME, HOURS
16
17
18
Figure 24: Outflow Concentration for Inverted Triangular Inflow Concentra-
tion with Two-Hour Triangular Inflow - Large Hypothetical Pipe,
Free Inflow and Outflow, 5 °/o Slope
496
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WATER RESOURCES ENGINEERS
a Systems Associates Company
August 14, 1975
Dr. Albin Brandstetter
Research Associate
Water and Land Resources Department
Pacific Northwest Laboratories
Battelle Memorial Institute
P. 0. Box 999
Ricliland, Washington 99352
Dear Dr. Brandstetter:
Subsequent to our submittal of the hypothetical pipe simulations,
we discovered the following problems in the water quality simulation model:
1. The time step used in these simulations was too
long (the criteria is At < L/2, where L is the
length of pipe, or distance between adjacent nodes).
When this situation occurs, the mass balance is no
longer maintained.
2. We discovered a programming error in the computation
of the volume under the drawdown profile of the water
surface at free outfalls. Thus computed qualities
at these points were in error.
3. We found another programming error in the compu-
tation of volumes at storage nodes when the storage
node is full at the start of the simulation. (This
situation occurs for the case of the constant inflow
hydrograph.)
Fortunately (or perhaps unfortunately, since we would have discovered these
problems earlier), previously reported comparisons of computed results to
measured results on prototype systems involved systems or points of
measurement which were not affected by the two errors we discovered, and
the time step used in these comparisons was proper.
With your kind permission, we have rerun all simulations,
correcting the errors discovered in the initial runs. Tables 68 through
71 in the main text, which summarize the results of the water quality
simulations, have been revised from the values reported in the draft
report to show the correct simulation results. Outflow concentration
plots shown in Figures 49 through 66 of the main text are shown for the
WRE model on the following pages. SWNM results for these cases are
shown also for comparison. Note that we have shown the concentration
curves for the case of storage and diversion also in these figures.
710 SOUTH BROADWAY / WALNUT CREEK, CALIFORNIA 94596 / TEL (415) 933-4500
Walnut Creek. California / Springfield, Virginia / Austin, Texas
497
-------
Dr. Albin Brandstetter
August 14, 1975
Page 2
With respect to the hydraulic model, some significant improvements
have been made during its use and application since the original simulations
were performed. One of the most significant changes has been a change in
the stability criteria which allows longer time steps to be used. Since
the hydraulic simulations had to be rerun to generate input data for the
quality model, the improved hydraulic model was used. Tables 75 and 76
in the main text have been revised to reflect the run times with the
refined model.
In Hamburg, West Germany, the WRE model has been used by KOCKS,
Engineers, Germany, and WRE to develop SESIM (Stadt-Entwasserungs-
Simulationsmodell). The most important changes are as follows:
SURFACE RUNOFF MODEL
- Contribution of impervious areas to runoff:
An inputted portion of the impervious areas (e.g.
30 percent) is allowed to create surface runoff
immediately after rain start. This portion is
increased exponentially until the surface retention
is satisfied.
- Capacity of program:
The basic capacity has been increased to 450
catchment areas. An additional program can mix
up to 3,150 runoff hydrographs to create a unique
input file to the sewer transport model.
SEWER TRANSPORT MODEL
- Computer time:
The necessary computer time has been greatly
reduced by:
(1) Converting very short pipes to orifices and
thus avoiding offenses against the Courant-
criterium. Thus, larger time steps may be
used.
(2) Optional skipping of entry and exit loss compu-
tations if they are included in the roughness
coefficients. This by itself saves 39 percent
of the Sewer Transport central processing time.
(3) Optional dampening of large oscillations supports
convergence of weir flow, thus enabling larger
time steps.
- Energy losses:
Friction losses may be computed optionally with
Manning's or Prandtl-Colebrook's (rough, turbulent)
formula.
498
-------
Dr. Albin Brandstetter
August 14, 1975
Page 3
- Real-time control:
To test the influence of real-time control the
sewer transport model was given the capability of
simulating local control of weirs.
- Capacity of program:
The sewer transport model has been changed to handle
up to 3,000 conduits and nodes by using background
storage.
I wish to personally thank you for including this appendix.
Your project has been one of the best I have seen from the standpoint of
objectivity in reporting comparisons of models.
Sincerely yours,
WATER RESOURCES ENGINEERS, INC.
Larry A. Roesner, Ph.D.
Principal Engineer
LAR/djs
499
-------
I£O •
X
r
5 75'
5
£C
5 50 -
u
8
25 -
/ " -•-
I
\
i
i
i
9.00 10.00 M.OO /2.0O 13.00 I4.0O
TIME, HOURS
.
Inflow
— — Free Inflow & Outflow
Storage & Diversion
SWMM Results
J5.00 <6.OO 17.00 18.
Figure 49. Outflow Concentrations for Constant Inflow
Concentrations with Two-Hour Triangular
Inflow - Small Hypothetical Pipe, 0.05% Slope
Inflow
Free Inflow Q. Outflow
Sforoge fi Diversion
SWMM Results
0 -
9.0O 10.00 II.OO 12.00 13.00 14.00
TIME, HOURS
»5.00
I6.OO
17.00
18. OO
Figure 50. Outflow Concentrations for Triangular Inflow
Concentrations with Two-Hour Triangular
Inflow - Small Hypothetical Pipe, 0.051 Slope
500
-------
Inflow
Free Inf/ow £ Outflow
Storage fi Diversion
SWMM Results
9.00
(0.00
11.00
12.00
13.00 14.00
TIME, HOURS
15.00
IG.OO
17.00
18.00
125
IOO
X
6
I «
£ 50
§
25 -
Figure 51. Outflow Concentrations for Inverted Triangular
Inflow Concentrations with Two-Hour Triangular
Inflow - Small Hypothetical Pipe, 0.05% Slope
1
Inf/ow
— Free JnfJow S Ouff/ow
Storage 6 Diversion
SWMM Resu/fs
9.00 (0.00 11.00 12.00 13.00 14.00
TIME, HOURS
15.00
16.00
(7.00
18.00
Figure 52. Outflow Concentrations for Constant Inflow
Concentrations with Two-Hour Triangular
Inflow - Small Hypothetical Pipe, 0.5% Slope
501
-------
125
Inflow
——• Free Inflow S Outflow
Storage & Diversion
SWMM Results
9.00 IO.OO IJ.OO (2.00 13.00 I4.0O I5.0O (6.OO 17.00 18.00
TIME, HOURS
Figure 53. Outflow Concentrations for Triangular Inflow
Concentrations with Two-Hour Triangular Inflow -
Small Hypothetical Pipe, 0.51 Slope
125
Inflow
Free Inflow S Outflow
Storage S Divers/on
SWMM Results
9.00 10.00 11.00 12.00 I3.OO 14.00
TIME, HOURS
15.00 16.00 I7.0O 18.00
Figure 54. Outflow Concentrations for Inverted Triangular
Inflow Concentrations with Two-Hour Triangular
Inflow - Small Hypothetical Pipe, 0.51 Slope
502
-------
(00
X
?
o
K
75-
g so
25 -
Inflow
—— Free Inflow & Outflow
Sforage & Diversion
SWMM Results
9.00 (0.00 ((.00 (2.00 (3.00 (4.00
TIME, HOURS
(5.00
16.00
I7.OO
I8.OO
Figure 55, Outflow Concentrations for Constant Inflow
Concentrations with Two-Hour Triangular
Inflow - Small Hypothetical Pipe, 5% Slope
Inflow
— Free Inflow 6 Outflow
Storage 6 Diversion
SWMM Results
9.00
IO.OO
(1.00
12.00 13.00 14.00
TIME, HOURS
(5.00
16.00
(7.00
18.00
Figure 56. Outflow Concentrations for Triangular Inflow
Concentrations with Two-Hour Triangular Inflow
Small Hypothetical Pipe, 5% Slope
503
-------
125
Inflow
—— Free Inflow £. Ouff»ow
Storage & Diversion
SWMM Resulfs
9.00 10.00 11.00
12.00 /3.OO /4.0O
TIME, HOURS
/5.00 16.00 /7.00 /8.00
Figure 57. Outflow Concentrations for Inverted Triangular
Inflow Concentrations with Two-Hour Triangular
Inflow - Small Hypothetical Pipe, 51 Slope
125
100
o>
E
§ 75
2
O
u
50 -
25 -
Inflow
—— Free Inflow & Outflow
Storage £ Divers/on
SWMM Resulfs
9.00 10.00 11.00 J2.00 13.00 (4.0O 15.00 16.00 I7.0O 18.00
TIME, HOURS
Figure 58. Outflow Concentrations for Constant Inflow
Concentrations with Two-Hour Triangular
Inflow - Large Hypothetical Pipe, 0.05% Slope
504
-------
Inflow
— Free Inf/ow 6 Outflow
Storage £ Diversion
SWMM Results
9.00 10.00 11.00 12.00 13.00 14.00 15.00 »6.00 17.00 18.00
TIME, HOURS
Figure 59. Outflow Concentrations for Triangular Inflow
Concentrations with Two-Hour Triangular
Inflow - Large Hypothetical Pipe, 0.051 Slope
Inflow
Free Inflow fi Outflow
Storage fi Diversion
SWMM Results
9.00 10.00 U.OO 12.00 13.00 (4.00 15.00 16.00 17.00 18. OO
TIME, HOURS
Figure 60. Outflow Concentrations for Inverted Triangular
Inflow Concentrations with Two-Hour Triangular
Inflow - Large Hypothetical Pipe, 0.05% Slope
505
-------
(25
IOO
\
f
8 "
5 50
25 -
Inflow
—— Free /nfiow & Outflow
Sforoge £ Diversion
SWMM Results
9.00 IO.OO ll.OO 12.00 13.00 I4.0O
TIME, HOURS
(5.00 (6.00
17.00
(8.00
Figure 61. Outflow Concentrations for Constant Inflow
Concentrations with Two-Hour Triangular Inflow
Large Hypothetical Pipe, 0.51 Slope
125
IOO -
o>
5 75
o
o
50 -
25 -
Inflow
—— Free Inflow & Outflow
Storage 6 Diversion
SWMM Results
9.00
(0.00
((.00
/2.OO
/3.00
T/ME,
(4.00
HOURS
15.00
—1
(6.00
—I
(7.00
(S.OO
Figure 62. Outflow Concentrations for Triangular Inflow
Concentrations with Two-Hour Triangular
Inflow - Large Hypothetical Pipe, 0.5% Slope
506
-------
9.00
Inflow
—— Free Inflow & Outflow
Storage & Diversion
SWMM Results
10.00
M.OO
HOURS
15.00
(6.00
/7.00
re.oo
Figure 63.
Outflow Concentrations for Inverted Triangular
Inflow Concentrations with Two-Hour Triangular
Inflow - Large Hypothetical Pipe, 0.51 Slope
125
•00
o>
E
S
Z
O
u
50 -
25 -
Inflow
— Free Inflow & Outflow
Storage & Diversion
SWMM Results
9.00 10.00 11.00 12.00 /3.00 14.00
TIME, HOURS
15.00
16.00
17.00
Figure 64. Outflow Concentrations for Constant Inflow
Concentrations with Two-Hour Triangular Inflow -
Large Hypothetical Pipe, 5% Slope
18.00
507
-------
125
100-
t»
rH
i
5 50 H
o
0
Inflow
—— Free Inflow & Outflow
Storage & Diversion
SWMM Results
, .—, , ,
9.00 10.00 II.OO 12.00 13.00 14.00 /5.00 I6.0O
TIME, HOURS
I7.OO
(8.00
Figure 65. Outflow Concentrations for Triangular Inflow
Concentrations with Two-Hour Triangular
Inflow - Large Hypothetical Pipe, 51 Slope
Inflow
—— Free Inflow & Outflow
Storoge fi Diversion
SWMM Results
9.00
IO.OO
U.OO
/2.00
13.00 14.00
TIME, HOURS
J5.00
16.00
I7.OO
I8.OO
Figure 66. Outflow Concentrations for Inverted Triangular
Inflow Concentrations with Two-Hour Triangular
Inflow - Large Hypothetical Pipe, 51 Slope
508
-------
APPENDIX F
SELECTED COMPUTER INPUT AND OUTPUT
Examples of computer input and output for each ofr the seven
tested models are assembled in a separate volume.* The output,
in most cases, is self-explanatory. Reference to the respective
user's manuals is needed in some instances where output data
categories are identified by abbreviations and to identify
input data categories. It was not within the scope of this
study to duplicate the user's manuals to provide all details
required for input and output interpretation.
The input and output examples are selected from computer runs
which include the following simulations:
1. large hypothetical catchment, 0.1% slope, dry
condition, 2-hour triangular rainstorm;
2. small hypothetical pipe with upstream storage
and downstream diversion, 0.5% slope, 2-hour
triangular inflow, all three inflow concentrations
(if modeled).
ft
The title of this separate volume, an extension of this work
is "Assessment of Mathematical Models for Storm and Combined
Sewer Management, Appendix F: Selected Computer Input and
Output" (EPA-600/2-76-175a) and can be obtained at the_
National Technical Information Service, Springfield, Virginia
22151.
509
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-76-175a
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Assessment of Mathematical Models for Storm
and Combined Sewer Management
5. REPORT DATE
August 1976 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Albin Brandstetter
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Battelle Pacific Northwest Laboratories
Water and Land Resources Department
Battelle Blvd.
Richland, Washington 99352
10. PROGRAM ELEMENT NO.
1BC611
11.
68-03-0251
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory
Office of Research and Development
U. S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA-ORD
15. SUPPLEMENTARY NOTES
See also Appendix F, EPA-600/2-76-175b
16. ABSTRACT
Mathematical models for the nonsteady simulation of urban runoff
were evaluated to determine their suitability for the engineering
assessment, planning, design and control of storm and combined
sewerage systems. The models were evaluated on the basis of
information published by the model builders and model users. Seven
models were also tested by computer runs using both hypothetical
and real catchment data. Most of the models evaluated include
the nonsteady simulation of the rainfall-runoff process and flow
routing in sewers; a few include also the simulation of wastewater
quality, options for dimensioning sewerage system components, and
features for real-time control of overflows during rainstorms.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATl Field/Group
:ombined sewers, Hydraulics, Hydrol-
ogy, *Mathematical models, Open
Channel flow, Overflows, Runoff,
Sanitary sewers, Sewage, *Sewers,
Storm sewers, Unsteady flow,
*Urban planning, Wastewater,
*Water pollution, Water quality.
Combined sewer over-
flow, Optimal con-
trol, Optimal design,
Urban hydrology,
*Urban hydrologic
models, *Water quality
control.
13B
13. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS /This Report)
UNCLASSIFIED
21. NO. OF PAGES
530
20. SECURITY CLASS (This page)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
510
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