This is a educational material to change a types and determine all efficient sizes of conduits for flood control in SWMM.

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Seoul National University of Science and Technology
Professor Eun-Sung Chung

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 In this training section, you will design different types of
conduits
 Types of each conduit will be replaced by open channel flows,
gutters, and pipelines based on your constructed SWMM file
 You will learn and check what values are needed to design
conduits in SWMM
 You will learn how to determine the smallest diameter of
pipelines with the design rainfall data
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Before
After
S1
S2
S3
S4
S5
S7
S6
O1
RainGage

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T= 12 mins T= 54 mins
T= 2hr 14mins T= 6hrs 3mins

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 Change the type (shape) of
the link element
 Click conduits from the
side menu and then select
a conduit
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 Change the type (shape) of the link
element
 Properties for the selected
conduit will appear in the
screen
 Click shape
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 Change the type (shape) of the link element
 Cross-section editor will appear
 You can choose the shape of the cross-section
 For example, if you select “Circular”, it can be referred to as a culvert
 If you select “Trapezoidal”, it can be referred to as a open channel
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 Change the type (shape) of the link element
 Values needed for the cross-section will automatically change when
you select a single shape
 You can select numbers of barrels and enter values relating to the
cross-section
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Conduit ID Type Type of shape
C1 Open channels Trapezoidal
C2 Gutters Trapezoidal
C3 Pipelines Circular
C4 Open channels Trapezoidal
C5 Open channels Trapezoidal
C6 Open channels Trapezoidal
C7 Pipelines Circular
C8 Open channels Trapezoidal
C9 Open channels Trapezoidal
C10 Open channels Trapezoidal
C11 Pipelines Circular
 Change the type (shape) of the link element
 Change the types of each conduit by following the tables below

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 Change the type (shape) of the link element
 Change the type of each conduit using the following information
Type of shape Cross section D (m) Z1 Z2 b (m) h (m) n
Trapezoidal
(Open Channel)
- 5 5 2 2 0.05
Trapezoidal
(Gutter)
- 0.0001 25 0 1 0.016
Circular
(Pipeline)
1.5 - - - - 0.016

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 Properties for link elements
 Values relating to link elements
can be entered manually from the
highlighted box
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 Checking the results of flooding
 When flooding occurs after the SWMM run, there will be a difference
in flooding loss in the status result

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 Checking the results of flooding
 When flooding occurs after the SWMM run, there will be a difference
in the summary results

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 Determination of efficient sizes for pipelines (C3, C7 and C11)
 Start with each culvert at the largest available diameter, 1.5 m and
reduce by 0.1 m.
 Make a series of SWMM runs, reducing the size of conduit C3 until
flooding occurs
 Then you can find the efficient pipeline diameter without flooding.
 Repeat this process for conduits C7 and C11
 Make sure that you handle the conduits in the upstream first
 Decide the efficient diameters for three pipelines (C3, C7 and C11)

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 Determine the efficient
diameters of three conduits
(C3, C7, and C11) for two
different rainfall events.
 Draw a hydrograph of each
rainfall event for junction
J3 and outfall. Compare
results for two events.
Rainfall 1
0:00 1
0:05 1.14
0:10 1.33
0:15 2.23
0:20 2.84
0:25 5.49
0:30 9.95
0:35 4.12
0:40 2.48
0:45 1.46
0:50 1.22
0:55 1.06
1:00 1
1:05 0.95
1:10 0.91
1:15 0.87
1:20 0.84
1:25 0.81
1:30 0.78
1:35 0.75
1:40 0.73
1:45 0.71
1:50 0.69
1:55 0.67
Rainfall 2
0:00 0.49
0:05 0.56
0:10 0.65
0:15 1.09
0:20 1.39
0:25 2.69
0:30 4.87
0:35 2.02
0:40 1.21
0:45 0.71
0:50 0.6
0:55 0.52
1:00 0.39
1:05 0.37
1:10 0.35
1:15 0.34
1:20 0.32
1:25 0.31
1:30 0.3
1:35 0.29
1:40 0.28
1:45 0.27
1:50 0.26
1:55 0.25
Exercise 2

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