Note: Tributary Area to a Node in SWMM 5 or InfoSWMM
Here are the steps you neeed to take to calculate the tributary area of a node in InfoSWMM:
Step 1: Use the DB Editor to get the total area in your model using the Data Statistics Tool.
Step 2: Use the Process options in InfoSWMM to ONLY simulate surface runoff and flow routing.
Step 3. Copy the Node name and Total Inflow Volume from the Juntion Summary Output Table to Excel
Step 4: Find the Total Wet Weather Flow during the simulation from the Wet Weather Inflow Row in the Flow Continuity Table.
Dry Weather Inflow 0.000 0.000
Wet Weather Inflow 0.782 0.255
Step 5. Make a new column in Excel to calculate the tributary area.
The Tributary Area of a Node = Total Inflow Volume / Total Wet Weather Flow * Total Subcatchment Area from Step 1.
You will now have the tributary area for each node. You can verify this number = the total tributary area at the outfalls should equal the Total Subcatchment Areafrom Step 1.
Maximum

Maximum
 
Lateral

Total

Time

of

Lateral

Total

Tributary
 
Inflow

Inflow

Occurrence

Volume

Inflow

Inflow

Area
 
Node

Type

CFS

CFS

days

hr:min

10^6 gal

10^6 gal

acres

P001

JUNCTION

5.54

10.86

0

2:27

0.1

0.255

14.74

P005

JUNCTION

2.14

7.42

0

2:26

0.039

0.155

8.96

P009

JUNCTION

5.78

5.78

0

2:25

0.106

0.106

6.13

P011

JUNCTION

0.7

0.7

0

2:34

0.01

0.01

0.58

OUTLET

OUTFALL

0

10.84

0

2:28

0

0.255

14.74
