Node ponding option, Can any one explain how it function in SWMM 5

Under Kinematic wave routing, I want to know how the node ponding option control the flow of the system. What are the equations and what are the parameters govern the behavior of the ponded water when re introduce to the stream network? Is it just a balancing the volume at each calculation time step or any other method?

According to the manual under Dynamic wave routing, when we defined constant ponded area, considering the water depth at the node it will control the discharge form the node (please correct me if I'm wrong)

Under Kinematic wave routing, ponded water is stored simply as an excess volume. My issue is how this excess volume re introduced to the stream.

Thank you

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Replies

• I need to clarify my comments,  the ponded water is reintroduced in the DW solution but not the KW solution.

• When we define ponded area, Internal Outflow quantity will be changed in to zero and also the Flood flow time series shows zero value.

To avoid loss from the network, I used to define some ponded area value and then there was no loss. But I don't understand how that ponded area behave. May be it behave as a linear reservoir or may be just releasing the volume of water, required to totally fill the node at the calculated time step.

SWMM 5 manual mentioned there is a option to store the excess volume as a ponded  fashion and reintroduced into the system when capacity permits.

Thanks lot Bob

• I think it is just a loss from the network and is not reintroduced in the KW solution but it is in the  DW solution. It shows up graphically as a flood flow and int he continuity check it is summed in internal outflow.

************************** Volume Volume
Flow Routing Continuity acre-feet 10^6 gal
************************** --------- ---------
Dry Weather Inflow ....... 66.125 21.548
Wet Weather Inflow ....... 0.000 0.000
Groundwater Inflow ....... 0.000 0.000
RDII Inflow .............. 0.018 0.006
External Inflow .......... 0.000 0.000
External Outflow ......... 26.379 8.596
Internal Outflow ......... 37.254 12.140
Storage Losses ........... 0.000 0.000
Initial Stored Volume .... 0.000 0.000
Final Stored Volume ...... 4.606 1.501
Continuity Error (%) ..... -3.172

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