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Maximum Ponded Depth

Hello sir!

In a status report the Volume of flooding in a node and the Maximum Ponded Depth can be seen. From the computed Volume of flooding, how does SWMM compute for the Maximum Ponded Depth? 


depth = Volume / Area, what area is being considered?

Thank you very much!

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  • It uses the Surface Ponding Area



    Tip for The Ponding Allowed Option in SWMM 5

    Normally, it is better to have smaller ponding allowed area in SWMM 5 due to considerations outlined in this earlier blog and 2nd Blog but if you have a low lying area with ponding allowed it is better if you have a larger ponding area so that the depth above the rim elevation of the node is small and you do not set up reverse  flow and cause flooding at other modes due to the  higher HGL.  Figure 1 illustrates a typical HGL profile and Figure 2 shows the better flooding  graphs as you increase the ponding surface area for the low lying node.

    Figure 1.  HGL around a low Lying Node

    Figure 2.  Smoother Flooding Graph due to Higher Surface Ponding Area

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