how-to-subtract-upstream-flow-to-get-net-catchment (1)

Dear All,

I am trying to update an I&I report done by a consultancy using SWMM5 modelling.  

The sewer flow gauged seems to be difficult to be used in SWMM model, because we only gauge flow data including upstream flows. In SWMM, we could only assign junctions with net ADWF for any subcatchments,  I was trying to lag upstream and downstream flows and get net inflow from subtraction of two series of data. However, there is no proper lag time as sewer travel time changes with flow and my flow data for downstream have so many minus value.

If you have any suggestion on this NET inflow thing, please help.

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