I'm assuming that for the flow information, you are using the "channel flow.srn" time series... Am I right?
If so, Than your math will probably never give you the results you are expecting.
The reason is that most of the model output time series have "instantaneous" values. This means that if you set the output time for the time series to be hourly, for example, each value in the time series will be the instantaneous flow (in m3/s) at the last time step before the time to output happens. This for sure will cause problems if you use the value as if it was the flow for the entire period since the previous output (one hour before), because the flow can change a lot in the meantime, usually decreasing.
And this problem will happen independently of the method for the interpretation of the values in the time series, Original or Interpolated (the default method).
For concentrations, because the model will convert them to mass, you always should use USE_ORIGINAL_VALUES : 1
This will tell the model that the value to be used in a time step is the same as it founds in the input time series.
If you do not set this to 1, the values will be interpolated, and than the concentration will vary during the discharge period, which is unlikely what you want. Interpolation is used for variables like temperature, that you have values at specified times and the model needs to guess which value are in the middle. Usually, in these cases, we make a linear interpolation.
Regarding what you are trying to do, the best approach is to use this in Drainage Network input file:
Code: Select all
INTEGRATE_FLOW : 1
INTEGRATE_FLOW_DT : 86400.
INTEGRATE_MASS_FLUX : 1
INTEGRATE_MASS_FLUX_DT : 86400.
The keyword INTEGRATE_FLOW will integrate the flow and is required when you want to integrate the mass of a property, that is done using the two keywords inside the block of the property. Each property you want to integrate the mass should have those two keywords. If you do not set INTEGRATE_FLOW_DT and INTEGRATE_MASS_FLUX_DT they assume the default value of 86400 (a day).
Both the flow and the mass are the ones that are LEAVING a node, so if you want to know how much flow and mass goes from node 10 to 11, you have to set the node 10 in the timeserieslocation file.
I think this will give the kind of answer that you are looking for.
Thanks for the information provided by David