Ref: http://communities.bentley.com/products/hydraulics___hydrology/f/5925/t/101651Hello Scott,
I have an additional questions with regards to my model. I have been reviewing some of the information and confirming with hand calculations and came across something which does not make sense. In my model my K-6 catchment outlets to CB-1 which then has an orifice restriction that forces the water to pond at the node.
As a check I took the runoff hydrograph from K-6 and transferred it into Excel. I then routed it through a 'pond' (catchbasin with ponded area in my case) and produced an outflow hydrograph which would discharge into the underground system. After this was completed I then copied the outflow hydrograph produced by SewerGEMS for my catchbasin into Excel for comparison.
I have included my graph of inflows and outflows which I produced from excel as well as the outflow I obtained from SewerGEMS. I noted that there is a discrepancy in the outflow curves where SewerGEMS appears to be discharging for a longer period resulting in a larger outflow volume. I then went back into my spreadsheet and calculated total volumes of the inflow, outflow, and outflow from sewergems, here is how they compared:
Inflow = 78.26m3
Outflow = 78.24m3 (slightly different due to some assumptions in my routing spreadsheet)
Outflow from SewerGEMS = 95.32m3
As you can see the graph which I copied from SewerGEMS for comparisons appears to have invented additional flow at the catch basin node. Other than the discrepancy at the end of the graph they are almost identical which was what I was looking for. I was wondering if you had ever seen this before or know what would be causing it?
Any information or help would be greatly appreciated. Thanks again for the help on the above issue I had wondered if the outlet was summing the other catchments as well but was looking for confirmation. If you have any questions or need more information please let me know.
Thanks again,
Ryan