HydroCAD Inflow Graph

[ChuckCD]

I have developed a model of proposed open infiltration basin(s) that are chained together by overflowing into each other as the runoff makes it to the low end of the site and final overflow. Each of these basin(s) is set up as a Pond with a drainage sub-catchment defined. I have a problem where one basin that is flowing into the other is not appropriately shown in the graph. Basically I have a 0.56 Ac drainage area to Basin #1 that shows an overflow of 1.18cfs. Basin #1 flows via a swale No2 to Basin #2. Basin #2 also has a swale No3 (Showing 2.29cfs) directed into it along with Swale No2. The Graph for Basin #2 should have an inflow of +-3.47cfs but it only has 2.82cfs. I am being questioned by the reviewer as to why it does not have the complete inflow amount. He says it should show two separate inflow amounts on the graph. I don't think HydroCAD has this option. I think it simply adds the two together and provides the Peak of the two flows.

Any help would be greatly appreciated!!

 

[psmart]

If you're trying to verify hydrograph addition you should compare the hydrograph VOLUME not the peak. Volumes will always add directly (conservation of mass) but peak flows will add directly only if the peaks occur at the exact same time.

If you want a more detailed look at the hydrograph addition process, right-click the tabular hydrograph and select "Inflows". This will show a separate column for each inflow hydrograph so you can verify the addition.

For further details, including illustrated examples, please see

http://www.hydrocad.net/peakflow.htm

Peter Smart
HydroCAD Software

http://www.hydrocad.net