Pond Storage Volume: Hydraflow vs. PondPack 1

[froude]

Hello All,

I am trying to reconcile why, when using the same Modified Rational parameters, Hydraflow (Autodesk) and PondPack produce starkly dissimilar pond storage needs (Hydraflow calculates only half the storage need that PondPack calculates). Both programs seem to use storage-indication methods for routing. Other approximation methods I use generate numbers closer to PondPack than Hydraflow.

Does anybody have any experience with this? Thanks in advance!

 

[psmart]

I don't have a direct answer, but I would break down the problem: Look at the pond inflow first. Proceed to the pond routing only after you've got a matching inflow.

Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[Yakman256]

Check the Hydrographs. Some programs use time of concentration multiplayer to change the shape of the hydrograph. You'll find hydrographs generated by Hydraflow has the traditional triangle shape where the bottom of the hydrograph is 2X the Tc. Other programs will use a mutiplier to make the hydrograph more of a trapzoidal shape or use 3X the Tc as the bottom of the Hydrograph to generate more volume. I had the same problem with the VTPSUHM program when comparing it to Hydraflow. Bottom line, don't use the Rational Method routines within Hydraflow for Routings. Use PondPack.