Multiple frequency storm meteorological models.

[leibadarou]

Hello from Greece!
I am a first time user of HEC-HMS 5.3 and I have a basin model with several subbasins. Every subbasin has its own IDF curve and different precipitation measures. I would like to use the "frequency storm method" into the meteorological model. Apparently I need to have different meteorological frequency storm parameters for every subbasin.
Is there a way to use the frequency storm method and have different frequency storm parameters for every subbasin of the same basin model?
If I create different meteorological model for every subbasin, where in the program I set which model corresponds to which subbasin?
Thank you in advance for your time!
Best regards,
Jenny

 

[beej67]

Just curious - how big are these basins to have their own IDF curves?

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[leibadarou]

Every basin extends for approximately 100 km2.

 

[psmart]

And do you actually have accurate IDF data for each of these areas? It's rare for the IDF data to vary significantly on that scale. That's why beej67 was asking about the size.

Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[beej67]

^this.

I would take a hard look at your IDF info and see if it truly varies that much between them. If it does, I'd ask myself why, and whether perhaps it was synthesized properly. Then I'd think about combining the data in some way to form one IDF relationship for your study area, that could be applied to both basins. Then your issue goes away.



Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[leibadarou]

I asked Hec-Hms team and responded that I can not use more than one IDF curve with "frequency storm method". They are working on it on the new version of Hec-Hms. Instead I used Precipitation gages and gage weights for each basin. Each gage had its own IDF Curve. I calculated precipitation from my IDF Curves for every gage and for different return periods. Then I run simulations for every Return Period. By the way precipitation calculations were not so different but I was obligated by the project to use all of them. Thank you for your help and support!