SCS curve numbers for rainfall-runoff model using ArcHydro

Question

I'm trying to assign curve numbers to one of my subbasins using ArcHydro (subbasin parameter from raster) following a tutorial as you can see here: https://docs.google.com/file/d/0B6GUNg-8d30vSEJaYTliOEpJTWc/edit?usp=sharing

when I turn to the step after generating my own SCS curve number, I was amazed to see that, I don't have the option to apply my CN values as you can see here: https://docs.google.com/file/d/0B6GUNg-8d30vb2RsalJpXzVtSGM/edit?usp=sharing

As far as I know, I didn't skip any step while going through the whole process, anyone have any suggestion? Is there any option inside Hec-HMS to provide curve numbers for my subbasins, however?

cherry_maetulfo · Answer

hi Zheng. . 
i am also stuck in generating CN Grid. . 
I'm also wondering how did you manage to solve it using spatial analyst tools. .
can you share me processes how did you do it. ?
i am really not familiar with the tools in Spatial Analyst toolbox. .

what to put on
>zone data
>zone field
>value raster

if i have already generated a table out of it, where will i go next?

thank you for entertaining this question. .

ketakiagarwal · Answer

Thanks!I was facing the same issue.This helped!

RajibMozumder · Answer

I run into the same issue recently and did a workaround outside of the Geo-HMS.

The Zonal Statistics as a Table in Spatial Analyst was used to create a CN Grid table for each HydroID in the subbasin layer. This table was joined to the subbasin layer first, and then the field calculation was used to populate the CN field.

Hi Zheng,
Wow ... what a coincidence! I did the same thing and was able to submit the project on time.