Determining Pixel-by-pixel Catchments in ArcHydro

Question

I used ArcHYDRO to prepare HydroDEM (5m) without sinks, Flow direction (FDR) raster, flow accumulation raster (FAC). As I understand FAC, value of pixel shows number of pixels that contribute to this pixel. Now, let say I derive drainage line from FAC (in raster form), I would like to link somehow all pixels that contribute to particular pixel in my drainage line, in way that I have separate contributing areas for each pixel in that drainage with clear relation to this pixel. How do I do that?

The main goal is to derive height difference between pixel in the drainge and any pixel that contribute to it and only to it.

Answer 1

Are you looking to calculate Melton Ratio? SAGA GIS has a tool to calculate it in the 2.1 Beta release. If you've never used SAGA before, it can be a little intimidating, but the hydrology tools are well worth learning, and it's certainly easier than figuring out how to get ArcMap to do things it doesn't want to. Someone else here may have an ide how to do it in ArcMap, though.