Create 'sub basins/catchments' of a defined size

[nickbartzis1]

Hi All,
I'm trying to work out how to mimic output from 'global mappers watershed analysis' using ArcGIS.
It is straight forward to get the watercourcses and flow accumutalition grid. But i'm stumped with being able to get basins size with a defined upstream cell count/ area.... I have attached pics to demostrate.

Dem.png is a sample of the DEM
watershed_5000.png is Global mapper watershed output, with stream threshold of 5000 cells
watershed_500.png is Global mapper watershed output, with stream threshold of 500 cells
GM_function.png is shows the global mapper function window.

I have seen reference 'por points' but this is a manual process and i'm sure arc has a better way to do this.

Can anyone point me to the function within Arc that does this?

cheers
Nick

[MarkBoucher]

Arc Hydro takes the Flow Accumulation (fac) and with a Stream Definition function allows you to put in the number of cells at which to start a stream. Then with Stream Segmentation and then Catchment Grid Delineation you get a catchment grid. Another function converts the grid to polygons.

[Anonymous User]

Original User: nick_gmail

Thanks, i have not yet tried to implement your suggestion (soo busy) but it sounds fairly straight forward.
Thanks again!
Best regards
Nick