Hi Baxter,

Try to have a look at r.water.outlet in Grass manual. I used it to delineate more than 9 subcatchments
using drainage map created by r.watershed. You need first to zoom in at the outlet cells to define the 
exact northing and easting coordinates and then zoom out again to capture the entire area you are
after. Then, you should be able to define all cells drain to this outlet cell.

The DEM I was using is 25 m resolution.
I wish this would help. Let me know if you have further enquiries.

Cheers,

Tarek Sadek

Ph.D. Student
Department of Civil and Environmental Engineering
University of Melbourne
Parkville, Vic. 3052
Australia

Tel: +03 344 7178
Fax: +03 344 6215

E-mail address: sadek@aqua.civag.unimelb.edu.au

This is a reply to: 

> We are delineating the watersheds of several endoreic basins. One
> project is in the prairie pothole region of North Dakota and the
> other is in the HAPEX Sahel region in Nigeria. Both present similar
> problems in that the r.watershed routines sub-basins that do not
> cover the entire watershed. We have achieved marginal results after
> applying the following:
> 1. Use a blocking mask that is an inverse of the dem
> 2. Use a mask that is the outside region of the dem
>
> Using these two parameters does cause the drainage network to
> drain to the interior (pool area).
>
> Has anyone had similar experiences or have any suggestions!
> We intend to model the hydrology of these pools with tools
> similar to r.water.fea. So every cell and its drainage direction
> are important to the simulation.
>
> Thanks--
> Baxter Vieux
> Environmental Modeling and GIS Laboratory
> School of Civil Engineering and Environmental Science
> University of Oklahoma....
> temporarily at....
> Eaux Continentales
> ORSTOM
> Montpellier France
>



