Volume Calculation of Area for Reservoir Analysis using Grass

GRASS GRASS user
1

Greg:
1. Create mask defining your reservior.
2. Bias elevation model by subtracting lowest point in resevoir
    from all cell values.
3. Invert elevation model to make the hole a hill (r.mapcalc again)
4. Use r.volume (with mask set) to calc volume of hill.

Regards, Jim Hinthorne, CWU GIS Lab.