Flow directions. Variety of algorithms; must chose those that best balance physical understanding, quality of data, and computational
efficiency.
•D-infinity, until channel-initiation criteria is met, then D-8.
•For channels, follow greatest downslope plan curvature.
•For flat areas: flow toward outlets, away from edges.
D-8
D-∞
On a cone
On a plane
From Tarboton, 1997, Water Resources
Research, 33:309-319
Flow Downslope