Channel Size & Order Influences

Stream order is often cataloged with the readily measured channel size, or width, data to enable comparisons of both order and width across watersheds.

Knowledge of the channel width helps operational forecasters in understanding the relevant magnitude of obstructions, as well interpreting relative roughness ratios. Widths are ranked from:

• < 1 ft
• 1 - 5 ft
• 5 - 15 ft
• 15 - 30 ft
• 30 - 50 ft
• 50 - 75 ft
• 75 - 100 ft
• 100 - 150 ft
• 150 - 250 ft
• 250 - 350 ft
• 350 - 500 ft
• 500 - 1000 ft
• > 1000 ft

For example, on relatively large channels with widths of 500 to 1000 feet, velocity is greater and roughness less than for the same type, but relatively narrow channels with widths 5 to 15 feet.

Image courtesy of FISRWG