Cowan's Method for Estimating Roughness $n$

Method Summary

Figure 4: Cowan method for determining roughness coefficient $n$ (Cowan, 1956; McCuen, 2004).

Basic $n$

Figure 5: Cowan basic roughness value $n_1$ (Cowan, 1956; McCuen, 2004).

Channel Irregularity

Figure 6: Cowan adjustment for channel irregularity $n_2$ (Cowan, 1956; McCuen, 2004).

Cross-Section Changes

Figure 7: Cowan adjustment for channel cross-section changes $n_3$ (Cowan, 1956; McCuen, 2004).

Obstructions

Figure 8: Cowan adjustment for channel obstructions $n_4$ (Cowan, 1956; McCuen, 2004).

Vegetation

Figure 9: Cowan adjustment for vegetation $n_5$ (Cowan, 1956; McCuen, 2004).

Meandering

Figure 10: Cowan adjustment for channel meandering $n_6$ (Cowan, 1956; McCuen, 2004).