HYDROCAL (version 1.0.0)

n_brownlie1981: Compute form roughness via Brownlie (1981)

Description

n_brownlie1981 calculate Manning's n using the Brownlie (1981) Method for estimating form roughness.

Usage

n_brownlie1981(depth, slope, d16, d50, d84, restrict = TRUE)

Value

Manning's n

Arguments

depth

flow depth (H) in meters (m). The original model was calibrated for 0.025 m < H < 17 m.

slope

channel slope (S) in (m/m). The original model was calibrated for 3*10^-6 < S < 0.037.

d16

grain size (d16) in millimeters.

d50

grain size (d50) in millimeters. The original model was calibrated for 0.088 mm < d50 < 2.8 mm.

d84

grain size (d84) in millimeters.

restrict

allows for function parameters to restrict certain values. Type bool. Default TRUE.

References

Brownlie, W. R. 1981. Prediction of flow depth and sediment discharge in open channels. Report No. KH-R-43A. W.M. Keck Laboratory of Hydraulics and Water Resources. California Institute of Technology.

Examples

# Result: Manning's n of 0.022
n_brownlie1981(10,0.02,1,1.1,1.2)

# Result: Manning's n of 0.018
n_brownlie1981(2.5,0.01,0.1,0.2,0.5)

# Result: Manning's n of 0.045
n_brownlie1981(15,0.003,0.6,0.9,1)

# Result: Depth must be within 0.025 and 17 m.
n_brownlie1981(20,0.003,0.6,0.9,1)