n_direct {HYDROCAL}

Compute total channel roughness via direct field measurement

Description

n_direct calculate Manning's n using direct measurements

Usage

n_direct(radius, slope, velocity, restrict = TRUE)

Arguments

radius

hydraulic radius (R) in meters

slope

channel slope (S) in m/m

velocity

average velocity (U) in meters per second

restrict

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

Value

Manning's n

Examples

# Result: Manning's n of 0.710 
n_direct(2,0.05,0.5)

# Result: Manning's n of 3.216
n_direct(10,0.03,0.25)

# Result: Manning's n of 5.440
n_direct(22,0.12,0.5)

# Result: Hydraulic radius cannot be negative.
n_direct(-2,0.12,0.5)