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Estimate velocity from discharge and hydraulic geometry coefficients

Source: R/calc_velocity.R
calc_velocity.Rd

Uses the relationship \(U=k*Q^m\) (parameter names and definitions as in Leopold and Maddock, 1953; default values for k and m as in Raymond et al. 2012)

Usage

calc_velocity(Q, k = u(0.194, "m s^-1"), m = u(0.285, ""))

Arguments

Q

discharge (m^3 s^-1)

k

coefficient representing velocity at unit discharge (usually m/s; e in Raymond et al.)

m

exponent in velocity-discharge relation (unitless; f in Raymond et al.)

Value

v (= V = U), stream flow velcoity, in the same units as k

References

Raymond, Peter A., Christopher J. Zappa, David Butman, Thomas L. Bott, Jody Potter, Patrick Mulholland, Andrew E. Laursen, William H. McDowell, and Denis Newbold. Scaling the gas transfer velocity and hydraulic geometry in streams and small rivers. Limnology & Oceanography: Fluids & Environments 2 (2012): 41-53.

Leopold, L.B., and Thomas Maddock Jr. The Hydraulic Geometry of Stream Channels and Some Physiographic Implications. Report. Professional Paper, 1953. USGS Publications Warehouse. https://pubs.er.usgs.gov/publication/pp252.

Examples

Qs <- seq(1,9,2)
calc_velocity(Q=Qs)
#> [1] 0.1940000 0.2653269 0.3069080 0.3377961 0.3628782
calc_velocity(Q=Qs, k=0.4)
#> [1] 0.4000000 0.5470658 0.6328000 0.6964869 0.7482024
library(unitted)
calc_velocity(Q=u(Qs, "m^3 s^-1"), m=u(40))
#> unitted numeric (m s^-1)
#> [1] 1.940000e-01 2.358587e+18 1.764420e+27 1.235160e+33 2.867491e+37
calc_velocity(Q=u(Qs, "m^3 s^-1"), k=u(0.36, "m s^-1"))
#> unitted numeric (m s^-1)
#> [1] 0.3600000 0.4923592 0.5695200 0.6268382 0.6733822