Calculates stream power for each cross section in the input xs_dims data frame.
stream_power(
xs_dims,
discharge_method = c("model_measure", "regional_curve", "width_relationship"),
discharge_value = NULL,
region = NULL,
drainage_area = NULL,
width_method = NULL
)data frame; A data frame of cross section dimensions.
character; The method for calculating discharge (Q). Must be one of: "model_measure", "regional_curve", "width_relationship".
numeric; The discharge value (single value or vector) to use for the stream power calculation. Required if discharge_method = "model_measure".
character; The regional curve name used to calculate discharge. Required if discharge_method = "regional_curve". This parameter is passed to the RegionalCurve::RHG function. See the RegionalCurve package for a list of regions with discharge relationships.
numeric; The drainage area (single value or vector) used by the RegionalCurve::RHG function to calculate discharge. Required if discharge_method = "regional_curve".
character; The name of the width relationship used to calculate discharge (Q) from width. Required if discharge_method = "width_relationship". Must be one of: <list goes here when implemented>
Returns the input xs_dims data frame of cross sections with the calculated stream power variables added.
Stream Power Equations Stream power is the rate of energy dissipation against the bed and banks of a river or stream per unit downstream length. It is given by the equation:
$$\Omega = \rho g Q S$$
where \(\Omega\) is the stream power (kg/m/sec), \(\rho\) is the density of water (assumes 1000 kg/m^3), \(g\) is acceleration due to gravity (9.8 m/s2), \(Q\) is discharge (m^3/s), and \(S\) is the channel slope (m/m).
Unit stream power is stream power per unit channel width, and is given by the equation:
$$\omega = (\rho g Q S) / b$$
where \(\omega\) is the unit stream power, and \(b\) is the width of the channel (m).
https://en.wikipedia.org/wiki/Stream_power
Lane's Balance Equation Stream power in the Lane's Balance equation is simply represented by discharge \(Q\) and slope \(S\):
$$\omega = Q S$$
Determining Discharge
The discharge_method parameter specifies the source used for the
discharge factor in the stream power equations.
model_measure Use this option to supply an estimate of
discharge from a hydraulic model or field measurement.
regional_curve Use this option to use an estimate of
discharge from a regional curve.
width_relationship Use this option to use an estimate of
discharge from a width relationship
# Calculate cross section dimensions
xs_dims <- cross_section_dimensions_L2(xs = fluvgeo::sin_riffle_channel_sf,
xs_points = fluvgeo::sin_riffle_channel_points_sf,
bankfull_elevation = 103,
lead_n = 1,
use_smoothing = TRUE,
loess_span = 0.5,
vert_units = "ft")
#> [1] "Sinsinawa"
#> slope and sinuosity complete
#> xs 1 metrics complete
#> xs 2 metrics complete
#> xs 3 metrics complete
#> xs 4 metrics complete
#> xs 5 metrics complete
#> xs 6 metrics complete
#> xs 7 metrics complete
#> xs 8 metrics complete
#> xs 9 metrics complete
#> xs 10 metrics complete
#> join of reach_geoms and xs_reach_geoms complete
# Calculate stream power
xs_dims_sp <- stream_power(xs_dims,
discharge_method = "regional_curve",
region = "Illinois River",
drainage_area = 41)