calc_A: Calculate Flow Area

In jschap1/WSEw: River Geometry Package for Studying Water Surface Elevation-Width Relationships

Description

Calculates cross sectional area of flow for a particular water surface elevation, ranging from empty channel to bankfull conditions.

Usage

calc_A(x, b, WSE, N = length(x), method = "trap")

Arguments

x	distance from horizontal datum
b	channel bed elevation
WSE	water surface elevation
N	spatial discretization, do not modify, except possibly for Riemann method
method	"trap" "riemann" or "simpson" Default is trapezoidal.

Details

Takes cross section info as input. calc_A_from_WSEw() is more efficient if WSE-w info is available Uses a numerical method to approximate the integral of the difference between WSE and bed elevation The numerical method only counts area where the WSE is higher than the bed elevation Needs more work to figure out how to implement arbitrary spatial discretization Need to do code testing, too. Confirmed that riemann and trap methods give similar results, but are they correct? Combine with calc_WP function/put in the same R file

Value

A true cross sectional flow area

Examples

calc_A(x = cross_sections$x[[1]], b = cross_sections$b[[1]], WSE = 138)
x <- c(1,1,1,2,3,4,4,4)
b <- c(3,2,1,1,1,1,2,3)
A <- calc_A(x, b, WSE = 3)
A <- calc_A(x, b, WSE = 2)

jschap1/WSEw documentation built on May 12, 2019, 10:50 a.m.