Description Usage Arguments Details Value Note Author(s) References Examples
View source: R/getRatingPoints.R
For a given open channel profile defined by z
in the vertical,
x
in the horizontal, slope m
, and Strickler value
k
, streamflow velocity is calculated for the water levels
l
according to the Strickler formula
v = k*R^(2/3)*m^(1/2)
with hydraulic radius R = area/radius.
1 | getRatingPoints(z, x, k, m, l, plot = FALSE)
|
z |
numeric vector. Altitude [m] with respect to e.g. sea level or any other reference point. |
x |
numeric vector. Points along the channel profile where
|
k |
real number or numeric vector. Defines the Strickler
value(s) [m^(1/3)/s]. In case of a vector, |
m |
real number. Slope of the river bed perpendicular to the channel profile, m = tan(α). |
l |
numeric vector. Positive water levels [m] for which the corresponding discharge should be calculated. |
plot |
logical. Plot the channel profile? |
The reference point for water levels l
is defined as the point in
x
where z
reaches its minimum.
Numeric matrix with columns water 'level' [m], profile 'area' below the water table [m^2], wet profile 'radius' [m], interpolated 'k', streamflow 'velocity' [m/s], and 'discharge' [m^3/s].
The Strickler formula is also known as Manning or Gauckler formula.
Original code provided by Alain B.
Strickler, A. (1924). "Beitraege zur Frage der Geschwindigkeitsformel und der Rauigkeitszahlen fuer Stroeme, Kanaele und geschlossene Leitungen". Schweizerische Bauzeitung, Heft 23.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | ## quadratic profile
z <- c(10,0,0,10)
x <- c(0,0,10,10)
k <- sample(0:100,size=length(z))
m <- 0.03
l <- 1:10
pq <- getRatingPoints(z=z,x=x,k=k,m=m,l=l,plot=TRUE)
print(pq)
plot(x=pq[,'level'],y=pq[,'discharge'])
## trapezoid
z <- c(2,0,0,2)
x <- c(1,3,4,6)
k <- 30
m <- 0.1
l <- seq(0,1.5,by=0.2)
pq <- getRatingPoints(z=z,x=x,k=k,m=m,l=l,plot=TRUE)
print(pq)
plot(x=pq[,'level'],y=pq[,'discharge'])
## 'natural' channel
z <- c(9,9,9,10,9,8,7,6,7,8,7,6,5,4,3,4,5,6,5,4,1,4,5,6,7,8,9,8,7,8,8)
x <- c(1:25,23:28)
k <- sample(0:100,size=length(z))
m <- 0.03
l <- 1:13
pq <- getRatingPoints(z=z,x=x,k=k,m=m,l=l,plot=TRUE)
print(pq)
plot(x=pq[,'level'],y=pq[,'discharge'])
|
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