estimateBaseflow: Estimate baseflow

In hydro-giub/hydroBE: Miscellaneous Functions of the Group of Hydrology Bern

Description

Baseflow summarises the runoff contributions from slowly varying hydrological storages after the offset of a rain event and can be estimated by the interpolation of local minima.

Usage

estimateBaseflow(y, win = 5, r = 0.9, plot = FALSE,
                 use.spline = FALSE, ...)

Arguments

y	numeric vector. A strictly regular streamflow series (usually on a daily basis).
win	integer. Block width in number of time units to find local minima.
r	real number. Denotes the ratio for constraining baseflow ordinates out of the local minima; often set around 0.9.
plot	logical. Plot runoff and corresponding baseflow series?
use.spline	logical. Interpolate baseflow ordinates by spline smoothing?
...	additional arguments. Passed to spline.

Details

The series will be truncated to the last length(y)%%win entries in y to match whole multiples of win. A baseflow ordinate x(t) is defined by

x(t-1) > r*x(t) < x(t+1)

where x is a local minimum in a window of length win. Missing values do not satisfy this inequality (see 'Examples').

Value

Numeric vector with estimated baseflow values.

Note

Package EcoHydRology provides a different approach for baseflow estimation.

Author(s)

Simon S

References

Gustard, A., A. Bullock, and J. M. Dixon (1992). "Low flow estimation in the United Kingdom". Report No. 108. Institute of Hydrology.

Examples

## handling of NAs
y <- rnorm(202)
y[sample(1:200,2)] <- NA
b <- estimateBaseflow(y=y,plot=TRUE)

## mimic a streamflow series
n <- 400
f <- c(10,8,6,3,2,1,0.1,0.01)
p <- exp(rnorm(n))
y1 <- filter(p,filter=f/sum(f),sides=1)
y2 <- sin(seq(0,4*pi,length.out=n))+1 
y <- y1+y2

## use spline interpolation
b <- estimateBaseflow(y=y,plot=TRUE,use.spline=TRUE)

## estimate the baseflow index (BFI)
sum(b,na.rm=TRUE)/sum(y[!is.na(b)])

hydro-giub/hydroBE documentation built on Sept. 20, 2019, 9:27 a.m.