CSHShydRology (version 1.4.2)

ch_fdcurve: Plot Flow Duration Curve

Description

A flow duration curve is a plot of flow magnitude against exceedance probability. The plot may contain the Gustard Curves (default) or they can be omitted. The default is for curves to be plotted against probability, but an option is to plot against the normalized exceedance probability. In that case, the x axis represents a normal distribution.

Usage

ch_fdcurve(DF, normal = FALSE, gust = TRUE, metadata = NULL)

Value

Plots the flow duration curve and returns a data frame containing:

exceedance probability

probability

flow

d=flow values

Arguments

DF

a dataframe of daily flows from ch_read_ECDE_flows

normal

If normal = TRUE then exceedance probability is normalized. Default is FALSE.

gust

If TRUE (the default), adds the curves from Gustard et al. 1992 are added.

metadata

dataframe of metadata, defaults to HYDAT_list.

Author

Paul Whitfield

Details

Create a Flow Duration Curve based upon Observations.

References

Gustard, A., A. Bullock, and J.M. Dixon. 1992. Low flow estimation in the United Kingdom. Institute of Hydrology, 292. Wallingford: Institute of Hydrology.

Vogel, R.M., and N.M. Fennessy. 1994. Flow-duration curves. I: New Interpretation and confidence intervals. Journal of Water Resources Planning and Management ASCE 120:485-504.

Vogel, R.M., and N.M. Fennessy. 1995. Flow duration curves II: A review of applications in water resources planning. Water Resources Bulletin 31:1030-9.

Examples

data(HYDAT_list)
data(CAN05AA008)
# plot with Gustard 1992 curves
test <- ch_fdcurve(CAN05AA008, normal = FALSE, gust = TRUE)
# plot with normalized exceedance probability
test <- ch_fdcurve(CAN05AA008, normal = TRUE, gust = FALSE)