streamdef {lfstat}

Streamflow Deficit

Description

Calculates the streamflow deficit. Deprecated, use find_droughts instead.

Usage

streamdef(lfobj,
          pooling = c("none", "MA", "IT", "IC"),
          threslevel = 70,
          thresbreaks = c("fixed","monthly","daily","seasonal"),
          breakdays = c("01/06","01/10"),
          MAdays = 7,
          tmin = 5,
          IClevel = 0.1,
          mindur = 0,
          minvol = 0,
          table = c("all", "volmax", "durmax"),
          na.rm = TRUE)

Arguments

lfobj

An object of class "lfobj"

pooling

The pooling procedure used, "MA" stands for moving average, "IT" is the inter event time and "IC" is Lena Tallaksen's inter event time and volume criterion.

threslevel

The threshold level, 70 means that Q70 should be used as threshold

thresbreaks

The periods for which separated thresholds should be used, 'fixed' uses a constant threshold, 'monthly' uses monthly breaks, 'daily' takes daily threshold levels. If 'seasonal' is specified, you can enter the break days manually using 'breakdays'.

breakdays

A vector of break days if thresbreaks = "seasonal". Please enter the break days using the format "

MAdays

If pooling = "MA" this is the number of days that should be averaged

tmin

Defines the number of days that low flow events must be separated within the "IT" or "IC" method.

IClevel

The ratio between inter-event excess volume in the "IC" method

mindur

The minimal duration of a low flow event in "IC" and "IT" method

minvol

The minimal deficit in a low flow period in "IC" and "IT" method

table

Should the output be a table of "all" deficit, "volmax" annual volume maxima or "durmax" annual duration maxima

na.rm

Should NAs be removed?

Details

When method 'MA' is applied, the first and last MAdays/2 are not averaged, their original value is taken instead!

Value

A data frame containing characteristics of all low flow periods.

d

The duration of the low flow event

v

The drought volume (negative Values, as it is a deficit)

mi

The drought magnitude, i.e. the (positive) ratio between deficit volume and deficit duration

Qmin

The minimum flow of the low flow period

startyear

Year of the start of the low flow period

startmonth

Month of the start of the low flow period

startday

Day of the start of the low flow period

Please note that when using the "IT" method the end date of the low flow period is not necessarily start date + duration.

Author(s)

Daniel Koffler and Gregor Laaha

References

Gustard, A. & Demuth, S. (2009) (Eds) Manual on Low-flow Estimation and Prediction. Operational Hydrology Report No. 50, WNO-No. 1029, 136p.

See Also

streamdefplot, createlfobj, find_droughts

Examples

data(ngaruroro)
ng <- subset(ngaruroro, hyear > 1980)

# Full Table
streamdef(ng, pooling = "MA", MAdays = 6)

# Annual Volume-Maxima only
streamdef(ng, pooling = "MA", MAdays = 6,table = "volmax")