bfi: Baseflow Separation

In USGS-R/DVstats: Functions to manipulate daily-values data

Baseflow Separation

Description

Extract baseflow from a daily streamflow record using the method proposed by the Institute of Hydrology (1980a,b).

Usage

bfi(Flow, Dates, Start = NULL, End = NULL, by = "water year", f = 0.9,
  N = 5L, STAID = "Unknown")

Arguments

Flow	the daily streamflow to be separated missing values are not permitted within the time specified by Start and end.
Dates	the date for each x, should be of class "Date." Missing values are not permitted.
Start	the start date for the analysis, can be either a character string or class "Date."
End	the end date for the analysis, can be either a character string or class "Date."
by	string describing how to construct turning points. See Details.
f	the factor for identifying turning points.
N	the time perod for period for calculating the turning points.
STAID	the station identifier for the data.

Details

The original description of constructing turning points proposed dividing water years into 5-day increments and selecting the minimum flow for each period. Gustard and others (1992) describe using continuous 5-day increments rather than restarting on the water year.

The bfi program developed by Wahl and Wahl available at https://www.usbr.gov/pmts/hydraulics_lab/twahl/bfi/ uses the continuous record for constructing the N-day periods. The argument by can select either water year, continuous or calendar year records.

Value

an object of class "baseflow" and inherits class "data.frame" of the selected data, a data frame of the baseflow information, and other information about the analysis.

References

Gustard, A., Bullock, A., and Dixon, J.M., 1992, Low flow estimation in the United Kingdom: Institue of Hydrology Report No. 108, 88 p. and appendixes.

Institute of Hydrology, 1980, Low flow studies: Wallingford, Oxon, United Kingdom, Report No. I, 41 p.

Institute of Hydrology, 1980, Low flow studies: Wallingford, Oxon, United Kingdom, Report No. 3, p. 12- 19.

Examples

## Not run: 
library(smwrData)
data(ChoptankFlow)
# Process by calendar year as that is the retrieval range
ChopBFI <- with(ChoptankFlow, bfi(Flow, datetime, by="calendar year",
STAID="01491000"))
head(ChopBFI, 20)

## End(Not run)

USGS-R/DVstats documentation built on Oct. 11, 2022, 6:03 a.m.