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Importing flow data from the National River Flow Archive (NRFA)

import_nrfa.Rd

The import_nrfa function downloads mean daily flow data from the NRFA for a user-defined set of sites (gauging stations). Data can be optionally filtered by date.

Usage

import_nrfa(sites, start_date = "1985-01-01", end_data = Sys.Date(), tidyup = TRUE)

Arguments

sites

Vector of site (station) IDs to extract data for. NAs and blanks ("") are ignored

start_date

Start date for flow data extraction (YYYY-MM-DD format). Default = "1985-01-01".

end_date

End date for flow data extraction (YYYY-MM-DD format). Default = today's date.

tidyup

Whether or not csv files downloaded by the function to the users working directory should be deleted afterwards. Default = TRUE.

Value

A tibble containing daily flow data for the specified sites, with the following columns: flow-site_id, date, and flow (in m3/s). (The NRFA database does not contain information about the quality of the flow data.)

Details

The National River Flow Archive (NRFA; http://nrfa.ceh.ac.uk) is the main archive of river flow data for the United Kingdom, and contains data from over 1500 gauging stations. This function downloads flow data from the NRFA as a series of CSV files, one per site, and collates them into a single data set.

The function initially imports flow data for all dates and then filters out records that are before start_date or after end_date. If the data does not span the entire range of dates provided, additional records are created and the flow and quality values defined as NA on these dates.

A warning message is produced for every site that cannot be found on NRFA.

If a site ID is duplicated in the 'sites' argument, that site is only searched for once and a warning message is produced.

Examples

# Import data for selected sites and dates (and keep downloaded CSV files for inspection)
# import_nrfa(sites = c("1001", "2001"), start_date = "2000-01-01", end_date = "2019-12-31", tidyup = FALSE)

# Returns flow = NA if site exists but no data available for the specified date range
# import_nrfa(sites = c("1001"), start_date = "1900-01-01", end_date = "1900-01-05")

# Returns data only for sites that are present in NRFA; see warning messages for missing sites
# import_nrfa(sites = c("1001", "hello"), start_date = "2010-01-01", end_date = "2010-01-05")