fasstr (version 0.3.1)

calc_annual_flow_timing: Calculate annual flow timing

Description

Calculates annual the timing (day of year) and date of occurrence of portions of total annual flow of daily flow values from a streamflow dataset. Calculates the statistics from all daily discharge values from all years with complete annual data, unless specified.

Usage

calc_annual_flow_timing(
  data,
  dates = Date,
  values = Value,
  groups = STATION_NUMBER,
  station_number,
  percent_total = c(25, 33.3, 50, 75),
  water_year_start = 1,
  start_year,
  end_year,
  exclude_years,
  transpose = FALSE
)

Arguments

data

A data frame of daily data that contains columns of dates, flow values, and (optional) groups (e.g. station numbers). Leave blank if using station_number argument.

dates

Column in data that contains dates formatted YYYY-MM-DD. Only required if dates column name is not ' Date' (default). Leave blank if using station_number argument.

values

Column in data that contains numeric flow values, in units of cubic metres per second. Only required if values column name is not 'Value' (default). Leave blank if using station_number argument.

groups

Column in data that contains unique identifiers for different data sets, if applicable. Only required if groups column name is not 'STATION_NUMBER'. Function will automatically group by a column named 'STATION_NUMBER' if present. Remove the 'STATION_NUMBER' column beforehand to remove this grouping. Leave blank if using station_number argument.

station_number

A character string vector of seven digit Water Survey of Canada station numbers (e.g. "08NM116") of which to extract daily streamflow data from a HYDAT database. Requires tidyhydat package and a HYDAT database. Leave blank if using data argument.

percent_total

Numeric vector of percents of total annual flows to determine dates. Default c(25,33.3,50,75).

water_year_start

Numeric value indicating the month of the start of the water year for analysis. Default 1.

start_year

Numeric value of the first year to consider for analysis. Leave blank to use the first year of the source data.

end_year

Numeric value of the last year to consider for analysis. Leave blank to use the last year of the source data.

exclude_years

Numeric vector of years to exclude from analysis. Leave blank to include all years.

transpose

Logical value indicating if the results rows and columns are to be switched. Default FALSE.

Value

A tibble data frame with the following columns:

Year

calendar or water year selected

DoY_'n'pct_TotalQ

day of year for each n-percent of total volumetric discharge

Date_'n'pct_TotalQ

date (YYYY-MM-DD) for each n-percent of total volumetric discharge

Default columns:

DoY_25pct_TotalQ

day of year of 25-percent of total volumetric discharge

Date_25pct_TotalQ

date (YYYY-MM-DD) of 25-percent of total volumetric discharge

DoY_33.3pct_TotalQ

day of year of 33.3-percent of total volumetric discharge

Date_33.3pct_TotalQ

date (YYYY-MM-DD) of 33.3-percent of total volumetric discharge

DoY_50pct_TotalQ

day of year of 50-percent of total volumetric discharge

Date_50pct_TotalQ

date (YYYY-MM-DD) of 50-percent of total volumetric discharge

DoY_75pct_TotalQ

day of year of 75-percent of total volumetric discharge

Date_75pct_TotalQ

date (YYYY-MM-DD) of 75-percent of total volumetric discharge

Transposing data creates a column of 'Statistics' (just DoY, not Date values) and subsequent columns for each year selected.

References

• Barnett, T.P., Pierce, D.W., Hidalgo, H.G., Bonfils, C., Santer, B.D., Das, T., Bala, G., Wood, A.W., Nozawa, T., Mirin, A.A., Cayan, D.R., Dettinger, M.D., 2008. Human-Induced Clanges in the Hydrology of the Western United States. Science 319, 1080-1083.

Examples

# NOT RUN {
# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat())
if (file.exists(tidyhydat::hy_downloaded_db())) {

# Calculate annual flow timings with default percent of annual totals
calc_annual_flow_timing(station_number = "08NM116") 

# Calculate annual flow timings with custom percent of annual totals
calc_annual_flow_timing(station_number = "08NM116",
                        percent_total = 50)
                             
}
# }