fasstr (version 0.3.1)

plot_flow_duration: Plot flow duration curves

Description

Plots flow duration curves, percent time a flow value is equalled or exceeded, for a streamflow dataset. Plots statistics from all daily discharge values from all years, unless specified. Data calculated using calc_longterm_stats() function then converted for plotting.

Usage

plot_flow_duration(
  data,
  dates = Date,
  values = Value,
  groups = STATION_NUMBER,
  station_number,
  roll_days = 1,
  roll_align = "right",
  water_year_start = 1,
  start_year,
  end_year,
  exclude_years,
  complete_years = FALSE,
  custom_months,
  custom_months_label,
  ignore_missing = FALSE,
  months = 1:12,
  include_longterm = TRUE,
  log_discharge = TRUE,
  include_title = 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.

roll_days

Numeric value of the number of days to apply a rolling mean. Default 1.

roll_align

Character string identifying the direction of the rolling mean from the specified date, either by the first ('left'), last ('right), or middle ('center') day of the rolling n-day group of observations. Default 'right'.

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.

complete_years

Logical values indicating whether to include only years with complete data in analysis. Default FALSE.

custom_months

Numeric vector of months to combine to summarize (ex. 6:8 for Jun-Aug). Adds results to the end of table. If wanting months that overlap calendar years (ex. Oct-Mar), choose water_year_start that begins before the first month listed. Leave blank for no custom month summary.

custom_months_label

Character string to label custom months. For example, if choosing months 7:9 you may choose "Summer" or "Jul-Sep". Default "Custom-Months".

ignore_missing

Logical value indicating whether dates with missing values should be included in the calculation. If TRUE then a statistic will be calculated regardless of missing dates. If FALSE then only statistics from time periods with no missing dates will be returned. Default FALSE.

months

Numeric vector of month curves to plot. NA if no months required. Default 1:12.

include_longterm

Logical value indicating whether to include longterm curve of all data. Default TRUE.

log_discharge

Logical value to indicate plotting the discharge axis (Y-axis) on a logarithmic scale. Default FALSE.

include_title

Logical value to indicate adding the group/station number to the plot, if provided. Default FALSE.

Value

A list of ggplot2 objects with the following for each station provided:

Flow_Duration

a plot that contains flow duration curves for each month, long-term, and (option) customized months

See Also

calc_longterm_daily_stats

Examples

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

# Plot flow durations using a data frame and data argument with defaults
flow_data <- tidyhydat::hy_daily_flows(station_number = "08NM116")
plot_flow_duration(data = flow_data,
                    start_year = 1980)

# Plot flow durations using station_number argument with defaults
plot_flow_duration(station_number = "08NM116",
                   start_year = 1980)

# Plot flow durations and add custom stats for July-September
plot_flow_duration(station_number = "08NM116",
                   start_year = 1980,
                   custom_months = 7:9,
                   custom_months_label = "Summer")
                   
}
# }