Calculate cumulative daily flow statistics — calc_daily_cumulative

Calculate cumulative daily flow statistics for each day of the year of daily flow values from a daily streamflow data set. Defaults to volumetric cumulative flows, can use use_yield and basin_area to convert to area-based water yield. Calculates statistics from all values from all complete years, unless specified. Returns a tibble with statistics.

calc_daily_cumulative_stats(
  data,
  dates = Date,
  values = Value,
  groups = STATION_NUMBER,
  station_number,
  percentiles = c(5, 25, 75, 95),
  use_yield = FALSE,
  basin_area,
  water_year_start = 1,
  start_year,
  end_year,
  exclude_years,
  transpose = FALSE
)

Arguments

data	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	Name of 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	Name of 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	Name of 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	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.
percentiles	Numeric vector of percentiles to calculate. Set to `NA` if none required. Default `c(5,25,75,95)`.
use_yield	Logical value indicating whether to calculate area-based water yield, in mm, instead of volumetric discharge. Default `FALSE`.
basin_area	Upstream drainage basin area, in square kilometres, to apply to observations. Three options: (1) Leave blank if `groups` is STATION_NUMBER with HYDAT station numbers to extract basin areas from HYDAT. (2) A single numeric value to apply to all observations. (3) List each basin area for each group/station in groups (can override HYDAT value if listed) as such `c("08NM116" = 795, "08NM242" = 10)`. If group is not listed the HYDAT area will be applied if it exists, otherwise it will be `NA`.
water_year_start	Numeric value indicating the month (`1` through `12`) of the start of 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 whether to transpose rows and columns of results. Default `FALSE`.

Value

A data frame with the following columns, default units in cubic metres, millimetres if use_yield and basin_area provided:

Date

date (MMM-DD) of daily cumulative statistics

DayofYear

day of year of daily cumulative statistics

Mean

daily mean of all cumulative flows for a given day of the year

Median

daily mean of all cumulative flows for a given day of the year

Maximum

daily mean of all cumulative flows for a given day of the year

Minimum

daily mean of all cumulative flows for a given day of the year

P'n'

each daily n-th percentile selected of all cumulative flows for a given day of the year

Default percentile columns:

daily 5th percentile of all cumulative flows for a given day of the year

P25

daily 25th percentile of all cumulative flows for a given day of the year

P75

daily 75th percentile of all cumulative flows for a given day of the year

P95

daily 95th percentile of all cumulative flows for a given day of the year

Transposing data creates a column of "Statistics" and subsequent columns for each year selected.

Examples

# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat())
if (file.exists(tidyhydat::hy_downloaded_db())) {

# Calculate annual daily cumulative volume statistics
calc_daily_cumulative_stats(station_number = "08NM116") 

# Calculate annual daily cumulative yield statistics 
# with default HYDAT basin area
calc_daily_cumulative_stats(station_number = "08NM116",
                            use_yield = TRUE) 

# Calculate annual daily cumulative yield statistics 
# with custom basin area
calc_daily_cumulative_stats(station_number = "08NM116",
                            use_yield = TRUE,
                            basin_area = 800) 
                            
}
#> Warning: One or more years contained partial data and were excluded. Only years with complete data were used for calculations.
#> Warning: One or more years contained partial data and were excluded. Only years with complete data were used for calculations.
#> Warning: One or more years contained partial data and were excluded. Only years with complete data were used for calculations.
#> # A tibble: 365 x 11
#>    STATION_NUMBER Date  DayofYear  Mean Median Minimum Maximum     P5    P25
#>    <chr>          <chr>     <dbl> <dbl>  <dbl>   <dbl>   <dbl>  <dbl>  <dbl>
#>  1 08NM116        Jan-~         1 0.114 0.0971  0.0354   0.271 0.0537 0.0740
#>  2 08NM116        Jan-~         2 0.224 0.193   0.0689   0.515 0.106  0.147 
#>  3 08NM116        Jan-~         3 0.333 0.288   0.100    0.727 0.157  0.220 
#>  4 08NM116        Jan-~         4 0.443 0.382   0.131    0.961 0.208  0.300 
#>  5 08NM116        Jan-~         5 0.551 0.482   0.164    1.19  0.258  0.384 
#>  6 08NM116        Jan-~         6 0.658 0.571   0.198    1.40  0.309  0.459 
#>  7 08NM116        Jan-~         7 0.768 0.666   0.231    1.61  0.360  0.534 
#>  8 08NM116        Jan-~         8 0.883 0.762   0.265    1.81  0.410  0.607 
#>  9 08NM116        Jan-~         9 0.998 0.865   0.300    2.26  0.459  0.686 
#> 10 08NM116        Jan-~        10 1.11  0.957   0.337    2.76  0.508  0.763 
#> # ... with 355 more rows, and 2 more variables: P75 <dbl>, P95 <dbl>