add_cumulative_yield: Add a daily cumulative water yield column to daily flows

In fasstr: Analyze, Summarize, and Visualize Daily Streamflow Data

Add a daily cumulative water yield column to daily flows

Description

Add a column of rolling daily cumulative water yields on an annual basis to a daily streamflow data set. Adds the water yields from each day with the previous day(s) for each year, in units of millimetres. Converts cumulative discharge to a depth of water based on the upstream drainage basin area from basin_area argument. The cumulative flows restart every year and are only calculated in years with complete data.

Usage

add_cumulative_yield(
  data,
  dates = Date,
  values = Value,
  groups = STATION_NUMBER,
  station_number,
  basin_area,
  water_year_start = 1,
  months = 1:12
)

Arguments

data	Data frame of daily data that contains columns of dates, flow values, and (optional) groups (e.g. station numbers). Leave blank or set to NULL 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 or set to NULL 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.
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.
months	Numeric vector of months to add cumulative flows. For example, 3 for March, 6:8 for Jun-Aug or c(10:12,1) for first four months (Oct-Jan) when water_year_start = 10 (Oct). Default summarizes all months (1:12).

Value

A tibble data frame of the source data with an additional column:

Cumul_Yield_mm

cumulative yield flows for each day for each year, in units of millimetres

Examples

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

# Add a column based on water years starting in August
add_cumulative_yield(station_number = "08NM116", 
                     water_year_start = 8)
                     
# Add a column based on water years starting in August with a custom basin area to calculate yield
add_cumulative_yield(station_number = "08NM116", 
                     water_year_start = 8,
                     basin_area = 800)
                     
}

fasstr documentation built on Sept. 30, 2024, 9:24 a.m.