Calculates the long-term mean annual discharge (MAD) from a daily streamflow data set. Calculates statistics from all values, unless specified. Returns a tibble with statistics.

calc_longterm_mean( 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, months = 1:12, percent_MAD, transpose = FALSE )

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

dates | Name of column in |

values | Name of column in |

groups | Name of column in |

station_number | Character string vector of seven digit Water Survey of Canada station numbers (e.g. |

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

roll_align | Character string identifying the direction of the rolling mean from the specified date, either by the first
( |

water_year_start | Numeric value indicating the month ( |

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 |

months | Numeric vector of months to include in analysis (e.g. |

percent_MAD | Numeric vector of percents of long-term mean annual discharge to add to the table (ex. |

transpose | Logical value indicating whether to transpose rows and columns of results. Default |

A tibble data frame of numeric values of a long-term mean (and percent of long-term mean if selected) of selected years and months.

# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat()) if (file.exists(tidyhydat::hy_downloaded_db())) { # Calculate the long-term mean annual discharge (MAD) using only years with no missing data calc_longterm_mean(station_number = "08NM116", complete_years = TRUE) # Calculate the long-term MAD and 5, 10 and 20-percent MADs using only years with no missing data calc_longterm_mean(station_number = "08NM116", complete_years = TRUE, percent_MAD = c(5,10,20)) }#> # A tibble: 1 x 5 #> STATION_NUMBER LTMAD `5%MAD` `10%MAD` `20%MAD` #> <chr> <dbl> <dbl> <dbl> <dbl> #> 1 08NM116 6.20 0.310 0.620 1.24