R/old_udout.R

In taywater/pwdgsi: Philadelphia Water Department Green Stormwater Infrastructure

old_udout <- function(dtime_est, 
                                     waterlevel_ft, 
                                     orifice_height_ft,
                                     orifice_diam_in,
                                     #DEFAULT VALUES
                                     discharge_coeff = 0.62){ #Orifice discharge coefficient
  
  #1. Prepare data
  #1.1 Initialize data frame
  df <- tibble::tibble(dtime_est = lubridate::force_tz(dtime_est, tz = "EST"),
                       depth_ft = waterlevel_ft)#, #observed data
  #elapsed_time_hr = 0, 
  #WL_above_orifice_ft = 0,
  #slow_release_vol_ft3 = 0) 
  
  #2. Calculate Orifice Outflow
  # Orifice equation:
  # Q_orifice = C * Area * sqrt(2 * gravity * depth) * time
  
  #2.1 Calculate area of orifice (ft2)
  orifice_area_ft2 <- pi*((orifice_diam_in[1]/12)^2)/4 #area of orifice (ft2)
  
  df <- df %>%
    dplyr:: mutate(#2.2 calculate elapsed time (hrs) 
      elapsed_time_hr = difftime(dtime_est, dplyr::lag(dtime_est), units = "hours"), #difftime(lead(dtime_est), dtime_est, units = "hours"),
      
      #2.3 Calculate height of water above orifice (ft)
      WL_above_orifice_ft = depth_ft - orifice_height_ft[1],
      
      #2.4 Set height of water to 0 if below elevation of orifice
      WL_correction = ifelse(WL_above_orifice_ft < 0,0, WL_above_orifice_ft),
      
      #2.4 Calculate total discharge through orifice
      slow_release_ft3 = discharge_coeff*
        orifice_area_ft2*
        sqrt(2 * 32.2 * WL_correction) * 
        60*60 * #convert cfs to cfhr     
        as.numeric(elapsed_time_hr))


  return(df$slow_release_ft3)
}