calculate_total_drainage_area(x)

library(dplyr)
source(system.file("extdata", "walker_data.R", package = "nhdplusTools"))
catchment_area <- select(walker_flowline, COMID, AreaSqKM) %>%
  right_join(prepare_nhdplus(walker_flowline, 0, 0,
                            purge_non_dendritic = FALSE, warn = FALSE), by = "COMID") %>%
  select(ID = COMID, toID = toCOMID, area = AreaSqKM)

new_da <- calculate_total_drainage_area(catchment_area)

catchment_area$totda <- new_da
catchment_area$nhdptotda <- walker_flowline$TotDASqKM

mean(abs(catchment_area$totda - catchment_area$nhdptotda))
max(abs(catchment_area$totda - catchment_area$nhdptotda))