add mainstem lookup csv

workspace/00_enhd_nwm_network.Rmd

@@ -185,10 +185,13 @@ fline <- right_join(fline, net_new, by = c("COMID" = "comid"))
 
 write_sf(fline, "cache/enhd_atts_fline.gpkg")
 
-
 fst::write_fst(net_new, "cache/enhd_nhdplusatts.fst")
 arrow::write_parquet(net_new, "cache/enhd_nhdplusatts.parquet")
 
+# Only used once.
+# mainstem_lookup <- select(net_new, nhdpv2_comid = comid, mainstem_id = levelpathi)
+# readr::write_csv(mainstem_lookup, "data/mainstem_lookup.csv")
+
 ### ONLY RUN IF CHANGED ###
 # sbtools::authenticate_sb()
 # sbtools::item_replace_files("60c92503d34e86b9389df1c9", "cache/enhd_nhdplusatts.csv")