diff --git a/workspace/00_enhd_nwm_network.Rmd b/workspace/00_enhd_nwm_network.Rmd
index a7450cd34e509c5202e37c40e4441b716fc3f9a4..1f4a2451179e86d32078de8f781dc96acc8ad846 100644
--- a/workspace/00_enhd_nwm_network.Rmd
+++ b/workspace/00_enhd_nwm_network.Rmd
@@ -184,9 +184,19 @@ 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.
+# use infrequently!! 
+# mainstems <- sf::read_sf("https://www.hydroshare.org/resource/4a22e88e689949afa1cf71ae009eaf1b/data/contents/mainstems.gpkg")
+# 
+# mainstems <- select(sf::st_drop_geometry(mainstems), 
+#                     id, uri)
+# 
+# mainstems <- mutate(mainstems, id = as.integer(id)) %>%
+#   rename(mainstem_id = id)
+# 
 # mainstem_lookup <- select(net_new, nhdpv2_comid = comid, mainstem_id = levelpathi)
+# mainstem_lookup <- left_join(mainstem_lookup, mainstems, by = "mainstem_id")
 # readr::write_csv(mainstem_lookup, "data/mainstem_lookup.csv")
+# R.utils::gzip("data/mainstem_lookup.csv")
 
 ### ONLY RUN IF CHANGED ###
 # sbtools::authenticate_sb()
diff --git a/workspace/data/mainstem_lookup.csv.gz b/workspace/data/mainstem_lookup.csv.gz
new file mode 100644
index 0000000000000000000000000000000000000000..3291f82b95832fbe0e8a06277ab6720487093022
Binary files /dev/null and b/workspace/data/mainstem_lookup.csv.gz differ