274-dev: drop 名称不明 and ベリベツ川 from the watercourse shortlist

Author's calls: 名称不明 has no name to use, and ベリベツ川 is mostly farm
waterway now and sits west of 川端橋, outside the range.

デチン沢川 kept pending verification — 沙流川水系, 河川コード 8101070000
(the 「その他」 group), 42.87965 / 142.43823.

Notes that the list is a shortlist to pick from, not a set of things each
of which earns a line.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S6MpcBisZYhX45oDGRRJoz

wip/274-dev.md

@@ -110,7 +110,6 @@ Offset is closest approach; under ~30 m means the road crosses it.
 
 | km | Offset (m) | Watercourse | Water system | Source |
 |--:|--:|---|---|---|
-| 37.38 | 171 | ベリベツ川 | — | OSM only |
 | 41.02 | 58 | 砂金川 | 石狩川水系 | both |
 | 43.64 | 84 | 草木川 | 石狩川水系 | both |
 | 44.00 | 21 | 草木舞沢川 | 石狩川水系 | both |
@@ -123,7 +122,6 @@ Offset is closest approach; under ~30 m means the road crosses it.
 | 58.26 | 9 | ホルカクルキ川 | 石狩川水系 | both |
 | 58.56 | 52 | 滝沢川 | 石狩川水系 | both |
 | 59.54 | 58 | 松竹沢川 | 石狩川水系 | both |
-| 63.02 | 8 | 名称不明 | 鵡川水系 | W05 only |
 | 66.86 | 161 | 石山の沢川 | 鵡川水系 | both |
 | 67.62 | 5 | サヌシュッペ川 | 鵡川水系 | both |
 | 70.22 | 32 | 穂別川 | 鵡川水系 | both |
@@ -145,13 +143,14 @@ Offset is closest approach; under ~30 m means the road crosses it.
 | 107.29 | 18 | 滝の沢川 | 沙流川水系 | both |
 | 107.83 | 134 | ルウケシオマナイ川 | 沙流川水系 | both |
 
-Three to treat with care:
+Excluded by the author, 2026-09-10:
 
-- **名称不明**, 63.02 km, 8 m off. W05 carries it with no name at all — the register has
-  a name-shaped hole. Absent from OSM.
-- **デチン沢川**, 102.90 km, in 日高 town. In W05, missing from OSM.
-- **ベリベツ川** is named in both datasets, but the W05 geometry never comes within 300 m
-  of the road while OSM puts it 171 m away at 37.38 km, right at 川端橋.
+- **名称不明** (63.02 km) — W05 carries it with no name; dropped.
+- **ベリベツ川** (37.38 km in OSM, never within 300 m in W05) — mostly converted to farm
+  waterway, and it sits marginally west of 川端橋, outside the range.
+
+**デチン沢川**, 102.90 km, is 沙流川水系, 河川コード 8101070000 — the 「その他」 group rather
+than a named river of its own. Pending the author's check against the NII database.
 
 **サヌシュッペ川** is not a disagreement: it runs beside the road rather than crossing it,
 so each dataset is tangent at a different reach (62.46 / 67.62). The crossing is at
@@ -165,6 +164,9 @@ counter to its parent river, so the name records a hydrological fact. The same e
 appears on **ホロカユウパロ川** elsewhere in the 石狩川 system — the Ainu form behind 夕張.
 route01's ホロカクルキ川 is a slip: the writer applied the Ainu form to the Japanese name.
 
+This list is a shortlist, not a programme. Most of these are minor streams and are here
+so they can be picked from, not because each earns a line.
+
 ### PoI, in road order
 
 | km | Offset (m) | Kind | Name |