The Zenibako River originates north of Mount Okuteine, near the border with Sapporo City. It runs through mountain woods and meets the Zenibako-tōge River (銭函峠川) as it emerges from the Zenibako Mountain Pass (銭函峠, Zenibako Tōge). Katsuraoka-machi (桂岡町, Katsuraoka Town) is situated around the left bank of its middle course. The river turns eastward where it passes under the Sasson Expressway and National Route 5. It runs through the urban area of Zenibako, turns north, then enters the Ishikari Bay 200 meters southwest of Zenibako Station. The course lower than Route 5 was consolidated with concrete after the 1962 flood.
Biochemical oxygen demand of the water in 2004 was 0.1 mg/L, which means good condition. Water of the upper stream is utilized by the Zenibako Purification Plant in Katsuraoka-machi for the east part of Otaru City's water service. Water hardness of Zenibako is 29 mg/L.
- - Sasson Expressway
- Zenibako Bridge (銭函橋) - Japan National Route 5
- Naka-no-hashi or Naka-no Bridge (仲の橋)
- Sawa-no-hashi or Sawa-no Bridge (沢の橋)
- Zenibako Shimo-no-hashi or Zenibako Shimo-no Bridge (銭函下の橋)
- - Hakodate Main Line
- Zenibako Bridge (銭函橋) - Hokkaidō Prefectural Highway 225, Otaru-Ishikari Line.
- 北海道新聞「昨年度小樽市内の河川水質調査 １位は礼文塚と銭函」(Hokkaido Shimbun "Report in River Water Quality of Otaru City; Tops are Rebunzuka and Zenibako"), January 4, 2000.
- 小樽市 「水道施設位置図[permanent dead link]」 (Otaru City "Water Service Location Map")
- 北海道新聞「小樽の水はうまい！ 中細分化 多数の水源と施設 作りたての味を家庭に」(Hokkaido Simbun "Water of Otaru is delicious: Many small sources and plants serve flesh taste for home"), October 4, 2000. .
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