Shizunai River

Shizunai River (静内川) is a river in Shinhidaka, Hokkaidō, Japan. The Shizunai River drains from the Hidaka Mountains into the Pacific Ocean.

Etymology
The Shizunai River was known as Shibuchari and Shibechari. This name was derived from Shipe-ichan, meaning "a salmon spawning place" in Ainu.

The name Shizunai is derived from the Ainu language and has three possible sources:
 * Shiputnai – A marsh at the origin of the Ainu.
 * Shuttonai – A marsh with many grapes.
 * Shutnai – A river at the foot of a mountain.

Course
The Shizunai River flows generally southwest from its headwaters in the Hidaka mountains at the confluence of the Koikakushushibichari and Koibokushushibichari rivers. It flows into Lake Takami (高見湖), a reservoir created by the Takami Dam. Past the dam, the Shizunai river flows into Shizunai Flood Control Reservoir (静内調整池). Past the Shizunai Dam, the river encounters Futa Dam before leaving the mountains for the flood plain. The river flows past the outlying communities of Shizunai before entering the Pacific Ocean just northwest of Shizunai harbor.

Natural history
The Shizunai River was designated as a wildlife protection area in 1965. Whooper swans overwinter on the Shizunai River.

History
The Shizunai River basin was the home of the Ainu leader who led Shakushain's revolt against the Shogunate-era Yamato people, especially the Matsumae clan, in the 1660s. In the Edo period the region was used for gold mining.

List of bridges and dams
From river mouth to source:
 * Shizunai Bridge (静内橋)
 * Rubeshibe Bridge (碧蘂 橋)
 * Misono Bridge (御園橋)
 * Futa Dam (双ダム)
 * Shizunai Dam (静内ダム)
 * Menashi River Bridge (目梨別橋)
 * Takami Dam (高見ダム)
 * Takami Bridge (高見橋)
 * Ibetsu Bridge (威別大橋)

List of (named) tributaries
From river mouth to source:
 * 1) Left — Hidaka Mena River (日高目名川)
 * 2) Right — Perari River
 * 3) Left — Mount Sumi River (炭山) charcoal or coal mountain river
 * 4) Left — Shunbetsu River
 * 5) Right — Poyoppusawa River
 * 6) Right — Pisenaisawa River
 * 7) Left — Penkeonikemushi River
 * 8) Left — Ponpanbetsu Creek
 * 9) Left — Penkebetsusawa River
 * 10) Left — Porokaunnai River
 * 11) Right — Ibetsusawa River
 * 12) Right — Abeunnai River
 * 13) Confluence Left — Koibokushuchchari, Right — Koikakushuppichari