Kinokawa River

This river flows almost in a straight line west along the Median Tectonic Line at the southern foot of the Izumi Mountains in northern Wakayama Prefecture, and enters the Kii Channel in Wakayama City. It is called Kinokawa because it is the first river in Kii Province. It is a first-class river. Its upstream is the Yoshino River, which originates from Mount Odaigahara (1,695 meters) in Nara Prefecture, and is called Kinokawa once it enters Wakayama Prefecture, but the River Law defines the entire river as Kinokawa. It has a length of 136 kilometers (55 kilometers within Wakayama Prefecture), and a drainage area of ​​1,750 square kilometers. If the drainage area of ​​the upstream Totsukawa River due to the construction of the Sarutani Dam is added, the area becomes 2,113 square kilometers. Most of the drainage basin is mountainous, but the Wakayama Plain at the river's mouth is the largest in the prefecture, and the population of the drainage basin in the prefecture accounts for 55% of the prefecture's population. The upper reaches of the Yoshino River have the appearance of a gorge, but on the north bank up to the middle reaches of Kokawa River there are alluvial terraces, and downstream there are composite alluvial fans. The development of the river mouth delta is not remarkable, but the old river channels of the Waka River, Donyu River, and Suiken River, which suggest changes in course, remain inside the beach ridge. The flow rate has changed significantly, and the Osako and Otaki dams have been built upstream. The history of water transportation is long, including the transport of Yoshino lumber, rice tribute to Mount Koya, and Mikazura salt to Hashimoto Shioichi. There are also records of the O-no-minato gate at the river mouth and the Kamagaki boats. In the early modern period, river ports such as Funato, Konohashi, Ozu, Kudoyama, Hashimoto, and Gojo, as well as the castle town of Wakayama Minato, developed as boats traveled up the river. Since bridges were not permitted until the Meiji period, crossings on the Koya, Kumano, and Kamigata highways were also bustling. Water transportation declined with the opening of the Wakayama Line, and the river ports were turned into towns with railway stations. In addition to water transportation, the water is also used for agricultural purposes. In the early Edo period, the construction of many weirs, such as the Fujisaki and Oda weirs, by the dedicated farmer Oohata Saizō (author of the Jikata no Kikigaki), led to the development of rice paddies in the river basin. Currently, water is diverted to the Nara Basin. The use of the river for drinking water and industrial purposes is also expanding.

[Yoichi Koike]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

和歌山県北部、和泉(いずみ)山脈南麓(なんろく)の中央構造線に沿って、ほぼ直線状に西流して和歌山市で紀伊水道に入る川。紀伊国第一の川なので紀ノ川という。一級河川。上流は奈良県の大台ヶ原山（1695メートル）に発する吉野川で、和歌山県に入ってから紀ノ川とよぶが、河川法では全体を紀ノ川とする。延長136キロメートル（和歌山県内55キロメートル）、流域面積1750平方キロメートル。なお猿谷(さるたに)ダムによる十津川(とつかわ)上流の流域変更分を加えれば2113平方キロメートルとなる。流域の大部分は山地であるが、河口の和歌山平野は県内最大で、県内の流域人口は県人口の55％に及ぶ。上流吉野川は峡谷の様相を示すが、中流粉河(こかわ)までの北岸には洪積段丘が、下流には複合扇状地がみられ、河口三角州の発達は顕著ではないが、流路変遷を思わせる和歌川、土入(どにゅう)川、水軒(すいけん)川などの旧河道が浜堤の内側に残る。流量変化が著しく、大迫(おおさこ)、大滝(おおたき)のダムが上流につくられている。吉野材の流送、高野山(こうやさん)への貢米輸送、橋本塩市への三葛(みかづら)塩の運送など水運の歴史は古く、河口の男之水門（雄湊）(おのみなと)や鎌垣(かまがき)船の記録もあり、近世には川上船が往来して船戸、粉河、麻生津(おおづ)、九度山(くどやま)、橋本、五條(ごじょう)などの河港や城下町若山湊(みなと)が発展した。明治まで架橋が許されなかったため、高野、熊野、上方(かみがた)の各街道の渡津もにぎわった。水運は和歌山線の開通とともに衰え、河港は鉄道駅の在町に変わった。水運だけでなく農業用水の利用も多い。江戸初期の篤農大畑才蔵（『地方(じかた)の聞書(ききがき)』の著者）による藤崎(ふじさき)、小田(おだ)の井堰(いせき)築造など多くの井堰によって流域の開田が進んだ。現在では奈良盆地へも分水している。上水や工業用水の利用も広がっている。

［小池洋一］

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