November 28, 2021
Nishikigawa is the main stream of the second-class water system Nishikigawa that flows through Yamaguchi Prefecture. The length of the river including the tributaries is 331.8km, and the basin area is 884.2km2, both of which are the largest rivers in Yamaguchi Prefecture.
Nishiki River originates in Shunan City (formerly Kano Town, Tsuno District) in the northeastern part of Yamaguchi Prefecture. After flowing down to the southeast, it meandered to the northeast near the Sugano Dam, flowed into Iwakuni City (formerly Nishiki-cho, Kuga-gun), then joined the tributary Usa River and meandered to the southeast again, and then towed to the southeast again. Pour into the Seto Inland Sea via Mikawa Town, former Iwakuni City). In the downstream area (1-chome, Kusunokimachi, Iwakuni City) near the river mouth, it splits into the Imazu River, which goes straight to the east, and the Monzen River, which turns to the right and goes south, forming a delta at the mouth of the river.
One of the peculiar topography of the Nishiki River basin is the river capture topography, which was taken into the Nishiki River basin by the downcutting action of the Fukaya River, which was once a Takatsu River basin. It is known that there are several places in other water systems near the western Chugoku Mountains, which are mountainous areas.
Kuga-gun in the Nishiki River basin was damaged by the Ruth typhoon in October 1951, with 309 dead and missing, 1228 seriously and lightly injured, 1159 houses spilled, 1507 road breaches, 587 bridge spills, and 1263 embankment breaches. I put it out. For this reason, hydraulic engineering work was actively carried out.
The Sugano Dam and Kodo Dam have been constructed in Shunan City, which is the upstream area, and mainly generate electricity and supply domestic and industrial water to the southern part of Shunan City. Flood control is also carried out as a countermeasure.
The Ikimigawa Dam, a tributary that joins in Mikawa-cho, Iwakuni City, has the Ikimigawa Dam, which plays a role in supplying industrial water and controlling floods. In addition, the Hirase Dam is under construction in Nishiki-cho, Iwakuni City, but when it is completed, this dam will have the largest hydraulic capacity in the basin, and it is expected to greatly contribute to the reduction of flood damage in the downstream area. ing.
Shinju Bridge, Monzen Bridge (Bridges over the Imazu River and Monzen River in Iwakuni City, respectively. Both are National Highway No. 188)
Imazu River Bridge, Monzen River Bridge (Bridges the Imazu River and Monzen River in Iwakuni City, respectively. Both are Iwakuni Minami Bypass)
Nishikibashi (Kuina, Iwakuni City / Hoki National Highway No. 2. Over the branch with National Highway No. 187)
Deai Bridge (Nishiki-cho, Iwakuni City, National Highway 434 near the confluence with the main stream of Nishiki River on the Usa River. It spans the branch with National Highway 187)
Watase Bridge (Across Lake Sugano (Lake of Sugano Dam) in Shunan City. National Highway No. 434)
Cormorant fishing is held around Kintaikyo Bridge from June to September every year.
The hardness of underground water is very low, and it is used as water for preparing sake.
There used to be no large roads in Kinkawa-cho in the middle basin, and boat transportation was popular. Boating disappeared when the Iwahi Line (currently Nishikigawa Railway Nishikigawa Seiryu Line) opened in 1963.
On May 21, 1970, 1000 cubic meters of sludge spilled from the abandoned mine of the Japan Mining Kawayama Mining Works in Kawayama, Mikawa-cho. As it flowed into the Nishiki River, the intake of the Iwakuni City waterworks downstream was temporarily suspended.
Goera japonica (a habitat with a name related to this river)
Nishikigawa Railway Nishikigawa Seiryu Line (Adopted for company name and line name because it is a line along this river)