Yufutsu Plain

A plain in southwest Hokkaido, spanning Chitose City, Tomakomai City, and Yufutsu County. It is also called the Yufutsu Plain, containing a lot of marshes and peatlands. The shallow sea that separated the center of Hokkaido from the peninsula has turned into land, and remains include remnants of marine lakes such as Utonite Swamp, Benten Swamp, and Toasa Swamp. Volcanic ash from the Usu and Tarumae systems has fallen and accumulated in layers, causing alluvial deposition of the Abira and Azuma rivers, and beach ridges caused by coastal currents can be seen, but productivity is low and the land conditions are not good. Development has progressed for rice cultivation, dairy farming, etc., but the construction of the Tomakomai Industrial Port has made it a hinterland, and trading companies, factories, and housing have moved in significantly. Furthermore, with the progress of development in the eastern part of Tomakomai, agricultural land is being converted into sites for thermal power plants, oil storage bases, and large automobile factories.

[Narabe Osamu]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

北海道南西部、千歳(ちとせ)市、苫小牧(とまこまい)市、勇払郡にわたる平野。湿地や泥炭地を多く含み、勇払原野ともいう。北海道の胴体部と半島部を切り離していた浅海が陸化したもので、ウトナイト沼、弁天沼、遠浅(とおあさ)沼などの海跡湖が残されている。有珠(うす)、樽前(たるまえ)系の火山灰が降下して何層にも堆積(たいせき)し、安平(あびら)川、厚真(あづま)川の沖積が進み、沿岸潮流による浜堤列もみられるが、低生産性で土地条件はよくない。米作、酪農などの開拓も進んできたが、苫小牧工業港の建設でその後背地となり、商社、工場、および住宅の進出が著しい。さらに苫小牧東部地区開発の進行で、農耕地は火力発電所、石油備蓄基地、大型自動車工場用地に変わってきている。

［奈良部理］

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