Mabechi River

It flows north through the northeastern part of Iwate Prefecture and empties into the Pacific Ocean at Hachinohe City, Aomori Prefecture. It is a first-class river. It is 142 km long and has a drainage area of ​​2,050 square kilometers. It originates in Sodeyama in the northeastern part of Kuzumaki Town, Iwate County, Iwate Prefecture, flows south, and then detours near Mabuchi in the same town, changing direction to the north, joining the Hiranuka River and Appi River to enter Aomori Prefecture, where it joins the Kumahara River and Sarube River, and flows eastward and empties into Hachinohe Bay. The name of the river is said to come from the Ainu word Mabetsu (meaning big river). From the source to the prefectural border, the area is a paleozoic strata zone with many cliffs on both banks, and river terraces have developed in the upper reaches. The area where it joins the Appi River forms the Basenkyo Gorge, and is designated as Orizume Basenkyo Prefectural Natural Park. During the Taisho era, four power plants were built, and the water is used for drinking water and irrigation. In Aomori Prefecture, it forms a long, narrow valley bottom plain, and the area around its mouth is the coastal industrial zone of Hachinohe City. The Tohoku Shinkansen, IGR Iwate Galaxy Railway, Aoimori Railway, National Highways 4 and 104 run along the middle and lower reaches of the river.

[Kano Seiichi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

岩手県北東部を北流し、青森県八戸(はちのへ)市で太平洋に注ぐ川。一級河川。延長142キロメートル、流域面積2050平方キロメートル。岩手県岩手郡葛巻(くずまき)町北東部の袖山(そでやま)に源を発して南流、同町馬淵付近で迂回(うかい)して向きを北に変え、平糠(ひらぬか)川、安比(あっぴ)川をあわせて青森県に入り、熊原(くまはら)川、猿辺(さるべ)川と合流、東流して八戸湾に注ぐ。川名はアイヌ語マベツ（大きな川の意）に由来するという。源流から県境までは古生層地帯で両岸とも絶壁をなす所が多く、上流部には河岸段丘が発達する。安比川との合流点一帯は馬仙峡(ばせんきょう)の峡谷をなし、折爪(おりづめ)馬仙峡県立自然公園に指定されている。大正時代に4発電所が設置され、上水道や灌漑(かんがい)用水に利用される。青森県では細長い谷底平野を形成し、河口一帯は八戸市の臨海工業地帯となっている。なお、中・下流沿いを東北新幹線、IGRいわて銀河鉄道と青い森鉄道、国道4号、104号が走っている。

［金野靜一］

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