Lake Ikari - Ikariko

This artificial lake is located in the northeast of Nikko City in northern Tochigi Prefecture. It was completed in 1956 (Showa 31) by damming the Ojika River, a tributary of the Kinu River. It was constructed as part of the Tone Special Project of the Comprehensive National Land Development Act (1950), and has a usable water storage capacity of 46 million cubic meters, a length of 267 meters, and a height of 112 meters. It is a multi-purpose gravity concrete dam for flood control, irrigation, and power generation. With an area of ​​3.1 square kilometers, it is the largest artificial lake in Tochigi Prefecture. There is an observation deck in the middle of the lake, and trout are released into the lake, making it a great place to relax. The valley along the Oga River has fragile bedrock, and in 1682 (Tenwa 2) a landslide caused Lake Ko-Isori to appear in roughly the same location and size as the present-day Lake, but in August 1723 (Kyoho 8), it burst its banks, causing a major flood in the downstream area and killing over 1,500 people. National Route 121 runs along the lakeshore, and buses can be taken from Kawaji Onsen Station on the Yagan Railway.

[Mitsue Hirayama]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

栃木県北部、日光市(にっこうし)の北東部にある人造湖。鬼怒(きぬ)川支流の男鹿川(おじかがわ)をせき止めて1956年（昭和31）完成。国土総合開発法（1950）の利根(とね)特定事業の一環として築造され、有効貯水量4600万立方メートル、長さ267メートル、高さ112メートル。洪水調節、灌漑(かんがい)、発電の多目的、重力式コンクリートダム。湖の面積3.1平方キロメートルは栃木県内の人造湖中最大。湖の中ほどに展望台があり、マス放流も行われ、憩いの場となっている。男鹿川に沿う谷は岩盤がもろく、1682年（天和2）山崩れにより、現在とほぼ同位置・同規模の古五十里湖の出現をみたが、1723年（享保8）8月に決壊し、下流一帯が大洪水となって死者千数百人に達した。湖岸を国道121号が走り、野岩(やがん)鉄道川治(かわじ)温泉駅からバスが通じる。

［平山光衛］

出典　小学館　日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について　情報 | 凡例