Taisho Pond

This dammed lake is located in Kamikochi in the Northern Alps in central-western Nagano Prefecture. It was formed in 1915 (Taisho 4) when Mt. Yake in the southwest of Kamikochi erupted and lava flow dammed the Azusa River. Originally, it was 1,540 meters north to south, about 250 meters east to west, and 6 meters deep at its deepest point. The lake, with the dead trees of the banks of the Azusa River standing in the lake with Mt. Hotaka in the background, was a natural beauty of the first order, but due to mudflows from Mt. Yake and soil from the surrounding mountains, it is now about one-third of its original size, and it is more appropriate to call it a wide part of the Azusa River rather than a pond. It also serves as a balancing reservoir for a hydroelectric power plant, but it is in danger of disappearing if things continue as they are, and related organizations have begun to consider countermeasures.

[Hiroyoshi Kobayashi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

長野県中西部、北アルプスの上高地(かみこうち)にある堰止湖(せきとめこ)。1915年（大正4）上高地南西部の焼岳(やけだけ)が大噴火し、溶岩流が梓川(あずさがわ)をせき止めてできたもの。当初は南北1540メートル、東西約250メートル、最深部は6メートルであった。穂高(ほたか)岳を背景に梓川河畔の樹木が枯れ木となって湖中に林立する景観は、第一級の自然美をなしていたが、焼岳の泥流や周囲の山々からの土砂が流れ込み、現在では当初の約3分の1になり、池というより梓川の河幅の広い部分といったほうが妥当である。水力発電所の調整池の役割りも果たしているが、このままでは消滅する危機にあり、関係機関が対策の検討を始めた。

［小林寛義］

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