山形県の湖沼に関する地方湖沼学研究
1980 年 34 巻 p. 10-16
詳細
1980 年 34 巻 p. 10-16
Most lakes in Yamagata Prefecture are distributed in volcanic region. We can rarely find lakes in granitic area such as Asahi and Iide mountain districts as well as in Shonai Plain, So far as the origin of the lake basin is concerned, most lakes are formed by landslide dams or volcanic mudflows and only a few lakee may be placed under the category of the crater lake. Among them, Lake Torinoumi whose surface rises 1,575 meters above the sea-level is the unique high mountain lake in Yamagata Prefecture. Lake Ohtori-ike with the maximum depth of 68 meters has the largest area (0. 408 km^2) of the lakes in Yamagata Prefecture. Generally, the total inorganic matter in solution in a lake water is less than 60 mg/l and calcium bicarbonate is the dominant salt in the lake waters. In the case of the lake waters associated with the volcanic activity such as Lake Tsuruma-ike and Lake Sakazuki-ko, the main dissolved mineral is calcium sulfate. Concerning Lake Ukishima-ohnuma, Lake Koke-numa and Lake Hakuryu-ko, the total residue on evaporation exceeds 100 mg/l. Judging from the author's research from 1,957 to 1,980 and the ecological data ever published, the type of the lakes in this prefecture may safely be summarized in the following table. [table]
