千曲川における寛保2年 (1742年) 洪水の規模推定について

抄録

Historical data were analiesed for evaluation of the 1742 flood at the Chikuma River in Japan. From the corps damage ratio data at 18 villages along the Chikuma River, the maximum flood heights were estimated at each villages. These maximum flood heighs were plotted and maximum flood stage profile was g i ven. Th i s estimation was verified by flooding marks.
Nax i mu m flood discharge total flooding a rea and volume were calculated from this profile. Then, it i, vas clearfied that the 1742 flood at Chikuma River was the higgest one in 300 years and had heavy rainfall area at right tributaries of the upper Chikuma River.