Abstract
A stationary front activated by Typhoon 4 in 1998 dropped a record breaking rainfall on the east side of the Nasu Mountains of more than 1200 mm over six days which caused flood disasters in the upper and middle reaches of the Abukuma River basin. Results of field surveys of the areas and those of a runoff analysis are reported. Besides the heavy rainfall, the analysis shows a high runoff efficiency of 0.73.
The middle reaches of the basin were secured through improvement in countermeasures based on experiences in the 1986 flood. The upper reaches which in the past had a low frequency of flooding and therefore did not have improved preventative measures, suffered serious damage by sudden huge floods accompanied landslides, driftwood and sedimentation.
