金沢大学環日本海域環境研究センターChanges in hydro-erosinal environment and pond sedimentation during past 100 years in Kobe district are discussed with precipitational data and pond sediment information. Analyses of precipitational data show that the years when erosional phenomena, such as landslides, debris flows etc., happened were related to excess amount of critical daily rainfall (annual summation of exess amount over 100 mm/day and 50 mm/day). There are some dominant periods (80, 25, 15, 10 and 7 years) in the excess rainfall datasets. Analyses of physical properties of core samples from the two ponds in the Rokko Mountains show that there are rapid coarsening in the heavy rainfall times, especially in 1967 when severe natural disaster happened due to landslides, debris flows and floods. Comparing the sedimentation rate before the Kobe earthquake inferred from the core sample from Kawauso-ike on after the earthquake from sediment traps in the same pond shows significant increase in the rate after the earthquake
