Reconstructing modern hydro-environmental fluctuations inferred from lacustrine Sediment in Lake Onuma, Hokkaido

Abstract

Surface core sediments obtained from Lake Onuma, Hokkaido, were used to reconstruct hydro-environmental changes during the past 100 years. The physical properties of lacustrine sediments record both physical environmental and artificial changes in the lake-catchment system. Fluctuations in the mineral content and density of the core sediment indicate an increase of sediment discharge from 1950 to 1970. This may be related to land transformations such as land reclamation for agricultural use and the construction of resort areas in the catchment. The relationship between observed river discharge and precipitation near the Lake Onuma system is different in summer and winter. This indicates that the earth-surface processes in snowfall areas are different for the summer period (rainfall) and winter period (snow accumulation/snowmelt).