Integration of tracer techniques and hydrometric approaches in catchment hydrology : research on hydrological processes in the Kawakami experimental basin, central Japan

The Kawakami experimental basin, located in the mountain region of central Japan, has been monitored since 1985. Complex hydrological processes occurring in the forested mountain catchment were studied using both isotope and chemical tracers and hydrometric approaches. Tritium concentration data of soil water, groundwater, and stream water provided information on residence times of each as well as the mixing ratio of stream water with soil water and groundwater. Stable isotope data, such as deuterium and oxygen-18, showed the spatial characteristics of each stream water source. Additionally, hydrometric data including tensiometric and piezometric potentials revealed the physical dynamics of subsurface water in the catchment. All these data are necessary for consideration of flow mechanisms in the catchment, especially for stormflow and water quality studies.