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To understand the rainfall-runoff process and sediment delivery process in headwater catchment, hydrological observation and the monitoring of suspended sediment concentrations (SSC) was conducted at a forested headwater catchment in Japanese Alps region. The study site is Nodagasawa watershed (37 ha) within Terasawayama Station, Research Forest of Shinshu University, Japan. At this catchment, notably quick rainfall-runoff response was observed as with the runoff characteristics reported in other catchment underlain by granite. The suspended-sediment concentrations synchronized with the rising and falling of runoff. Between runoff and SSC in flood events, counter-clockwise hysteresis were often found. These hysteresis infer that the abundant unstable sediment was produced during rainfall event from several sediment sources (such as the riverbank collapse, road surface erosion) located on and around the channel.
