Mixing analysis of groundwater recharge sources for better watershed management

摘要

This paper describes application of three-end member mixing model with isotopic tracers to analyse groundwater recharge sources in the Nasu Fan, Japan. Relative contribution of river water accounts for 50-60% at areas adjacent to interrupted rivers, and precipitation fallen onto the fan is dominant recharge source at the other areas. Contribution ratio of paddyfield water is 30% at most. Implication of such results for better watershed management is given.