木津川砂州における伏流水の流動過程と水質特性

抄録

Subsurface flow and its water quality in a sandbar are closely related to stream ecological system as elements composing physical environment. The present paper aims to investigate about the flow behavior and the quality change of subsurface water in the sandbar of the Kizu River located in Kyoto, Japan. Soil particle-size and permeability of the sandbar were tested by laboratory experiments for lots of geological samples. A hydraulic model for the subsurface flow was established from observations of subsurface water table and field tracer tests. Numerical results simulated accurately the measured data of water table at many observation wells, and visualized in detail the spatial flow distribution under the sandbar. Based on water quality tests for samples pumped on flow lines of the subsurface water, relationships between change of water quality and existence of vegetation on the sandbar were discussed in connection with rainwater infiltration.