Water quality distribution at the spring of cliff-erosional valley in fluvial fans and its factor—Comparative study among Fans in Ina basin, Central Japan—

Abstract

In the scatter diagram, which took the dissolved calcium ion equivalent concentration to the x-axis, and took the sum of HCO3, SO4, and NO3 to the y-axis, the value of the groundwater and spring water in a fluvial fan is plotted around the line which the value of the river water from the catchment forms. Using “distance from a river-water-quality line” in this scatter diagram, the origin of spring water in the cliff-erosional valley of two dissected fans are compared. Consequently, the more valley erosion is progressing, the more spring water is similar to the catchment river water quality. It was suggested that the groundwater flow in dissected fan changes with development of erosional valley.