Study on regional and long-term groundwater flow system for safety assessment on geologic disposal, 4; Research on the modeling approach of geomorphic changes

Hanatani, Ikuo; Munakata, Masahiro ; Kimura, Hideo

In order to evaluate the influence on a long-term groundwater flow system by geomorphic change, we carried out the numerical simulation of the changes in the longitudinal profile of river-bed for four rivers in a sedimentary rock area, and plotted the distribution map of the amount of gully erosion for 125,000 years. According to the results, the erosion estimates of the two rivers emptying into the inner bay ware different from the two rivers emptying into broad ocean. The estimates of the former group ware 50-300 m that varied widely from downstream site to upstream site. On the other hand, they ware 150-250 m ranging over the whole watershed in the latter group. Furthermore, the movement rates to the upstream of the erosional fronts formed with sea level decrease ware estimated 0.7-1.0 meter per year.