| Lake Kasumigaura, which is the second largest lake in Japan, was developed for flood control, agriculture land form, and water resource development. The development changed the shore beach into concrete protection and decreased shorefront vegetation. Therefore, many restoration projects were conducted to restore shore beaches and shorefront vegetation. The projects achieved good results on restoration and established the basic technique for restoration at local scales. Subsequently, planning methods were required for basin-scale vegetation restoration of Lake Kasumigaura. Therefore, in the present study, a planning method was developed through a case study onendangered species of submerged vegetation restoration at the basin scale. First, we selected the endangered submerged vegetation species and conducted field transplant experiment to clarify the physical and chemical environment preferences. After the experiment, we determined the preferences at every growth stage for sustainable vegetation maintenance. Second, we conducted 3D hydraulic simulations of Lake Kasumigaura, considering the climate characteristics and water balance of the Lake Kasumigaura basin and extracted a suitable area for restoration on the basis of the preferences. The suitable areas extracted by the methods matched to the vegetation areas in terms of the experience and past observation. These results indicated that the method considering the preferences at a local scale accurately extracted the suitable restoration area from the basin. The results also indicated that the method could extract the physical environment characteristics along the shoreline of Lake Kasumigaura and help in the selection of optimized restoration techniques. Subsequently, we will further develop the method to concentrate on the vegetation restoration area for effective basin management. |
