A NOTE ON LAKESHORE RESTORATION CREATING HABITAT OF PLANTS

A method for restoring the lakeshore using beach nourishment was studied, taking Lake Hinuma as an example. Field measurements on lakebed topography, grain sizes of bed materials, change in water level and salinity with time, and classification of lakeshore vegetations were carried out. Depth changes in median diameter of bed materials were measured. The content rate of fine sand had a peak approximately at the depth of closure due to waves, whereas the content rate of silt and clay and the salinity increased with the depth. The habitat of Brackish-water clam Corbicula japonica was located along the depth zone satisfying the condition that salinity is larger than 3 and bed materials are composed of fine sand. Using this information, the lakeshore restoration creating habitat of animals and plants could be done through the formation of a lakebed with a gentle slope using fine sand. A flat lakebed is formed first in the shallow water zone, and a barrier island is planned to be formed by wave action due to the shoreward sand movement. A wetland landward of this barrier is useful for the habitat of animals and plants.