On the relation between river mouth improvement and coastal protection- an example of Ayaragi coast in Yamaguchi Prefecture

Relation between river mouth improvement and coastal reservation is studied by taking the Ayaragi coast in Yamaguchi Prefecture as an example.In this pocket beach of around 2 km long shoreline three rivers flow into the sea and at their mouths river mouth closure has been caused by storm waves in winter.As the measures against this, dredging of thr river mouth bed was extensively conducted before extending paralell jetties of enough length at the river mouth to induce beach erosion on the adjacent coastline.This situation was analyzed by the comparison ofaerial photographs and bottom sounding data.Extension of the jetty is considered to be best solution against beach erosion.