抄録
Seawater in fishing ports should be clean not only because it is used for washing the seafood but also because
it is used to stock live fishes. Additionally, the interest in seawater quality increases due to the use of the anchorage
as a caring place of the fry. On the other hand, to ensure tranquil waters in a small fishing port so that the
fishing boat can be moored safely requires the insta11ation of breakwaters over and over again, which makes a
great effort for a small fishing port. But, such an effort results in fact to the deterioration of water quality in the
basin. To improve on this, an exchange hole in the breakwater is often installed, which brings fresh open sea
water into the interior. This however can create some problems : these exchange holes tend to decrease the tranquility
of inside waters and, for low waves the the open sea water introduction is hardly effectual.
The authors have proposed a new structure that combines the open-hole breakwater with a submerged
mound that is installed in front of the breakwater. The fresh seawater is driven into the basin by raising the
mean water level in the pool that is surrounded by the submerged mound. They proposed also : a technique for
calculating the amount of flow ; a design method of this facility system that combines the submerged mound, open
holes and outlets ; and facility specification that is based on scaled model tests and site investigation. This system
was already adopted and constructed in many fishing ports, such as, the Shikanosima fishing port in Fukuoka Prefecture, Yokata fishing port in Ishikawa Prefecture etc.
