Abstract
Topographic changes off the mouth of the Tedori River flowing into the Ishikawa coast facing Sea of Japan were investigated by using sea bottom sounding data collected between March 1986 and March 1989. Twelve sets of contour maps off the rivermouth were compared including the ones obtained during the elongation period of rivermouth jetties, which had beenextended by November 1988. Extension of jetties caused large scale scouring around the jetties. On the Ishikawa coast extending between the Tedori rivermouth and Kanaiwa Port north of it, southward longshore sand transport dominates and countermeasures using many detached breakwaters had been conducted. Development of southward longshore currents carrying sand off this rivermouth jetties implies that this coast is still being eroded since there are no large rivers supplying sediment to this coast.
