Wave Setup at River Mouths in Japan

Abstract

     Empirical study on wave setup at river mouths is becoming very important in terms of river mouth morphology change, navigation transportation, saline intrusion into river and water environment especially for a river which has a lagoon or lake at the entrance. Each year, there have been many extremely events that caused the wave setup occurring around of Japan. One of them is the continuously big wind from Japan Sea impacted to the coastline during the winter; this will created a very high wave and then caused a significant wave setup height at river mouths. In this study, there two river mouths, namely Yoneshiro River and Iwate River which faced to Japan Sea, will be concentrated on. The main objectives of this study are to investigate the influence of wave setup height to sand spit evolution at Yoneshiro river mouth, and the effect of regularly extreme wind to wave setup height at river mouth. The final results will be contributed a technical diagram of relationship between wave setup height with offshore wave height and average water depth at river mouth. This empirical study is helpful for river authority, coastal management and coastal engineers to find out the best solution in controlling the river mouth morphology change and environment.