An estimation of the height of waves invading into the Shonai Navigation Basin which will be formed between the new reclamation lots No.13, and West 2nd and 4th of Nagoya Port is presented in this report. Since the navigation basin extends more than 8km and the waves developing during typhoon are of major concerns, ordinary practices of wave model test do not apply. The method of geometric optics was employed in this study in order to investigate the amount of wave height reaching the Shonai River which is located at the end of the Shonai Navigation Basin. The applicability of the geometric optics was confirmed by the results of a small scale test (1/1000). The small scale test also gave the informations on the distribution of wave heights in the navigation basin. The reflection coefficient of the quay wall under planning was studied by another test with a scale of 1/25, yielding average value of 0.7.* Wave diffraction diagrams were also prepared with the aid of a digital computer for the waves diffracted from the entrance of the breakwaters located some 4km off the navigation basin.
　Based on these analysis and experimental data, the height of the invading waves reaching the Shonai River is estimated as less than 30% of the wave height at the entrance of the navigation basin for the waves generated inside the breakwaters, and as less than 15% of the wave height at the entrance of the breakwaters for diffracted waves.