2005 Fiscal Year Final Research Report Summary

Beach profile change during storm

Research Project

Project/Area Number	16560452
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	水工水理学
Research Institution	Chuo University
Principal Investigator	MIZUGUCHI Masaru Chuo University, Faculty of Science and Engineering, Professor, 理学部, 教授 (50011234)
Project Period (FY)	2004 – 2005
Keywords	berm erosion / swash / fileld
Research Abstract	Some twenty Ultrasonic wave gages, which also detect the bottom level without water, are employed along the Hasaki observation pier, covering from the swash zone to outside of the surf zone. Observation has been carried out continuously and the data during a very severe storm is analyzed. The followings are revealed from hourly-average based analysis. 1)Berm erosion starts when large waves with significant long wave energy reach the berm top as the tide rises. 2)Berm erosion stops after some hours when the eroded beach slope becomes mild or the berm disappears though the same wave condition continues. Wave by wave approach is also tried for the swash oscillation and beach profile change. It is shown that the net volume flux of the sediment at the offshore end of the awash zone is positively proportional to the difference between integrated onshore 1.5 power of Shiels parameter and the offshore one.

(2 results)