Seasonal to decadal morphodynamics in an integrated watershed composed of a steep river and barred coasts

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K06229
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Hydraulic engineering
• Research Institution: Kanazawa University
• Principal Investigator: Umeda Shinya 金沢大学, 環境デザイン学系, 准教授 (30313688)
• Research Collaborator: YUHI Masatoshi ; KARUNARATHNA Harshinie
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 海岸 / 河口 / 河川 / 底質輸送 / 汀線 / 砂州

Outline of Final Research Achievements

Seasonal to decadal variability of shoreline position at a long multi-barred beach with gentle slopes was investigated using a dataset of biannual shoreline surveys of 23 years. EOF and spectral analysis were conducted to describe characteristic patterns of shoreline variation at multiple scales in time and space. A alongshore uniform shoreline migration toward offshore in summer and onshore in winter was dominant in the first EOF mode which secondarily exhibited a long-term trend of shoreline recession. The shoreline pattern reconstructed on a longer time scale represented a large scale shoreline undulation whose scale and migration speed were comparable to shoreline sand waves observed in various coasts. The shoreline pattern reconstructed on a shorter time scale represented alongshore uniform shoreline migration toward onshore and offshore in about five-year cycles, which corresponded to the average cycle of net offshore sandbar migration observed at the site.

Free Research Field

海岸工学