Japan's Beach Erosion

Reality and Future Measures

Beaches in Japan have been eroding since the 1970s because of artificial land alterations and unsustainable coastal development. Almost all causes of the beach erosion in Japan are due to anthropogenic factors — as a result of human activity. This book presents the state of the beaches throughout Japan, looking at the current reality and the classification of causes of beach erosion using real-life, illustrated examples. It then goes on to look at practical models which can be used to predict changes to different types of beaches, and concludes with investigation of beach erosion as a wider structural problem. Lessons learnt show the manner in which excessive coastal development without clearly identified measures for beach protection can have widespread global ramifications.

This second edition presents new findings from field studies carried out on Japanese beaches, along with the development and improvement of the numerical model presented previously. In addition to the first edition, six new examples of the beach erosion in Japan are included, as is new analysis of the BG model (a model for predicting based on Bagnold's concept), which can be applicable to various field problems.

Originally published in Japanese (2004), this updated version gives clear practical guidance to coastal engineers working to prevent irreversible beach erosion and sustainable coastal development policy.

Contents:

• What is Beach Erosion?

• Beach Erosion — Current Reality:

  • Classification of Causes of Beach Erosion
  • Beach Erosion Due to Obstruction of Longshore Sand
  • Beach Erosion Triggered by Construction of Wave-Sheltering Structures
  • Beach Erosion Due to Decrease in Fluvial Sediment Supply
  • Beach Erosion Triggered by Offshore Sand Mining/Dredging
  • Beach Erosion Triggered by Construction of Detached Breakwater as Countermeasure
  • Disappearance of Natural Sand Dunes Due to Excess Planting of Coasta Forest
  • Disappearance of Sandy Beach Triggered by Construction of Gently Sloping Revetments

• Practical Models for Predicting Beach Changes:

  • Characteristics of Practical Models
  • Prediction of Stable Shoreline on Pocket Beach
  • Three-Dimensional Model for Predicting Beach Changes Using Hsu and Evans' Model
  • Predictive Model of Three-Dimensional Beach Changes on Coast with a Seawall by Expanding Hsu and Evans' Model
  • Simple Model for Predicting Three-Dimensional Beach Changes on Statically Stable Beach
  • Shoreline Change Model on Coasts Composed of Sand of Mixed Grain Size
  • Predictive Model of Shoreline and Grain Size around River Mouth
  • Contour-Line Change Model Considering Stabilization Mechanism of Longitudinal Profile
  • BG Model Predicting Three-Dimensional Beach Changes Based on Bagnold's Concept and Applications

• Beach Erosion as Structural Problem:

  • Introduction
  • Institutional (Legal) Issues Related to Beach Erosion
  • Technical Issues Related
  • Concrete Measures

Readership: Coastal engineers, development planners, students, researchers and practitioners of civil engineering.