PARABOLIC EQUATION OF STATIC EQUILIBRIUM THEORY FOR HEADLAND-BAY COAST AND ITS APPLICATION TO BEACH NOURISHMENT

Headland-bay coast is a major type of coastal terrain, which accounts for 51 percent of the coastal line of the world and the headland beach is the most important part of the headland-bay coast terrain. Since 1940s, marine geologists and coastal engineers have devoted a lot of researches to the headland bay coast. Especially, the publication of the parabolic bay shape equation (PBSE) in late 1980s and the development of software MEPBAY in 2003, which have played a crucial role in emulating the shape of a balanced coast and assessing the headland-bay shoreline stability. In this paper, we reviewed the concept of a static equilibrium headland-bay, and its application to the understanding of the transformation between the static equilibrium and the dynamic equilibrium, the protection of the straight sand beaches by offshore breakwaters, and the stability enhancement of downstream of single headland point and spur dikes. The parabolic equation is proven effective for the static equilibrium headland-bay coast. Appropriate artificial structures and static equilibrium beaches are significant to the development and protection of the coastal zone. Limitations and uncertainties of the parabolic bay shape equation are also discussed.