Modeling of Equilibrium Shoreline of Headland Bay Beaches

Authors

Mohamed Ahmed Elmarakby, Irrigation and Hydraulics Engineering Department, Civil Engineering Department, Faculty of Engineering, Tanta University, EgyptFollow
Ahmed Elshinnawy, Irrigation and Hydraulics Engineering Department, Civil Engineering Department, Faculty of Engineering, Tanta University, EgyptFollow
Bakenaz A. Zeidan, Professor, Irrigation and Hydraulics Department, Faculty of Engineering, Tanta University, 31527, Tanta, EgyptFollow

Abstract

Engineering tools for predicting a long-term reaction of beaches include equilibrium beach formulations. They are used to assess how human interference (protection works, breakwaters, ports etc.) has affected the shoreline reaction since they Specify the final orientation of a beach on a time scale of years. One of the equations for determining the Static Equilibrium Planform (SEP) of Headland Bay Beaches (HBBs) that can be found in the literature is the Parabolic Bay Shape Equation (PBSE). The placement of the down-coast control point (P_o), which is the down drift limit from which the PBSE is applied, has a significant impact on the SEP. The direction of the mean wave energy flux at the diffraction point should be used to determine the P_o point, according to the literature. The resulting planform shape does not suit the SEP for such circumstances, particularly when the headland structure is low-crested or submerged. However, this approach is no longer available when applied to a state of equilibrium embayed beaches in zones with a wide range of wave climate directionality and/or in cases where the point of diffraction is located far from the equilibrium shoreline, especially when the headland structure is low-crested or submerged. Employing 20 HBBs in Spain, this study explores the determination of the Po point of the SEP with such conditions. It also examines the significance of wave climate directional spreading on the SEP shape. Results indicate that the further the diffraction point is from the shoreline, the wider the segment of the beach that is impacted by the coastal barrier. Based on the analysis of the field cases, to find the Po point, a new formula has been developed. The model showed good results for several natural and artificial bay beaches with (R²= 0.8902 and a RMSE =2.098^o) in the estimation of the angle that locates the down-coast control point of low-crested HBBs.

Recommended Citation

Elmarakby, Mohamed Ahmed; Elshinnawy, Ahmed; and Zeidan, Bakenaz A. (2023) "Modeling of Equilibrium Shoreline of Headland Bay Beaches," Journal of Engineering Research: Vol. 7: Iss. 6, Article 17.
Available at: https://digitalcommons.aaru.edu.jo/erjeng/vol7/iss6/17