Validity of Equilibrium Beach Profiles

In analytical approaches, beach profiles are estimated based on the assumption that the equilibrium condition is reached. Under this assumption, a variety of models have been proposed in the literature with an attempt to estimate a beach profile with the help of accessible variables like particle settling velocity. The study reported in this thesis was conducted to increase the accuracy of beach profile estimations. In this regard, ini-tially, the particle settling velocity predictions were improved. In the interest of parti-cle settling velocity, a new search splitting pattern through genetic algorithm, has been proposed that can be used to optimize the settling velocity equation with a high degree of accuracy. However, it was realized that the beach profile estimations were not sig-nificantly enhanced through the improvements. In particular, it was deemed necessary to investigate whether the difference between an actual and an estimated equilibrium beach profile (EBP) was due to the limitations in the equilibrium beach profile meth-odology or the identified profile was, in fact, out of equilibrium. Therefore, it was thought imperative to first verity if a profile has reached its equilibrium condition. To this end, in this thesis, a boundary based profile scale factor is proposed, which through a normalized coordinate system, will lead to a unique global profile scale factor. The global profile scale factor is then employed to determine an initial linear beach profile. The amount of erosion and accretion that causes the initial linear profile to transform to the natural EBP is calculated. Accordingly, the balance between the amount of ero-sion and accretion will identify a turning point distinguishing the erosion and accretion areas on the profile. This turning point helps to evaluate whether the profile is in equi-librium condition or not. The proposed model was validated through various beach profiles resulting in high degrees of accuracy and reliability as presented in the thesis.