Application of the stability index in artificial sand nourishment projects in Cuba

Effective sand nourishment for beach regeneration requires selecting sediments from a borrow zone compatible with the native materials, ensuring their stability and longevity. In Cuba, most of its beaches are predominantly covered by biogenic-marine sediments, and assessing the suitability of borrow sand presents unique challenges. This article compares two methods for assessing sand suitability in Cuba, where biogenic-marine sediments predominate: the Stability Index ( Si ) method and the traditional approach proposed in the Shore Protection Manual, herein referred to as the Overfill Factor ( Ra ) method. The Si method assesses compatibility by comparing grain-size distributions without assuming log-normality, while the latter uses the statistical parameter to estimate overfill requirements. The purpose of this study was then to provide a first assessment on this topic by evaluating a method that possibly allows for better adjustment than traditional methods, with the case studies on the beaches in Cuba specifically covered by biogenic-marine sediments. Using real-life case studies of artificial sand nourishment projects on beaches in this geographic region with varied sedimentary characteristics, we determined the performance of both Si and Ra methods in classifying borrow materials. The results of this initial approach suggest that the Si method offers greater flexibility when evaluating borrow zones, providing more accurate results and the possibility of utilizing areas that would have been discarded by conventional methods. The possibility of more efficient use of natural and economic resources is also becoming evident. Furthermore, it indicates that the application of Si is feasible in subsequent artificial sand replenishment projects in Cuba and on similar beaches with biogenic-marine sediments in the Caribbean region. This study represents the first application of a specific methodology to be applied for evaluation of the suitability of sand for Cuban projects, with the aim of its introduction as an additional tool for future studies.