Optimization of beach profile spacing: an applicable tool for coastal monitoring

Juan José Muñoz-Perez,Andrés Payo,Jorge Roman-Sierra,Luís Moreno,Marina Navarro

doi:10.3989/scimar.03417.15a

Abstract

This paper presents a simplified and straightforward method for determining optimal beach profile spacing from an economic point of view with an admissible error. This error can be computed theoretically by comparing different profile spacings from two consecutive bathymetries. When a beach sediment budget (from previous monitoring surveys) or the volume density of a beach nourishment project is known, a virtual bathymetry can be designed; therefore, a unique real bathymetry would be needed. The method is applied and analysed for beaches with different characteristics regarding tide, energy, morphology and natural features. The results indicate that the estimated errors are proportional to a beach heterogeneity factor, depending on each particular beach case, such that large spacings do not necessarily induce large errors. In our case, profile spacings of 100 m induce average errors of less than 5%. Moreover, differences in tidal range and the existence of rocky reefs do not seem to affect the results.

Highlights

Beach survey designingUnderstanding the dynamic behaviour of a beach is essential for effective engineering design and requires short- and long-term monitoring, which includes periodic and emergency topo-bathymetric surveys (Jimenez and Sanchez-Arcilla 1993) based on profiling or on grid surveys
SUMMARY: This paper presents a simplified and straightforward method for determining optimal beach profile spacing from an economic point of view with an admissible error
The methodology presented allows the most cost-effective profile spacing to be determined as a function of a specific volume error for any kind of beach

Summary

Introduction

Beach survey designingUnderstanding the dynamic behaviour of a beach is essential for effective engineering design and requires short- and long-term monitoring, which includes periodic and emergency topo-bathymetric surveys (Jimenez and Sanchez-Arcilla 1993) based on profiling or on grid surveys. It is true that grid surveys provide accurate assessments of three-dimensional (3D) coastal morphology, but they require a high density of topographic and bathymetric data points to generate 3D surface maps (Bernstein et al 2003). Whether we use 3D mapping or a profiling strategy, the final aim is to apply a simplified and cost-effective method for determining changes in beach volume. Such a method would allow a coastal manager to design a coastal maintenance strategy that takes into account the majority of beach spatial variability

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