ABSTRACT
Phillips, A. and Bastola, S., 0000. Assessing vegetation and shoreline responses in reduced wave climates using Google imagery.
Segmented breakwaters are a well-known shoreline protection feature used throughout various coastal environments. These structures can produce a range of shoreline responses, including tombolo and salient features. These responses depend on the sediment properties, geometry, and hydraulic properties of the structure, wave energy, and associated spectra. Numerical and empirical approaches are widely used to predict the shoreline response of the structure. However, there are limited studies on the vegetative response of segmented breakwaters. Vegetation, despite being a more natural shoreline feature that may provide additional levels of protection while providing a habitat for plants and animals, is rarely included in current design efforts that consider structural shoreline protection. This study has a twofold objective. The first part is to review the detached breakwater database to assess the empirical shoreline response classification system, and the second part is to focus on exploring the drivers of vegetative response by using Google imagery and satellite data on the vegetation growth behind such structures. The study tested the existing shoreline response function in predicting shoreline and vegetive response for three project sites from coastal Louisiana. Empirical classifiers observed significant variation in the predicted shoreline response, indicating that despite providing insights, their applicability should be carefully evaluated for each location. Several projects fell into classifications that did not reflect real-world conditions. The shoreline and vegetative response of the three detached breakwaters based on historical imagery of the study site and the analysis of the normalized difference vegetation index estimated from Sentinel satellite data behind the detached breakwater showed varying degree of vegetative response. Predicting the vegetative response of detached breakwaters is crucial, because it influences the stability of the shoreline behind these structures. For shoreline protection and restoration efforts to be effective, designers must include vegetation and habitat considerations in the design process.
