This study investigated the main and interactive effects of nearshore breakwaters and marsh vegetation on faunal abundance and diversity along an eroded shoreline in Bon Secour Bay, Alabama. In summer 2016, eight replicates of three vegetation treatments plots (naturally vegetated, planted, and open) were established along a breakwater-protected and an adjacent no breakwater shoreline. After which, three methods were used to evaluate nekton quarterly from summer 2016 to summer 2018; Breder traps along the shoreline and lift nets and trawls in nearshore waters. Data were analyzed using the Shannon-Weiner diversity index and ANOVA. Results showed breakwaters supported significantly more abundant and diverse communities along the shoreline and in parallel nearshore waters than similar no breakwater sites. However, the main vegetation treatment effects were not significant. These findings suggest that living shoreline projects with nearshore breakwater support can be beneficial for fisheries enhancement in high-wave energy environments.

Living shorelines and other nature-based solutions have become more widely accepted as a cost-effective, multi-functional, and sustainable approach to coastal resilience. However, in spite of growing stakeholder support, a planning-level understanding of the hydrodynamic impact of living shorelines is not well-developed. Not only do these features vary in size, shape, and structural characteristics, but the wave environment in which they exist can be quiescent or extreme. The work presented in this paper explores the hydrodynamic effects of living shoreline features in such a way that can be generalized across a range of varying physical environments. In a series of Simulation WAves Nearshore (SWAN) simulations, we investigate the effect of wave period, wave height, bed slope, living shoreline feature length in the cross-shore direction, and feature friction coefficient on wave attenuation. Results showed that higher wave period, higher wave height, milder slopes, longer feature lengths, and higher feature roughness largely correlated with higher wave attenuation. However, only on mild slopes did additional feature lengths result in appreciable additional attenuation. Characteristic lengths were thus computed to better illustrate the cost-effectiveness of additional feature lengths given a particular wave environment. These characteristic lengths provide one way to evaluate the hydraulic efficacy of proposed living shoreline projects. In this way, regardless of the particularities of individual project sites, we aim to help planners screen potential living shoreline projects before pursuing more detailed, costly analyses. / Master of Science / Living shorelines and other nature-based solutions have become more widely accepted as a cost-effective, multi-functional, and sustainable approach to coastal resilience. However, in spite of growing stakeholder support, a planning-level understanding of the hydrodynamic impact of living shorelines is not well-developed. Not only do these features vary in size, shape, and structural characteristics, but the wave environment in which they exist can be quiescent or extreme. The work presented in this paper explores the hydrodynamic effects of living shoreline features in such a way that can be generalized across a range of varying physical environments. In a series of Simulation WAves Nearshore (SWAN) simulations, we investigate the effect of wave period, wave height, bed slope, living shoreline feature length in the cross-shore direction, and feature friction coefficient on wave attenuation. Results showed that higher wave period, higher wave height, milder slopes, longer feature lengths, and higher feature roughness largely correlated with higher wave attenuation. However, only on mild slopes did additional feature lengths result in appreciable additional attenuation. Characteristic lengths were thus computed to better illustrate the cost-effectiveness of additional feature lengths given a particular wave environment. These characteristic lengths provide one way to evaluate the hydraulic efficacy of proposed living shoreline projects. In this way, regardless of the particularities of individual project sites, we aim to help planners screen potential living shoreline projects before pursuing more detailed, costly analyses.