Across the Mississippi Gulf Coast, hardened infrastructure (e.g., bulkheads, seawalls) is the dominant method of shoreline stabilization among private properties. In recent years, living shorelines have become an increasingly popular alternative; however, formal economic analyses of small-scale green and grey shoreline protection infrastructure in the region are lacking. Therefore, I conducted an ex post cost-benefit analysis on a 46 m shoreline at Camp Wilkes along Biloxi Bay, MS. Camp Wilkes, a privately-owned recreational campground, installed a bulkhead in 2016 that failed shortly after and replaced it with a living shoreline in March 2019. Using NIST’s Economic Decision Guide Software (EDGe$) Online, I performed a comparative cost-benefit analysis of both shoreline protection measures – namely the existing living shoreline and a hypothetical wooden bulkhead – over a 60-year time interval. While initial costs of living shorelines and bulkheads are similar, living shorelines have significantly lower maintenance and replacement costs and are often more effective at mitigating coastal erosion under biophysical conditions like those experienced at Camp Wilkes. Additionally, the living shoreline poses several unquantified non-market benefits (e.g., increased community involvement and educational opportunities) not offered by the bulkhead. It follows that similar coastal properties with conditions suitable for living shorelines are likely to see a greater return on investment when installing living shorelines rather than bulkheads or other hardened structures. This cost-benefit analysis will help to inform the shoreline stabilization decision-making process for coastal property owners in the northern Gulf of Mexico.

Wave energy is a key factor in the coastal environment as it influences multiple components including erosion and hydrodynamics. This importance highlights the need for wave climates to be considered in the design of conservation and restoration projects. Currently, the majority of site specific wave climate considerations are determined through the use of wave models. However, current wave models do not incorporate both wind and wake waves. In fact, the exact influence vessel-generated waves have on wave climates is relatively unknown. Wind and vessel-generated waves have significant differences when analyzing wave characteristics. To determine the influence of wake waves on wave climates, Twenty DIY wave gauges were deployed in Back Bay, MS before, during, and after July 4th weekend in 2019. This deployment time period was targeted in order to capture data with both maximum and minimum boat activity. Wave gauges were deployed randomly throughout Back Bay, but included areas with expected high boat activity (e.g., adjacent to a boating channel) and expected low boat activity. Hourly wave statistics were calculated from raw gauge data including; significant wave height, average wave height, and maximum wave height. Hourly statistics were compared between predicted maximum boat activity (i.e. daylight hours) and predicted minimum boat activity (i.e. nighttime hours). Preliminary results revealed that during times of high boat activity, significant have height was increased by a minimum of 20 cm. Understanding how vessel-generated waves influence wave climates will illustrate the need for including wake waves in site specific wave climate considerations. Site specific wave climate considerations that include wake waves have the potential to improve conservation and restoration project designs.

The state of Alabama has spent hundreds of millions of dollars on shoreline restoration projects, with one goal being to enhance shoreline habitats for fisheries species. For example, $3 million was spent in 2010 to rebuild Little Bay Peninsula and shelter Little Bay in Mississippi Sound. Despite this significant financial investment, post-restoration monitoring of how this project benefits fisheries species has so far been limited. To address this, we deployed an array of acoustic tracking receivers in Little Bay and adjacent Little River to monitor the habitat use of red drum. We established that red drum as small as 12 cm can carry acoustic tags, and have begun tracking the movements of red drum of all age-classes, including young-of-the-year juveniles that have never previously been tracked. We will use this initial tracking data to identify hotspots of red drum activity, where we will deploy additional receivers to form VPS arrays, which can triangulate the location of a fish to within a few meters. This will allow us to describe with exceptionally fine-scale spatial resolution the ways in which red drum use the restoration structures and the habitats they enhance within the Little Bay seascape. If sufficient funding can be secured, we also have a unique opportunity to compare fish habitat use and movement in an established restored habitat (Little Bay Peninsula) to that in a newly restored habitat, Point aux Pins Peninsula, where breakwater protection structures were installed in August 2020. The metrics of habitat use and function derived in this study will be used to assess the value of future coastal restoration initiatives for red drum and other economically and culturally important species.

The Mobile Bay National Estuary Program (MBNEP) secured funding from the National Fish and Wildlife Foundation (NFWF) Gulf Environmental Benefit Fund (GEBF) to perform engineering and design studies to develop a solution to stabilize and protect priority in-river wetland spits and restore marshland throughout the intertidal portions of lower Fowl River. This project will reduce the risk of future harm to habitats necessary for sustaining a healthy fishery and improve water quality from this significant watershed to Mobile Bay. Restoration of these important coastal spits and wetlands within the lower reaches of Fowl River was a significant priority action identified in the recently completed Fowl River Watershed Management Plan. This presentation will provide an overview of the stressors impacting these marshes including sea level rise, subsidence, salinity, and other issues; discuss the initial Marsh Study work that was done in coordination with the MBNEP Science Advisory Committee (SAC), and how results form that study are informing the project design; discuss permitting, funding, and other challenges that have arisen during project development; present lessons learned in this ongoing project; and give an update on the status of the project. The presentation will also give the audience a view of how watershed management planning provides a road map to implementation projects; and provide a real world example of how coordination among scientists and stakeholders, which includes numerous agencies, organizations, communities, and the private sector, can be brought together to develop integrative coastal management strategies and implementation projects.

Shoreline erosion is a fundamental concern to residents and stakeholders along the Gulf Coast. While much attention has focused on barrier islands and marshes, less investigation has occurred along sandy, estuarine shorelines that support woodlands or residential areas. Properties along these shorelines are increasingly fortified by seawalls and rip-rap, whereas adjacent non-walled properties are rapidly eroding. This study investigates linkages between erosion and nearshore sedimentation along two shorelines at Bon Secour Bay, Alabama (Weeks Bay NERR), and Perdido Bay, Florida (Tarkiln Bayou Preserve S.P.). Both shorelines are similarly oriented (NW-SE), are not protected by structures, and are not buffered by marsh. Time-averaged erosion rates are 0.30 – 0.67 m/yr (1992 – 2018) and 0.55 m/yr (1994 – 2018) at study areas along Bon Secour Bay and Perdido Bay, respectively. Discriminant analysis of sedimentary parameters of five subaqueous sediment cores in the upper 1 meter of the nearshore substrate indicate that relatively fine-grained size fractions (median size and smaller) and organic matter content are predictor variables that distinguish a somewhat coarser and organic substrate at Bon Secour Bay relative to Perdido Bay, likely as a result of greater fetch (energy) and fluvial inputs. Wood fragments, shell hash, and coarse sand in the basal deposits of two cores possibly represent a transgressive ravinement surface. Nearshore cores are contextualized with sediments collected from discrete bottom samples and boreholes along the adjacent beach, indicating that sediment supply is from the eroding shoreline. As a secondary product of this research, shallow groundwater levels along the estuarine beach reveal that rainfall events increase the water table elevation for a sustained duration, which likely exacerbates shoreline erosion if compounded with wave energy.

In the wake of the Deepwater Horizon oil spill, large-scale breakwater projects have been constructed to restore and conserve marshes across the northern Gulf of Mexico. These breakwater projects are often termed living shorelines due to the perceived increase in secondary productivity around the breakwaters and within the fringing marsh shoreward of these structures. However, evaluations of the effectiveness of breakwaters at preserving natural shorelines are limited. To evaluate the effectiveness of large-scale breakwaters at protecting or restoring marshes in high wave energy environments, we conducted experimental plantings and a shoreline monitoring program landward of eight-year-old breakwaters (OBW) and reference no breakwater sites (NBW) along Bon Secour Bay, AL. The OBW and NBW complexes cover 0.6km and 1.2km of consecutive shoreline, respectively. In both the OBW and NBW sites, eight replicates of planted vegetation (nursery-grown Spartina alterniflora sods), natural vegetation, and no vegetation treatments were established along the shoreline. Vegetation monitoring took place over three years and evaluated plot percent cover and species composition. Additionally, the perimeters of all the natural S. alterniflora patches were field mapped using an RTK GPS across breakwater treatments. Results from fixed-plot monitoring showed a positive impact of large-scale breakwaters on natural fringing marshes and no impact on planted marshes. The RTK monitoring showed no discernable impact of breakwaters on S. alterniflora extent, but did show that S. alterniflora behind breakwaters experienced little to no upland migration while those in no breakwater areas retreated significantly. Cumulatively, these results suggest that large-scale breakwaters could have an impact on preserving fringing marsh vegetation in high wave energy environments.