Policy analysis of shoreline restoration options on private shorelines of Puget Sound

Puget Sound shorelines have historically provided a diversity of habitats that support a variety of aquatic resources throughout the region. These valued natural resources are iconic to the region and remain central to both the economic vitality and community appreciation of Puget Sound. Deterioration of upland and nearshore shoreline habitats, have placed severe stress on many aquatic resources within the region (PSAT, 2007). Since a majority of Washington State shorelines are privately owned, regulatory authority to legislate restoration on private property is limited in scope and frequency. Washington States’ Shoreline Management Act (RCW 90.58) requires local jurisdictions to plan for appropriate future shoreline uses. Under the Act, future development can be regulated to protect existing ecological functions, but lost functions cannot be restored without purchase or compensation of restored areas. Therefore, questions remains as to the ecological resilience of the region when considering cumulative effect of existing/ongoing shoreline development constrained by limited shoreline restoration opportunities. In light of these questions, this analysis will explore opportunities to promote restoration on privately owned shorelines within Puget Sound. These efforts are intended to promote more efficient ecosystem management and improve ecosystem-wide ecological functions. From an economics perspective, results of past shoreline management can generally be characterized as both market and government failure in effectively protecting the publics’ interest in maintaining healthy shoreline resources. Therefore coastal development has proceeded in spite of negative externalities and market imbalances resulting in inefficient resource management driven by the individual ambitions of private shoreline property owners to develop their property to their highest and best use. Federally derived property rights will protect continuation of existing uses along privately owned shorelines; therefore, a fundamental challenge remains in sustainable management of existing shoreline resources while also restoring ecological functions lost to past mistakes in an effort to increase the ecologic resiliency within the region. (PDF contains 5 pages

Urban-industrial shoreline restoration techniques: Duwamish Waterway and Elliott Bay

Title: Urban-industrial shoreline restoration techniques: Duwamish Waterway and Elliott Bay Seattle’s present-day Elliott Bay and south-harbor industrial area comprises approximately 5,300 acres, 80 percent of Seattle’s industrial area. This man-made landscape is enormously productive, providing approximately 225,000 regional jobs, totaling $7-9 billion in annual payroll. Seattle’s industrial environment displaced another highly productive landscape, eliminating 98 percent of native intertidal, shallow sub-tidal, and riparian fish and wildlife habitat in the former Green-Duwamish estuarine wetland and nearshore system. Working in this complex environment, the Port has restored, created or enhanced 31 acres of habitat at 16 sites during the past 25 years. The port’s “Century Agenda” commitment includes restoration of 40 acres of additional habitat by 2026. Recent port restoration actions emphasize replacing inert armored, steep industrial shorelines, with riparian slopes and emergent marsh area, protected with large-woody-debris. Shoreline restoration actions in rural and non-urban areas have been well documented; however, use of “living” urban-industrial shoreline restoration techniques has not been successfully demonstrated. Unique challenges associated with urban-industrial restoration include surface and buried infrastructure, contaminated industrial fill, incompatible land uses, vessel wake/prop wash erosion, adjacent armored shorelines, interrupted hydrology, and urban storm-water. The Port has designed and tested durable urban estuary shoreline restoration techniques, including re-shaping degraded bank-lines, to create inter-tidal and shoreline areas stabilized with native emergent and riparian vegetation. The Port has also integrated passive public shoreline access improvements with habitat restoration, encouraging public education and stewardship. The Port has confirmed six restoration designs, progressing from “partial restoration”, in sites constrained by adjacent features, to “full restoration”, for sites with adequate site conditions. The Port will be applying these designs in future, area-wide bank-line rehabilitation projects, including working with agencies to obtain programmatic approvals. Presenter: George Blomberg, [email protected], 206.787.319

Occohannock on the Bay Living Shoreline Project

Presentation report on Occohannock on the Bay (Camp Occohannock) Living Shoreline restoration project. Project Purpose: Demonstrate living shorelines as cost-effective, hybrid green-gray infrastructure approach for protecting local communities from coastal hazards while enhancing coastal resilience and ecosystem health. Project awarded ASBPA Best Restored Shore Award for 202

Using XBeach to Describe the Performance of an Intertidal Vegetation Shoreline Stabilization Treatment

The purpose of this project is to predict the hydrodynamic and morphodynamics of an engineered vegetation-only shoreline restoration project in Little Lagoon, Alabama under different storm and sea level rise scenarios. Little Lagoon is a shallow, single-inlet lagoon located in Baldwin County, Alabama that has been experiencing shoreline erosion for the past 28 years. A living shoreline using vegetation only (Spartina alterniflora) was implemented in the southwest corner of the lagoon, located within Bon Secour National Wildlife Refuge, to create habitat, improve water quality, and prevent future erosion. This research compares “with-project” and “without-project” hydrodynamics and morphodynamics using XBeach in a one-dimensional transect-based mode to assess potential project performance. This was done using four storm scenarios and five sea level rise scenarios. The with-project and without-project scenarios were compared using profile shape, gross sediment change, and wave height behind the vegetation. Results from this project indicate that the emergent marsh vegetation shoreline contributions to overall shoreline stability are negligible, likely due to the already stable nature of the shoreline. The results from this project will aid practitioners in the future design and implementation of vegetation only shoreline restoration projects along stable shorelines

Developing a Shoreline Restoration Suitability Model for North Indian River and Mosquito Lagoon, Phase II

This project successfully created a living shoreline restoration prioritization model and a mangrove hydrodynamic habitat suitability model for 180 miles of estuarine shorelines in Mosquito Lagoon and northern Indian River. Shoreline model data are available for direct download as a spatial dataset (https://stars.library.ucf.edu/shorelines/), or for online viewing in a GIS storymap: (https://ucfonline.maps.arcgis.com/apps/MapSeries/index.html?appid=45caa29e80e6441c8bf6f75c542860af). New empirical wave data were created through hydrodynamic modeling. Frequency analysis was applied to characterize wave climate in study area shorelines. Wind-wave measurements observed in the field validated that actual wave heights above 2 cm were well represented by the model. Modelled hydrodynamic data were combined with shoreline data (collected in the field during the project Phase I) to develop fundamental knowledge regarding hydrodynamic habitat suitability of IRL shoreline species. Through this analysis, strong relationships between mangrove presence and wind wave hydrodynamics were illuminated, such that the probability of mangrove persistence was predicted at the project site scale based on wave climate. Additionally, the influential role of site intertidal slope and its interaction with site hydrodynamics was confirmed. This is a transformative source of information from the perspective of Planning, Design and Engineering (PD&E) of shoreline stabilization projects and regional-scale restoration planning. Mangroves were found on shorelines with overall lower incoming wave height distributions as compared to shorelines without mangrove vegetation. Mangrove presence became less likely as wave height increased, suggesting that there is a critical wave magnitude-frequency combination above which it is increasingly unlikely that mangrove vegetation will persist. Where wave heights exceeded 5 cm 20% of time, there was over an 80% chance of mangrove persistence. Where wave heights were 8 cm 20% of time, chance of mangrove persistence dropped to 50%. Where wave heights were over 15 cm 20% of time, there was less than 10% chance of mangrove persistence. While wave climate was found to explain the greatest variance within a generalized linear model of mangrove distribution, the influence of shoreline slope was also found to be significant. Low shoreline intertidal slopes were found to increase the threshold wave climate mangroves can survive. For example, the 80th percentile wave height associated with 50% probability of mangrove survival was 8 cm when slope was 0.2, increased to 9 cm when slope was lower than 0.2, and decreased to 4 cm when slope was greater. The presence of oysters or seagrasses at the shoreline were also correlated with wave height; however, conditions within the project area were insufficient to create robust hydrodynamic habitat thresholds for these important coastal ecosystem engineers. There are therefore future research opportunities to apply frameworks developed herein to broader study areas, which will potentially lead to discovery of flow-ecology relationships for a more diverse suite of coastal ecosystem engineers. All study shorelines were classified within a prioritization model according to need and urgency of stabilization. Shoreline sites classified in Urgent need (18% of study shoreline) should be triaged for immediate stabilization. Shoreline sites classified as Priority (10% of study shoreline) will eventually move to the Urgent category without intervention. Shorelines classified as Vulnerable (6% of study shorelines) are sites for pre-emptive restoration. Sites within the Wetland category (38% of study shorelines) do not need to be restored at this time and can serve as reference sites for living shoreline stabilization. Shorelines with hard armoring (28% of study shorelines) may represent opportunities to increase long-term shoreline resilience or restore shoreline ecotone functionality. Analysis of Hardened shorelines in context of local wave climate and slope indicate that many hardened shorelines in the project study area may not actually require armoring. Living shoreline containing mangrove forest could be expected to stabilize many currently hardened shorelines. All study shorelines were classified according to likelihood of mangrove persistence based on hydrodynamic habitat suitability. Within the study area, 68% of the shoreline was characterized by 50% or greater probability of mangrove persistence. At the site scale, likelihood of mangrove persistence can also be increased by design of an equilibrium shoreline slope, adding elasticity to stabilization site designs in areas that are on the borderline of mangrove hydrodynamic habitat suitability. Severe erosion was three times more likely to be observed on shorelines without mangrove vegetation, where over 60% of sites had escarpment heights greater than 30 cm. Similarly, shorelines with mangrove were more than two times as likely to be characterized by no to low levels of erosion. Managers and practitioners within and outside of the direct project area can benefit from this work. First, the actual hydrodynamic habitat thresholds for mangrove discovered in this study can be transferred to other locations within and outside of the Indian River Lagoon system. Locations throughout Florida that fit within the mangrove temperature, salinity and hydrology habitat zones may apply the hydrodynamic habitat knowledge developed herein to site-scale project planning. Second, the synergy between regional-scale project prioritization data and site-scale habitat suitability design tools demonstrated in this project can be a framework for future restoration planning efforts. Provision of information both at a broad geographic scale for use in regional planning, and making the information sufficiently detailed such that it can be applied at the site scale can help managers and practitioners understand when and where restoration is needed, and also the appropriateness of nature-based or green-grey hybrid designs on a site-by-site basis. Widespread investment in this type of information, and dedicated strategies to adopt such information in project PD&E may increase restoration success and impact on a regional scale

Assessment of mudpuppy (Necturus maculosus) presence along the St. Clair-Detroit River System using environmental DNA and occupancy modeling

The mudpuppy (Necturus maculosus) is cryptic, fully aquatic salamander within the Great Lakes region. Once abundant throughout its range, evidence now suggests that there have been declines due to habitat loss and lampricide use. Information on the status of mudpuppies along the St. Clair-Detroit River System (SCDRS) is lacking, and since they are important bio-indicators, they could be a gauge for restoration success. Environmental DNA (eDNA) and occupancy modeling were used to determine best detection practices for this cryptic species. Mudpuppy eDNA was detected at all known mudpuppy sites with the addition of one site. Occupancy was highest at shoreline restoration sites, while reef restoration did not affect mudpuppy occupancy. Additionally, eDNA resulted in the highest detection probability. Restoration efforts have shown to be successful by increasing the occupancy of this indicator species; therefore, these efforts should be used as a template for other restoration practices

Vertebrate Animal Behaviors and Abundances on Estuarine Shorelines Stabilized with Biodegradable Materials Utilizing Wildlife Cameras

Living shoreline stabilization is a restoration technique that utilizes natural materials as breakwaters, plus vegetation landward of the breakwaters, to protect coastlines. This research does not provide information about how new, biodegradable restoration materials affect vertebrates that utilize these shorelines. For this project, I monitored 18 restoration sites along Canaveral National Seashore with wildlife trail cameras: 3 made with cement-infused jute breakwaters, 3 with metal gabion oyster shell breakwaters, and 4 with previously used breakwaters manufactured from plastic mesh oyster shell bags. This project used 4 sites as positive controls (intact vegetation) and 4 as negative controls (highly eroded, no vegetation). Wildlife cameras were used to continuously observe vertebrates for 1-month intervals, pre- and post-stabilization. I observed and recorded a total of 1,044 vertebrates (993 mammals, 51 birds), representing 15 species. The most abundant of these species was Procyon lotor (North American raccoon), and the least abundant was Anas platyrhynchos (mallard duck). The most common behavior among all recorded species was foraging and the least common was swimming. There were 3 observed vertebrate species utilizing restoration materials as a perch for stalking prey, suggesting that the presence of such material did not inhibit their behaviors. These vertebrates damaged neither the restoration materials nor plants deployed behind the breakwaters. Thus, there were no recorded observations of negative vertebrate interactions with these materials. However, all species had fewer post-restoration observations at all control sites

Impacts of Shoreline Restoration and Source of Nutrient Enrichment on Macrophytes and Epiphytic Algal Communities

Macrophytes and their epiphytic algal communities are integral for optimizing littoral ecosystem functioning in lakes. Epiphytic algae’s placement on the plant’s surface can reduce light and nutrient availability (i.e., nitrogen and phosphorus) for the host macrophyte. Macrophyte and epiphytic algal proximity complicates these primary producer group interactions and responses to bioavailable nutrients in the water column or porewater. For example, epiphytic algae may have a competitive advantage over surface water nutrients compared to macrophytes, which may have a competitive advantage over porewater nutrients via root systems. Muskegon Lake’s industrial history and designation as an Area of Concern prompted shoreline restoration, where macrophyte surveys were conducted pre- (2009-2010) and post- (2011-2012) restoration. For my thesis, I continued the macrophyte survey in 2018 to determine restoration impacts on the macrophyte community. An epiphytic algal survey also was included to evaluate interactions with their host macrophyte (Vallisneria americana) and to determine algal community structure variation across habitats. To further evaluate V. americana-epiphytic algal interactions, I examined both primary producer groups responses to source of nutrient enrichment (sediment porewater and/or surface water). Fluctuations in hydrologic and meteorological conditions among all survey years, largely due to water levels, obscured restoration-induced macrophyte changes and slowed ecosystem improvement. By 2018, however, we had seen an increase in restored habitat quality compared to the reference habitat based on Coefficient of Conservatism values and macrophyte biomass and density increases. My results also indicated a negative impact of epiphytic algal biomass and density on V. americana in Muskegon Lake and the mesocosm experiment. During the experiment, water column nutrient enrichment induced phytoplankton accumulation, reducing light and subsequent macrophyte and epiphytic algal biomass. Porewater nutrient enrichment helped alleviate the negative influence of phytoplankton biomass on macrophyte and epiphytic algal biomass when the water column was enriched. These studies reinforced the importance of environmental variation and biological interactions in influencing macrophyte community structure. Managers can use this knowledge to choose restoration locations that will enhance macrophyte success: intermediate light and hydrologic exposure will help mitigate epiphytic algal growth, and shallow slope could help increase habitat resiliency to climactic scale environmental shifts