Town of Shelburne Bank Stabilization and Living Shoreline Project

In 2020, Coastal Action, in partnership with CB Wetlands and Environmental Specialists Inc. (CBWES Inc.), and the Town of Shelburne, installed a living shoreline along the waterfront to address erosion, storm surges, flooding, and changing land use. Shelburne’s natural coastline resilience has been impacted through sediment transport, infilling coastal habitats, shoreline hardening, wharves, and boat launches. While the town has historically relied on sea walls, stone armoring, and infilling to protect its waterfront, in recent years, the town has acknowledged that maintaining the infrastructure will become a burden on limited resources. In 2016, Shelburne used the Canadian Index of Multiple Deprivation and found that the town has the highest vulnerability in the region with critical infrastructure, such as buildings and roads, located within meters of the coast. Increasing precipitation and stronger storms will contribute to high tidal water levels, higher storm surges at the coast, and more overland flooding. The living shoreline was installed to absorb and slow overland flow while also protecting against wave erosion. The project was designed and implemented on a small section of the public shoreline on the town’s historic waterfront and has brought environmental benefits to the site including habitat and erosion control, aesthetic improvements, and potential cost reductions for slope protection. The case study illustrates a partnership between local government, an environmental non-governmental organization, and the private sector to demonstrate and learn from using a new approach to shoreline protection.

Read the Summary Link to Full Case Study

Understanding and Assessing Impacts

In 2014, the Town of Shelburne developed a Municipal Climate Action Plan (MCCAP) to identify hazards and risks associated with projected changes in climate. As sea levels continue to rise, Nova Scotia will experience magnified high tides, increased storm surges, and increased coastal erosion rates. Flooding includes coastal flooding and inland flooding from hurricanes and winter storm events. Shelburne’s history of armoring, infilling, and introducing impermeable surfaces at the coast affected the natural ability of the land and shore to mitigate flooding and erosion. Removing vegetation and replacing it with parking lots and roadways has increased overland flow. The MCCAP identified flooding and erosion as a risk to public safety, systems, and property in Shelburne. The main streets along the shore are the primary access to the local hospital, fire service, and municipal wastewater treatment plant. Other critical infrastructures at risk are parking lots, historic and commercial buildings, and port facilities. The Ecology Action Centre estimated that water levels exceeding 3.4m would flood critical roads and impact many of the town’s historical landmarks.

Identifying Actions

In 2012, the Insurance Bureau of Canada saw an increase in the number of water-related claims by its members. Overland flooding and coastal erosion are not covered by home insurance unless the water source stems from drains and sewers, hence their interest in municipal infrastructure. The MCAAP preliminary risk assessment identified the municipal infrastructure’s risk due to climate change. Coastal flooding and erosion were selected as a priority for adaptation. In 2018, Coastal Action, an environmental charitable organization, recommended implementing a living shoreline to stabilize an eroding bank along the waterfront. The main goal of the living shoreline was to create an environment that adapted to changing conditions. Coast Action identified a 15m location in the historic waterfront district where the bank and boulder armouring was slumping and required maintenance. Coastal Action engaged CBWES Inc. to develop a living shoreline site plan including plant selection and installation, and site management and maintenance. CBWES Inc. noted that the need for maintenance would decrease with time as the living shoreline became established. After five years it would be mostly self-sustaining and require only light maintenance such as pruning of the shrubs to maintain their health and desired size, which the town agreed to provide. The Shelburne living shoreline installation used logs, haybales, and native vegetation to naturalize and stabilize the bank. Vegetation reduces overland flow, reduces wind and wave energy, and increases shore stability. The logs prevent cars from driving into the newly restored area. Haybales limit potential wave scouring, absorb peak flows, reduce wave and wind energy, and provide nutrients.

Implementation

In August 2020, community volunteers, municipal staff, and project partners installed the living shoreline. Four zones of vegetation were planted between the top layer and the bank. Zone 1 is located closest to the parking lot and includes herbaceous perennials, flowering perennials, and small fruit-bearing shrubs that serve to protect from overland flow while the vegetation provides visual appeal. Zone 2 is comprised of a layer of vegetation approximately 1.2m wide. A variety of medium-sized shrubs were planted in this zone to increase plant and habitat diversity. Zone 3 consists of large shrubs to protect the second zone of vegetation above it from wind and wave action. A row of haybales separates the third zone from the transition zone to the water. The transition zone is 2.4m-3.7m wide and consists of salt-tolerant grasses and perennials.

Outcomes and Monitoring Progress

The Shelburne living shoreline project demonstrates an alternative to shoreline hardening for erosion protection and establishes institutional capacity for nature-based adaptation. The project restored approximately 93 m2 of self-sustaining, natural shoreline and is predicted to absorb an average of 27.3 m3 of storm water per year thereby reducing overland flow, erosion, scouring, and flooding impacts at the 15m section of the waterfront. The project has improved the shoreline aesthetic, built partnerships across the community, and engaged residents with hands-on involvement in shoreline restoration and climate change action. Shelburne does not have plans to install more living shorelines but monitoring this living shoreline for performance that includes successful establishment of the vegetation and erosion prevention will be a driver for expanding the living shoreline approach.

Next Steps

In 2021, new regulations were introduced for the Provincial Coastal Protection Act that aimed to address the current gap in municipal coast regulations. During the implementation of Shelburne’s Living Shoreline Project, regulations to enforce the legislation were being developed as are implementation tools including province-wide flood line mapping. The town is in the process of reviewing its municipal plan and by-laws. Shelburne has completed sustainability, climate change action, economic development, and business district revitalization planning. Shelburne values the economic and cultural assets of its waterfront and knows the risk posed by climate change to these assets.

Resources

Link to Full Case Study:

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