Medium fidelity lab

NATURAL RESILIENCE

Using Nature-based Solutions to Enhance Coastal Protection

By Joanna Eyquem

Coastal flooding and erosion are a direct threat to the health and safety of people living in coastal communities, and cause damage to local infrastructure and property. The majority of Canada’s coastal population is located along the East (Atlantic) and West (Pacific) coastlines, where sea levels are rising due to irreversible climate change.

Action is required NOW to manage the growing risks to coastal communities. A recent report from the University of Waterloo’s Intact Centre describes how Canada can scale-up the use of nature-based solutions, in tandem with ‘grey’ infrastructure, to protect communities along the East and West coastlines. Importantly, action must consider natural processes along the coast to a greater extent than has occurred to date. Reduction of flooding and erosion at one site, if not carefully designed, can cause instability further along the coast and degradation of coastal ecosystems on which communities depend.

Canada does not yet have a strategic planning framework or standard classification of approaches for coastal risk management. Coastal risk management responses identified by the Intergovernmental Panel on Climate Change (IPCC) include Protection, Accommodation, Retreat and Avoidance, as well as non-intervention.

A suite of options should be appraised to select appropriate approaches along Canada’s east and west coasts. Coastal protection measures can be divided into two key categories: • Grey Infrastructure: hard, engineered coastal protection measures, and;

Nature-Based Solutions: measures that depend on, or mimic, natural systems to manage flood and erosion risk, Nature-based solutions are further subdivided into those that are: • Predominantly sediment-based, such as adding sediment or sand to beaches (a process known as beach nourishment) • Predominantly vegetation-based, such as saltmarsh or coastal wetland restoration.

Overview of coastal protection measures utilized in Canada Table 1: Overview of coastal protection measures utilized in Canada

Grey Infrastructure Underutilized Nature-Based Solutions

Predominantly sediment-based

Predominantly vegetation-based

• Seawalls • Detached / Nearshore Breakwaters • Attached Breakwaters / Headlands • Submerged Breakwaters / Reefs • Permeable Revetments* • Impermeable Revetments* /

Retaining Walls • Groynes • Storm Surge Barriers / Tidal Sluices • Sea Dikes / Embankments / Levees • Dynamic Revetment* / Cobble Berm • Submerged Sills / Perched Beach • Beach Nourishment • Island Restoration or Enhancement • Dune Restoration or Stabilization • Cliff Stabilization / Revegetation • Salt Marsh and Coastal

Wetland Restoration • Submerged Aquatic Vegetation • Bioengineering - Coir Rolls (made of coconut fibre) • Bioengineering - Natural Fibre Blankets