Shores are vulnerable to both rising sea levels and increased numbers and intensity of storm events as the climate warms (see How Will Sea Level Rise Affect Antigonish?). The vulnerability of a shoreline to erosion, or the rate that it erodes, is related to the exposure to wave action and to the composition of both the bedrock and the material on top of it. This is highly variable in the Antigonish region.
The process of coastal erosion on Nova Scotia shores is beautifully and concisely explained in a two page brochure called Understanding Nova Scotia’s Coastlines by Natural Resources Canada. In this publication they emphasize responsible coastal development which must consider the process of natural shoreline change to avoid costly damage and adverse alteration to natural shorelines.
Erosion rates vary around the province, because waves, tides and the presence of sea ice vary. Also, sediment supply (coming from offshore or by the erosion of adjacent shores) determines the stability of a beach or waterfront. When sediment is available, beaches build seaward but when sediment is limited, beaches erode.
The most dynamic shores are barrier beaches and coastal headlands. In Nova Scotia, they are favoured sites to build homes and cottages. Unfortunately, both are extremely vulnerable to rising sea level. Coastal headlands may erode rapidly to form steep cliffs, which then become partially protected from erosion by the accumulation below of boulders, and wide sand beaches. The stability of barrier beaches is closely linked to what is happening at adjacent headlands. Beaches benefit from sand supply coming from eroding headlands, but beach stability is threatened once the headland is depleted. Barrier beaches experience different types and rates of change depending on their composition, size and shape. Low barrier beaches can naturally rebuild, as long as there is a sediment supply.
The processes of coastal erosion discussed in the brochure are emphasized and illustrated for well-known beaches and headlands in the Antigonish area in a report by Dan Utting. He concludes that because the coastline is so diverse, to assess coastal hazards it is important to first determine the coastal geomorphology. His report includes aerial photos of Mahoney’s Beach, Jimtown, Monks Head and Pomquet Beach.
The Natural Resources Canada Brochure goes on to say that increased construction of shoreline armouring to protect houses threatens the natural capacity of shorelines to buffer inland areas from erosion and flooding. Engineered shore protection structures, such as retaining walls, diminish the supply of sediment to beaches.
If you are planning to purchase or develop shoreline property, first investigate and assess the property. What type of shoreline is it? What is its composition? How high or wide is it? Shorelines may look more stable in the summer. Walk the shore in the fall and winter too. Talk with neighbours to learn about typical changes in the shoreline or the history of erosion and flooding. Consult with experts to discuss the character and evolution of the shoreline and what the future will bring. Obtain older vertical air photos of the property to examine past shoreline changes. Lastly, plan a safe setback for your property so that natural shoreline changes do not threaten it over the time you (or your children) plan to use it.
We have been discussing the process of coastal erosion and the vulnerability of developing property near shores. The importance of protecting beach and dune habitat for not only the diverse life that they support, but for the integrity of inshore areas, is presented in a report by Sue Abbott (Bird Studies Canada) called Healthy Beaches and Dunes for Tomorrow. This report explains that beaches and dunes are dynamic landscapes that are constantly adapting to changing environmental conditions. Beaches and dunes are interconnected with the land behind them. Barrachois (brackish ponds) and salt marshes are common features behind beaches and dunes. These coastal wetlands are essential nurseries for fish and wildlife. We are fortunate in Nova Scotia to have different types of sandy beaches, such as sand spits and barrier beaches. Beaches and dunes are dynamic features that provide habitat for plants and wildlife – some of which are rare such as the endangered Piping Plover.
While many of us enjoy the beaches and coastlines of Nova Scotia as recreational areas, some have property or wish to purchase property that is located on coastlines, wetlands, rivers or lakes. Shoreline properties are valuable and beautiful in many ways, but they also carry with them the risk of erosion and flooding. Owning and/or living on them is a privilege and includes a responsibility to care for this special ribbon of life. Wise stewardship of the edge where land, water and air meet is vital to preserving water quality, soil integrity and the health and beauty of the ecosystems linked to your property.
As already noted, there are a number of points to consider if you are buying shoreline property. But what if you have already bought a home, or have built on your shoreline property and you are having problems with erosion? What are your options? What can you do to preserve your land without causing more damage to the ecosystem? One option is to explore the idea of using Living Shorelines for erosion control and mitigation. You can find an excellent resource for this relatively inexpensive, simple, yet effective method on the Ecology Action Centre website, including videos and how-to-do-it-yourself instructions. For those interested in finding experts who will work to create a healthy shoreline for them, businesses such as Helping Nature Heal are available to help.
There are some simple but important rules to follow when living by shorelines. The most important guidelines are to keep building construction and development as far back as possible from the shoreline and to maintain the area between your home and the shoreline as naturally as possible, leaving the trees, shrubs and natural vegetation in place. Developing and maintaining shorelines this way will save you time, energy and money in the long run – and you will have the added enjoyment of knowing that you are helping to reduce your ecological footprint and the impact of climate change.
by H. Mayhew and L. Buckland-Nicksshare this: