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Adapting to Climate Change: An Introduction for Canadian Municipalities
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Annapolis Royal's Tidal Surge Project
This example illustrates the kind of practical steps that even small communities with limited capacity can take to reduce their vulnerability to climate change.
CARP discovered that a tidal surge during a severe storm was a rare but real threat to coastal zones in their region.
Annapolis Royal, Nova Scotia, is a small coastal community located on the southern shore of the Bay of Fundy. It is vulnerable to flooding because much of the region is below sea level as a result of Acadian settlers using dykes to reclaim land from the sea during the 17th century, and the fact that land has been naturally sinking for thousands of years.
It is anticipated that climate change will cause coastal communities to experience a rise in sea level and an increase in the frequency and intensity of storm surges and coastal erosion. Annapolis Royal residents wanted to know whether the risk of flooding would increase in the future and what infrastructure, such as roads, bridges and buildings, would be vulnerable.
To fill these knowledge gaps, the Tidal Surge Project (the coastal flooding component of the Annapolis Climate Change Outreach Project) was undertaken in 1998. With minimal resources, a citizens-based group, Clean Annapolis River Project (CARP), conducted an assessment of the town's vulnerability to storm surges. The primary goal was to identify and gather information on potential threats, including floods during times of extreme tides and storm surges, so the community could put appropriate emergency-response plans and procedures in place.
CARP discovered that a tidal surge during a severe storm was a rare but real threat to coastal zones in their region, particularly if it occurred concurrently with an unusually high tide (the latter happens several times each year). Using future climate change scenarios and resulting sea level rise predictions, storm surge floods were mapped at four and six metres above mean sea level (see map). With the information gathered, CARP was able to identify wide potential risk zones for tidal surge flooding and some possible implications for people living in the region.
In response, adaptive planning measures have been taken. For example, the detailed maps outlining potential flood zones effectively demonstrated the need for proper dyke maintenance, and the need to raise these structures has been acknowledged by the provincial government. The maps also enabled Annapolis Royal to identify areas of particular concern and to take measures to reduce potential economic loss and human harm. The mapping process revealed that the Fire Department was situated on a small rise, which would prevent it from being flooded during extreme weather. However, it would also become an island, isolated from the rest of the community. The Fire Department's emergency response plans have since been modified, including rehousing much of the rescue equipment (previously stored solely at the station) to deal more effectively with areas that could become isolated during a flood. The Fire Department has also acquired a boat.
THE CHALLENGE OF FINDING CRITICAL DATA The Clean Annapolis River Project (CARP) searched records from museums, newspapers, and historical societies to discover the types of events that had occurred in the past and to estimate changes in climatic and tidal factors. This information was compiled into a 10-page list of major storms, which was further narrowed down to those that had a storm surge component. The Saxby Gale of October 4-5, 1869, the most severe, was used as a model for flood predictions. Finding precise elevation data was also crucial to the project. Digital mapping was rejected as a source of elevation data because of inaccuracies and lack of detail. The standard contour interval in the 1:10 000 digital map packages is five metres, which can legally be anywhere between 2.5 and 7.5 metres. This is significant when a few centimetres can be the difference between a disastrous flood and a non-event. Instead, CARP obtained 20-year-old, 1:2000 scale paper maps with 2 m contours and 1/10 m spot elevations. With this more detailed information, they were able to determine the locations at most risk from tidal surge flows and the areas most in danger of flooding. |
CONTACT Steve Hawboldt PO Box 395 |
The results of the project were presented to citizens in a series of public forums. The mock disaster scenario that followed engaged the town's fire, medical, and emergency response teams. The public was also involved, allowing citizens to observe the potential effects that a flood might have on their lives and enabling them to explore how to minimize property damage and harm during a real disaster. As a result of this public-outreach effort, one homeowner particularly at risk decided to renovate and raise his home by more than half a metre.
This project led to a number of spinoffs, including further research to produce more precise elevation data. The Centre of Geographic Sciences (COGS) in nearby Lawrencetown has worked with LIDAR and Sidescan radar to gain a more accurate picture of the shoreline. Most significantly, the provincial Emergency Measures Organization (EMO) has begun to closely monitor the patterns and heights of the tides throughout Nova Scotia.
CARP's Tidal Surge Project demonstrated that even with limited resources, communities can reduce the uncertainty of climate change effects and find ways to adapt. Because Annapolis Royal is sinking and storm surges have been known to cause floods in the past, the adaptations recommended by this vulnerability assessment (raising the dykes, relocating emergency equipment, revising and practicing emergency response plans, etc.) will provide benefits regardless of impacts brought on by climate change.