Higher sea levels driven by climate change could cause extensive flooding in coastal areas of Campbell River by 2100, and plans are underway to reduce the risks, according to a new report from the city.

Municipal officials organized two workshops last week to field questions from the public about the findings, and to get feedback about how to adapt to changes on the coastline.

Flood mitigation infrastructure will develop gradually, said Amber Zirnhelt, the cityB次元官网网址檚 manager of long-range planning and sustainability.

B次元官网网址淚t will be long-term, slow process,B次元官网网址� she said. B次元官网网址淲eB次元官网网址檙e not talking about tomorrow going and building a big seawall along Campbell River.B次元官网网址�

The two-part report describes a number of practices used around the world to deal with sea-level rises, ranging from offshore reefs to seawalls to homes elevated on piles.

David Reid, an architect working with the city on sea-rise planning, described some of the pros and cons of those techniques during a presentation at Willow Point Hall on Nov. 29. Dikes, for example, tend to block the scenery.

B次元官网网址淚f your house is low and the dike is high, then you canB次元官网网址檛 see the view anymore, which is highly undesirable,B次元官网网址� Reid said.

And more importantly, dike failures can lead to widespread deaths, something thatB次元官网网址檚 occurred in the Netherlands, he said. For that reason, policymakers frequently ask people to sleep at a level higher than the crest of the dike.

B次元官网网址淚f the dike fails, we donB次元官网网址檛 want you to die,B次元官网网址� Reid said.

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ItB次元官网网址檚 the kind of consideration that more coastal communities will be wrestling with as they plan for the future.

Sea rise is practically inevitable, said Grant Lamont, a coastal engineer with Northwest Hydraulic Consultants, which was hired by the city to study ocean dynamics.

B次元官网网址淭hereB次元官网网址檚 less and less uncertainty today within the scientific papers and scientific community that sea-level rise is going to happen,B次元官网网址� he said. B次元官网网址淭he uncertainty is about when.B次元官网网址�

The flood projections are based on a one-metre rise in sea levels by 2100 in combination with elements including a major storm event, king tide, storm surge and wave action, Zirnhelt said.

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The report indicates that if nothing were done to prepare for that kind of scenario, water would flood a large section of downtown, stretching across the lower parts of Hwy. 19A, Dogwood St., Shoppers Row and other streets.

Water would also hit various public works, including communications and electrical utilities that run underground. The downtown fire hall would also be affected.

In Willow Point and south B次元官网网址� an area B次元官网网址渧ery exposed to high storm winds and waves from the open reaches of the Strait of GeorgiaB次元官网网址� B次元官网网址� water would hit various utilities and the lower floors of some buildings and low yards. The boat ramp would be at risk, along with the grounds and boathouse of Sybil Andrews Cottage.

Surging seas would squeeze out habitat and walking areas along the foreshore, and rock armouring would be at a greater risk of B次元官网网址渇ailure or overtopping due to increased wave height,B次元官网网址� according to the report.

Elsewhere in the city, public beach areas at Sequoia Park and nearby low-lying buildings and parking areas would also be affected by rising seas, and sanitary gravity sewers would be at risk.

Erosion may also affect the stability of steep slopes along the stretch of coastline between Evergreen Rd. and the Maritime Heritage Centre.

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In North Campbell River, key risks include water hitting the lower floors of several buildings in the Agricultural Land Reserve along with damage to pocket beaches and sensitive shoreline areas.

The bluffs area would also be at risk of erosion and slides, which could in turn threaten the sites of existing homes, along with utility and stair routes.

The report notes that greenhouse gas emissions due largely to human activity are the primary driver of sea-level rise, as higher temperatures cause thermal expansion of ocean waters and accelerated melting of ice sheets and glaciers.

In Campbell River, the effect of rising oceans is checked somewhat by a slight upheave of the areaB次元官网网址檚 land mass, but B次元官网网址渟ea-level rise is happening faster than the land is rebounding,B次元官网网址� the report states.

The one-metre figure comes from provincial guidelines based on projections from the UNB次元官网网址檚 Intergovernmental Panel on Climate Change (IPCC), which brings together experts from around the world to assess published literature about climate change and to provide information to governments.

Several governments are already planning for a 1.6 metre rise, and B.C.B次元官网网址檚 one-metre figure may be revised upwards as new information becomes available, Zirnhelt said.

B次元官网网址淲e have to plan with that factor of uncertainty in mind,B次元官网网址� she said.

david.koch@campbellrivermirror.com
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