enviro craps

Headline - Plans to create B.C.'s first 'living dike' move ahead in Mud Bay

West Coast Environmental Law are leading a misguided pilot study for Delta and Surrey municipalities, with the glowing ambition of providing flood protection while saving marshland from sea level rise. However at such small scale, this stage of the experimental project can not replicate the massive natural damage that would befall implementation of the full Engineering Plan, which involves covering an internationally important wetland with megatons of river dredge.
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Around $200 million would be required to transport and pump Fraser River sand onto the tidal flats, plugging it with replacement vegetation in progressively higher lifts over a 25 to 30 year period. Then, more sand will be required every 2 to 6 years to keep the new land from being submerged by ongoing sea level rise. Big money will be wasted, and the existing ecosystem will be destroyed.

​​The current saltmarsh is stable, healthy, and in spite of diking has grown in size by 20% since 1930 as demonstrated by aerial photography set out in a study by Gailis et al, 2021. Nature is already providing, and adding to, the buffer that Living Dike proponents think they can improve on. Even if the geoengineering gamble goes well, existing vegetation and micro-organisms would be smothered with sand, and wildlife displaced; collateral damage in the battle to impose a brave new designer environment.

What drives such eco-fantasy is the repetition of false alarm that sea levels will rise 1 M by the end of this century. Not only is that prediction based on an impossible CO2 emissions trajectory (RCP8.5), but it also ignores real-world experience. We are already 1.2 C into the UN’s not-to-be-exceeded 1.5 C temperature rise limit since pre-industrial, yet local sea levels have risen only a few inches in response. In the last 30 years sea levels recorded at Cherry Point WA (the closest tidal station to Mud Bay and sharing the same fetch of ocean water) have even trended downward:
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​Part of the Living Dike rationale is that it will obviate the need to raise existing dikes. From the Vancouver Sun article: “The old-school way to deal with sea-level rise would be to raise and harden the dike,” said Enda Murphy, a senior research engineer with the National Research Council of Canada. “The concept of the living dike is to expand and make use of the marsh in front of the dike.”. However, in order to prevent storm overtopping in the 1 M sea level rise scenario, the Mud Bay Living Dike is designed to crest at 5.1 M (see figure 8 of the Engineering Plan) which is 1.6 M higher than the 3.5 M elevation of the current dike. So, it looks like there is still quite a lot of old-school dike raising going on here.

The Engineering Plan is silent regarding the subsidence impact that will take place from the enormous mass and compaction of the 1.3 million cubic metres of river sand placement, estimated to weigh about 200 million metric tons. For comparison, according to the Director of the UBC Coastal Adaption Lab (Vancouver Sun, December 2020): The City of Surrey calculated adding one metre to their dykes would cause them to subside by about 50 centimetres. If the same degree of subsidence takes place due to the overburden of the Living Dike it would take 50 to 60 years, not 25 to 30, for project completion. How can this retarded construction pace keep up with the accelerating sea level rise forecasted?
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This is a dangerous game of chance being promoted by a group of lawyers who see themselves as eco-social crusaders. While the bureaucrats are apparently blinded by the shimmering green political mirage surrounding the project and obscuring the sensibilities needed for careful governance. As quoted in The Narwhal, the Senior Project Engineer for the City of Surrey said: We know we just have to try it and see if it works … roll the dice.