Jan 20, 2023

Plans to create B.C. 's first 'living dike' move ahead in Mud Bay Back to video Work is expected to begin later this year with sediment, natural materials and plants added to almost a kilometre of shoreline at three points along Mud Bay. The project will be monitored to determine its impact on water and wave heights during high tides and storms and, if successful, could delay or reduce the need to raise dikes. Sunrise presented by Vancouver Sun Start your day with a roundup of B.C.-focused news and opinion delivered straight to your inbox at 7 a.m., Monday to Friday. Email Address Sign Up By clicking on the sign up button you consent to receive the above newsletter from Postmedia Network Inc. You may unsubscribe any time by clicking on the unsubscribe link at the bottom of our emails or any newsletter. Postmedia Network Inc. | 365 Bloor Street East, Toronto, Ontario, M4W 3L4 | 416-383-2300 Thanks for signing up! A welcome email is on its way. If you don't see it, please check your junk folder. The next issue of Sunrise presented by Vancouver Sun will soon be in your inbox. We encountered an issue signing you up. Please try again Article content “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.” The project will involve adding sediment dredged from the Fraser River to gradually increase the elevation of the foreshore in three areas. Sand berms, bags filled with oyster shells, and brushwood dams will be tested to provide stabilization, while vegetation will be planted to enhance the salt marshes. Advertisement 3 Article content Scientists test oyster shell-filled bags in a wave simulation chamber in Ottawa. Photo by Mitchel Provan, National Researc /jpg The tests are part of a pilot project to create a living dike along parts of Mud Bay in Surrey and Delta. Photo by Mitchel Provan, National Researc /jpg At a lab in Ottawa, Murphy and his team have tested various natural barriers in a wave chamber to determine the best fit for the B.C. coast. It is expected that during storms, the marsh will provide flood protection by decreasing the size and speed of waves, while storing water and reducing coastal erosion. The dike could become a model for projects in other B.C. communities preparing for a sea-level rise of at least a metre by 2100 due to climate change. It also fits with a provincial shift in flood management priorities outlined in B.C.’s draft flood strategy , which is currently accepting public feedback . The document highlights the need for more nature-based solutions. The work to create the living dike began almost a decade ago when B.C. communities began to realize the challenges sea-level rise will bring, said Deborah Carlson, a staff lawyer with West Coast Environmental Law. Advertisement 4 Article content Raising dikes is complex and costly and carries a high environmental footprint. “We wanted to make a case for doing things differently in Boundary Bay,” she said. The pilot project recognizes that as sea levels rise, infrastructure isn’t the only thing at risk. “Coastal squeeze” will see important habitat on the foreshore drowned as water levels rise and butt up against hard barriers, such as dikes, creating a bathtub effect. A living dike will be created along parts of Mud Bay. Photo by Francis Georgian /PNG Mud Bay in Surrey. Photo by Francis Georgian /PNG Carlson said getting the project off the ground was complicated by the various levels of jurisdiction in the intertidal zone. While wildlife management is a provincial responsibility, the federal fisheries ministry is also involved, as well as several First Nations and the municipalities of Surrey and Delta. Advertisement 5 The Delta portion of the pilot project, about 200 metres near the south end of 96 Street along Boundary Bay, will cost about $1.5 million, with half of that, $750,000, paid by the federal government and half by the municipality, said city manager Sean McGill. The City of Surrey is in the process of putting the project out to tender and declined to comment until that process is complete. Its website notes that the project is currently engaged in a provincial environmental assessment. Work is expected to begin on two of the Surrey and Delta pilot sites later this year. If successful, work on a third site will be done from 2024 to 2027. The federal funds must be spent by 2027. Advertisement 6 Article content University of B.C. professor Kees Lokman said there are no examples of similar projects in the region, although there are horizontal levies in the United States and living dikes in the Netherlands. “There is not one solution to fit all,” he said. “We have to understand local conditions,” including sediment, waves and wind. The B.C. project must be monitored and supported by various stakeholders, including members of the Semiahmoo First Nation. Lokman said the pilot project takes into account some of the uncertainties involved in establishing the living dike, including how fast sea levels will rise, how well the plants become established in the first few years, and the impact of erosion. If it is successful, it could provide a framework for smaller communities and First Nations to follow across B.C. He said the process of designing the living dike with input and understanding of the values of all the various shareholders will be the key to its success.