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Boundary Bay Dike Upgrades and Wildlife Protection

July 28, 2016

Our work on the Boundary Bay Dyke upgrade intended to protect the City of Delta from coastal storm flooding. What we didn’t know is that it would require special measures to protect some very important local residents—reptiles!

The Boundary Bay dike system protects low-lying land in Delta, British Columbia. When sections of the dike were damaged by high water levels and storm waves, we were called in by the Corporation of Delta to redesign and reinforce them. Our mandate also included construction specifications and supervision, permitting, cost estimates, tender reviews, contract administration and a fishery serious harm assessment. Once work got underway, however, the scope was expanded to cover an unanticipated wildlife protection aspect.

First constraint: Time

At the outset, we believed that time would be the most important driver in the project. Key funding criteria meant that the work needed to be completed within just two months. This was compounded by environmental permit restrictions for working in an intertidal zone. Our Coastal Engineering team worked in concert with our Environment & Geoscience team to ensure the project met all required criteria and was delivered on time and on budget.

Second constraint: Hibernating snakes

During construction, we became aware that the site was home to a large garter snake hibernaculum (mass of hibernating snakes). Our biologists quickly got to work capturing the reptiles and safely transferring them into bins, where they would be allowed to safely complete their hibernation period. After two days of work in a space not much bigger than an office cubicle, we captured nearly 500 snakes and handed them over to the Wildlife Rescue Association.

Once spring temperatures rose above 14°C, the snakes were released back into their home habitat in Boundary Bay, reclaiming their territory and reestablishing their dens.

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About snake hibernation

Snake hibernation is actually called brumation. This process is different from mammal hibernation in that instead of living off fat reserves during cold winter months, snakes reduce their energy use by allowing their body temperature to drop.

The group we rescued was made up of three sub-species of garter snakes: the common garter, the Northwestern garter and the Western terrestrial garter. It’s common for these types to winter together in burrows and under rocks. The snakes ranged in length from 10 centimeters to one metre.

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Sustainability achievements

  • We rescued nearly 500 hibernating snakes from a construction site.
  • We worked with the Wildlife Rescue Association to ensure the rescued snakes would be provided adequate care and returned to their habitat when weather conditions permitted.
  • We conducted a fishery serious harm assessment to ensure local marine life would not be adversely affected by the project.

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