Saturday, February 25, 2023

Life's A Beach

Another storm and more washed up sailboats around the city's beaches but more importantly is the ongoing damage to the seawall everytime a storm happens and how it highlights our failed efforts to try and push back against the ongoing erosion damage. Last year around the same time we had a nasty storm that took out the seawall and Kits pool and cost a few million to repair and experts say this trend is only going to get worse.

Ironically it's the seawall itself that aggravates the problem by increasing the waves energy as they get redirected after hitting the wall and then begin scouring the seafloor which ultimately results in the seawall itself collapsing. 

Removing the seawall and allowing the beach to revert to its natural state and installing an elevated boardwalk along the shoreline might be the ultimate solution but according to Parks Board estimates the cost of replacing the seawall around Stanley Park would be at least $250 million.

Another approach to combatting beach erosion is to construct "living dikes" along the shoreline which means adding soil and salt marsh vegetation to low lying areas along with sand, rock and driftwood berms which is what the cities of Surrey and Delta are doing around Boundary Bay. 

A similar approach is building a "dynamic revetment" or cobble berm of gravel and cobble-sized rocks to mimic a natural storm beach. Unlike seawalls this allows wave action to rearrange the stones into a stable profile that disrupts wave action and dissipates the waves energy as the rocks move around. Eventually sand settles in between the stones and a beach begins to form. This is what they've been successfully building at nearby Washaway Beach in North Cove,Washington State to counter the massive erosion the community was facing. 

Both of these approaches also have the pleasant side affect of promoting the habitat that supports ecosystems for a wide variety of migratory birds, and coastal marine life.

With tides and sea levels predicted to continue rising and winter storms only getting worse, how we approach the management of our shorelines will determine whether or not life's a beach or if we will even continue to have one.