The Habitat Skirt

Maybe you’ve heard of the Vancouver Convention Centre (VCC) at the heart of downtown, headquarters of the 2010 Winter Olympics media. Maybe you’ve even seen its impressive glass windows yourself, overlooking the Burrard Inlet. But do you know what is hiding beneath the surface of the waters surrounding it?

Figure 1. Photograph of the Vancouver Convention Centre habitat skirt displaying the various organisms that have attached (LMN Architects 2011)

Photograph of the Vancouver Convention Centre habitat skirt displaying the various organisms that have attached (LMN Architects 2011).

A marine environment teeming with life, thanks in part to the habitat skirt!

(If you haven’t heard of the VCC before, here’s some background.)

The marine habitat skirt at the VCC is the first of its kind, an innovative response to Fisheries and Oceans Canada‘s (DFO) habitat compensation requirement. Through discussion between DFO, the environmental consultant company Tetra Tech EBA, and the marine foundation design company WorleyParsons Westmar, the habitat skirt was born.

At a cost of $8.3 million and built as part of the VCC expansion project, the habitat skirt borders three sides of the building. Funded by different levels of government, it was installed in just four days in May 2008. Using 362 precast slats, it was assembled by fitting them into 76 frames, with the end result looking like a giant 5-tiered staircase. Each frame weighs 40 tonnes, or the weight of an average male adult sperm whale. The habitat skirt offers 477 m of extended shoreline and 6,122 m2 of surface area. This is equivalent to the length of five Canadian football fields and the floor space of the entire White House!

The habitat skirt hangs suspended in the water column, spanning the entire 5 m intertidal zone. This means that at low tide, all five levels of the skirt can be seen above water, and at high tide, most or all of it is underwater. On top of each tier is a 15 cm-deep tidal pool, and channels run beneath the building itself; both are flushed daily by the tidal cycle. The habitat skirt also has ribbed surfaces to increase habitat complexity and help retain moisture. Its material and structure work to limit concrete cracking and increase the skirt’s resiliency to impacts from objects and wave forces. The aggregate texturing of the skirt encourages marine life to attach by replicating the conditions of a natural shoreline.

Photo of the Vancouver Convention Centre habitat skirt at low tide (WorleyParsons Westmar 2009). All five levels of the habitat skirt can be seen, with its ribbed horizontal surfaces and tidal pools.

The horizontal surfaces and sloped vertical edge of the habitat skirt are meant to mimic the replaced gradual slope and reestablish coastal marine habitat. Not only does the skirt provide habitat for many invertebrates, which support predatory species such as sea otters, it also provides connectivity with existing coastline for migrating juvenile fish, specifically salmon.

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