I recently participated in WEAO’s 9th Annual Student Design Competition. The challenge was to come up with innovative stormwater management solutions for Exhibition Place, Toronto. “The Ex”, as it’s known locally, is a bunch of parking lots and buildings that house major events that attract thousand of visitors annually.
The problems are:
- poor water quality of stormwater runoff – because of all of the cars and asphalt and no pre-treatment before the runoff enters Lake Ontario
- urban heat island effect – hot days then feel VERY hot
- flooding on Lakeshore Boulevard, which is south & downstream of Exhibition Place. The sewers on Lakeshore Boulevard receive runoff from Exhibition Place and the Gardiner Highway, so two very impervious areas that would have high peak runoff converge underneath Lakeshore
- the systems underground are old and not necessarily “designed” for conditions like peak flow
- the subsurface soils are mainly fill (because this area was Lake Ontario before it was filled in!) and likely contaminated
- the groundwater level is probably pretty close to the surface, since Exhibition Place is so close to Lake Ontario – which means infiltration won’t be so easy
- they need all the parking spots they can get!
Seven student teams from across Ontario went forth on solving this problem for the City of Toronto (our “client”). Our designs all implemented green infrastructure solutions – like bioretention, permeable pavement, green roofs, surface and subsurface detention (like cisterns for catching roof runoff). We showed that it was possible to reduce peak flow and runoff volumes from Exhibition Place by retaining it first, releasing it slowly. We also showed that we could improve water quality by filtering it, and reduce urban heat island effect by having lots of plants around.
The price tag was super high though! The range of estimates that our student teams came up with was between $5- and $12-million!!!
I’m left wondering if the City of Toronto will implement something as ambitious as this. I’ve seen many pilot projects get built to demonstrate the effectiveness of low impact development (LID) technologies – but it seems that there is some conservative faction that says “we don’t know enough, need more data, more time, more regulations” – and so we don’t build LIDs out at the large scale. Anecdotally, we’re often told that LIDs don’t work in the winter, or don’t work in urban areas, or need the best infiltrating soils possible to be effective. That line of thinking holds us back, especially when there are countless studies that prove the opposite.
What we proposed in the Student Design Competition is far more than a “pilot project”. I think it’s the right time to move beyond pilot projects for LIDs though. We have a lot of them already, we need to move into “normalizing” LIDs. That means including them in City development plans, ensuring that municipal operations staff (those folks who make sure streets are swept and sidewalk trees don’t fall on people) know what they are and how to maintain them. LIDs don’t work everywhere – I don’t think they are a be-all-end-all solution. But to adapt to climate change and reduce environmental and societal impacts of flooding, we need to normalize some new solutions that we know work.
I hope that Exhibition Place takes on the ambitious project of a green infrastructure re-design! And what better place for it? There are many green initiatives there already, like LEED buildings, waste management plans, and solar panels on roofs. The next step to normalizing LIDs is to implement them site-wide at a place visited by thousands of people every year – Exhibition Place.