Tuesday, March 31, 2009

Greenwashing Parking Lots

Parking lot newly resurfaced. Asphalt surface allows for zero infiltration of rain.

Last year the city announced with some fanfare the creation of green standards for parking lots. These standards give guidelines for building parking lots that will reduce their impact on the environment. Current construction methods are simple and cheap but add to a host of environmental problems. Black asphalt bakes in the sun. The cumulative effect of all the parking lots in the city along with other urban structures increases the urban heat island effect. When rain hits an asphalt surface, it heats up and quickly runs off into the nearest sewer. This warm water runoff in downtown Toronto is quickly routed toward watercourses such as the Don River. The flush of warm water along with all the grit, oil, and other pollutants it picks up along the way is the major cause of habitat degradation in our river systems.

The green standards seek to reduce these effects with a number of design changes. Foremost is the inclusion of permeable paving surfaces. This type of surface allows for infiltration of rain water into the underlying soil. Another consideration is to break up the expanse of asphalt by planting trees within the parking lot. Additionally swales can be added to capture runoff from the surface before it hits the sewers.

All this sounds great but it has apparently fallen on deaf ears when it comes to actually applying these methods. This past winter a parking lot in Stan Wadlow Park at the edge of Taylor-Massey Creek was resurfaced. The parking lot was completely resurfaced with asphalt. Only one small island around a hydro pole was left for planting. On the south side of the parking lot a swale was dug but this will have next to no effect because the asphalt surface has been graded to slope away from it toward the middle where there are two storm drains. This means that less than 1% of the total parking lot runoff will flow into the swale.

Storm drains in centre of parking area. Asphalt is sloped down toward them which collects all the runoff.

Swales are meant to trap runoff but this one will capture none. Curb stones prevent most runoff reaching the swale and the asphalt is sloped away from it.

So, it seems that on the surface the city has tried to apply the new standards but the application here is paper thin. The city needs to set a higher standard when redesigning its own parking lots. How do they expect private parking lot builders to do better when they fail so miserably?

One small area left open. Since it's next to a hydro pole there won't be any shade trees, just decorative shrubs.


brian said...

Really intriguing that TRCA, FODE, TMP, COT PFR and Hydro would allow car parking in a ravine protected area....but not dirt jumps, skills parks, or off road trails...

more than "Green Footprint Policy" in mouth here...

Donwatcher said...

Hello Brian,

Your comment is a little off-topic (this post is about green building standards). However it does broadly fit under the subject of appropriate human use of natural areas. One could argue that if parking lots don't belong then neither does anything else... shouldn't we leave nature to take care of itself?

We really need to carefully evaluate the appropriateness of every human built structure in the ravines and their potential impacts on the environment. This should apply to everything, including parking lots, hockey arenas and bicycle skill parks.


Anonymous said...

The Parking lot in question has been there for over 30 years, it is not a NEW lot.

The reconstruction of the lot, was a 'maintenance' decision by the City.

There was no E.A. required, and no NGO or citizen or agency had any legal standing to oppose it, nor were they asked for their input.

It is important to note that the local councillor who sympathizes with environmental concerns requested that IF the parking lot were to be redone, that the amount of paved area be reduced and that 'green' standards be utilized.

It does appear she may have been mislead by staff in charge of the parking lot project as to the nature of the 'green standards'; either that or the staff/contractor in question simply did not know what they were doing.

Anonymous said...

Though I do not own a car I must say that I think it is not unreasonable to have parking available BUT it is unfortunate (to be kind!) that they are not built and maintained to a high "green level'. This lot may have been there for ages and this may have been 'maintenance' BUT the City/TRCA etc should have made a better job of setting a good example. Who is the local councillor? Is she going to do some follow-up?

Donwatcher said...

Janet Davis is the local councillor.

Anonymous said...

I wrote to Janet Davis and got this response. Hmmm

"Thank you for your email and for your interest and commitment to greening the city.

I have forwarded your concerns on to Councillor Davis. However, please note that she asked that as many green elements be incorporated into the design of the new parking lot at Stan Wadlow as the limited budget permitted. As a result, the parking was reduced by 40% in order to incorporate storm water elements. She also requested that the entrance to the park be designed to be more pedestrian- and bike-friendly.


Paula Wansbrough
Constituency Assistant to Councillor Janet Davis"