Monday, September 07, 2009

Elevated Wetlands

Elevated Wetlands

This summer I had the opportunity to work on the Elevated Wetlands. The company I have been working for this summer, Urban Forest Associates, has a maintenance contract with the city to service the equipment and take care of the pods.

Their position next to the Don Valley Parkway makes them very prominent. Of all the things in the Don they seem to evoke the most questions and comment. People wonder: what are those things? I have heard them described as giant teeth stuck in the ground, giant polar bears or strange grey elephants. In fact, the Elevated Wetlands are an art installation, created by an artist named Noel Harding. They were commissioned by the Canadian Plastics Industry Association and are made entirely from recycled plastics. In his words, "the Elevated Wetlands are a symbol of the interface between urban and wilderness forms". In one sense it is good that they get conversations going. It makes a good starting point when talking about other Don issues.

Schematic diagram of the Elevated Wetlands

Water is pumped from the Don River using solar power into the highest pod. It then flows through each pod, falls to the next one and then eventually drains out into a wetland at the base. There are three pods on each side of the Don Valley Parkway. Eventually the water flows back into the river. Whether it is much cleaner is hard to say since I don't believe it has ever been tested. However, two wetlands exist where none were before so that is definitely a bonus.

Water pours into base wetland. The wetland provides habitat for a variety of flora and fauna.

It turns out that the pumping equipment installed is quite finicky and breaks down regularly. Not only that but the some critical pieces are German made and parts have to be ordered from a company in Chicago. Another problem is that since the system is solar powered the water doesn't flow at night or during cloudy days. On the east side the solar panels are obscured by trees which don't get sun until about 10:30 AM.

One of the jobs to be done is weeding the pods. this requires clambering up a ladder to get into the pods. To get from one pod to the next you can climb up over the spout which can be a little precarious. This is additionally tricky because wasps like to nest in the crevices that line the walls of each pod.

I was under the impression that the pods were miniature wetlands, brimming with water and filled with aquatic plants. Upon climbing into the pods I was disappointed to find the surface is actually regular soil and the pods are not wetlands but miniature forests. They are really just glorified flower pots. From the ground the water looks like it is falling freely into each other from one to the other but in fact it falls into hidden buckets that route the water underground to the next one. There are drip lines that water the plants so that they are not totally isolated from the water system.

Spout above aimed at bucket below

Water pours from spout into a receiving bucket

The wetlands at the base are small but functioning. While we were weeding I noticed green frogs amongst the reeds. Cattails and and the invasive phragmites grass dominate the edge but there are also swamp milkweed, water plantain, and water lily.

Fellow worker, Laura, cleaning the solar panels in the upper pod


Anonymous said...

I cycle past them quite often and this year it seems they have been flowing most days I see them. Thanks for the background on them and for your, as always, interesting comments.

Boyd M L Reimer said...

Thanks for this, John. We were just cycling there on Monday.

Unknown said...

If the water is not drinkable, the city had better post signs on the lower one stating that as we saw cyclists drinking the cold water on a very humid day recently.

We tried it too and it seemed ok. If we get sick from it we will definately sue the City of Toronto over the absence of proper signage!!

Anonymous said...

Sunshine, it isn't the city's fault that you are a complete moron.

FYI you shouldn't drink water that flows out of downspouts either.