It appears on the left-hand side when you drive north on the DVP from Bloor to Eglinton. It looks like three oversized planters, giant grey moose teeth with greenery growing out of their tops. From the front of one tooth a spout waters a second tooth, and again a spout waters the third tooth. Yes, an ecological system.Powered by solar panels, the planters take water from the Don River and filter it through growing plants using waste plastic as soil. The water that goes in is polluted and the water that emerges is clean. The artwork brings ecology and science to the forefront and makes us question and "see" the river below.Elevated Wetlands by Noel Harding (who passed away recently) is, like the sculptor, an oddity. He once floated an elephant on a barge down a river in Holland. He made Canadian Arte Povera (an Italian art movement making use of poor material, "impoverished" art). Harding didn't only get his materials from hardware stores, but from junkyards. How does one describe a clear plastic bag filled with crumbled white paper hanging from a ceiling as anything but Arte Povera?But what is Elevated Wetlands, his sculpture built in the late 1990s? The aesthetic quality of a public sculpture is of paramount importance. It reflects back to viewers a sense of quality - call it excellence - that allows them to feel comfortable in the urban space they occupy. Elevated Wetlands is in many ways the opposite. It doesn't make you feel at peace with your urban environment, but the converse. It doesn't seem to belong, but it does. It asks viewers to question, to ask why, to enquire about the existence of the work itself. It's the perfect oddity for a highway landscape. It's an aesthetic work outside the domain of what we usually associate with modern classical sculpture. It appears chunky and heavy but simultaneously elegantly organic. Harding was able to imagine and create a public sculpture outside of the complex competition system in which the more radical the scheme, the less likely it was to win. I was outside his home in Caledon. He was watching the barbeque, and I was watching a model, Elevated Wetlands in miniature. I remember coveting it, wanting one for my garden, my elevated roof deck. We ate red meat, drank and argued into the night, but it's the sound of its drip, the water from one spout into the next plastic container, that persisted. Elevated Wetlands is not just uniquely anti-aesthetic, but intelligent. Not just the filtering - it fruitlessly filters polluted water that it can do little to change - but that it is a sculpture as system. The artist is displaying a mechanized system for betterment. He's used sunlight to power pumps that circulates water to grow plants and purify the water.When I drive the DVP, I don't just see Harding's sculpture. I see an amateur scientist at work. I see the oddity of the sculpture's shape as a reflection of the sculptor's madness. I can't help but smile and wonder if the sculpture is working, are the trees alive, is the river clean.