First flush

23 July 2012 Ideas Life

On a whim, I decided to go for a bike ride today. I left my wallet and phone behind and spent a couple hours on the Grand River Trail. It’s a great ride; I started at the Economical Insurance Trailway (point 13 on the above-linked map) and continued to Kolb Park, then turned around. It wasn’t too hilly, but I did have to work up a sweat at times. It was about equal difficulty on the way there and on the way back, which is nice - it stops me from coasting too much.

But that’s not what I wanted to write about. As I passed Bingemans on the way down, it started to rain a little. By the time I reached the Victoria St. underpass, it was a veritable torrent of fat, hot raindrops soaking my clothes through to the skin. I didn’t mind, the air was still warm so I decided I would continue riding along the river until the rain stopped.

It stopped after 10 minutes or so. I found myself riding through Kolb Park - and there was a slightly overgrown fork off the main trail that looked interesting. I veered left and ducked under the sodden, low-hanging branches. After about a minute my path was blocked; a dead end. But there  was a footpath down to the river. So I propped my bike up onto a tree, and walked down to the water’s edge.

As the tree canopy opened up before me, I saw a little beach of sorts - strewn with rocks and weeds and springy mud. An insect buzzed incessantly around my ear. A flock of ducks were floating in the water; a seagull stood guard from a rock on the opposite side of the river. Through the overgrowth, in the distance, I could spot a new suburban development, creeping toward the river from Breslau.

I had found quite an idyllic spot. I set my rain-streaked glasses down on a rock; took off my shirt and wringed it out; skipped a few rocks; stretched my legs; and after a sort while, I figured it was time to head home.

But as I walked back up the footpath to my bike, I heard the sound of rushing water grow louder. It wasn’t the river. It was a surge of water coming down the riverbank. In the time it had taken me to stop and take a breather, the intense but brief rainfall had filtered through the sewer system to end up here. It wasn’t an idyllic beach at all. It was a drainage area.

I scampered back down to take a look at the runoff. This was the first flush phenomenon in action - one of those concepts that I had learned theoretically, but hadn’t experienced first-hand. I could see the runoff making its way through the rocks while I stood on one of the larger ones. It was a thick brown liquid, kind of like hot chocolate, no doubt tainted with oil and sediment from the nearby industrial area. It smelled of sewage. Cigarette butts floated in the inky mixture. And it was travelling fast. Rocks the size of my fist were being displaced by the powerful flow. A spider, who had been basking atop a rock, was swept under. I moved to higher ground as the toxic effluent began to touch my shoes.

When the runoff met the water’s edge, it formed a visible brown streak as the river carried it downstream, cigarette butts and all. The ducks stayed put, seemingly unfazed. This must have been an all-too-common occurrence for them.

To imagine that this was happening at innumerable points up and down the river, as a result of rainfall lasting less than half an hour, baffled me. Is our water even being treated properly? Is the wastewater treatment system so overwhelmed by an afternoon shower that it had to divert raw sewage into the river?

After about 10 minutes, the effluent started to clear up. It was still brown, but less oily-looking. Does anybody test this water? I wondered. And if they do, a 10-minute delay would give wildly different results. I pondered all this as I rode back home.

This isn’t necessarily a suburban problem; but we need to be smarter with how we develop urban areas. We can’t accept the status quo - hectares of new impermeable pavement and kilometre after kilometre of engineered concrete sewer lines. If we want to keep the natural beauty of the Grand while encouraging population growth in the region, we need to incorporate the natural environment into our water filtration system on a large scale - before it gets dumped into the river.

Sam Nabi

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