Some years ago, the government of my previous adopted home of Singapore had an epiphany. They realized that people like rivers and canals, and would pay a premium to live along them, especially if their banks had been developed into pleasant recreational areas. There was just one problem: the river and the canals were smelly, toxic dumps. So the government spent a few years dredging the selenium, corpses and rusting bicycles off of the bottom and laying running paths and green belts along the sides. Now the waterways are lovely and people will pay a premium to live along them.

Beijing is an arid town that needs all the open water it can get. You'd think, what with the canals lacing the city and the lakes in the center of town that the city would be off to a passable start. Unfortunately the canals are just one of many ecological disasters that have not yet ascended to the top of the great pre-Olympic "to-do" list. That's a shame, because Beijing has a lot of hard edges, and could use a little softening. Making the canals slightly less dreadful would be a lovely step in the right direction and would, in my book, rank close behind improving the air quality as a way of raising overall quality of life.

Last Sunday Mrs. Imagethief and I decided to take a long walk. It was hot, but the sky was blue and it seemed like too nice a day to stay indoors. We walked a half a kilometer south to the canal that runs east-west, just behind Soho New Town. Behind the east side of the wholesale market there are steps that lead down to the canal bank, and we thought it would be interesting to wander east along the canal bank, through some neighborhoods that we had never ventured into.

To the city's credit, the canal has a nice, wide walkway running along it. Unfortunately, you have to be a bit of a masochist to want to get too close to the canal itself. The flow has been partially blocked by the roadworks behind Soho and the water gives off a distinct odor of swampy staleness. Months of styrofoam has accumulated on the surface, backing up at the baffles where Xi Dawang Lu crosses the canal and leaving hundreds of meters of oily, grayish scum floating on the surface. As we walked east the styrofoam eventually tapered off, only to be replaced by an even less appealing drift of hundreds of used sanitary napkins and condoms. Mrs. Imagethief and I were astounded at the sheer numbers. It seems that everyone in Beijing is screwing, on the rag or both. Huge quantities of untreated effluent must be dumped into the open canals.

Naturally, people were fishing in this water. Little knots of anglers gathered at intervals, especially in the shade of overpasses and bridges, nursing their long poles and watching their tiny, straw-like floats bobbing in the oily water. Fishing in Xihai I can understand, but fishing in the canal is essentially fishing in a stew of hepatitis (perhaps explaining in part China's high hepatitis rate). Even if you don't eat your catch --an eventuality almost too horrible to contemplate-- the mere act of handling fish and fish hooks that have been immersed in that water seems like gambling with your liver. One man rode his tricycle past with a large fishnet coiled in the back.

As we went further east the amount of debris in the water diminished. Just before Gaobeidian Lu the canal widens into a lake with a park at the shore. Here people were still fishing, but they had traded the long poles and slender floats of the minnow-chasing canal fishermen for sturdier rods and tackle suitable for larger prey. Perhaps they were after the snakeheads (黑鱼) I've sometimes seen fishermen pull from the canal that leads from the Beijing Zoo to the summer palace. Many of the fishermen were gathered by a concrete embankment where suspiciously frothy, grey water poured into the lake from a large, underground pipe. But the only man who had caught anything was fishing by himself in a stagnant backwater near the road, where a small sluice gate had trapped another drift of floating garbage. Near where he was fishing small eels darted in waves from the spaces between the rocks lining the lakeshore to gulp air from the surface. A strange bloom of bright red water fleas had also erupted from the rocks, and swirled in unnatural looking clouds along the water's edge. The fisherman's catch net hung in the midst of the red cloud, and something he had caught earlier shifted restlessly in the mesh.

Across Gaobeidian Lu the character of the canal changed again. Water poured fromt he lake through a large sluice gate into a much broader section of canal with steep concrete banks. Divided by the lake and fed by effluent, the direction of flow had shifted to the east. There was no floating trash, but the water had a grim, unhealthy look to it and streams of bubbles percolated up from the ooze lining the bottom. Narrow lanes lined both sides of the canal, with stunted trees providing just a touch of shade. On the south bank was one of Beijing's lost neighborhoods of old, brick houses, where the city's creeping development has engulfed what used to be a semi-rural village. Children were playing loudly and a young woman squatted on the burning, concrete embankment with her head in her hands and a mobile phone to her ear. Behind the houses loomed the twin smokestacks and cooling towers of an immense power station, which, we assumed, was responsible for another current of foamy, grey water pouring into the canal from another underground pipe. An forest of dark green algae had bloomed around the confluence. On the north side of the canal was a strip of light industrial buildings draped in sullen abandonment.

As we walked under the fifth ring road industry gave way to another old residential neighborhood and a handful of ramshackle courtyard houses. Someone had planted a small plot of tomatoes and some sprays of bright flowers along the canal bank. Dogs were everywhere, including a few hefty specimens who would have raised eyebrows inside the fourth ring road. At a public exercise yard two teenagers played ping pong while three younger children sheltered from the sun in the shade underneath the the table. It was only a few kilometers from our neighborhood, but it felt like another city. We could hear the roar of the Jingtong expressway from the far side of the houses.

After nearly three hours of walking our feet and hips were sore from the relentlessly flat concrete, so we decided to head for home. We turned left and walked one block back up to the expressway. Suddenly we were in Beijing again, at the Broadcasting Academy stop on the Batong line. Ten minutes on the train and we were home.

The canal was awful. Polluted, smelly and grim, and topped with that comical, disgusting flow of sanitary pads and condoms. It was, in short, everything you'd expect of an unreconstructed, industrial urban waterway in a poor megalopolis. But at the same time it was pleasant; quiet, shady and green. Perhaps it is impossible to defile any stretch of water so completely that you can't see the potential. And it surely does have potential. If the city can ever get around to cleaning it out and routing the worst of the waste elsewhere, the canal could be a cool, green strip through a city that is too hot and noisy for its own good.

But I'm not holding my breath. Unless, that is, I'm walking along the canal.