Unless you’re from a galaxy far, far away, you know municipalities in the capital region dispose of sewage by pumping it out to sea. And you’ve probably heard that $780 million has been earmarked for a land-based treatment plant to halt this noxious practice.
But what most of us don’t realize is that even when the new plant is up and running, we’ll continue to dump raw sewage in the ocean — much less, to be sure, but still significant amounts.
The problem lies beneath our feet. There are more than 1,600 kilometres of sanitary sewers in Greater Victoria, and for various reasons, some of them leak like sieves.
Part of the blame attaches to aging infrastructure. In older areas of Victoria, sewer lines were laid down 100 years ago. These are often fragile clay pipes, buried in a common trench alongside storm drains.
When the sewer line decays, the result is cross-contamination. Basically, household waste leaks into the storm drain and ends up wherever that pipe empties — into local creeks and streams perhaps, or straight into the ocean. Either way, the results are ugly.
An area of Willows Beach in Oak Bay was closed to swimming in 2011 when a sewer line collapsed and the effluent leaked into a storm drain.
Some of the culprits are illegal suites, where amateur handymen did the plumbing and mistakenly routed sewage lines into storm drains. Cross-connections of this kind were a leading cause of pollution that overwhelmed the Gorge Waterway in the 1980s.
No one knows how many of these linkages exist, in part because new ones are constantly being created, and in part because owners of illegal suites are understandably close-mouthed when inspectors show up at their door.
In a few cases, municipal sewer lines were deliberately tied into storm drains. In years gone by, this was common practice in urban centres. Most cities, Victoria included, have instigated cleanup projects to remove the problem. But some of these combined sewers still survive in the Uplands area of Oak Bay.
Last, and most troubling, during periods of wet weather, sanitary sewers sometimes absorb rainwater. They’re not supposed to do that.
But when the pipes are old and fragile, it happens. An engineering study in James Bay three years ago provides an example of the potential magnitudes involved.
During a 24-hour downpour, as much as 400,000 litres of rainwater per hectare may flow into the sewage pipes beneath James Bay. Some experts suspect that is an overestimate. But whatever the precise figures are, enormous volumes of rainwater flood the sewers during storms.
The study found this extra pressure can overwhelm the system and cause overflows of human waste into the surrounding environment. Inevitably, some of that pollution reaches the ocean.
Local authorities, of course, are aware of all these issues. The Capital Regional District conducts tests every six months to look for contamination in storm drains.
Aging infrastructure is slowly being replaced, and the new land-based treatment plant will relieve some of the pressure on overtaxed sewer lines.
And Victoria is by no means alone. Every city in the country, to a varying extent, suffers the same problem.
That said, progress is slow. There were 43 instances of high-rated contamination of storm drains in 2011. (“High-rated” means significant amounts of human waste were detected, and the risk of public contact was serious enough to warrant concern.) A year later there were 38 — not much of a reduction.
It would be frustrating (to put it mildly) if we spent $780 million and discovered later that we’re still polluting the ocean.
Build the new treatment plant, if you will. But if we really want to clean up our act, that is just a start.
