|Flooding on the Don Valley Parkway in|
Toronto (from the Toronto Star)
The impact on the city’s water infrastructure was swift and damaging: Sewers backed up, roads became rivers and homes flooded.
As extreme weather events become more frequent, the question keeps coming up: Why can’t our infrastructure handle it? There are a few reasons.
Hundreds of year ago, there was no water infrastructure to speak of in large cities. Cities rose, residents threw their wastewater directly into the streets and, eventually, it made its way to the water course. Disease was rampant.
Then, in the 1600s and the 1700s, cities in the United Kingdom evolved to having a single pipe sewer system to collect mainly rain water , but sewage also found its way into this pipe. That was an improvement over tossing your chamber pot in the street, to be sure. Starting in the 1800s, the sewer systems began to be separated (one pipe for rainwater and the other for sewage). The ideal system we have today for most new developments is to have two separate wastewater pipes: one for rainwater, and one for sewage.
|Lakeshore Blvd during the flooding (from Global News)|
The quality and standards of engineering wastewater systems have evolved. There are innovations, new
theories, new understandings and new procedures that are developed and applied as time goes by. What was the design standard for infrastructure in the 1970’s is different from today. In addition, government has created regulations that limit pollution to our natural water bodies. Add to that the changing weather patterns and the increasing number of severe weather events, and you have many systems that can easily be overwhelmed.
So, why don’t cities address these issues once and for all?
In a city like Toronto, in which most of the original water infrastructure is approaching the end of its life cycle, it would take a huge investment. Imagine it this way: You own a car. But it’s now come to a point where you either need to increase the investment and upkeep to keep your old car running – or you face the massive cost of replacing it outright. If you’re a city and you’re looking at your sewer system, it’s more cost effective to make repairs and replacements slowly. When a road needs to be rebuilt, for example, the city might address the sewer issue for that section at that time.
The July flood should serve as a reality check for Toronto residents. That one isolated event caused a huge amount of damage and pain. Imagine that, if most municipalities continue along this rate, there could be failures of infrastructure in a way that nobody has seen before. We need to ask ourselves: What is the inconvenience and the cost of that?