Beach Pollution
A day at the beach shouldn't stop at the water's edge.
Over 70% of our city is urbanized. Our concrete landscape leaves rain and snow with nowhere to go. Underground storm sewers take runoff to our rivers and lakeshore. This 'stormwater' is contaminated by pollutants: pet, bird and animal droppings add bacteria (E.coli); roads and parking lots add heavy metals, oil, grease and toxic chemicals. The mix degrades water quality and harms fish and other aquatic life. The problem is most severe in parts of the city where storm sewers are connected to sanitary sewers carrying household and business wastes that need treatment.
During storms too much runoff in the sewers can push sewage straight to the beach. This is why beaches are closed. Toronto has a total of 14 city beaches that vary in water quality. For example, Sunnyside Beach is often polluted by sewage overflows making it unsafe for swimming. Cherry Beach is protected from sewer outfalls and is one of our cleanest beaches.
Toronto's Combined Sewers:
Living with the consequences of a mistake made long ago
PCBs and mercury are the reason we are warned against eating Lake Ontario fish, but it's bacteria, E.coli, that is responsible for unsafe or 'closed' beaches.
Sources of E.coli in our beaches include pet waste, bird droppings, agricultural runoff (upstream) and sewage overflows from Toronto's over capacitated sewer system. Deteriorating sewer pipes and illegal sewer connections are another likely factor.
Marie Curtis Park Beach, Sunnyside, Gzowski, Budapest Cherry Beach, Beaches Park, Woodbine, Kew, Balmy and Hanlan's Point and Ward's Island are all effected by Toronto's sewage overflow problems. Centre Island, Bluffer's Park and Rouge Beach suffer beach closures due to bacteria but there is less certainty about the source of the E.coli.
Toronto's plumbing problem
Sanitary sewer pipes collect household sewage and wastewater from our bathrooms, kitchens and laundry rooms and carry it to treatment plants, like the Ashbridges Bay Sewage Treatment Plant located in the Portlands.
Separate storm sewers or 'street grates' drain rain and surface water runoff from our roads and property, which travels through an additional set of underground pipes. These pipes end in the nearest creek, river or Lake Ontario.
At least that is the way it is supposed to work.
Toronto's Combined Sewer System
In some areas of the city the separated sewer systems (sanitary and storm sewers) actually connect underground. When the skies are clear, sewage flushed into the system is pumped to the treatment plant. However, on rainy days the extra volume of rainwater drained from the street grates, is to much for the system to handle. Rain and and sewage mix in the pipes. Some of the mixed waste still travels to the treatment plant, but the rest - some 9.5 billion litres a year, backups and overflows into our beaches and rivers. This is the equivalent of shutting down Toronto's sewage treatment plants for a week, every year.
Periodically, a heavy downpour can deliver too much volume to Toronto's main sewage treatment plant to quickly. When this happens the City is forced bypass treatment at the plant and send sewage out into Lake Ontario, untreated. This has been known to happen up to 14 times a year.
The problem area, or combined sewer overflow (CSO) area, covers all of downtown Toronto, and parts of North Toronto, East Toronto and out to Scarborough. There are over 80 combined sewer outfalls that dump sewage into the Don and Humber Rivers and the lakeshore.
The pipes are separated in the rest of the City because these areas were largely developed after Ontario brought in legislation that prohibits the connection of sanitary and storm sewers in all new developments. However, illegal cross-connections may trigger a sewage overflow incident even in these areas.
Over the years the City of Toronto has taken the opportunity to separate 70% of the combined underground pipes.
Separating the other 30% of the combined sewers is viewed as disruptive. The City does intend to separate the pipes if and when the opportunity arises. It is not known many combined sewers can still be separated, and often separated sewers have been reconnected down the line. Another solution is needed.
Ontario also states that sewage spills from combined sewer systems can only happen 5% of the time in a given year. This is forcing municipalities to deal with their CSO problems. However, in reality the province is doing little to enforce this standard.
Urbanization
An increase in impervious surfaces decrease the infiltration of stormwater into the ground.
With urbanization that city has choice - build more underground connections to our flawed sewer system or require stormwater retention and infiltration on individual properties and developments.
For example,
Malls in the US have installed sloped vegetative trenches to capture and infiltrate 98% of the contaminated stormwater runoff, keeping this wet weather clear of the sewer system and recharging the base flow of the nearby creek or river with cleaner groundwater.
In other cases residential and commercial streets have been redesigned to achieve the same goals by getting rid of curbs and gutters and installing swales and vegetative buffers between the road and the the homes/buildings.
Disaster Rains
Major storm a tough reminder of problems with Toronto's drainage system
The flaws in Toronto's heavy reliance on sewer pipes and overflow storage tanks to management wet weather were exposed with dramatic results in May of 2000.
Heavy rains poured volumes of water into both storm and combined sewers, which immediately backed up flooding homes, businesses and city streets with sewage and chemicals. E.coli contaminated nearly every river, creek and km of shoreline.
To alleviate backups the City had no choice but to shut down its main sewage treatment plant (Ashbridges Bay) and open the gates to allow sewage to flow untreated into Lake Ontario.
While storms of this size are near impossible to contain through either natural or sewer-based drainage systems, witnessing the event gave residents a view of water running off concrete and over pavement with no where to go. This scene is repeated during most wet weather events in the City. The way we build in Toronto continues to direct rain and snow into our over capacitated sewer system, instead of into the ground.
In some areas of the city storms dumping as little as 2 mm of rain can cause combined sewer overflows into our rivers and beaches. New development standards for parking lots, roads, houses and buildings can fix a problem of this size and end the majority of combined sewer overflows and bacteria contamination at many of our beaches.
It is a challenge to change the way we develop and installing a natural drainage system across the city will take time. But to date the City has no real plan to even start down this path.