one concern i have about making the mouth natural is will it trap water like a wetland? this may cause smell to linger i think. it's too bad that storm sewers drain into our rivers. all that gas and oil ends up there
Here is one possible solution...
from
www.globeandmail.com
Wetland project springs to life
Custom-made swamp will help clean water as it flows into Lake Ontario, mayor says
JEFF GRAY
Mayor David Miller hopped on a bulldozer yesterday to highlight Toronto's latest waterfront development project, but it isn't exactly a show-stopping tourist attraction: It's a swamp.
The city is creating a natural wetland just south of High Park, meant to use nature's own tricks to strip pollutants from water in the city's storm sewers before it seeps into Lake Ontario.
And Mr. Miller, eager to demonstrate that things are finally starting to happen on the city's long-neglected waterfront, told reporters the environmental project is evidence that progress is being made.
"This year marks the beginning of real action on the waterfront," the mayor said at the wetland site, which is due to be completed in 2007 but was still a field of frozen mud yesterday. ". . . Waterfront revitalization is happening and today is more evidence that change is under way."
He then listed other changes on the waterfront expected to take shape this year: the West Don Lands development, the Western Beaches Watercourse and the HT0 "urban beach park" near Harbourfront.
The 140-metre-long future wetland, located in Mr. Miller's old ward at Lake Shore Boulevard West and Colborne Lodge Drive, is one of four planned for the west end, and will make the water running out of the storm sewers and into the lake much cleaner, the mayor said.
Storm water runoff after a rainfall or snowfall heads from streets and sidewalks into sewers, picking up oil, grease, road salt and pet feces along the way. The water then flows directly into the lake, taking these pollutants with it. The result is that numerous beaches are deemed too polluted for swimming.
But Mr. Miller and city water officials say the $5.9-million project to create four wetlands will make a significant, measurable difference to water quality in the area, which is near Sunnyside Beach.
In the new system, storm water runoff would be channelled through an oil-and-grit separator before it flows into the new wetlands, where finer particles will be allowed to settle and other pollutants will be absorbed by plants. Even the sun's ultraviolet rays will help clean the water, which moves slowly along using only gravity.
The city is already using a similar process at facilities in Etobicoke and Scarborough, and other municipalities, especially in new developments, are putting in similar custom-made wetlands to deal with the water runoff problem.
The wetland project touted yesterday is part of a 25-year, $1-billion plan to help with water quality that spans Toronto's waterfront.
Kim Fry of the Toronto Environmental Alliance said the wetlands are a "good step in the right direction." But she said the city needs to do more to prevent pollutants from getting into the storm sewers in the first place.
"In some ways, it is a bit of a stopgap -- a necessary stopgap," Ms. Fry said.
One problem is the amount of pavement in the city, which is the real root of the storm water problem. Soil and natural vegetation simply absorb the water and eliminate runoff, but pavement is impermeable, and sends water burbling into the sewers.
Ms. Fry said the city needs to forbid people from paving parts of their front lawns to create parking spaces. She said this practice remains a major source of new pavement. "What we're doing is we're increasingly getting rid of the green spaces in the city that normally act as natural filters."
Ms. Fry also said the city should force homeowners to disconnect their eavestrough downspouts from the storm-sewer system. (The city runs a voluntary downspout disconnection program.)
Outlying municipalities north of Toronto should be coaxed into taking measures as well, she said, as their contaminated runoff also ends up in the Don and Humber Rivers that flow into the lake.
