Two of Scarborough’s storm water ponds are scheduled to be dredged by the city.
The Lansing pond at Kennedy Commons and the Sisters of St. Joseph pond at Warden Avenue and St. Clair Avenue have been in use since the mid-1990s.
The city estimates the cost of dredging both ponds will be around $750,000.
Ralph Toninger, a representative from the Toronto Region and Conservation Authority (TRCA), spoke about the maintenance and upkeep of the ponds.
“These ponds have on average a 10-year life-cycle,” he said. “The city has about seven storm water ponds that require annual or multi-year maintenance. These two ponds are well past their 10-year deadline for dredging.”
It’s estimated both ponds hold a total of 5,500 tons of sediment. However, they are at 50 per cent of their maximum capacity.
All storm water ponds are designed to reach only 50 per cent capacity to prevent them from overflowing their banks.
There are concerns some of the sediment could be toxic given that the ponds are used for road run-off, which includes gasoline, engine oil and transmission fluid and salt from the winter.
“The point of these two ponds was to deal with road run-off and flooding,” Toninger said. “The cattails and other vegetation biologically break down the nasty run-off. Depending on the quality of the sediment, it could be reused as backfill or sent off to be treated for contaminants.”
The TRCA is also studying all the ponds across Toronto to find ways to improve the storm controls system for both efficiency and quality.
“The city is working on improving many storm water controls, adding catch basins and reducing the amount of salt used on roads in the winter,” Toninger said. “This all contributes to improving the lifespan and usage of the storm water ponds.”