City talks sewers and development in Ward 32
About two dozen East End residents gathered at the Balmy Beach Club on Dec. 3, to hear an update on the state of sewage and storm drain infrastructure in the Beach.
The meeting, organized by Ward 32 councillor Mary-Margaret McMahon, was run by Toronto Water General Manager Lou di Gironimo, Manager of Stormwater Management Ted Bowering and Manager of Development Engineering for Toronto and East York District Doug Bleaney. It was both an update on the plans to alleviate flooding issues south of Queen Street during major storms, as well as to address concerns raised during the Queen Street East Visioning Study on the capacity of infrastructure in the Beach, and what effects increased density might have on that capacity.
The short answer to what impact condo developments might have on sewage capacity, according to Bowering, is none. The Beach has a combined sewer system, which carries sewage during dry weather, as well as runoff from buildings during wet weather. Because the sewers were designed for carrying storm water, the amount of space taken up by actual sewage is a small fraction of the overall capacity of the pipe.
“We could never fill it up with sewage,” said Bowering.
Di Gironimo agreed, emphasizing that the size of developments in the Beach are not large enough to make any difference to the amount of sewage flow.
“Sixty-five additional units, the vast majority of the time, is really not going to have an impact on the dry weather flow,” he said.
The key point to consider is whether a development adds to the amount of rain water making its way into the combined sewer.
“We have to make sure there's no increase in wet weather flow from new development,” said Bowering.
Builders are responsible for ensuring that their project won't increase the amount of rain entering the sewers. This can mean anything from more grass and porous driveway materials, to building a temporary storage tank for heavy rains, which captures heavy rain unable to be absorbed by the system during a storm, then is emptied back into the sewer during dry weather. The development on Kipendavie Avenue features the tank solution.
The key number is that at least 50 per cent of annual rain fall can be absorbed or otherwise dealt with on site. In many cases, new developments actually improve the local situation, since current standards are far more stringent than in the past, Bleaney said.
“You're dealing with an older site that's being redeveloped to a new design standard,” he said.
However, during extreme rain events, the sewers can sometimes back up with excess rain water, due in part to the number of homes with downspouts and basement drains still directly connected to the system. Additional problems occur when the ground water isn't being taken into the storm system; because manhole lids for the combined sewer are perforated, water can enter the sewer from the street, backing up the system even more. As well, surface water can sometimes pool for extended periods. These and other factors can end up causing basement flooding, and di Gironimo and Bowering also spent time updating the city's plan to deal with flooding in over 30 areas across Toronto, including the Beach south of Queen Street, also known as 'Area 32'.
Solutions have been chosen including increasing the capacity of the area's sewers, separating sewers on some streets, installing catchbasins at spots with excessive surface ponding, sealing manhole covers and building relief sewers in certain spots.
Downspout disconnection has been mandatory in the Beach area – as well as all other areas of the city served by a combined sewer system – since late 2011. There are also subsidies available to homeowners looking to install backflow valves on their sanitary sewer line, as well as for installing sump pumps for foundation drains.
As to when any of these solutions are set to be implemented, Bowering said realistically, it will likely be 2017 or later by the time the major improvements are completed.
“There's a whole raft of projects that are backed up in our capital plan,” he said.
Di Gironimo explained that although 2017 may seem far away, even projects given top priority usually take three years for the design, tendering and construction processes. A storm sewer underneath Woodbine Avenue south of Queen Street East, curving west under Lakeshore, will likely happen sooner, he said, as it is considered an emergency project, so it can jump the line.
“That's just logistics, it takes that long to do it,” he said.
He also said Toronto Water's priorities are based on a balance between the cost of a potential project, weighed against the number of households that would benefit. The good news, he said, is that his department's budget for flooding relief projects is in place and set to increase.
“The commitment's been made by City Council,” he said.
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