Thank you, Mr. Chair and members of the committee. I want to thank you for inviting me and for the opportunity to testify on the water quality of the Great Lakes.
I am, as noted, the executive director of engineering and construction services for the City of Toronto, responsible for engineering design and construction for all of the water, waste water, stormwater, and transportation infrastructure in the City of Toronto. This is as a result of a recent promotion last year. Previous to that I was the director of water infrastructure management for the city and so have overarching responsibility for infrastructure planning, dealing with all the water, waste water, and stormwater infrastructure in the City of Toronto.
I've led a number of environmental stewardship initiatives, including on climate change adaptation and a strategy to help reduce the risk and impact of flooding from extreme events and the development of the City of Toronto's innovative wet weather flow master plan, which I'll get into in some detail. The plan itself was aimed at addressing such water quality impacts as storm sewer and combined sewer overflow discharges, ultimately to improve water quality within the city's six watersheds and along the 43-kilometre waterfront, which includes 11 waterfront beaches. The ultimate objective of the plan, while aimed at improving water quality, was really directed at delisting Toronto as an area of concern in the Great Lakes basin.
As an aside, I am a professional engineer, having spent most of my professional career dealing with matters and projects on the Great Lakes.
I'd like to provide now a bit of background concerning the context for the city of Toronto and its dubious distinction as one of the AOCs in the Great Lakes basin. That started back in 1987 with identification by the International Joint Commission. To give a few facts about Toronto, it has a population of 2.7 million. The area of the city is 640 square kilometres. The principal land use is residential, about 45%. One thing we take for granted is that about 23% of our land area is open space and natural.
About 30% of the land area, which is really in the older area of the city, is serviced by combined sewers. That's a single pipe that carries both raw sewage and stormwater runoff when it rains. Inherent in the way these systems were configured back in the late 1800s and up to about 1950 is that during heavy rains there's a spillage of combined sewer overflow, as we call it. It's a mixture of raw sewage and stormwater runoff. We have about 80 outfalls across the city, 34 of which discharge to Lake Ontario.
The rest of the city is serviced by separated storm and sanitary sewers. When it rains, the stormwater runoff is discharged through 2,600 storm sewer outfalls, 70 of which are located along our waterfront. The remainder basically dot the ravine systems. We have six watersheds across the city. We have about 10,000 kilometres of sewer pipes, some of which date back to the mid- to late-1800s, so we have a significant infrastructure backlog, both in terms of sewers and water mains as well as our treatment facilities.
One of the things we often forget about is our green infrastructure. We have about 370 kilometres of water courses. These are open channels, if you will, but they are part of our ravine system and part of our natural heritage.
I should highlight at this point that because combined sewer overflows contain raw sewage, much of the attention was directed historically across Ontario to dealing with the discharge of combined sewer overflows, particularly where the discharge impacted a beach area.
Fast forward a bit into the mid-1980s. The U.S. EPA as well as the Ontario Ministry of the Environment undertook a number of studies to look at the characterization of wet weather flows, in which they were looking at the makeup of storm sewers and combined sewer overflows. Curiously enough, coming out of the very fulsome and detailed technical assessments, what they found was that the water quality— the chemical constituents—in stormwater was very similar to that for combined sewer overflows for many contaminants.
The data are very variable, so that statistically speaking, when you compare the concentration in storm sewers with that of combined sewer overflows, they are statistically speaking similar, save for a few parameters such as bacteria and some of the nutrients, which for combined sewer overflows are higher, notably because of raw sewage. But for most water quality parameters they are similar.
I want to dwell on the bacteria piece for just a second. The Ontario provincial water quality objective for bathing beaches is 100 counts of E. coli per 100 millilitres. The concentration in combined sewer overflows is typically about a million counts, and in stormwater, it's typically on the order of a few hundred thousand counts. So in both cases, you're three to four orders of magnitude higher than where you need to be to protect those beach areas for swimming. The bottom line is that if we're going to get serious about water pollution in the Great Lakes basin, and certainly in the near-shore, we have to deal with stormwater runoff as well, in addition to combined sewer overflows.
In 1987 the International Joint Commission or IJC identified Toronto as an area of concern, largely dealing with the impacts of the impaired beneficial uses associated specifically with the discharges of combined sewer overflows and storm sewers. These discharges not only impaired water quality but aquatic biota and fisheries, sediment quality, and benthic invertebrates. They contributed to fish consumption advisories, loss of fish habitat, and nutrient enrichment, which also contributed to nuisance algal growth.
I noted earlier that most of the action had focused on projects specific to sewer discharges in a localized area. In 1998 the City of Toronto amalgamated six local municipalities with one regional government. That basically provided the necessary framework to deal with stormwater in an integrated way and led to the development of the city's wet weather flow master plan. The plan was innovative on a number of fronts. One is that it was a watershed-based plan extending across all six watersheds. I need to highlight that all of the watersheds except one extend well beyond the city limits, but the city undertook this on a watershed basis, in the way that you need to do to deal with stormwater across all six watersheds.
It also used a hierarchical approach to looking at stormwater, meaning that we looked at a number of options, beginning at the source. Where rain falls onto an individual lot or property, what are the kinds of things we could do to reduce stormwater runoff or improve water quality? One of the basic things is the disconnection of roof downspouts from our sewer system.
Then we looked at the conveyance system within the municipal road allowance. What could we do there to do much the same thing? Options that we considered looked, for example, at introducing leaky pipes instead of the conventional plastic or concrete pipes for stormwater runoff, to basically let the stormwater infiltrate into the ground in order to try to re-establish some of the natural hydrologic cycle.
Then ultimately, for what you couldn't achieve at source or within the conveyance system, you have “end of pipe”. We looked across the entire city at open space opportunities where we might be able to construct a stormwater pond or wetland. As well, we looked in the downtown core, where we are space-constrained—there is no open space available—and had to bite the bullet and look at underground storage systems, such as underground tanks or storage tunnels.
The development of the plan relied on computer simulation modelling, so we were looking at “what if” scenarios and at what the expected improvements would be in water quality within our watersheds. We had a whole lake model, which looked at the impacts of the watersheds and the sewers so far as the waterfront area of the city was concerned, as a way of helping us to direct the final outcome of the planning and assess the pros and cons of the various options. One of the factors was cost, obviously, and the timeframe for implementation. The plan was undertaken in accordance with the Province of Ontario's Environmental Assessment Act, with fulsome public consultation, including consultation with such stakeholders as the approving agencies, through the entire process.
Here are some of the salient outcomes of the plan.
Mandatory downspout disconnection was one. The city took the bull by the horns and mandated the disconnection of all residential roof areas from the city system in a phased approach, so that by the year 2016 some 350,000 properties will have their downspouts disconnected.
About 20% of the city is serviced by roadside ditches.There is a requirement to maintain the existing roadside ditch system, because we recognize the hydrologic as well as the water quality function of the system.
Then in the longer term we identified areas in the city in which there would be an opportunity to install these leaky pipe systems as the city renews its aging infrastructure. Then ultimately, at the end of the system we identified across the city opportunities for about 170 green facilities or stormwater ponds or wetland areas.
Unfortunately, where we were space-constrained we had to bite the bullet and go underground, with underground storage systems, tanks, and tunnels, and so we identified 16 combined sewer overflow facilities and 27 stormwater facilities underground.
While we have already constructed a number of these facilities, arguably the most significant project that we have under way is what we call the Don River and central waterfront project. From our standpoint, the implementation of that project will, we hope, ultimately lead to the delisting of Toronto as an area of concern.
The project deals with most of the remaining combined sewer overflows in the city—about 50 of them in total—and involves the construction of an interconnected deep tunnel system 23 kilometres long, located largely along the lower Don River and right across our central waterfront area.There are 15 underground storage shafts, each approximately 30 metres in diameter and about 50 metres deep that, in conjunction with the deep tunnels, will store about 570,000 cubic metres of wet weather flow.
An innovative high-rate treatment facility based on the technology we've been testing with our colleagues at Environment Canada over the last decade would be constructed abutting our Ashbridges Bay sewage treatment plant.
The flows from this integrated storage system would be treated through this high-rate treatment facility, ultraviolet disinfection, and discharged to Lake Ontario.
We've undertaken computer simulation modelling based on all of the work that we've done. We feel we can achieve water quality improvements to the inner harbour, which was really where the designation of the AOC for Toronto all began. Most of the inner harbour would meet international blue flag criteria for swimming beaches if the City of Toronto opted for the creation of swimming areas in the inner harbour.