Man-made Humber islands would solve two problems at once

Officials often come to city council to propose new bylaws, garbage fees or tree-planting programs. It is not every day that one of them suggests creating an archipelago. That was what Lou Di Gironimo did this month when he presented a clever plan to build a series of small islands off the mouth of the Humber River on the western waterfront.

Mr. Di Gironimo is the general manager of Toronto Water, the city agency that makes sure clean water comes out of your tap. A compact 48-year-old with shaved head and goatee, he is one of those smart, hard-working civil servants who confound the stereotype of the lay-about city hall bureaucrat wallowing in gravy.

When I met him in his 24th floor office in city hall’s east wing, he held forth for nearly an hour on the vast job the city faces renewing its aging network of water pipes and sewer lines. With the organized mind of the woodworker that he is in his spare time, he’s always looking for fitting solutions. “We don’t shy from the challenges,” he says of his Toronto Water crew. “We’re problem-solvers.”

The islands project appeals to him because it neatly solves two of his problems at once. Problem 1: he has too much dirt.

Digging all those new sewer tunnels and burying all those water pipes will produce around 800,000 cubic metres of “excavated fill” over the next 10 years. Tunnelling for the Eglinton Crosstown transit line will produce another 800,000. Then there is all the fill from digging foundations for the condos and other buildings shooting up around the city. Creating the Humber Bay islands would require 2 million cubic metres, absorbing much of Toronto’s excess and avoiding the cost of shipping it to landfill sites.

Problem 2: pollution from the Humber River. Toronto has done a great job of cleaning up its swimming beaches. Eight of 11 now boast Blue Flag status, consistently exceeding tough international standards for water quality and general cleanliness. But two western beaches, Marie Curtis and Sunnyside, a favourite of Toronto bathers for generations, are affected by the pollutants flushed into the lake from the Humber, especially after rainstorms.

The city thought it might be able to solve the problem by putting a floating curtain at Sunnyside to block Humber outflows and by treating the enclosed water with ultraviolet light. A pilot project in 2009 and 2010 showed that it would be far too tricky and expensive.

So Mr. Di Gironimo and his staff dusted off the Humber islands concept, first proposed in a little-known study a decade back. The islands would extend about a kilometre into the lake on the eastern side of the Humber mouth. Connected by an underwater berm, they would deflect the Humber’s waters out into the deep lake water, away from the beaches.

Apart from killing two birds with one stone, the islands would give Torontonians a new chance to enjoy one of the city’s best features: its lakefront. Mr. Di Gironimo envisions a series of treed oases linked by bridges and laced with walkways.

Toronto already has several man-made fingers stretching into the lake, from Bluffer’s Park and Ashbridge’s Bay Park in the east to Humber Bay Park in the west. That is not to mention the Spit, the great arm formed of construction rubble and fill that sweeps into the lake from the foot of Leslie Street. They are wonderful places, thronged by migrating birds and enjoyed by walkers and cyclists. The Humber islands would be a great asset.

In addition to the Humber islands, Mr. Di Gironimo envisions building a “storm-water wetland” on the other side of the waterfront, just south of the Ashbridges Bay wastewater treatment plant, to hold sewer overflows. Fronted by beaches and pathways, it would connect the eastern waterfront parks with the Spit.

It is all quite a few years and many millions of dollars away. City council has only agreed to Mr. Di Gironimo’s request for a study. All the same, at a time of lowered expectations and pinched vision in government, it’s great to see a mandarin who isn’t afraid to think big.