Not only that, but there is ample parkland on the island.
That map is indicating that parkland is needed IN those orange zones. Putting more parkland on the island isn't going to solve the problem like putting a subway station on the island won't solve the problem of more transit being needed downtown.
The rail deck park, if it ever happens, will do a lot to alleviate that issue.
Here's the problem w/that thesis, from the point of view of the City and the maps shown above.
The downtown population is somewhere around the 300,000 mark at this point and still growing.
The current stat shows that there is less than 4m2 per person of park space in downtown.
The goal is at least 12m2.
A difference not less than 8m2.
Multiply that by 300,000, you get 2.4M meters squared of park space required.
That's 240ha or 600 acres.
The entirety of downtown Toronto is ~14km2 excluding the Islands. Which is about 1,400ha or 3,000acres.
So we're short about 20% of all the land in downtown Toronto.
Lets be entirely clear; there is pretty much zero chance of hitting the 12m2 goal in downtown.
But if you want to get anywhere near close, there are only really 3 principle opportunities of sorts.
1) The Island Airport - 200 acres
2) Decking over the entire rail corridor as parkland (key problems here include that the entire eastern rail corridor is elevated and most people will not walk to walk up 3+ storeys of stairs to access a park (also presumes the cost of air rights and construction are otherwise affordable.)
Rail Deck Park as proposed - 9.3ha/23 acres.
Everything remaining eastward to Simcoe ~3ha/7.5 acres.
Eastern Corridor - 8ha/20acres (Yonge - Cherry)
3) Removal of Gardiner/DVP (below Eastern) - 20ha/50 acres ** (assumes you bury/remove Lakeshore Blvd as well, or place an elevated park over Lakeshore at grade.
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All of that is nothing but hideously expensive, logistically challenging and much of it impractical and unlikely, even in the longer term.
You could pick up a small amount of space by narrowing/removing portions of Bayview, or consolidating the Bala Sub on the east side of the valley with the Don Branch (opening up park space connected to Bayview.
Even if you add all of that, and the Islands, you don't hit the theoretical goal.
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In the end, without the Islands, you max out at 100 acres or so, plus maybe some additional land in the Don Valley......let's say 120 acres.
With the Islands, you get to 320 acres in that scenario, or just over 1/2 the shortfall.
But that assumes the downtown population stays largely flat.
If, as expected,it adds another 200,000+ you're almost back to where you started, even with all of the above.
All of which assumes we don't use one iota of that space for housing or other purposes.
I just don't see how its possible to meet the recreational/outdoors needs of our downtown without that space in the medium to long term.