[Kitsune]

I think there was a question at the mayoral presser on not closing the DVP - I think an investigation is coming. I recall that the forecast called for rain but nowhere near this much - the warning came late.

Having said that I wonder how much on the ground monitoring there is for the DVP.

AoD

The Ontario Storm Prediction Centre stated this morning that thunderstorms with amounts 30-50mm was expected. Toronto got 30mm in 30 minutes at one point .. they failed to recognize the possibility of training thunderstorms. This is a ongoing problem not just with the OSPC .. but with ECCC in general. Hopefully there fancy new radars will provide them better insight as they adjust to them.. hopefully.

 

[mburrrrr]

Love this feature. Maybe they could connect it to the gate key switch.
Green = good, ready to go. Maybe a little sweep, confirm the road is clear and double check the weather.

 

[rdaner]

So am I correct in assuming that despite not being complete the work in The Portlands did lower the water build-up by the amount that got past the plug? Not that I need proof but it is nice to see projects begin, in a small way, to improve things!

 

[reinventingthewheel]

So am I correct in assuming that despite not being complete the work in The Portlands did lower the water build-up by the amount that got past the plug?

I believe it is the most exact statement that can be made about it!

 

[mburrrrr]

The water was pushing at a good clip through the Keating channel.
End result - see sugar beach.

The surface water appeared to be pushing back up stream.

 

[Northern Light]

so how long until the waters drop? before the weekend right?

They've already dropped considerably. Paths/roads that were covered are now dry or at least drying out.........

Waters will like recede to normative levels (If there are no more storms) within 24 hours of now.

 

[Northern Light]

Except that these so called 100-year event are happening more and more often - and the trend with increasing temperature is upward. Like today we are dealing with basically all highways in the core and all heavy transit getting interrupted - that’s unacceptable.

AoD

This is correct. The generally accepted standard in Toronto has been that the DVP should be flooded ideally no more than once in 25 years; though in practice once in 5 was tolerable.

We're now closing in on once every 2 years, at least briefly..........

*****

This is not just something to blame on climate change, though that may have a role; its sprawl and increased hardscape. Remember my arguments against paving over backyards and cutting down tree canopy; this (in part) is the result.

So is greater density (greater base flow in the sewer means it overflows sooner).

So its a combination of more intense rainfall over a shorter period, combined with fuller sewers, and less natural storage/infiltration for water.

This is why we need to be careful about cutting down mature trees and replacing homes w/lawns w/buildings that occupy more lot area.

That doesn't mean you can't build better, somewhat denser, and w/less paved area.........that you can do......but its a thoughtful, nuanced exercise in which some of the land you recover by building taller you devote to more parkspace.

Its not an argument for SFH-based sprawl, nor against towers, its an understanding of math.....volume of water, stored, and displaced. Hard surfaces cause problems, for which mitigation can be extremely expensive.

And if you don't do green roofs that fully offset permeable space loss........you need even more............but of course doing fully green roofs is expensive and means things like mid-building mechanicals.....which in turn makes housing less affordable, its all rather nuanced and complicated which is why I have an allergy to simplistic arguments from any perspective.

 

[skycandy]

I REALLY wanted to get down there to check it out this afternoon but dealing with water issues in my home (located very close to Dundas / DVP) plus an out of town meeting later (made difficult by power outages and flooded roads) made that impossible. Just got home this evening and snapped a couple of cell shots from Dundas St. Sludge and muck still there but at least the water continues to recede.

I just want to say that extreme rainfall forecasts are among the most challenging in the weather biz. The 2013 Billion dollar flood was most difficult because training storms (which form very quickly upwind from the deluge over your head are not always easily predictable and blow up suddenly). In addition, the weather model guidance did horribly on that event, including a new shiny 250-metre resolution model which should presumably do better…. Instead it had a blob of thunderstorms over Kitchener)..

Today’s event was handled better by the models and was correctly depicted as a ‘spin-off’ cluster of storms which originated from last night’s epic Chicago derecho event (big wind with some tornadoes). Yes, the Ontario Storm Prediction Centre could have issued the rainfall warning a bit sooner when it became more evident the main cluster of storms would cross the city. And yes higher rainfall amounts should have been introduced earlier. But I always wonder what pre-storm mitigation can be done upon hearing a warning? Close the DVP a little sooner? Adjust Go Train schedules just prior? (It’s easier with a tornado warning: go to your basement now!). My two cents worth . Here are the pics:

 

[chrisw]

Thanks! I was thinking of a ‘canal’ that would be empty and ready to receive high level water during an event like today then released at a later time. Like I said I really don’t know about these things but delaying water buildup might help.

Instead of a 'canal' what you really need to think about is the concept of a 'sponge' city.

These can be natural like ponds or soccer fields (dry retention pond). The whole field can be used to hold water during a storm event. The flow out is controlled by the size of the outlet pipe.

Similarly they can be made out of plastic. It provides structural support while also allowing areas like parking lots or fields to retain water.

Here's a good video. Actually a good portion is about Toronto as the creator is from here.

Some screenshots from the video. You also have buildings in Japan where the ground floor is designed to be able to hold water and not be damaged.

 

[UtakataNoAnnex]

FYI's, about last night Chi-town's derecho...

https://www.accuweather.com/en/severe-weather/derecho-turns-deadly-tornado-reported-near-chicagos-ohare-airport/1669875

...and what's a derecho:

Derecho - Wikipedia

en.wikipedia.org

 

[Northern Light]

Instead of a 'canal' what you really need to think about is the concept of a 'sponge' city.

These can be natural like ponds or soccer fields. The whole field can be used to hold water during a storm event. The flow out is controlled by the size of the outlet pipe.

Similarly they can be made out of plastic. It provides structural support while also allowing areas like parking lots or fields to retain water.

Here's a good video.

Some screenshots from the video. You also have buildings in Japan where the ground floor is designed to be able to hold water and not be damaged.

View attachment 581034View attachment 581035View attachment 581036

This is the right idea.........which to be clear, we are going the opposite direction of generally.

We continue to experience more sprawl upstream, and more density {which includes toilet flows, showers flows, dishwashing flows etc.) not only without more sponge, but with less.

Its not just a simple matter of more greenspace, thought that's convenient shorthand.

Its a variety of things.......

But aside from just increasing infrastructure elevation (which will be the solution in some cases).............

Here's what I would like to see:

1) More total green area, this is everything from greened boulevards, to fewer driveways, to green roofs and yes, parks etc. Toronto is nowhere near the percentage of green space it could be.

2) Where you can't do green, increase infiltration.........permeable paving of laneways and low volume side streets. Same for all parking lots, if allowed at all.

3) Maximum feasible green roofs..........Anything not absorbed must come off the building or its in your unit..........where's it going?

4) High quality tree canopy...........you need things that drink excess water and can store it for future use.

5) We need to talk about one problem w/towers, even w/o lots of parking........deep foundations mean less absorption capability of soil and strand the water table. If you build down to bedrock.........where is the water supposed to go?