Could the stranded GO Train in Toronto's Don River valley have been avoided on July 8, 2013? Could use of known flood risk mapping and real-time flood level monitors avoided the near catastrophe? Yes. And yes and yes. In fact, on May 29, 2013 flooding was deeper but the peak at 5 a.m. missed the trains!
It is likely that if there had been fatalities among the 1400 GO Train passengers, Metrolinx employees or Toronto's first responders, the Ontario government would have called an inquiry (see clipping at right). The Ministry of Labour, who recognizes the occupational health and safety hazards of flooding, would likely have found that Metrolinx failed to identify known workplace hazards or identify safe work practices for its employees.
And that provincial inquiry would have revealed that:
Mock Go Train Drowning Inquiry newspaper clipping. This near miss could
have been fatal to passengers, Metrolinx workers, or first responders.
ii) July 8, 2013 observed flow rates and flood levels were not rare or unexpected from a flood risk management perspective - i.e., could have been anticipated - in fact, on May 29, 2013, just 40 days and forty nights before the incident, flood levels peaked 20 cm higher,
iii) monitoring real-time flood levels were rising rapidly upstream of and beside the flood site could have guided train dispatchers to not send the 5:30 train (GO Transit 835) into the flooded Don River valley,
iv) train frequency increase (more than rain frequency) contributed to the near tragedy, and increased risk exposure as the number of Richmond Hill trains on this line doubled since 1996,
v) any tragedy that occurred was avoidable.
Inquiries get to the bottom of risk issues following deaths. For example, the Walkerton Commission of Inquiry has resulted in a comprehensive risk management strategy for managing drinking water risks in Ontario. But this was only after Walkerton’s drinking water system was contaminated with deadly bacteria, seven people died, and more than 2,300 became ill. The goal of the Inquiry was to answer questions:
|GO Train Flood July 8, 2013 - Toronto Don River Valley|
- What actually happened?
- What were the causes?
- Who was responsible?
- How could this have been prevented?
- How do we make sure this never happens again?
What Actually Happened?
River levels at the upstream East Don River flood level monitoring site (TRCA's East Don at York Mills HY022 gauge) were already rising when the previous by "5:00 pm" train level Union Station. Upstream flood levels were even higher when the stranded "5:30" train, Go Transit 835, left Union Station - this warning sign was not used by Metrolinx to assess the risk to their route further downstream. Graphs are generated from TRCA's online archive.
|Metrolinx GO Train frequency has doubled from 3 to 6 return|
trains per day from Union Station to Richmond Hill since 1996.
Cause 1). Train frequency has doubled over the past 19 years, increasing exposure to flood events.
The Richmond Hill GO Train service started in 1978 and frequency has increased. In 1996, service was cut to 3 trains per day while currently there are 6 trains during the afternoon / evening period (a 100% increase in risk exposure).
|Train operation was halted or detoured during previous Don River floods|
as documented in the 1981 Flood Inquiry Report.
The Keating Channel Flood Inquiry Report for Premier Davis in 1981 documented frequent flooding decades earlier, even when urbanization of the Don River Watershed was not as intense as it is now.
Cause 3). Water levels rose to expected design flood levels on July 8, 2013, but measurements were ignored / not considered.
The key concern here is that design flood levels experienced on July 8, 2013 were not rare (see footnote 1 on correlation of storm vs. flood severity). The 2-year return period flood level is 79.45 metres near the Evergreen Brick Works, across from the flooded GO Train site. In common terms, this flood level can be expected every 2 years, and so over a long period, it has a very high risk of occurring (about 17 times between the start of service in 1978 and the flood of 2013).
Higher safety-risk flood levels of one metre higher are not rare from a flood risk management perspective. Even a higher 10-year flood level (80.41 metres) has a 88% risk of happening at least once over 20 years. This is illustrated on the graph below which compares expected design flood levels, risk of reaching these levels over time, and actual real-time flood levels recorded July 8, 2013. These design flood levels are from a Evergreen Brick Works presentation and, a site located beside the stranded train location - the Brick Works has a comprehensive flood risk management strategy.
|Recorded Don River Flood Levels at Todmorden July 8, 2013 (per TRCA).|
Design Flood Levels per MMM (2008) per Evergreen’s Urban Watershed Forum 2015.
Flood risks were known. Upstream flood levels had risen. Local flood levels were rising.
So, the causes include more frequent trains travelling through a highly flood prone part of the Don River valley, and the operator Metrolinx having ignored measured flood levels.
Surprisingly - even higher flood levels were recorded on May 29, 2013 but trains missed this peak due to timing. The May 28, 2013 Union Station departures occurred before the rise in flood levels and the May 29, 2013 Richmond Hill trains arrived near Todmorden after the peak flood levels has subsided (GO Transit may have modified schedule). The maximum track flooding on May 29, 2013 appears to be 20 cm deeper than on July 8, 2013 - rainfall in East York was over 40% greater.
|May 29, 2013 flood flow rates at the incident site higher than July 8, 2013 flood flows by 10 cubic metres per second.|
TRCA from Todmorden Flood Monitoring Gauge
|May 29, 2013 Flood Levels Worse Than July 8, 2013|
“I haven’t seen flooding on the Don Valley Parkway like this,” Toronto police Staff. Sgt. Brian Bowman told Breakfast Television. “One of my officers had, back in 1986. He saw it reach the top of the [concrete] jersey barriers, so it’s not unprecedented.”
Not only were flood levels July 8, 2013 not rare, flows were below common design flow rates (see footnote).
Who Is Responsible?
In Ontario, everyone is responsible for safety in the workplace. Employers and employees have a role. Reports suggest that Metrolinx, the employer, did not receive TRCA flood warnings and did not make use of monitored flood levels in the watershed to inform its operations. Perhaps it did not understand the workplace hazards on the Richmond Hill line.
|Ontario Ministry of Labour identifies drowning and other risks associated|
|Evergreen Brick Works beside the stranded GO Train site has a flood|
emergency plan and its building are flood proofed. Brick Works reported
higher flooding in May 2013 than July 2013 on their site.
TheStar.Com reported two days after the July 8, 2013 incident that stranded customers were offered $100 as compensation and Mary Proc, GO vice-president for customer service said "It is an exceptional gesture for an unprecedented circumstance." She did not acknowledge that while the inconvenience to passengers was unprecedented, the flood levels were not. She added “That was a night of firsts for us: The first time we had a month of rain in one night; the first time that any customer had to wait seven hours to be moved off a train, and the first time we deployed boats to take our customers off a train.” She did not acknowledge that more rain, more runoff volume, higher flow rates and higher flood depths occurred on May 29, 2013, or that a month of rain in one night is not an uncommon design event for prudent flood risk management. GO Transit (@GOTransit) did Tweet about Richmond Hill line disruptions at 3 a.m. on May 29, 2013 suggesting perhaps they are aware of flood conditions on the line before scheduled morning trains:
How Could This Have Been Prevented?
The East Don flood level graph above showed that the Don River had risen quickly by 5:30 p.m.. The graph below shows that flood levels where the train was stranded had risen nearly half way between the normal water level and the track level by 5:30 p.m.. By the time the stranded GO Train approached the Brickworks at 5:45 p.m., the real time level monitoring would have shown the Don River flood levels approaching the track - see graph below. But these levels were not used by Metrolinx.
This accident could have been prevented by having operational procedures included checking monitored flood levels and modifying service to avoid sending trains onto flooded tracks.
How Do We Make Sure This Never Happens Again?
|Environmental Commissioner mistakenly links GO Train flooding to|
climate change, ignoring known risk factors, watershed conditions,
and operational gaps contributing to flood risk and damages.
Obviously that is not an informed statement. By linking the GO Train incident to climate change and suggesting that risk mitigation efforts relate to emissions controls, the fundamental causes, responsibilities, and potential solutions to the near tragedy have all been grossly ignored.
To ensure this never happens again Metrolinx has had to suffer through 'near miss' in occupational safety terminology. Putting on a positive spin at their September 10, 2013 customer service update, Metrolinx suggested they received as many commendations as complaints (perhaps the commendations were directed to first responders?). Metrolink also highlighted the 126 mm of rainfall in the "Toronto area", failing to note that record was at Pearson Airport in the Etobicoke Creek watershed, not the Don River watershed where GO Transit 835 was stranded. Also Metrolinx would look at several areas of concern including:
- "identifying high risk areas,
- improving customer messaging systems, and
- upgrading the early warning storm warnings."
|Metrolinx Customer Service Report September 2013 refers to 'massive' and 'record' storm as causes to the serious incident.|
Metrolinx could identify high risk areas by reading the Flood Inquiry report from 1981 (a real Inquiry for Premier Davis ... not the mock one at the start of this post). It identifies railway line damage and flooding during ice-free conditions (i.e., no ice blockage of bridges) during the "Great Flood" on September 13, 1878, the spring of 1914, and during two storms in 1980 (March and April). Limited flooding was also reported on May 11, 1981 including the area of the Bayview Extension and the Toronto Brick Yards (the stranded GO Train location near the Evergreen Brick Works). The report indicates that train operation has halted, or trains were detoured during floods, including December 25, 1979, January 11, 1980, March 21, 1980, April 14, 1980, February 11, 1981 and May 11, 1981.
|Example historical flooding in vicinity of stranded GO Train during July 8, 2013 flood (1981 Inquiry report Table 1).|
|GO Train / GO Transit 835 passenger swimming from|
stranded train in Don River valley.
A post below to the blog www.thiscrazytrain.com has a comment from an apparent operator indicating that the flooding of the tracks was indeed frequent and that the operating procedures have now changed.
Back when I started as long as we could still see the rails we used to drive through that like it was nothing. Now the second the water starts touching the rails an automatic system declares an 'emergency' and the whole line is shut down. Not saying that's the right or wrong way, but its interesting how times have changed.
1 - Correlations of Storm Severity vs. Flood Level Severity. How could a record amount of rain have been recorded on July 8, 2013 but not a rare design flood level in the Don River flood plain? The answer is that record amounts of rain did not occur everywhere across the Don River watershed - conservatism in flood risk management and planning assumes extreme rainfall occurs over the entire watershed. The record rain occurred over one small part of the watershed, such that the resulting flow rates were not extreme, having less than 10 year return periods. So while the record rainfall had a 100 year return period somewhere beyond the Don River watershed (Pearson Airport in the Etobicoke Creek watershed), on average, overall, July 8, 2013 was less severe over the large Don River watershed. The video at the very bottom of the post shows the July 8, 2013 storm pattern from historical radar over the approximate Don River watershed area.
|Worse Flooding May 29, 2013|
Half the rainfall and worse flooding? Yes. Welcome to the world of hydrology where the anecedent soil moisture conditions, and the temporal and spatial patterns of storms over watersheds affect the cumulative runoff volume which can influence the peak flow and peak water levels as much as any local 'spot' measurement of rainfall.
|Toronto North York July 8, 2013|
Rainfall Just Half Mississauga
Despite this fact of lower, non-record Toronto-proper rainfall, the CBC reported the July 8, 2013 GO Train incident as a top weather story of 2013 saying:
"When you look at the amounts of rain that fell ... it was like Toronto was the bull's eye," said Phillips, who described it as "a direct hit with a drenching rain storm."
|Toronto East York July 8, 2013|
Rainfall Just Half Mississauga
The May 28-29, 2013 storm that caused higher flows and higher flooding on the GO Train tracks dropped 43% more rain than July 8, 2013 in the mid portion of the watershed according to the Toronto East York Dustan climate station records.
The CBC News story also fails to recognize the frequent flood-prone nature of the rail tracks where the GO Train was stranded. Such reporting is an example of "anchoring or focalism", the cognitive bias per Nobel Memorial Prize in Economics winner Daniel Kahneman, in which people rely too heavily on the first piece of information present (Pearson/Mississauga rainfall record) when it is in fact irrelevant to Toronto/Don Watershed flooding.
Here is a summary of mid watershed rainfall (East York), and flows and water levels (Todmorden monitoring site near the stranded GO Train site) for the May 2013 and July 2013 floods:
Date East York Rainfall Peak Flow Peak Flood Level
May 28-29, 2013 73.4 mm 190+ cms 80.9 m
July 8-9, 2013 51.4 mm 180+ cms 80.7 m