Forward: elements of this letter have been expanded in other posts:- storm intensity not increasing shows how the Weather Story has metastasized through media, economic reports and policy statements, just like anti-vaccine junk science,- Toronto overland flow factors affect flood risk includes recommendations on urban flood hazard management, backed up by informative new overland flood risk mapping, that would complement policy solutions in this letter,- GO Train flooding not new per 1981 provincial inquiry highlights incorrect explanation of rail flood damages by climate change, explained decades ago to Premier Davis using hydrology (Don Watershed development) and hydraulics (Keating Channel dredging),- Connecting dots on climate change shows how infographics and anecdotes have replaced data and statistics in the myopic explanation of flooding that points to climate change, and ignores factors in the rainfall-runoff process (watershed development, stormwater management), and runoff conveyance (infrastructure design and operation) and ignores Environment Canada rain data.
And here is the link to the Environment Canada report that was attached to the letter (Methodologies to Improve Rainfall Intensity-Duration-Frequency (IDF) Estimates: A Southern Ontario Pilot Study, Environment Canada Adaptation and Impacts Research Climate Research Division, December 2011). In response to our complaint to the CBC News Ombudsman, CBC has confirmed with Environment Canada that storm frequency is not increasing and has since updated their news item that misstated we are getting 20 times more storms now.
Ministry of
the Environment and Climate Change
June 7, 2015
11th Floor,
Ferguson Block
77 Wellesley
Street West
Toronto,
Ontario M7A 2T5
Re: Inaccurate Extreme Weather Statements and Technical
References in Ministry of the Environment
and Climate Change; Ontario’s Climate Change Discussion Paper 2015, and
Policy Consequences
Hon. Glen R. Murray,
I am writing to advise you of inaccurate statements made
regarding extreme weather in Ministry of
the Environment and Climate Change; Ontario’s Climate Change Discussion Paper
2015[i]
(the Paper) and to advise that policy outcomes and actions will be misdirected
if important causative factors in increased flood damages are not acknowledged
or addressed. While I write this as a Professional Engineer (with twenty five
years of experience in stormwater management, riverine and urban flood risk
evaluation and mitigation, and analysis of weather statistics), the inaccuracies
in the Paper are not nuances requiring technical expertise to recognize –
rather, they are clear errors that I trust you can correct and act upon to more
effectively address urban flood risks and damages.
Weather Statements and Technical References
Your introduction to the discussion paper indicates that “Severe
weather events are already driving up insurance costs and severely damaging our
infrastructure” - this is a well-founded statement[ii]. Insurance losses due to flooding have
increased, and several factors affecting losses are described later in this
letter.
Page 19 in the Paper indicates that “Ontario’s historical
data demonstrates significant changes in our temperature and precipitation
trends.24 ” The paper’s reference #24[iii]
does not support this
statement for the following reasons:
i) The cited article is on temperature
and precipitation prediction using global climate models (GCMs) and does not evaluate Ontario’s historical data.
ii) The authors’ derivative report[iv]
High-resolution temperature and
precipitation projections over Ontario, Canada: a coupled dynamical-statistical
approach (Q. J. R. Meteorol. Soc. (2014) DOI:10.1002/qj.2421), does not demonstrate future significant changes in precipitation. The Summary and Conclusions section, in fact,
predicts decreasing precipitation:
“Meanwhile, the projected
precipitation at most of the weather stations showed decreasing trends to
varying degrees. The results also disclosed apparent spatial variability in the
amount of precipitation but no evidence for the changes in the spatial patterns
of precipitation was found.”
Based on these
reasons it is inaccurate to claim increasingly severe weather is causing
insurance losses.
Page 19 in the Paper indicates “We are seeing … increasingly
intense weather events such as ice-storms, rain storms..” but provides no
reference document to demonstrate increasing intensities. The association of intense weather with ice
storms in the paper is an erroneous association that links events that have indeed
occurred and are top of mind (i.e., ice storms) with weather that has not had
any documented increasing intensity trends.
Scientifically, this
association between documented events and undocumented events is no more valid
than associating vaccines with increased autism.
For reference, Environment
Canada (EC) has completed an assessment of trends in historical rainfall
intensities and found no significant change[v]. EC's Adaptation and Impacts Research Climate
Research Division recently reviewed rainfall statistics and found significant
increases, as well as decreases, were detected at some rainfall stations in a
number of the extreme precipitation indicators.
However, the majority of station trends were determined to be
non-significant and no consistent geographical patterns for increases or
decreases were observed across Canada.
In most cases, the magnitude of the observed changes was also very
small. This report is attached
electronically for your reference. As an
example of historical trends, yearly
maximum observed rainfall depths observed over 5 minute to 24 hour durations that
are readily available for EC’s long-running Bloor Street gauge are shown below[vi]
- data trends show no increasing severity
in rainfall intensities[vii]
for any duration.
“As a result, weather
events that used to happen once every 40 years are now happening once every six
years in some regions in the country.”
However, no
analysis or documentation to support this statement is given – only a general
reference that “Environment Canada: Intensity-Duration-Frequency Tables and
Graphs” are used is provided. When
contacted for clarification, IBC referred the statement to the author at the University
of Western, who referred the statement to the Institute for Catastrophic Loss
Reduction (ICLR), who cited a research paper on climate prediction – not
historical observed weather[ix]. ICLR has asked for patience while they search
for the reference to support the statement that weather events are happening
more frequently. Meanwhile, the IBC’s
unsupported statement on historical weather changes continues to spread without
question through media and the economy:
i) Media: CBC Doc Zone – Weather Gone
Wild (http://www.cbc.ca/doczone/features/is-the-weather-really-getting-wilder)
ii) Policy Statements : The Canadian
Chamber of Commerce’s “A Climate Change Adaptation Strategy for Canada” (http://www.chamber.ca/download.aspx?t=0&pid=f95b0a18-3e6c-e411-a071-000c29c04ade)
iii) Economic Statements : TD Economic
Special Report Natural Catastrophies: A Canadian Economic Perspective http://www.td.com/document/PDF/economics/special/NaturalCatastrophes.pdf
iv) Advertisements : “Industry first –
Aviva Canada launching overland water protection for homeowners” (https://www.avivacanada.com/article/industry-first-%E2%80%93-aviva-canada-launching-overland-water-protection-homeowners)
Unfortunately, your Ministry’s document Ontario’s Climate Change Discussion Paper 2015 also promotes
statements on intense weather and historical trends that are not supported by
the Paper’s references or research by others. Inaccurate statements on the
cause of weather damages will lead to misdirected policies to mitigate the
damages caused by severe weather.
More accurate statements and effective policies require that
‘climate’ and ‘weather’ be distinguished in policy making. The Paper makes many
statements about ‘weather’. However, the
cited article provides no support for statements on ‘weather’ rain storms
(temporal scales of minutes to days) and instead speaks to ‘climate’ (temporal
scale of days to years). On precipitation, the research indicates ‘low
confidence in predictions’, and does not assess intense weather events, as
shown on excerpts from the Paper’s reference #24 on the next page.
In fact, the Paper’s reference only assesses changes in low
to moderate events (>20 mm/day) from an engineering design perspective,
even though the events were deemed to be ‘very heavy’. To illustrate this, the previous Environment Canada data have an average daily
maximum depth since 1940 of 45.9 mm[x],
which is over 230% greater than the reference’s ‘very heavy’ rain threshold. Accordingly, intense events causing severe
flooding and insurance damages are not characterized by the Paper – for comparison,
the City of Toronto threshold for a 100 year storm[xi]
is 85 mm, 425% greater than the ‘very heavy’ threshold in the Paper’s technical
reference.
 |
 |
| Add caption |
‘Very heavy’ precipitation threshold in Paper’s research (>20 mm/day) is
‘below average’ when compared to annual series of maximum daily rainfall from
Environment Canada. This demonstrates
the disconnect between ‘climate’ scale precipitation analysis and intense
weather events.
In brief, the Paper’s
reference does not address predicted weather on the temporal scale that causes
urban flooding, nor does it address severe weather characteristics – rather, it
addresses climate and only low to moderate events. While you should discount anecdotes on
weather (even mine), my professional experience with real-time rainfall
intensity reporting and subsequent responses to flood service calls for
constituents is that even isolated nuisance flooding begins at a precipitation
thresholds well above that of the Paper’s reference of 20 mm, meaning it does
not characterize storms causing urban flood damages.
The Paper Introduction states that “..extreme weather is now
part of the ‘new normal’.”. The statement
is made in the context of observed temperature changes this century and creates
and an erroneous association between average annual temperatures and short term
weather patterns. The ‘new normal’ is a
clever catchphrase but it is not supported by science as Environment Canada’s
review noted above shows no trend in historical normal / average or extreme
rainfall intensity statistics. It should
be noted that when climate prediction models claim ‘new normals’ or increasing
intensities, basic fact checking is often ignored. For
example, SENES Consultants’ report[xii]
for Toronto Environment Office in 2011 predicted doubling of 10 year return
period maximum hourly intensities (from 20 mm/hr in 2000-2009 to 39 mm/hr by
2040-2049), but under
reported today’s intensities by half in Table ES-3 of that report;
today’s 10 year return period[xiii]
maximum hourly intensity based on the Toronto Bloor Street, Ellesmere, and
Pearson Airport rain gauges[xiv]
is already 38.7 mm/hr which is already equal
to the predicted future intensity – so
the SENES report actually predicts no increase in rainfall intensities for moderately
severe 10-year storms parameters, and the SENES characterization of the
current moderate rainfall intensities is incorrect.
Policy Consequences
Increasing flood damages are real and can be linked to many
measurable, manageable factors including:
i) intensification / infill development results in greater
runoff to existing urban sewer infrastructure which increases flood risk; the
increase in impermeable, hard surfaces is readily observed and measureable and
I have quantified increases in roof footprint alone of 3% over a single decade
using geographic information system data in the municipality where I manage the
long term flood remediation program. The effects of rooftop, driveway and patio
intensification over several decades has a significant impact on runoff and
flood risk. While today’s high stormwater control standards for large sites may
mitigate some runoff impacts, these controls have not been required for
residential and most small commercial intensifications, and until the mid-1990’s
have not addressed the cumulative impacts of increased runoff volumes on flood
risks, but have only addressed peak flow management and only for large sites. Intensification has also impeded the overland
flow paths in urban areas that are critical to safely convey intensive storms;
Policy solution : require
municipalities to mandate on-site stormwater source controls for infill
development, regardless of size and type, i.e., include single family
residential infill. To support this,
continue to develop low impact development (LID) standards for ‘green
infrastructure’, and require Environmental Compliance Approval (ECA) for source
and conveyance controls to support their long term maintenance and
effectiveness (this may involve collaboration with Ministry of Natural
Resources and Forestry such that measures supporting their policies for flood
risk reduction are incorporated under your Ministry’s ECA’s, typically issued
only for end-of-pipe stormwater quality control measures).
ii) aging infrastructure results in more water infiltration
through cracks and sewers and manholes that settle over decades, using up sewer
capacity; in the municipality where I work, the amount of extraneous inflow and
infiltration in the sanitary sewer system is the greatest indicator or high
neighbourhood basement flooding risks;
Policy solution: require
municipalities to impose back-flow valves and sump pumps for infill development
in areas with high extraneous flow, and ban basements in areas with highest
extraneous flow to avoid increasing risk (e.g., no basements below ‘100 year
storm hydraulic gradeline’ indicating potential sewer surcharge levels/risks).
iii) plugging the relief overflows in sanitary systems (per
Ontario's Policy F 5-5 that limits overflow volume to watercourses) has
increased the potential for sewage back-up into basements instead of into
watercourses. While this is an effective
pollution protection strategy, it has increased flooding risks to communities. As
examples Hamilton’s Sterling Street sewage overflow regulator weir[xv]
was raised to reduce sewage spills even though there were basement flooding
risks noted in the ‘pre-approved’ Municipal Class Environmental Assessment
(MCEA) recommendation report; similarly the Kennilworth Avenue tank in Toronto,
a storage facilities constructed to reduce Lake Ontario beach closing, was
noted to be a cause of basement flooding during extreme events in the City’s “Area
32” basement flooding engineering study[xvi].
Policy solution: require greater
emphasis on social and financial impacts due to flooding in MCEA’s. Allow
sewerage overflows to watercourses in extreme events (e.g., no lower than 100
year events) as an interim measure to mitigate short term flood risks where a
municipality has identified approved long-term plans to improve infrastructure
to mitigate long term risks. Also, elevate the ‘Schedule’ of MCEA works that
may affect basement flooding from pre-approved Schedule A, to Schedule B so
that flooding impacts can be communicated to the public, including the
insurance industry, and so that alternative works can be considered that will
not increase basement flooding risk (e.g., Hamilton’s Sterling Street regulator
weir changes were ‘pre-approved’ Schedule A works requiring no consultation).
iv) underpinned / lowered basements exposes home contents
and finishings to greater flood damage risks as the basement is now closer to
the sewer elevation and surcharge levels during extreme storms;
Policy solution: require
municipalities to impose back-flow valves and sump pumps where basements are
lowered or ban basement lowering in areas with highest extraneous flow to avoid
increasing risks. Similarly, increase
the safety factor against sewer surcharging in new subdivisions by increasing
the design storm to 200 years from 100 years to check storm sewer design
resiliency. This would be in the order
of a 15-20% increase in design flow to check the resiliency of the new system
design and can accommodate future uncertainty in weather conditions over the
long life of the new infrastructure (over 80 years for storm sewers). Municipalities such as Ottawa have adopted
such check storms for new subdivisions and this is a very cost effective
adaptation strategy given uncertainty in weather predictions.
v) inadequately maintained foundation drains and private
sewer laterals in post WWII dwellings result in many flood calls to
municipalities when the systems clog or fail resulting in flooding not related
to the City's mainline sewer in the street;
Policy solution: education and
awareness of private side risk mitigations measures such as lining or replacing
private lateral drain connections, often blocked by roots that enter old clay
tile pipe, or foundation drains.
vi) construction sewer by-pass failure can result in more
back-ups during extreme events (contractors size by-bass pumps so they can take
sewers out of service during construction and the pumps have finite capacity
and cannot handle large storms). It was
acknowledged[xvii]
by the City of Toronto that this was a factor in the recent Union Station flood,
and so Toronto recently updated the contract specifications for by-pass pumping
to require more capacity to reduce back-up risks (see Engineering and
Construction Services Division Standard Specifications for Sewers and
Watermains TS 4.01 April 2013 as a reference).
My experience is that operational constraints during construction can
lead to flooding during even moderate events, causing residents to misinterpret
the severity of rainfall, by not appreciating (or being aware of) the short-term
hydraulic constraints in the system;
Policy solution: create/update
Ontario Provincial Standard Specifications and/or Designs to require greater
sewer by-pass capacity to mitigate flooding risk.
vii) Keating Channel / Don River outlet dredging affects the
frequency of Don Valley Parkway Flooding (“If you don’t dredge, it floods the
Don River and the Don Roadway and the Don Valley Parkway,” explains Angus
Armstrong, the harbour master[xviii]).
Since the federal Fisheries Act became a criminal act in the mid-1990’s,
maintenance of large and small drainage channels has been encumbered by
environmental constraints on municipalities, e.g., to dredge or remove
vegetation that reduced flood conveyance capacity. Similar to recent advances sewage overflow
controls, this is an area where the balance between positive environmental
protection and negative financial and social impacts due to flooding requires
adjustment, given significant historical flood damages and risk.
Policy solution: Require greater emphasis on public safety,
technical effectiveness (level of service to protect against flooding) and financial
benefits (deferred flood damages) as part of Environmental Assessments and
Municipal Class Environmental Assessments.
xiii) Basement flooding and insurance damages is correlated
with ‘urban flooding’ beyond valley features, when the overland flow system
concentrates runoff toward vulnerable buildings and infrastructure during
severe weather (I have confirmed this using City of Toronto historical basement
flood location maps for May 2000 and August 2005 storms and MNRF’s WRIP
enhanced data sets). The overland flow
system, unlike defined river valleys regulated by conservation authorities, is
not always defined by municipalities as it is may be simply low-lying topography. The overland flow system is typically beyond
the scale of conservation authority flood hazard mapping (traditionally mapped
for drainage areas of ½ square mile or 125 hectares), meaning it is not mapped
through engineering studies - what is not mapped cannot be managed. Property owners within these urban flooding
risk zones cannot recognize nor mitigate their property risks and
municipalities have no authority to regulate and manage risks.
Policy solution: Fund and require conservation authorities to
map urban flood risks by extending flood plain mapping through table land areas
(beyond valleys) for smaller drainage areas than traditionally analyzed. Manage urban flood risk areas in the same
manner as river flood plains, but perhaps using a two-zone concept where
development is not precluded in shallow flooding areas and where flood proofing
is completed. (Aside – urban flood risk
mapping can be completed cost effectively using common analysis tools (US Army
Corps’ HEC GeoRAS) and high resolution digital elevation models, based on my personal
experience updating and extending conservation authority hazard mapping).
None of the above factors affecting urban flooding can be addressed
by climate change mitigation efforts, such as emissions reductions proposed in
the Paper – they can be addressed instead by managing hydrologic impacts of
development, managing hydraulics of infrastructure and drainage systems, setting
broader environmental study goals, establishing more robust infrastructure
design criteria, and adopting construction/operational practices that limit
short term risks. Efforts put toward
managing emissions will not address the root causes of increased insurance
damages due to urban flooding.
Conclusions
The Paper has conflated the well-documented
climate/temperature trends that can be scientifically linked to emissions, with
the non-documented weather/intense rain trends that have not been observed or
documented by any credible source. While some may cite a high number of severe
storms and flooding in the former North York area of Toronto as evidence of
significant weather trends, this observation is one anecdote. Since it is not supported by Environment
Canada’s data, it is at best a convenient explanation for recurring flooding in
an under-designed, ‘overland relief flow challenged’ drainage system that has
been under study since the late 1980’s (e.g., during my first summer job in
engineering consulting). There may be other anecdotes on severe
weather, but the plural of anecdote is not data, nor is it evidence that could
be used to inform very important public policy.
The Paper has also erroneously associated observed events
(ice storms and temperature changes) with non-documented events (precipitation
and severe weather trends). Key statements related to trends in
historical precipitation are not supported by the Paper’s references. In
fact, no analysis of historical precipitation is included at all, and
no prediction of weather on the appropriate temporal scale to relate to flood
is included. By relying on errors, tangible
and measurable flood risk factors and mitigation approaches have been grossly
overlooked, and proposed mitigation policies related to emissions have been
proposed that will not address the root causes of increased insurance costs due
to flood damages.
I trust that you can correct the inaccurate statements in
the Paper and will identify and pursue policies that can effectively address
the flood risks damages due to severe weather.
This will require collaboration with other Ministries (Natural Resources
and Forestry (MNRF), Municipal Affairs and Housing (MMAH)) that have a key role
in flood risk management in Ontario, and municipalities who implement and
maintain flood remediation infrastructure. Essentially, ownership and
leadership on Provincial Policy for management of natural hazards must be
established in the appropriate Ministry/Ministries, and resources must be
assigned to advance appropriate, mitigative, evidence-based policies for managing
urban flooding. Traditionally, MNRF and
MMAH are engaged only on riverine flooding issues (i.e., in valleys), and
MNRF’s limited resources are currently focused on natural heritage issues
(e.g., Endangered Species Act and regulations) - accordingly risks to the well-being
of small, endangered aquatic organisms like Redside Dace are addressed with focused
attention, but risks to the economic well-being of Ontario cities due to urban flooding
are not. Based on its results-based plan[xix]
with priorities and key measures that relate to infrastructure revitalization
and economic prosperity, it may be most appropriate for the Ministry of
Economic Development, Employment and Infrastructure to develop policies related
to urban flood risk mitigation.
Please feel free to contact me if you require any
clarification on the content in this letter and to respond.
Sincerely,
Robert J. Muir,
M.A.Sc., P.Eng.
Toronto,
Ontario
Enclosed 1) About me
2) References in
this letter and notes
3) Methodologies to Improve Rainfall
Intensity-Duration-Frequency (IDF) Estimates: A Southern Ontario Pilot Study,
Environment Canada Adaptation and Impacts Research Climate Research Division,
December 2011 (electronic attachment)
P.S. – Your
leader has acknowledged recently that the Ontario government has to “test our
assumptions” in relation to major game-changing initiatives. Please do so on
the topic of extreme weather, urban flooding and climate change.
“There will
still be times when someone accuses us of having lost our way, of having chosen
the wrong priorities, and I know that can be hard to hear. But in moments in
great and important choice, when the stakes are high, and the consequences are
long-lasting, we have to test our assumptions.” Premier Kathleen Wynne, AGM,
June 6, 2015[xx]
1) About
me
Robert Muir
is a Professional Engineer who currently manages the long-term flood control
program for a GTA municipality. He has 20 years’ prior experience in
engineering consulting where, as a partner with his firm, he managed the
national water resources engineering practice. He has extensive experience in
the statistical analysis of meteorological, hydrologic and urban drainage data
for the purpose of flood risk management, infrastructure planning and
remediation, and litigation. Robert was a contributor to the Institute for Catastrophic
Loss Reduction’s Cities adapt to extreme
rainfall, Celebrating local leadership (2014) [xxi]
, a reviewer of their Best practices
guide: Management of inflow and infiltration in new urban developments
(2015)[xxii],
and was the Consulting Engineers of Ontario’s representative on the Ontario
Provincial Standards Drainage Committee.
He has developed and applied design tools for the low impact development
measures using analytical probabilistic rainfall / runoff models. In his spare
time, he has developed urban overland flow risk models to investigate
correlations between Toronto’s widespread 2000, 2005 and 2013 basement flood incidents
and neighbourhood scale topographic factors that can characterize flood
vulnerabilities and guide prioritization of remediation efforts. Through his
studies and research at the University of Toronto, Department of Civil
Engineering, he was the recipient of NSERC grants and the W.S. Wilson
Medal. He values evidence-based policies
and decision making.
[i] http://www.downloads.ene.gov.on.ca/envision/env_reg/er/documents/2015/012-3452.pdf
[ii] http://www.ibc.ca/on/resources/media-centre/media-releases/ibc-welcomes-ontario%E2%80%99s-climate-change-discussion-paper
[iii] http://www.ontario.ca/sites/default/files/moe_mapping/downloads/4other/CC/PDF/2014-BIS-Symposium-Proceedings.pdf
[iv] http://ontarioccdp.ca/Wang_QJRMS.pdf
[v]
Methodologies to Improve Rainfall Intensity-Duration-Frequency (IDF) Estimates:
A Southern Ontario Pilot Study, Environment Canada Adaptation and Impacts
Research Climate Research Division, December 2011. See Section 6.1 Trends in Precipitation and
its Extremes in Southern Ontario, page 77 for the following:
“Significant
increases, as well as decreases, were detected at some stations in a number of the
extreme precipitation indicators. However, the majority of station trends were
determined to be non-significant and no consistent geographical patterns for
increases or decreases were observed across Canada. In most cases, the
magnitude of the observed changes was also very small. These results are
consistent with the daily Canadian extreme precipitation trend analysis of
Zhang et al. (2001) and the Canadian component of global and North American
trend analyses of daily precipitation extremes by Alexander et al. (2006) and
Peterson et al. (2008), respectively.”
[vi]
Ontario data zip file download (IDF_v2.30_2014-12-21/IDF_Files__Fichiers/IDF_v2.30_2014_12_21_ON.zip)
includes trend plots for all Ontario gauges including Toronto Bloor Street file
(idf_v2-3_2014_12_21_615_ON_6158355_TORONTO_CITY_t.pdf) within the data set at
the following ftp link ftp://client_climate@ftp.tor.ec.gc.ca/Pub/Engineering_Climate_Dataset/IDF/IDF_v2.30_2014-12-21/IDF_Files__Fichiers/IDF_v2.30_2014_12_21_ON.zip
[vii]
Intensities in millimetres per hour (mm/hr) are derived from rainfall depths (mm)
by dividing by the duration
[viii]
http://iclr.org/images/Telling_the_weather_story.pdf
[ix]
Personal email communication with IBC, University of Western, and ICLR staff
[x] See
idf_v2-3_2014_12_21_615_ON_6158355_TORONTO_CITY.txt in the Environment Canada’s Ontario data
[xi] A
100 year return period storm has a probability of 1/100, or 1%, of occurring in
any year, and is a typical return period for urban drainage design (new
infrastructure and rehabilitation)
[xii] http://www1.toronto.ca/city_of_toronto/environment_and_energy/key_priorities/files/pdf/tfwcds-full-report.pdf
[xiii]
A 10 year return period storm has a probability of 1/10, or 10%, of occurring
in any year
[xiv]
City of Toronto,The Wet Weather Flow Management Guidelines, 2006. Page 32 “The
updated IDF curves were derived based on the rainfall statistic analysis from
three Toronto Gauges: Toronto Bloor Street (Gauge# 6158350 – 24 years record),
Ellesmere (Gauge# 6158520 – 21 years record) and Pearson Airport (Gauge#
6158733 – 24 years record), as part of the WWFMP Study. (Reference: Technical
Memorandum of October 16, 2000 – Regional Rainfall Analysis: Summary Plots/
Tables, prepared by XCG Consultants Ltd.)”
[xv] https://www.hamilton.ca/Hamilton.Portal/Inc/PortalPDFs/ClerkPDFs/committee-of-the-whole/2003/Oct21/PW03163.pdf
[xvi] http://www1.toronto.ca/wps/portal/contentonly?vgnextoid=9a11a66bffa51410VgnVCM10000071d60f89RCRD
[xvii]
As reported in http://www.torontosun.com/2012/06/06/open-sewer-caused-union-station-flood : “The city is having the TTC’s contractor
reconstruct a large sewer as part of the Union Station Revitalization project.
Crews had pulled out a section of the existing sewer and put pumps in place to
pump the sewage across during the installation of maintenance holes. The flood
started with a brief but intense rainfall that “sent a rapid surge of storm
water flowing through the city’s sewer collection system and wastewater
treatment plants.” During Friday’s storm, “sanitary and storm water overflowed
from the open section of the sewer” and flooded out into Union Station. “The
contractor and the project management team are working to put in place measures
to avoid a recurrence during construction,” the city stated in a press release.
[xviii]
http://news.nationalpost.com/toronto/old-hands-keep-the-don-flowing-smoothly
[xix] http://www.moi.gov.on.ca/docs/en/MOI-2014-15RbPBriefingBook-PartI-English.pdf
[xx] http://www.torontosun.com/2015/06/06/premier-kathllen-wynne-sets-out-the-battle-plan-for-ontario-liberals
[xxi] http://www.iclr.org/citiesadaptrain.html
[xxii]
http://www.iclr.org/images/I_I_Best_Practices_Guidelines.pdf
