galen heinrichs, p.eng – water & sewer engineering manager … · ‐city of saskatoon...
TRANSCRIPT
Galen Heinrichs, P.Eng – Water & Sewer Engineering ManagerMay 26, 2011
- Geography1 - BACKGROUND
2 – HOW BASEMENTS FLOOD
3 – PROGRAMS TO REDUCE THE RISK OF FLOODING
Large Scale Infrastructure Solutions
Small Scale Household Solutions
City of Saskatoon – Basement Flooding Solutions
- Two sewer systems
Edmonton
Banff
Calgary
Winnipeg
Regina
Lethbridge
South Saskatchewan
SaskatchewanNelson
Bow
Old Man
Red
Saskatoon
ALBERTA SASKATCHEWAN MANITOBA
Medicine Hat
Prince Albert
North Battleford
North Saskatchewan
Brandon
Qu’appelle
Assiniboine
- Geography1 - BACKGROUND
City of Saskatoon – Basement Flooding Solutions
- Two sewer systems
STORM SEWERS SANITARY SEWERS
TWO SEPARATE SEWER SYSTEMS
(Domestic Sewers)
STORM SEWER SYSTEM
conveys RAINWATER
destination : South Saskatchewan River
NOT connected to homes
SANITARY SEWER SYSTEM
conveys DOMESTIC SEWAGE
destination : WASTEWATER TREATMENT PLANT
ALWAYS connected to EVERY home
STORM SEWERS SANITARY SEWERS
TWO SEPARATE SEWER SYSTEMS
(Domestic Sewers)
NO Household Sewage NO roof or downspout leaders
NO catchbasins
- Geography1 - BACKGROUND
2 – HOW BASEMENTS FLOOD
City of Saskatoon – Basement Flooding Solutions
- Two sewer systems
- Seepage
- Weeping Tile: the Seepage Solution
- Sanitary Sewer Backup from Weeping Tile Overflows
HOUSEHOLD SEEPAGE FLOODING
Saskatoon homes built before 1960SEEPAGE FLOODING
HOUSEHOLD SEEPAGE FLOODING
WEEPING TILE(perforated pipe)
WEEPING TILE – The Modern Solution to Seepage Flooding
FloorDrain
Sanitary Sewer Line
WEEPING TILE CONNECTED TO SANITARY SEWER
WEEPING TILE – The Modern Solution to Seepage Flooding
Weeping Tile into Floor Drain
FloorDrain
Sanitary Sewer Line
WEEPING TILE CONNECTED TO SANITARY SEWER
In Saskatoon: 1960 - 2003Weeping Tile into Floor Drain
Water Level In Sewer
Sanitary Sewer Line
Sanitary Sewer Line
CONNECTED SANITARY SEWERS
SANITARY SEWER BACKUP - WEEPING TILE OVERLOAD
RAIN WATER exits as a SEWER BACKUP
RAIN WATER enters SANITARY SEWER
through WEEPING TILE
- Geography1 - BACKGROUND
2 – HOW BASEMENTS FLOOD
3 – PROGRAMS TO REDUCE THE RISK OF FLOODING
- Sump Pits
Small Scale Household Solutions
City of Saskatoon – Basement Flooding Solutions
- Two sewer systems
- Backwater Valves
FloorDrain
Sanitary Sewer Line
WEEPING TILE CONNECTED TO SANITARY SEWER
In Saskatoon: 1960 - 2003Weeping Tile into Floor Drain
SEALED
The “Modern” Sump Pit SolutionWeeping Tile connected to a Sealed Sump Pit
5
WEEPING TILE DRAINS TO STORM SEWER SYSTEM
Saskatoon Homes 2004 - 2011Weeping Tile into Sealed Sump Pit
THE BACKWATER VALVE SOLUTION
Backwater Valve
- Geography1 - BACKGROUND
2 – HOW BASEMENTS FLOOD
3 – PROGRAMS TO REDUCE THE RISK OF FLOODING
- Sump Pits
Small Scale Household Solutions
City of Saskatoon – Basement Flooding Solutions
- Two sewer systems
- Backwater ValvesFlood Protection Program
Flood Protection Program
Backwater Valve Sump Pit
‐ City of Saskatoon subsidizes SELECTED HOMES to upgrade plumbing to the January 1, 2004 standard.
20102005 2007
Offered Flood Protection Program
Total
567 427 346
Participation Rate 51% 52% 53%
1340
52%
Flood Protection Program
Program PAYS 100% of costs up to a ceiling of $2500 ($3000 in 2010)
HOMES DEEMED TO BE AT RISK of sewer backup may upgrade plumbing with a backwater valve and sump pit
Funded with a $3.00 Levy / water meter (raised to $4.50 in 2007)
85% Effective in eliminating damage from sewer backup
96% Effective in REDUCING damage from sewer backup
- Geography1 - BACKGROUND
2 – HOW BASEMENTS FLOOD
3 – PROGRAMS TO REDUCE THE RISK OF FLOODING
Large Scale Infrastructure Solutions
Small Scale Household Solutions
City of Saskatoon – Basement Flooding Solutions
- Two sewer systems
- Saskatoon’s Severe Rain Events
mm of RAIN
96.6mm
75.0mm in 45 minutes
1983JUN-24
City of Saskatoon Severe Rain Events
24 hour rainfall record
> 2000 Flooded Homes
2000+
mm of RAIN
47.4mm
1994MAY-17
50 Flooded Homes
City of Saskatoon Severe Rain Events
1983JUN-24
2000+ 50
mm of RAIN
56.0mm
160mm
800 Flooded Homes 30 DAY RAIN
Wettest 30 days since 1939
City of Saskatoon Severe Rain Events
1994MAY-17
1983JUN-24
2000+ 50
2005JUN-29
800
mm of RAIN
2007JUN-17
102mm
NEW 24hrRECORDOLD 24hr
RECORD
City of Saskatoon Severe Rain Events
2005JUN-29
1994MAY-17
1983JUN-24
2000+ 50 800 500
500 Flooded Homes
mm of RAIN
2007JUN-17
City of Saskatoon Severe Rain Events
2005JUN-29
1994MAY-17
1983JUN-24
2000+ 50 800 500
59.2mm
108mm
46.8mm
NEW 48hrRECORD
2007AUG-17/19
200
200 Flooded Homes
AUG 17 – 2007 7:10pm MESO SCALE CONVECTIVE COMPLEX
AUG 17 – 2007 9:20pm MESO SCALE CONVECTIVE COMPLEX
AUG 19 – 2007 12:00am MESO SCALE CONVECTIVE COMPLEX
mm of RAIN
2007JUN-17
City of Saskatoon Severe Rain Events
2005JUN-29
1994MAY-17
1983JUN-24
2000+ 50 800 500
85mm
2007AUG-17/19
200
2010JUN-29
400 Flooded Homes
30 DAY RAIN
169mm
400
MESO SCALE CONVECTIVE COMPLEX
2010
2005
1912
1942
2006
1923
1911
1991
2007
1927
520mm
420mm
385mm
374mm
366mm
366mm
362mm
360mm
351mm
350mm
TOP TEN Highest Rainfall Years
2007JUN-17
2005JUN-29
1994MAY-17
1983JUN-24
2000+ 50 800 500
2007AUG-17/19
200
2010JUN-29
400
Conclusions:2005-2010 : 4 of the 10 wettest years MESO SCALE CONVECTIVE COMPLEXCumulonimbus ThunderstormSynoptic Rain Events – combined with antecedent rainfall1 in 100 year events - Intensity/Duration/Frequency (IDF) CurvesNew Approach to Assessing the Effect of Storms and a New Solution
- Geography1 - BACKGROUND
2 – HOW BASEMENTS FLOOD
3 – PROGRAMS TO REDUCE THE RISK OF FLOODING
Large Scale Infrastructure Solutions
Small Scale Household Solutions
City of Saskatoon – Basement Flooding Solutions
- Two sewer systems
- Saskatoon’s Severe Rain Events- “Superpipe” storage tanks
SANITARY SEWER PIPE DESIGN
self-cleaning
deep enough to prevent freezing
minimum flow speeds
not too deep to maintain / build
cannot be designed for extreme events
Water Level In SewerSanitary Sewer Line
Sanitary Sewer Line
Water Level In Sewer
SANITARY SEWER STORAGE TANK (Superpipe) CONCEPT
PUMPED to SANITARY SEWER after storm subsides
Matching Superpipe Influence Zones to Flood Risk Zones
Superpipe Size = Estimated Volume of Flooded Basements
“SUPERPIPE” Project
Local Engineering
Local Contractors
Local Construction Management
Locally Manufactured Pipe
“SUPERPIPE” Project
2008 1.1 million litres $1.2 million
2.4 million litres $2.5 million
2009 1.0 million litres $1.9 million
0.4 million litres $0.9 million
2010 1.1 million litres $1.5 million
1.5 million litres $2.2 million
2011 1.6 million litres $2.4 million
2012 1.1 million litres $1.7 million
1.7 million litres $2.6 million
2013 1.6 million litres $2.4 million
$10.2 million
$19.3 million
36%
51%
Sr. Gov’t
Sr. Gov’t
- Geography1 - BACKGROUND
2 – HOW BASEMENTS FLOOD
3 – PROGRAMS TO REDUCE THE RISK OF FLOODING
Large Scale Infrastructure Solutions
Small Scale Household Solutions
City of Saskatoon – Basement Flooding Solutions
- Two sewer systems
SUMMARY:
BASEMENT FLOODING:
- Sanitary sewers will overflow during a severe rain
- Weeping tile allows rain water into sanitary sewers
- Pipe conveyance or resizing cannot solve overflows
SOLUTIONS:
- Different combinations of storms and rainfalls may cause overflows
- Backwater valves are at least 85% effective
- Storage tanks can be designed to capture overflows
ACKNOWLEDGEMENTS:
City of Regina
City of Winnipeg
www.saskatoon.ca“B” – Basement Flooding