Infiltration challenges from ground water:
Common and expected issues over time
THE SOLUTIONS:
• Wear and tear, cracks in pipes
After three years of gathering data, identifying the degree
of impact, and the various causes, we have three potential
large-scale solutions
• Manhole covers eroding below surface grade
Note: Based on the data gathered to date, the leading
factor to sewer backups during a storm is found to be
the increased and rapid flow of water from the weeping
tiles into the sewer system.
THE TIMELINE:
A summary of three years of information gathering
folded
downspouts
downspouts
Uncapped
Cleanout
roof drain
connection
leaky manhole
cover or frame
root intrusion
into lateral
Broken sewer
lateral
storm crossconnection
cracked or
broken pipe
leaky sewer
lateral connection
August 2010: Insurance Services with the Regional
Municipality receives the first call regarding a
sewer back-up
•
May–October 2011: Flow monitoring of the sewer
system in Timberlea was implemented
•
January 2011–August 2013: 11 reports were
completed studying various theories identifying
potential source of the sewer back-ups, and to
suggest solutions
•
May to October 2013: A third year of flow monitoring was conducted to validate the previous 2 years
of data collection
•
April 2014–Final options for solutions expected
•
2014–Solutions implemented
Please Note: Flow monitoring will continue until
at least 2018.
SANITARY SEWER
detoriated
manhole
•
STORM SEWER
storm crossconnection
Regional Municipality of Wood Buffalo:
1. Build a bypass pipe along Confederation Way/Brett
Drive taking the newer subdivision flow, and part of
the Timberlea flow downstream by an interception
system. This would reduce the overall pressure on the
Timberlea system, allowing room for the excess flow
in the Timberlea area during a storm.
2. Build a lift station that acts as a storage tank during a
storm event. It can then be drained into the existing
system once the storm recedes and flow is normalized.
3. Upgrade the entire Timberlea system with a second
pipe; or increase the size of the existing pipe to
accommodate the excess flow during a rainfall.
Disclaimer: We are currently reviewing the above
potential options including additional alternative options.
Once the final report is completed, a decision based on
the best option(s) will be selected.
Note: Minor solutions include correcting the pipe and
manhole degradation and plugging the manhole cover
vents if sunken.
Residents:
1. Place your downspouts down and away from your
home
2. Remove any downspouts connected directly to the
foundation drain and disconnect it, placing it down
and away from your home
3. Ensure the grading of your property directs water
away from your home
THE CAUSE:
During 2011 to 2012, significant increases to the sanitary
sewer flow during storms were recorded within some
areas of Timberlea.
BACKGROUND:
When parts of Timberlea were built, it was done to the
engineering servicing standards prior to 2000. During
that time, it was industry standard across the province to
connect the foundation drain (the weeping tile system) to
the sewer pipe. While that standard appears to have
been adequate in the past, the extreme amounts of rain
and snow we have had in recent years have challenged
the ability of the systems to handle these increased
volumes, compounded by the improper usage of the
drainage system. In recent years, as a result, a third pipe
system (storm) was introduced to newer developments to
connect to the weeping tile and keep that flow out of the
sewer system.
Inflow challenges from surface water: Water draining
into the sewage system through the foundation drain
(under the home) at an extremely fast rate.
• Downspouts are folded up on many properties, which
during a rainfall may cause water to go directly into the
home’s weeping tiles.
• On some properties, downspouts are hidden into the
ground which could mean it is directly being connected to the sanitary sewer system.
• Improper sloping (grading) on some properties is
directing water flow towards the home and into the
foundation’s weeping tiles.
• Surface water puddles over sunken manholes and
enters into the sanitary system through the manhole
cover vents.
For more information, please
contact the Construction Hotline
at 780-793-1054 or
[email protected].
TIMBERLEA DRAINAGE
INFORMATION
For drainage emergencies call the
Underground Services after hours line at 780.799.5823
www.woodbuffalo.ab.ca