Agenda Item No.: G.1.b.
Sanitary Servicing Strategy – Rat Creek Crossing (Highlands Tunnel Interceptor
Upgrading Project Completion).
strategy developing new projections
for sewerage system flows and
integrating plans for future
wastewater treatment.
6. That the Highlands Tunnel
Committee be disbanded.
Recommendation:
That approval in principle be given to
proceed with the Rat Creek Crossing
(formerly known as Highlands Project Stage
IV).
Report Summary
Asset Management and Public Works
Department, Drainage Services, is
requesting approval in principle to proceed
with the Rat Creek Crossing (formerly
known as Highlands Project Stage IV).
Report
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Previous Council/Committee Action
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At the July 27, 1993, City Council
meeting, the following motion was
passed:
1. That the river crossing portion of
the Highlands Project (Stage IV) be
deferred until the need for it is
demonstrated and approved by City
Council.
2. That a project be identified for
implementation in the 1994 Sanitary
Capital Budget to put the Highlands
Stage III into operation as a storage
device.
3. That the minor repairs of the twin
pipe river crossing identified during
the 1991 inspection be completed
by the Administration during the
winter of 1993/94.
4. That a regular inspection program
be maintained for the existing North
Highlands interceptor consisting of
visual inspections of the chambers
twice per year, and complete
internal inspections every 10 years.
5. That the Administration prepare a
Combined Sewer Overflow control
Routing:
Delegation:
Written By:
April 7, 2003
File: 2003PWD045
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In July 1993, City Council deferred the
completion of the river crossing portion
of the Highlands Project (Stage IV). At
that time it was determined that:
a) The existing North Highlands
Interceptor is in good structural
condition; and
b) The need for additional capacity to
convey flows from the north side
through the Highlands Interceptor
system had not yet been
demonstrated.
On July 21, 1998, City Council passed
the following motion: “That the Sanitary
Servicing Strategy for 21st Century be
approved.” This is a long-range
servicing plan that facilitates
development in new areas and
redevelopment within the existing City.
The river crossing portion of the
Highlands Project (Stage IV) is a key
component of the Strategy. It has been
determined that this sewer is needed to
convey wet weather flows from the north
side through the Highlands Interceptor
system. Approval to fund this project
has been given by the Sanitary Servicing
Strategy’s Management Committee.
This Committee is comprised of two
representatives from the Urban
Development Institute and three City
staff.
Transportation & Public Works Committee, City Council
W. D. Burn
Kurt Sawatzky/Paul Hoffart
Asset Management and Public Works Department
(Page 1 of 3)
Sanitary Servicing Strategy – Rat Creek Crossing (Highlands Tunnel Interceptor
Upgrading Project Completion).
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At the March 14, 2000, Transportation
and Public Works Committee meeting
the following motion was passed:
“That the Combined Sewer Overflow
Control Strategy – Implementation
Plan, as outlined in the February 9,
2000 Asset Management and Public
Works Department report, be
approved.”
The purpose of this $150 million
strategy is to reduce the environmental
impacts of the City’s combined sewer
system. Specifically, the Strategy
involves the construction of capital
works to reduce the spillage of untreated
runoff and sewage to the North
Saskatchewan River. Integral to this
strategy is the expansion of wet weather
treatment capacity at the Gold Bar
Wastewater Treatment Plant, and the
conveyance of wet weather flows to the
plant. The Rat Creek Crossing (formerly
known as Highlands Project Stage IV) is
one of the major conveyance elements of
the strategy.
Recently, the City retained a consultant
to complete the preliminary and detailed
design on the Enhanced Primary
Treatment project. This project will
increase the wet weather treatment
capacity at the Gold Bar Wastewater
Treatment Plant by the spring of 2006.
The work is being partially funded from
the Infrastructure Canada Alberta
Program. With this extra capacity, the
Gold Bar Wastewater Treatment Plant
will be able to treat wet weather flows.
Upon completion of the expansion of the
wet weather treatment capacity at the
Gold Bar Wastewater Treatment Plant,
the Rat Creek Crossing is required to
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convey wet weather flows to the Plant.
The design and construction is estimated
to require three years to complete. By
starting the design now, the construction
will be completed in the spring of 2006
in conjunction with the expansion of wet
weather treatment capacity at the Gold
Bar Wastewater Treatment Plant.
The Rat Creek Combined Sewer
Overflow spills untreated wastewater
into the North Saskatchewan River about
20 to 30 times in a typical year.
Construction of the river crossing will
reduce this number to under five times a
year, by transferring these overflows to
the Gold Bar Wastewater Treatment
Plant for enhanced primary treatment.
The risk of not proceeding with this
project is that the City of Edmonton will
be in jeopardy of violating its
commitment to Alberta Environment
with regards to the Combined Sewer
Overflow Control Strategy. Failure to
control combined sewer overflows may
result in charges being levied against the
City under the Alberta Environmental
Protection and Enhancement Act.
Since 1993, the conceptual design of the
Rat Creek Crossing has been revised.
Expert hydraulic analysis has been
incorporated into the plan by the
consultant to ensure proper operation
during all conditions. This has included
review by other external experts from
the consulting industry and municipal
sector.
Budget/Financial Implications
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(Page 2 of 3)
Estimated cost for the construction of the
Rat Creek Crossing is up to $24 million.
Sanitary Servicing Strategy – Rat Creek Crossing (Highlands Tunnel Interceptor
Upgrading Project Completion).
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Funding for this project is available in
the Drainage program.
Budget approval for construction of the
Rat Creek Crossing will be brought
forward to Council as part of the 2004
Capital Priorities Plan.
Justification of Recommendation
The purpose of the Combined Sewer
Overflow Control Strategy is to reduce the
environmental impacts of the City’s
combined sewer system. The Rat Creek
Crossing is one of the major conveyance
elements of the strategy. As a result of the
expansion of the Gold Bar Wastewater
Treatment Plant by spring of 2006, the Rat
Creek Crossing is required to convey wet
weather flows from the Rat Creek Combined
Sewer Overflow to the treatment plant. The
risk of not proceeding with this project is
that charges may be levied against the City
for failing to control combined sewer
overflows.
Background Information Available on
Request
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Highlands Tunnel Interceptor Upgrading
Project Completion - Transportation
Department report dated July 14, 1993
(City Council - July 27, 1993)
Sanitary Servicing Strategy Fund
Report, December, 1998.
The City of Edmonton Combined Sewer
Overflow (CSO) Control Strategy
Implementation Plan, June 2000.
Others Approving this Report

R. Garvey, General Manager, Corporate
Services.
(Page 3 of 3)