HomeMy WebLinkAboutEnv - 2012-02-16 - Presentation - Addendum to the 1995 Schneider Creek RemediaDate:February 16, 2012
To:Environment Committee
From:Diana Lupsa P.Eng, Design and Construction Project Manager
cc:Steve Allen P.Eng., Manger Design and Approvals
Subject:
SCHNEIDER CREEK REMEDIATION – CLASS ENVIRONMENTAL
ASSESSMENT ADDENDUM (HAYWARD AV. TO MANITOU DR.)
1. BACKGROUND
In 1995, the Grand River Conservation Authority (GRCA) through their consultant, Paragon
Engineering, in consultation with the City of Kitchener, undertook a Class Environmental
Assessment (EA) for the portion of Schneider Creek between Hayward Avenue and Manitou
Drive. The goal of the EA was to recommend remedial flood control measures to mitigate
flooding concerns in the creek as well as to mitigate erosion concerns in this section of creek.
The study area has been divided into three reaches (see Figure 1. Study area and location of
reaches):
Reach 1
- (Hayward Avenue to Budd Spurline) was constructed as a trapezoidal channel,
but over time the banks have been eroded to create vertical banks;
Reach 2
-(the triple crossing of the Spurline) there are three sets of culverts located on this
reach where Schneider Creek flows under the Budd Spurline owned by CN. Each of these
culverts is undersized, resulting in a significant backwater during flood events. Historical
flood events have resulted in the overtopping of the Budd Spurline tracks.
Reach 3
- (Spurline to Manitou Drive) is predominantly a natural watercourse, and shows
evidence of significant erosion in some locations. An existing armourstone wall protects an
adjacent well house near Manitou Drive, but the wall has begun to degrade. Erosion on this
well vegetated creek occasionally results in debris jams.
As part of the EA completed by Paragon Engineering in 1995, remediation alternatives were
identified and a preferred alternative was selected for each reach. However, the preferred
alternatives of the EA were not implemented. The flood and erosion issues continued and they
need to be addressed.
In accordance with the Association of Conservation Authorities of Ontario Class EA for
Remedial Flood and Erosion Control Projects (1993), an Addendum to an EA is required
whenever the time between the original EA completion and the proposed implementation of the
preferred alternative exceeds three years.
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Reach 1
Reach 2
Reach 3
reaches
Figure 1. Study area and location of
2. STUDY OBJECTIVE
The objective of this study is to complete an Addendum to the 1995 EA to re-characterize the
existing conditions, evaluate the original remediation alternatives for each reach in the context
of the new existing conditions, and then to either confirm the original preferred alternatives or
recommend a new preferred alternative that best reflects the existing conditions.
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This study has two proponents: the City of Kitchener and the GRCA, and is being carried out in
accordance with the 1993 Conservation Authorities Class EA process.
3. PREFERRED ALTERNATIVES
The remediation alternatives for each reach were evaluated with a consistent methodology. The
four evaluation criteria (technical, economic, environmental and social) have been used to allow
an alternative-to-alternative comparison.
A discussion of the original remediation alternatives from the 1995 EA and the updated
preferred alternatives are being provided for each reach as follows:
A. REACH 1
Reach 1 is exhibiting bank erosion, elevated peak flows as a result of development of the
upstream watershed and increased velocity as a result of channelization of the stream.
Remediation alternatives should aim to repair existing erosion areas and prevent further
erosion, and to restore the creek gradient.
Original Remediation Alternatives (1995):
Alternative 1 – Do Nothing
Alternative 2 – Channel Armouring
Alternative 3 – Natural Channel Design (Preferred 1995)
The remediation of erosion issues in Reach 1 was recommended to be accomplished through
natural channel design principles (Alternative 3) in the 1995 EA. The evaluation of alternatives
under this study, considering the revised existing conditions, also identified natural channel
design principles to be preferred approach to address erosion issues in Reach 1.
Although the development of the Peter Hallman Ball Yard has restricted the available area for
meanders to be constructed, the natural channel design principles still can be employed in this
situation, using riffle-pool sequences or in-stream shoals to simulate the energy mitigation
features of natural meanders. Shoals are lateral bars that would be spaced similarly to riffle
sections and alternate between left and right banks.
Preferred Alternative
Alternative 3 remains the preferred approach. Although the creek will not be able to be
meandered, a Natural Channel Design approach is still possible: shoals will be included in the
channel to improve low flow conditions, and access to the floodplain will be improved through
bank terracing. The concept plan for the preferred remediation approach in Reach 1 is shown in
Figure 2.Concept plan for the preferred remediation approach in Reach 1.
An additional component of the Reach 1 concept design includes the potential retrofit of a
stormwater wetland facility at the outlet of the storm system of St. Mary’s High School, first
identified in the 2003 Rehabilitation Study. The proposed retrofit would provide additional flood
storage and water quality benefit to Schneider Creek, mitigating erosion and flooding issues and
enhancing aquatic habitat potential.
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Figure 2.Concept plan for the preferred remediation approach in Reach 1
B. REACH 2
Reach 2 is experiencing flood and erosion impacts associated with the several hydraulic
constraints: the three culverts under the Budd Spurline, and the Balzer Road Bridge.
Remediation alternatives should aim to alleviate the flood risk to the Spurline and adjacent
properties, as well as to mitigate erosion due to flood flows (e.g., rail track washouts).
Remediation alternatives must be conscious of the existing land uses and infrastructure of the
site.
Original Remediation Alternatives (1995)
Alternative 1 - Improve Culvert No. 1 only.
Alternative 2 - Construct southwest bypass channel (flows from upstream culvert 1
diverted downstream culvert 2) and improve Culvert No. 3.
Alternative 3 - Construct northeast bypass channel (to convey design flows to the
north side of Spurline) and improve Culvert No. 1 and 3. (Preferred 1995)
Alternative 4 - Improve all three culverts.
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Alternative 5 - Split flow by constructing bypass northeast and southeast channels and
improving Culvert No. 1 and 3.
Alternative 6 - Convey Schneider Creek and Balzer to Culvert No. 3 and divert
Montgomery Creek through northeast bypass channel.
Alternative 7 - Relocate the Budd Spurline and remove the existing embankment from
Culvert No. 1 to Culvert3.
The conditions in the area of Reach 2 have changed since the 1995 EA in several ways that
impact the evaluation of the preferred remediation alternative:
Use of the Budd Spurline has decreased significantly since the closing of the Budd
Automotive manufacturing plant.
Triple M Metals has increased their operations; a significant portion of their business
infrastructure (buildings) was constructed close to the property line adjacent to the Budd
Spurline. The increase in use of the property suggests that construction of the northeast
bypass channel may no longer be appropriate, since it would require purchase of a
portion of the Triple M Metals property where their infrastructure is concentrated.
The proposed plan for a portion of the Trans-Canada Trail to follow Schneider Creek
through the study area may limit the feasibility of a northeast bypass channel, as the
path will occupy the limited space between the Budd Spurline and the Triple M Metals
property.
A more refined hydraulic study indicated that during the 100-year flow, the railway tracks
upstream of Reach 2 become flooded, making the tracks along Reach 2 inaccessible.
Even if 100-year flood protection were provided in Reach 2, the use of the tracks would
still be negatively impacted given the upstream flooding. The provision of flood
protection for the 100-year flow is not efficient considering these hydraulic conditions
and given the decreased use of the Budd Spurline. Therefore, it is recommended that a
lower design criteria (being the 25-year flow capacity) be adapted to evaluate the Reach
2 remediation alternatives.
As a result, the proposed northeast bypass channel would adversely impact the Triple M Metals
property and Trans-Canada Trail. These impacts are undesirable when considering the benefit
to the Budd Spurline railway which is no longer heavily used. Providing a 100-year level of flood
protection is no longer considered critical due to the decrease in use of the Budd Spurline
railway; a 25-year level of protection is considered acceptable. Due to these changes,
Alternative 3 is no longer the preferred alternative.
New Preferred Alternative
Based on a re-evaluation of alternatives in the context of updated existing conditions, this study
identifies as preferred the Alternative 4 - Improve all three culverts. The concept plan for the
preferred remediation approach in Reach 2 is shown in Figure 3. Concept plan for the preferred
remediation approach in Reach 2.
The Balzer Road bridge has been identified as a hydraulic constraint in Reach 2, similar to the
three existing culverts under the Budd Spurline. The removal of the Balzer Road bridge will
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improve the hydraulic conveyance of the reach, contributing to the provision of flood protection
and the reduction of erosion issues. The bridge also serves as the sole road access to the
industrial property located along the Budd Spurline between Culverts No. 1 and 2. However, this
is the only property that the Balzer Road bridge serves. The bridge is currently approaching the
end of its life cycle and will require significant repairs or replacement if maintained. When
considering these potential benefits and impacts, the removal of the Balzer Road bridge is
considered to be appropriate if the issue related to access of the private property can be
resolved (e.g., through alternate access from west side of creek, or purchase of property by the
City).
Part of the concept for Reach 2 is a potential future pedestrian bridge for the proposed Trans-
Canada Trail in place of the existing Balzer Road bridge. The proposed pedestrian bridge will
provide crossing opportunity while improving the hydraulic conveyance of the reach.
Figure 3. Concept plan for the preferred remediation approach in Reach 2
C. REACH 3
Reach 3 is exhibiting bank erosion, elevated peak flows as a result of development of the
upstream watershed, and increased velocity as a result of channelization of the stream.
Remediation alternatives should aim to repair existing erosion areas, prevent further erosion,
and to restore the creek to a configuration that provides energy mitigation. Remediation
alternatives must consider the constraints of the site.
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Original Remediation Alternatives (1995)
Alternative 1 – Do Nothing
(Preferred 1995 in the downstream part of the
Alternative 2 – Channel Armouring
reach)
(Preferred 1995 in the upstream part of the
Alternative 3 – Natural Channel Design
reach)
Preferred Alternative
There have been no significant changes in the existing conditions for Reach 3 since the 1995
EA, and therefore the implementation of both Alternative 2 and Alternative 3 remains the
preferred approach to address erosion issues in Reach 3.
Natural channel design (Alternative 3) was recommended to be implemented in the upstream
portion, restoring the creek to its historical channel and using the existing channel as an
auxiliary floodway, along with bank stabilization and minor channel adjustments (Alternative 2)
in the downstream portion. The split implementation of alternatives would provide an increase in
channel length to mitigate flow energy, and would protect the vulnerable infrastructure (well
house) near the downstream end of the reach. The concept plan for the preferred remediation
approach in Reach 3 is shown in Figure 4. Concept plan for the preferred remediation approach
in Reach 3.
In addition to the stream realignment and bank protection features, the implementation of the
preferred concept should encourage establishment of a riparian buffer to the creek and
increased hydraulic capacity through removal of the stored materials within the floodplain
adjacent to the creek, wherever possible.
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Figure 4. Concept plan for the preferred remediation approach in Reach 3
4. NEXT STEPS
The addendum will be presented for approval to the City of Kitchener Council (March 2012) and
the Grand River Conservation Authority Committee of the Whole (March 2012).
Upon filing of this Addendum along with the 1995 Environmental Assessment Report, and
following a 30-day public review period, the City of Kitchener intends to proceed with the
detailed design, approvals and implementation of the preferred alternatives as per the
preliminary schedule listed below:
Reach 1
– Implementation in Fall of 2012. The estimated cost for the implementation of
the preferred alterative for Reach 1 is approximate $1.4M;
Reach 3
– Implementation in 2014 (approximate $1.4M); and
Reach 2
– Implementation in 2015(approximate $2.7M).
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