Body: Council
Type: Agenda
Meeting: Public re Hills Lake Culvert
Date: May 16, 2024
Collection: Council Agendas
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Document Text
Public Council Agenda 5:00 PM - Thursday, May 16, 2024 Council Chambers Zoom Registration
Call to Order and Purpose of Meeting
a) Public Notice regarding Recording of Meetings
Recorded Meetings - Notice to Public 3
Chair’s Opening Remarks
Traditional Land Acknowledgement
We begin this gathering by acknowledging and celebrating these traditional lands as a gathering place of the first peoples and their ancestors who are entrusted to care for Mother Earth since time immemorial. We do so respecting both the land and the Indigenous People who continue to walk with us through this world. Today, the Township of North Frontenac is committed to working with Indigenous Peoples and all residents to pursue a united path of reconciliation.
Approval of Agenda
a) Approval of the Agenda for the May 16, 2024 Public Meeting
Be It Resolved That Council approves the Agenda for the Public Meeting dated May 16, 2024 regarding the Hill’s Lake culvert, as circulated.
Disclosure of Pecuniary Interest and General Nature Thereof
Presentation
a) Jewell Engineering re: Hill’s Lake Culvert
Be It Resolved That Council receives for information a presentation from Bryon Keene, Jewell Engineering regarding the Hill’s Lake Culvert and thanks him for his time spent today; And That Council instructs the Public Works Manager to provide a report at a future meeting with recommendations for Council’s consideration.
Presentation Buckshot Lake Road Culvert Replacement Buckshot Lake Road Culvert Hydraulic Review 2024 4 - 25
Public Comments
Adjournment
a) Adjournment of the Meeting
Be It Resolved That Council adjourns the Public Meeting at _______
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.m
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Members of Council, Staff, Delegates and attendees should be mindful of using names
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CULVERT ENGINEERING REVIEW
6253 BUCKSHOT LAKE ROAD
REPORT TO COUNCIL MAY 16, 2024
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Project Location
2
CULVERT
Page 5 of 25
Project Description
3
Failed Culvert at 6253 Buckshot Lake Road
• Outlet of Hills Lake
• 800mm Corrugated Steel Pipe
• Candidate for “Like for Like” replacement
Page 6 of 25
Concern
4
Lake Residents are concerned with the water levels on
Hills Lake
• Some concerned it is too low
• Some concerned it is too high
oSummer levels – too low
oExtreme flows – too high
Page 7 of 25
Project Goals
5
Determine a replacement configuration that:
• Improves (raises) summer normal water level
• Provides benefit (reduces flooding) during extreme
flow
Page 8 of 25
Survey
6
Topographic survey completed at the culvert and
various properties around the lake September 2023.
Lake Level used as baseline
Page 9 of 25
Survey
7
Page 10 of 25
High Flows
8
Page 11 of 25
Design Constraint
9
Determine a replacement configuration that:
• Improves (raises) summer normal water level
• Provides benefit (reduces flooding) during extreme
flow
oSafe Access – Private Driveway
Page 12 of 25
Analysis Results
10
- Low flows controlled by driveway culvert
- High flows controlled mostly by cross culvert
- Spill point in driveway is only 0.5m (18”) higher than water level
- Very little opportunity to change water level Page 13 of 25 Proposed Culvert Arrangement 11 Three – 600mm culverts Page 14 of 25 Proposed Arrangement 12 Page 15 of 25 Proposed Culvert Arrangement 13 Three – 600mm culverts • Raised 15cm (6”) above existing • Least cover permissible (12”) • Higher flow capacity before water spills Maximum size that can fit without raising the driveway Cannot raise the driveway – acts as a dam Page 16 of 25 Permits 14 Ministry of Natural Resources • Agree the culverts and driveway - dam • But, too minor to require a permit Mississippi Valley Conservation Authority • Requires a permit • Content with the engineering Page 17 of 25 SUMMARY 15 • Proposed culverts will: • Raise summer water levels as much as 6” • Not increase flooding • minor flow improvement at private crossing • But, municipal cross culvert governs during high flows • Access maintained for private crossing Page 18 of 25 Questions 16 Page 19 of 25 Uncertainties 17 Driveway culvert mostly missing during survey – could not verify the bottom elevation of upstream side. New culvert will be 6” above the lake level at time of survey Original 800mm culvert would have been lower due to larger size Page 20 of 25 Elevations 18 Lake Level
100.0m
800mm dwn invert
99.29m
Low point dwy
100.5m
Cross Culvert invert
99.48m
Cross Culvert size
1200mm – 1250mm
New Culverts invert
100.15m
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May 9, 2024 Township of North Frontenac 6648 Road 506 Plevna, ON K0H 2M0
Attn:
Darwin Sproule, P.Eng.
Public Works Manager
Re:
Township of North Frontenac
RFQ No. 2023-26 Buckshot Lake Road Culvert Replacement
Our File 230-5280 Dear Mr. Sproule, As requested by the Township of North Frontenac, Jewell completed a scoped hydraulic review of the failed 800mm CSP driveway culvert at 6253 Buckshot Lake Road that controls the outlet of Hills Lake. The scope of the review was to investigate replacement options for the failed culvert such that the normal water level of Hills Lake could be controlled higher and that the extreme high-water level would not be increased. The existing culvert has collapsed on the west side and at the time of our site visit a small 300mm culvert had been placed within the driveway in an attempt to provide some discharge capability from the lake. The downstream side of the 800mm culvert is still visible. All flows leaving Hills Lake exit through this driveway culvert and follow the north side of Buckshot Lake Road flowing easterly to the next cross-culvert, which was measured as a 1250mm CSP. This second culvert is much larger than the driveway culvert, but it is placed relatively high such that it would cause water to back up through the driveway culvert and to Hills Lake. The failed driveway culvert provides summer lake level control and the original plan to replace the culvert would have been to maintain the existing flow conditions. That is the summer level and extreme high Page 22 of 25
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levels would be unchanged. This was not favourable to the community.
Jewell completed a topographic survey in September of 2023 using total station survey
equipment. We were unable to acquire GPS signal and therefore the elevations we
collected were based on an assumed 100m elevation for the lake level at the time of the
visit.
The Concerns
Residents around the lake have expressed concerns that the water level is too high and
that the water level is too low.
These concerns are interpreted as some residents would like to see the normal summer
water levels to be maintained higher. Other residents are negatively affected by lake levels
when they are at their highest.
It is also understood that the outlet through the private driveway is blocked by beaver
requiring frequent maintenance by the municipal staff. Also the outlet may be frequently
adjusted using boards by residents wanting the water levels increased or decreased.
The replacement of the failed culvert provides some opportunity to seek to alleviate some
of the concerns.
Low Flows
During low flow conditions, the driveway culvert will maintain a minimum water level in
Hills Lake. The invert (bottom) of the upstream side of the driveway culvert maintains the
minimum lake level. If the bottom of the culvert is raised, the normal lake level would also
be raised.
High Flows
During high flow conditions, water would leave the lake through the culvert until the
culvert capacity was exceeded, then it would crest up and flow over the private driveway
(that acts like a dam). But, since the water downstream is held back in the ditch by the
configuration of the downstream cross culvert, the cross culvert takes over the control of
the lake during extremely high flow conditions.
This means that the size and elevation of the private driveway culvert is less of an influence
during high flow conditions.
Opportunities
Jewell reviewed opportunities to raise the normal lake level and still maintain the high lake
level such that during extreme high lake levels there would be no increase in water level.
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3
Given the downstream cross culvert controls the lake during high flows, there is no
configuration that can be changed to reduce the lake level except lower the private
driveway. Since the private driveway is frequently overtopped any lowering would
negatively affect the use of the driveway and this solution is not preferred.
Given that the driveway is so low, any raising of the driveway would also raise the
“damming” effect and cause more flooding. Any proposal that would include raising the
driveway is not an acceptable solution.
There must be a minimum of 0.3m of gravel over the culvert(s) in order to protect the
culverts from being crushed. So, raising the culverts is limited by the elevation of the top of
the driveway. Lowering the driveway as part of any solution would push the culverts lower
and consequently, the lake level lower.
The driveway then, cannot be raised or lowered as part of any solution.
Instead, various culvert configurations were reviewed and an optimal configuration was
found using three 600mm culverts. This allowed a modest increase of 0.15m in lake level
during normal conditions, but provided a slightly improved capacity during high flow
conditions.
Preferred solution – three 600mm culverts placed at 100.15m (0.15m higher than the
lake level at the time of our survey).
Permitting
The conservation authority and the Ministry of Natural Resources have permitting roles
regarding work around the waterway.
Mississippi Valley Conservation Authority requires a permit pursuant to their regulatory
role under the Conservation Authorities Act. Jewell met with representatives of MVCA to
discuss the project and their concerns were that no increase in flooding be created by the
culvert replacement. They were also concerned about the potential that the culverts and
driveway could be a dam under the Lakes and Rivers Improvement Act. This is
administered by MNRF.
Jewell met with MNRF representatives who reviewed the existing conditions as well as the
proposed solution and they agreed that the outlet (driveway and culverts) meet the
definition of a dam under the Act. However, they also explained that the Act has
exceptions for small dams or small contributing areas and the subject crossing is exempted
from requiring a permit. MNRF was satisfied that the proposal to replace the failed culvert
with three 600mm culverts set 0.15m higher than the existing would not trigger permission
from MNRF. This correspondence was relayed to municipal staff and MVCA.
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4
Thus, only the MVCA permit is required.
Summary
The driveway culvert is failed and must be replaced. The concerns noted by residents
regarding summer water levels too low and flooding during high flow conditions were
considered in the replacement design.
A preferred solution is to replace the failed culvert with three 600mm culverts set slightly
higher than the original culvert. This will maintain summer water levels approximately
0.15m (6 inches) higher and have no impact on flooding levels.
A permit will be required from MVCA and they have indicated willingness to issue a permit for
the preferred solution presented.
Sincerely,
Bryon Keene, P.Eng. Jewell Engineering Inc.
BUCKSHOT LAKE ROAD CULVERT HYDRAULIC REVIEW 2023 NOV 16 Page 25 of 25
