HomeMy WebLinkAboutENG 19-14 Cat/00 =`_ Report to
Revised
Executive Committee
PICKERING Report Number: ENG 19-14
Date: September 8, 2014
From: Richard Holborn
Director, Engineering & Public Works
Subject: Stormwater Drainage in the Hamlet of Claremont-
- Update on the Claremont Drainage Feature Cleanout
- File: A-1440
Recommendation:
1. That Report ENG 19-14 of the Director, Engineering & Public Works concerning
Stormwater Drainage in the Hamlet of Claremont be received;
2. That Council change the 2013 Capital Budget approval and corresponding funding
for the Claremont Drainage Feature Cleanout (Account 5410.1301) from $550,000
to $41,700 and that the Treasurer be authorized to fund the expenditure from a
transfer from the Rate Stabilization Reserve; and
3. That Staff be authorized to finalize the scope, and prepare Terms of Reference of a
Claremont Master Drainage Plan in order toinitiate a Request for Proposal for
consulting services for the study, with funds being proposed in the 2015 Current
Budget.
Executive Summary: After a number of complaints from affected residents, Council
approved the Claremont Drainage Feature Cleanout in the 2013 Capital Budget. Through
the detailed design process for the Claremont Drainage Feature Cleanout project it was
determined that the project was not feasible due to the shallow depth of the
TransCanada pipeline underneath the ditch. It is recommended that the Claremont
Drainage Feature Cleanout project be reduced to the expenditures for the consulting
services spent to date,and that funding be provided in the 2015 Current Budget for the
completion of a Master Drainage Plan for Claremont. The Master Drainage Plan will
analyze the existing drainage patterns and infrastructure in Claremont, identify
deficiencies and propose recommended projects to optimize and improve the drainage
system.
Financial Implications: This project was originally financed through the issuance of ten
year external debt. The project's scope and direction has changed significantly and
therefore the project is no longer proceeding as originally planned. Recommendation
Two reduces the 2013 budget approval to final project costs and provides an alternative
35.
•
Report ENG 19-14 September 8, 2014
Subject: Stormwater Drainage in the Hamlet of Claremont Page 2
financing source - Rate Stabilization Reserve. There are sufficient funds in this Reserve
to meet the revised project cost.
Discussion: Due to the age of development in the Hamlet of Claremont, the
drainage infrastructure in the community was not built to meet formal and current
engineering standards. The City periodically receives drainage complaints that are
primarily related to nuisance drainage issues caused by blocked driveway culverts, cross
road culverts, and roadside ditches requiring maintenance. These nuisance issues are
routinely resolved by City forces.
Staff are aware of two properties that have experienced repeated basement flooding •
from surcharging gravity foundation drains, and one property that has experienced
surface flooding from road drainage. These drainage issues are more serious in nature
and they have been mitigated through remedial works by the City and the affected -
homeowner.
It is worth noting that the.Region of Durham completed a study on the Central Street
drainage system in 1996 in response to drainage issues associated with the road
right-of-way (Stormwater Management Study for Road Improvements for Regional Road
No. 5 through the Town of Claremont, Paul Theil Associates, 1996). The
recommendations of that report were implemented when the Region reconstructed
Central Street in 1996.
The information in Tables 1 and 2 provides some context regarding the nature of the
drainage issues in Claremont. It can be seen from the information in the tables that the
drainage problems are mainly nuisance issues and occur primarily during the spring.
Table 1 - Summary of Flooding Complaints in Claremont since 2009
Type of Drainage Number of Complaints Action
Complaint over the last 5 Years
Basement Flooding 2 Resolved by private
contractors
Surface Flooding 1 City retained contractor to
raise the road curb
Wet yards due to the 4 No action at this time
Claremont Drainage Feature
Nuisance Drainage (Wet 7 Resolved by City forces or
yards, driveway culvert currently being reviewed.
replacements, re-ditching)
36 CORP0227-07/01 revised
Report ENG 19-14 September 8, 2014
Subject: Stormwater Drainage in the Hamlet of Claremont Page 3
Table 2 - Drainage Complaints by Season
Season Complaint was Received Number of Complaints
Spring • 9
Summer 2
Fall 2
Winter 1
An analysis of the rainfall data from 2009 to 2013 indicates that there have been some
significant rainfall events in Claremont during this period. A storm that occurred on July
25, 2009 is characteristic of the intense summer storms which frequently cause drainage
issues in urban areas. The storm was approximately equivalent to the City of Pickering's
2 hour, 50 year return period storm. Notwithstanding, the City's Customer Care Centre
did not receive any drainage complaints following this storm. The only customer care
complaint that was received following any of the large rainfall events that occurred from
2009 to 2013 was after the April 3, 2009 event, and was a request for an update on work
the City was completing on the Canso Drive ditch.
Claremont Drainage Feature
The 2013 Stormwater Capital Budget allocated funds for the Claremont Drainage
Feature Cleanout project. The Claremont Drainage Feature, hereinafter referred to as the
ditch, originates at a storm sewer outfall on Central Street west of Franklin Street and
flows south through private property, through Claremont Park, through more private
property and west under Old Brock Road south of Bovingdon Place (refer to Figure 1).
With respect to ownership, where the ditch is on private property the City has an 8 m
wide easement with the exception of the section through 4933 Brock Road.
CORP0227-07/01 revised 3 7
Report ENG 19-14 September 8, 2014
Subject: Stormwater Drainage in the Hamlet of Claremont Page 4
•
' ,giiiP 3.x~R 1 ,y. - •-5\ � •.~+¢li .I
'" 7e------ F:`• .it __ __ ! 1
1--•t_. ' ' \ LL �H I 11
s
\-
y - _.,-•�i PLC �•—''.�`•y_.` 1 v __"r"' S`.•- ,,.1
,,,. .:.. ...--- . ,2'.„:-.....\ --.._..-.:.':,.. Ink\l.......\-- ...... --$.,, v .„ ... -. ..
, ,
... ...- "5\ \:.:... '.. ... "\;, ..."\ - - 4 A ' ‘ .--• ' .. '',.' /
S • .1\9 4 ', l _ _. IrL,S,�_
•it `lE.�-6r`: •• /fie.;
• } t '
te•,
-,�" -. t tt_ `'Ll 1 Kam.•
-' 1! .1 + No Easement
}
;� t-2-- � ;i� Claremont Drainage
ti ,
t
Feature
Figure 1 — Claremont Drainage Feature
The drainage area of the ditch at the southern limit of the study area is 32 hectares (refer
to Figure 2). A significant portion of that drainage area.(9.3 hectares) is from the vacant
farm field north of Franklin Street, which is proposed for development by Geranium
Homes pending planning approvals from the provincial government, the Region of
Durham and the City of Pickering. The remainder of the drainage area is comprised of
roads and mainly low-density residential development.
•
•
38 CORP0227-07/01 revised
•
•
Report ENG 19-14' September 8, 2014 •
Subject: Stormwater Drainage in the Hamlet of Claremont • Page 5
\�\. /1 .
`\ -_...._.' . LANE STREET....
Y
4-H r 0 0I I O
, hii CD. C:i
J� O,' • a_
- j 0,02C+4-1.
Z:
i al
A 1 : . n J
t
iJ JOSEP• -C!4rf.M
DRAINAGE] - S . - G+RGr . •
'
-
` TFEE, z
AREA z I •
E .
-.,. vn' '• Q CL a' r-
CENTRAL ? '�-/ a " c Q F- ; S i R�_.ET .
in �n; L.
•
u'• W LLI`GT�N ST.
L SCi`J S
j i
PUB!. Q a !
Q STUDY AREA FORT 1 ° i!, / �'
� .s i �
�$.; i DITCH CLEANOUT < .' ,;U
'CLU_. ;7 Z, j �q.
X00'OV`/ p4`.__.___-.. I LAN E_.. 14-11 .a.-i:v // J 1 •
wEZ —AC - ------..- I /%/l S v
•
TRANS-CANADA � /
, i /
PIPELINE
'���
�.. y 3OVI,21D O
t ��
O: :I'LA"r i .........",
' LARE 1
:� /f, C ANT
Figure 2 - Claremont Drainage Feature Drainage Area
Flow to the ditch is controlled by a weir at a control.manhole on Central Street. The
control manhole was installed by the Region in 1996 to reduce the amount of flow being
conveyed to.the ditch in response to drainage concerns raised by residents. The
configuration of the system consists of the storm sewer from Central Street east of the
ditch (which includes drainage from Franklin Street), and the Barclay Street ditch which
flows into the control manhole. At the manhole, the outlet flow is split between the ditch
flowing south and the storm sewer continuing west along Central Street to its outfall near .
the Claremont Public School.
Staff retained Cole Engineering in 2013 to complete a design for the ditch cleanout and
secure the necessary approvals and permits from the Toronto and Region Conservation
Authority (TRCA) and the Ontario Ministry of Natural Resources (MNR). The scope of the
cleanout project was from Wellington Street to Bovingdon Place with the respective road
culverts representing fixed points that the cleanout project had to tie into.
• CORP0227-07/01 revised
39
Report ENG 19-14 September 8, 2014
Subject: Stormwater Drainage in the Hamlet of Claremont Page 6
The drainage ditch is being deemed as a watercourse by TRCA, which is subject to their
permit process under Ontario Regulation 166/06. Although redside dace are not found in
the ditch, the MNR deems it contributing habitat due to the presence of redside dace in
the subwatershed. As such, MNR's approval is required and any works must take place
during the timing window of July 1 to September 15.
Cole Engineering evaluated design slopes on the ditch of 0.5%, 1% and 2%. Regardless
of the design slope, the ditch would need to be excavated to provide the necessary
grades. It should be noted that the City's engineering standards specify that the minimum
acceptable slope on a ditch is 2%. To provide some context, the minimum acceptable
slope to allow for proper drainage on roads is 0.5%.
The City had the subsurface utilities mapped which determined that the TransCanada
pipeline is only 1.3 m below the ditch. Any work within the TransCanada right-of-way
requires their approval and the minimum allowable cover on the pipeline is 1.2 m. It
should be noted that this is TransCanada's main east-west pipeline and the costs
associated with relocating it would be significant. Staff have found that similar pipeline
relocation projects in surrounding municipalities cost in the order of millions of dollars.
Given the restriction of the shallow pipeline, the maximum possible slope which can be
achieved on the ditch is 0.5%. A ditch with a slope of 0.5% translates into 5 centimeters
of vertical fall for every 10 linear meters of ditch. It is difficult to construct a ditch with this
degree of precision. Furthermore, given the gentle slope of the ditch, vegetation growth
may prevent the ditch from functioning properly. As this ditch is regulated by both TRCA
and MNR, the City would need a permit to cut vegetation as this would constitute in-
water works.
While a 0.5% ditch will be an improvement over the existing condition, it is not certain
that the cost can be justified given the nature of the drainage complaints received to
date. There are 9 properties that would directly benefit from this cleanout and the
estimated cost to complete the project is approximately $385,000.00. Based on the
above, staff are recommending that the balance of the Claremont Drainage Feature
Clean Out project be cancelled and that alternative solutions be reviewed.
Given the constraints and the ineffectiveness of the resulting design of the ditch cleanout
project, staff are reviewing options and alternative methods of improving the drainage
system in Claremont. A cost-sharing arrangement for the proposed options will be
explored with the Region of Durham since Central Street is a Regional Road, and its
associated drainage infrastructure are an important component of any solution. The
options are presented below.
Option 1 - Complete a Master Drainage Plan Class Environmental Assessment for
Claremont
The purpose of completing a Master Drainage Plan is to comprehensively analyze the
existing drainage system throughout Claremont, identify deficiencies and recommend
40: CORP0227-07/01 revised
Report ENG 19-14 September 8, 2014
Subject: Stormwater Drainage in the Hamlet of Claremont Page 7
projects to improve the drainage system. This Master Drainage Plan would be very
similar to the Whitevale Master Drainage Plan that was completed in 2013.
Furthermore, given that Claremont was built prior to modern drainage standards, the
Master Drainage Plan will also determine the level of service that can be provided.
Setting the level of service is a policy decision made by the municipality that sets the
minimum standard for the drainage system. The purpose of setting the level of service for
the drainage system is to provide some protection for the City from claims should an
9 Y p p
event occur that is larger than the level of service set.
Some of the background work for the Master Drainage Plan has already been completed
through the Claremont Flood Mitigation Study completed by AECOM in 2012. Staff have
reviewed the AECOM study and have determined that the scope was too narrow, the
model overestimates flows, and the methodology used to evaluate alternatives is
oversimplified. However, the AECOM work is a good starting point and can be built upon.
This study could proceed in 2015 subject to budget approval.
Option 2 - Modify the Weir in the Control Structure on Central Street
This would be a scoped version of the Claremont Master Drainage Plan that would focus
on the feasibility of modifying the weir in the control manhole on Central Street to send
increased flow west to the outlet on Canso Street and less flow south to the ditch. It is
recommended that the analysis completed by AECOM be calibrated and that a field
survey determine whether there are any foundation drain connections along Central
Street. The hydraulic impacts of modifications to the weir in the control manhole on
Central Street can then be analyzed and a modified weir can be designed and
constructed. This project could proceed in 2015 subject to budget approval.
•
Recommendation
Staff recommend that the funds allocated for the Claremont Drainage Feature Cleanout
in the 2013 Capital Budget be reduced to the expenditures that have been spent on
consulting services to date, and that new funds be proposed in the 2015 Current Budget
to undertake the Claremont Master Drainage Plan. The Master Drainage Plan will
analyze the existing drainage system in Claremont, identify deficiencies and propose
recommended projects to optimize and improve the drainage system. By completing a
full analysis of the drainage system, the City can ensure that projects are prioritized to
maximize the benefit to the community as a whole.
Attachments:
1. Not Applicable
CORP0227-07/01 revised
41
Report ENG 19-14 September 8, 2014
Subject: Stormwater Drainage in the Hamlet of Claremont Page 8
Prepared By: Approved/Endorsed By:
lOr
Tom Dole, P.Eng. Ric and Holb!in, P. Eng.
Sr. Water Resources Engineer Dir-ctor, Engineering & Public Works
Prepared By: Approved/Endorsed By:
Marilee Gadzovski, M. Sc. (Eng.), P.Eng. r Stan Karwowski,-CPA, CMA
Division Head, Water Resources & f`'Division Head, Finance & Treasurer
Development Services
TD:Ir
Recommended for the consideration
of Pickerin ity Council
67])4 ? /1i
Tony Prevedel, P.Eng. j
Chief Administrative Officer
•
•
42 coRP0227-07/01 revised