HomeMy WebLinkAboutWD-23-86TOWN OF NEWCASTLE
hEETING: THE GENERAL PURPOSE AND ADMINISTRATION COMMITTEE
DATE: FEBRUARY 3, 1986
REPORT #: WD -23 -86 FILE #:
SUBJECT:
File #
Res. #
By -Law #
COURTICE NORTH STORM SEWER OUTFALL AND STORMWATER MANAGEMENT
REQUIREMENTS LOT 31, CONCESSION 3, FORMER TOWNSHIP OF DARLINGTON.
RECOMMENDATIONS:
It is respectfully recommended:
1. That this report be received; and,
2. That in response to their letter of January 10, 1986, outlining
requirements for approval of the storm sewer outfall for the Courtice
North Subdivision, the Central Lake Ontario Conservation Authority be
advised that the Town of Newcastle will ensure that prior to further
development of any of the remaining lands draining to ponds 5 and 6 of
the preferred Storm Water Management Plan for Courtice, either:
a) the lands to be developed will have sufficient on -site storm water
detention facilities to ensure that post - development flows do not
exceed pre - development flows;
b) the required pond, i.e., either pond 5 or pond 6 will be
constructed.
....2
vi. G 4)
Page 2
Report No. WD -23 -86
3. That with this assurance, the Central Lake Ontario Authority be
requested to expedite issuance of the required permits to allow
construction of the Courtice North Storm Sewer Outfall.
1;
Attached is a copy of a report summarizing both the Courtice Storm Water
Management Study, its issues and the Town's documented position on the
matter. It is suggested that Members of Council familiarize themselves with
this report since storm water management in Courtice is a significant issue.
The particular matter being considered at this time is the conformity of the
Courtice North Subdivision (Claret Investments) to this plan. Much
background work and, in fact, land acquisition for the subdivision has taken
place and, since the development is about to enter the construction phase,
final arrangements for a storm outfall must be made. A design has been
prepared which predicts storm water flows slightly in excess of that
prescribed by the criteria in the Courtice Storm Water Management Study,
however, C.L.O.C.A. is prepared to issue the necessary approvals conditional
on the Town giving certain assurances. In short, C.L.O.C.A. wishes to
ensure that any further development will have provisions for storm water
management which adhere to the philosophies set out in the Courtice Storm
Water Management Study.
Based upon a review of the potential development lands in the area, it is
felt that such assurances can be given with some confidence. Already, a
development proposed for lands owned by Pollard includes construction of
ponds on -site which will address their storm water detention needs.
Discussions relating to engineering for development of other lands in the
area are in progress, with storm water management being one of the main
issues.
....3
Page 3
Report No. WD -23 -86
ched is a portion of the preferred plan for storm water management in
Atta question and, in particular, the ponds
Courtice which indicates the area in q
in uestion, i.e., P.5 & P.6. The Courtice North Subdivision is shown
q For the information of Council,
outlined in heavy dashed lines on this map*
oposes commencement of construction of services for these
th e developer pr letion and issuance of building
lands within the next few weeks for comp
permits by the end of May.
RGD:jco
January 28, 1986•
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CENTRAL LAKE ONTARIO CONSERVATI
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TOWN OF NEV?CASM-E
PUBLIC WORKS DEPT.
100 WHITING AVENUE, OSHAWA, ONTARIO L1 H 3T3 (416) 579 -0411
REF NO.
January 10, 1986.
Mr. L. Sanchez, P.Eng.,
�. Totten Sims Hubicki Associates Limited,
lA King Street East,
P.O. Box 398,
Cobourg, Ontario,
K9A 4L1
Dear Mr. Sanchez:
Subject: Courtice North Storm Sewer Outfall and Stormwater Management
Requirements, Claret Investments, Lot 31, Concession 3,
Town of Newcastle - File: 18T -76048
Authority staff have reviewed the submission regarding the stormwater
management proposal and storm sewer outfall for the above noted devel-
opment.
The main elements of the submission, as I understand it, are essentially
as follows:
1. Minor storm drainage from the site up to the 1:5 year storm will out-
flow through the proposed outfall into a tributary of Black Creek,
while major storm runoff will flow overland to the west and into
Farewell Creek.
2. Development of the Claret subdivision will not increase pre- develop-
ment flows for the 1:100 year storm at Farewell Creek since the hydro -
graph from the Claret site will peak and dissipate well before the
upstream hydrograph peaks. Therefore, no detention facilities are
required at the present time to control major storm flows resulting
from development of the Claret Investments site.
3. Post development flows for the 1:5 year storm resulting from the
Claret site will increase by only 8 c.f.s. over pre- development
flows. Based upon our conversation, this increase is considered
to be minor and allowing it to occur will not seriously compromise
the intent of the Courtice Stormwater Management Study.
CENTRAL LAKE ONTARIO CONSERVATION AUTHORITY
Mr. L. Sanchez - 2 - January 10, 1986
4. While stormwater detention facilities are not required at the present
time to control increased runoff from the Claret subdivision, as dev-
elopment proceeds on other sites in the area, it will be necessary to
construct both ponds 5 and 6 shown on Alternative 1 of the Courtice
Stormwater Management Study in order to meet the intent of the study.
On this basis, Authority staff are willing to allow the Claret Investments
subdivision to proceed with the conventional storm drainage facilities that
have been proposed. However, before issuing permitsfor the proposal, we
ask that the Town of Newcastle submit written assurance that ponds 5 and 6
will be constructed at the appropriate stage when development of other pro-
perties in the area significantly increases post development flows as may be
determined by the Authority in consultation with the Town. We understand
that Town staff are willing to provide such assurances.
Thank you for your co- operation with regard to this matter. Should you wish
to discuss this matter further, please contact the undersigned.
Yours very truly,
Christopher L. Conti,
Conservation Services Manager.
CLC /klt
cc Mr. R. Dupuis, Director of Public Works, Town of Newcastle,/
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CORPORATION OF THE TOWN OF NEWCASTLE
PUBLIC WORKS DEPARTMENT
HAMPTON, ONTARIO
LOB iJO
R. DUPUIS, P. ENO., DIRECTOR
TEL. (416) 263.2231
987 -5039
REPORT TO THE GENERAL PURPOSE AND ADMINISTRATION COMMITTEE
MEETING OF MAY 22, 1984.
REPORT NO.: WD -51 -84
SUBJECT: STORM WATER MANAGEMENT IN
THE COURTICE URBAN AREA.
RECOMMENDATION:
It is respectfully recommended:
1. That this report be received; and,
2. That the Central Lake Ontario Conservation Authority
( CLOCA) be advised that after considerable review, the
Town of Newcastle does not propose to adopt the
specific requirements set out in the "Courtice Storm
Water Management Study" in reviewing drainage for
development proposals in the Courtice Area; and,
3. That CLOCA be advised that in depth consideration has
been given to a follow -up implementation strategy for
the recommendations of the "Courtice Storm Water
Management Study" and it has been determined that such
a proposal would be virtually impossible; and,
...2
Page 2
REPORT NO. WD -51 -84
4. That CLOCA be advised that in the alternative, the
Town will require development proposals in the
Courtice Urban Area to conform to the general
objectives relating to water quantity as expressed in
the Courtice Storm Water Management Study, Pages 40
through 43, inclusive; and,
5. That CLOCA be advised that the Town will consider
provisions for storm water quality in development
proposals in the Courtice Urban Area only where such
proposals are practiced and can be easily maintained;
and,
6. That CLOCA be provided with a copy of this report.
I
BACKGROUND REPORT:
In the mid 1970's, after definition of the Courtice Urban
Area, various development proposals were put forward for
consideration by the Town and other involved agencies. As
these proposals were randomly located in Courtice, and the
area was considered rather sensitive from an environmental
point of view, studies of an environmental nature were
initiated. One such study was the Courtice Storm Water
Management Study.
...3
Page 3
REPORT NO. WD -51 -84
V/ .6 (0
The Courtice Storm Water Management Study was prepared for
the Town under the guidance of a technical advisory
committee. However, it must be pointed out that this was
one of the first storm water management studies prepared in
the Province at a time when the state of the art was in its
infancy. Thus, the terms of reference for the study and the
understanding of the technical advisory committee may have
been somewhat idealistic, and not practical, from an
implementation point of view. In fact, in recent
discussions with the consultant who prepared the report, a
caution was expressed that it should be considered as a
guideline rather than gospel for storm water management in
Courtice.
Notwithstanding the above, the report and its
recommendations were adopted by CLOCA and have been used
rather stringently in'reviewing development proposals. The
Town, on the other hand, has never adopted the report but
has alluded to it'in area planning documents. On the Town's
part, the report has been recognized as a guideline.
Recently, development proposals in the area have again been
activated, and in some cases detailed engineering is being
prepared. Conflicting approaches between CLOCA and the Town
have been taken with respect to storm water management, and
several meetings of staff have been held in an attempt to
resolve them. Because of this, staff have at least agreed
that a common approach must be developed.
...4
Page 4
REPORT NO. WD -51 -84
Technical Difficulties with the Plan
There are many difficulties with respect to interpretation
of the recommended storm water management scheme and how it
is to be implemented. Firstly, the recommended scheme,
which utilizes very large trunk storm sewers and ponds, has
a very high cost. Conservative estimates, in 1980 dollars,
approximate $6.6 million. The Town is certainly in no
position to up -front such costs nor are individual
developers in a position to add their portion of such costs
to the servicing charges associated with development.
Other technical problems relate to the trunk storm sewers.
These sewers are designed for storms with twenty -five year
return frequency and accommodate, in some cases, more than
one watershed. Thus, they are very deep, large and costly.
As was experienced by the Town in the installation of a
portion of trunk storm sewer west of Prestonvale Road last
year, costs are high, wells can be dewatered and the
capacity of the sewer itself is never likely to be achieved.
Technology today has found that catchbasin lids will not
pass enough water to even approach the twenty -five year
capacity of the storm sewer.
Ponds present a problem. In many cases they are proposed
for location on lands not owned by a developer who wishes to
proceed. Accordingly, acquisition and construction are a
problem. Also, in many cases the proposed ponds are
virtually inaccessible for maintenance. Related to
maintenance, it is questionable whether the Town is in a
financial position to provide the type of maintenance which
would be required.
...5
V_/� 6 �0
Page 5
REPORT NO. WD -51 -84
These are only a few of the technical problems associated
with the recommended plan for management of storm water in
the Courtice area. The attached memo from the Director of
Planning reiterates some of the concerns already expressed
and presents other problems which would have to be
addressed. A fairly comprehensive review of the matter has
been undertaken and many more detailed concerns could be
outlined, however, for brevity, only the major problems have
been discussed.
Objectives of the Study
The general objectives of the study as outlined on Pages 40
through 43, inclusive, which are representative of storm
water management philosophy in general can, for the most
part, be accommodated.without too much hardship on either
the part of the Town or developers. Adhering to these
objectives where possible will ensure that increased runoff
to receiving streams is minimized during storms after
development has occurred and thus problems with erosion will
not be magnified. Accordingly, the Town should support such
objectives in reviewing development plans.
Water Quality
The study makes recommendations to ensure that water quality
in receiving streams such as the Farewell Creek is either
maintained or improved. Ponds designed to hold back water
from storms with up to a one - hundred year return frequency
are proposed, with the intention that they retain sediment
and allow for aeration of storm water before it is
discharged into the creeks. In fact, the state of the art
in.water quality considerations is presently inconclusive
and it is questionable whether the ponds will contribute to
improved water quality.
Page 6
REPORT NO. WD -51 -84
Also, as pointed out by the Director of Planning, these
ponds wil hold back runoff, allow it to increase in
temperature and thus create an adverse effect on the
receiving waters which are considered by CLOCA to be
important cold water fisheries. Bearing all of these facts
in mind, it is recommended that a requirement for
comprehensive water quality provisions not be imposed upon
development proposals.
Implementation Plan
As indicated previously there have been discussions between
CLOCA and Town staff to attempt to reach common ground and
compromises to attempt to accommodate the findings of the
Courtice Storm Water Management Study. From such
discussions it became apparent that if the intent of the
study is to be covered out to the letter, there' is a missing
ingredient, in the form of an implementation plan. Such a
plan would have to consider detailed engineering plans for
each and every subdivision proposal, correlate them with
each other, and formulate an implementation strategy for
construction and financial contribution. Because
development does not occur in an orderly fashion from
downstream up, this would be impossible, imposing delays
and /or financial hardships on individual development.
Therefore, although an implementation strategy would ensure
adherence to the specifics of the study, it would probably
all but eliminate development in Courtice.
...7
Page 7
REPORT NO. WD -51 -84
rnnrl itcinn
In short, although the intent of the Courtice Storm Water
Management Study is valid, its specific requirements are
very onerous, making development in the Courtice Area,
virtually impossible. Recognizing this, and the
desirability of ..some form of environmental protection in
Courtice, the recommendations of this report are proposed.
It is felt that they will very adequately address the
matters of water quantity and erosion, and recognize the
need to ensure reasonable water quality, but allow
development to proceed.
Resp tfully sub tted,
R.G. Dupuis P. En
P � 9 '. ,
Director of Public Works.
RGD:jco
May 8, 1984.
Attachment
TOWN OF NEWCASTLE u' APR 5 'OR4
fyFMRANDIJM TOWN OF NEWCASTLE
PUB: 'C 'NORKS D� PI
TO: R. Dupuis, Director of Public Works
FROM: T. T. Edwards, Director of Planning
DATE: April 13, 1984
SLUECT: Courtice Storm Water Management Study
File: PLN 16.1
Further to our meeting of April 9, 1984, I offer the
following comments in respect of the referenced study.
In July of 1981 staff report P- 118 -81 was submitted to the
then Public Works Committee. I attach a copy for your
information. Unfortunately I have no record, on file, of
how this report was dealt with.
My reading of the report indicates that Planning staff
supported either Alternative 1 or 2 since they would permit
_.review of individual submissions and investigation of
specific storm water management alternatives. This was
premised on the desire to permit development to proceed
without being constrained by plarl; up- stream or down - stream.
I concur with these earlier comments, however, I believe
that greater flexibility would be provided if we did not
limit ourselves to one particular alternative.
The study provides a number of recommendations (page 35 -38)
which speak to intent and the underlying principles to be
adhered to. I have the following comments in respect of
these recommendations.
i) Groundwater - The Gartner Lee study identified the
ground water regime of Courtice as the single most
predominant environmentally sensitive feature. The
Storm Water Management study suggests that
dewatering, associated with development, be localized
or temporary. Available information indicates a
perched watertable. Given this, it appears unlikely
that dewatering can be localized unless construction
is prevented from breaching the impervious clay
levels. While this may be feasible in residential
construction, the depth required for municipal
...2
R. nupuis, director of Public Works
Page 2
services would certainly result in widespread
dewatering unless extreme measures are taken by the
developers. Such measures could however be costly
and discourage development.
Existing Watercourses - Directly related to and to an
extent dependant upon the groundwater are the Black &
Farwell Creek systems. Existing official plan
policies and proposed zone regulations will protect
these features.
iii) Water Quality - This is of concern only insofar as
sedimentation and Coldwater fish habitat are
concerned. Retention of tree cover in valley areas
will assist in maintaining the water temperatures and
minimize erosion. However, the study seems to place
a greater emphasis on reducing sedimentation. While
detention /retention ponds are effective they tend to
raise water temperatures. On the other hand catch
basins are not entirely effective in removing all
sediments. The methods of controlling contaminants
would require a great deal of effort by the Town and
the results may not entirely justify the costs.
iv) Erosion Hazard Zones: The underlying premise is zero
change in runoff and rates. This point therefore
speaks to existing problems and is not relevant to
future development.
V) Pond Construction and Operation Requirements - No
objections are offered to the principle of
detention /retention ponds, however, I share your
concerns about maintenance and add my own with
respect to public liability and safety. If privately
owned and managed I have no objections.
In summary, I believe that no one implementation alternative
should be adopted. I would however, support adoption of the
objectives recited on Page 40. All other guidelines, save
and except those related to construction periods, should
remain as guidelines for consideration in each instance
without formal sanction.
I hope these nts are of interest.
---,9
T. T. Edwards, M.C.I.P.
Director of Planning
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