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Report
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Report To: Planning and Development Committee
Date of Meeting: June 5, 2017
Report Number: PSD-041-17 Resolution:
File Number: PLN 26.14.1 By-law Number:
Report Subject: Clarington Transformer Station Peer Review, Update
Recommendations:
1. That Report PSD-041-17 be received; and
2. That all interested parties listed in Report PSD-041-17 and any delegations be advised of
Council’s decision.
Municipality of Clarington
Report PSD-041-17 Page 2
Report Overview
Council accepted funding from Hydro One to retain a hydrogeologist to peer review the
Surface and Groundwater monitoring program imposed as part of the approval of the
Environmental Assessment by the Minister of Environment and Climate Change. The
Municipality’s hydrogeologist is providing his update on the peer review.
1. Background
1.1 Clarington Council and staff have been involved with the Clarington Hydro
Transformer since March of 2012. The Minister of Environment approved the
project in January of 2014 despite the objections/comments of Clarington Council
and residents.
1.2 In June 2014, to address ongoing concerns from community members and
residents, Hydro One proposed to Clarington to fund a peer review of their Surface
and Groundwater monitoring program. The peer review consultant, Mr. Steven
Usher of SLR Consulting (Canada) Ltd. was retained and has been work ing with
the residents, staff, Hydro One consultants and G360 group of scientists since late
October, 2014.
1.3 In September 2014, Council approved a road use agreement contingent on the
drilling of a deep monitoring well. The hydrogeologists agreed that the MW 5-14
site on Hydro One property was the most relevant location for this borehole and
monitoring well. The MW5-14 site already has monitors at 4 metres, 7 metres and
40 metres; the deep borehole monitor at 112 metres and another monitor at 52
metres are the result of drilling the deep borehole. This provides multi-level
monitoring (or a nested cluster of boreholes and monitors). This site will be the
location of the rotosonic multi-level drilling and monitoring well.
1.4 In April 2015, Council approved funding as a contribution to the rotosonic drilling of
up to $25,000, by resolution #C-136-15.
1.5 In February 2016, Council approved funding for tritium testing of up to $10,000 by
resolution #C-030-16. To date an interim payment of $5,000 was provided to G360
for sampling and tritium analysis on private wells and the interim report received in
July 2016.
1.6 In November, 2016 CLOCA entered into agreements with Hydro One which allows
access to the site and deep well for ongoing monitoring under the conditions set
out in the agreement. CLOCA has a Memorandum of Understanding with G360
for the rotosonic drilling and any scientific work by G360. CLOCA is host to the
Oak Ridges Moraine Groundwater Program (Dr. Rick Gerber), they are the legal
entity for the agreements. The Municipality is not party to the agreements.
1.7 In May 2017, Council approved the reallocation of funding for tritium testing to the
4 well cluster at MW5-14, provided Hydro One is willing to allow access via the
CLOCA agreement.
Municipality of Clarington
Report PSD-041-17 Page 3
2. Summary of the Peer Review Findings
2.1 The SLR report reviews the present state of the existing information and purposely
does not address the process by which it was achieved. Their review includes
information from all parties, being Hydro One, Stantec, G360 scientists, Enniskillen
Environmental Association, the Conservation Authority, Clarington, the Ministry of
Environment and Climate Change and the Oak Ridges Moraine Groundwater
Program. SLR staff conducted four site visits, attended six public meetings,
fielded two specific homeowner complaints, and reviewed both the 2015 and 2016
Annual Reports on Clarington’s behalf. The results are outlined below, their more
detailed report is Attachment 1.
2.2. Drilling of the deep borehole confirmed the absence of a shallow sand lens at
location MW5-14 which to the east hosts local wells. It also showed that the dense
aquitard soils extended down some 76 m to the Thorncliffe Aquifer where several
local wells draw their water. An intermediate layer of sand was found in the
aquitard at 52 m, and is consistent with the depths of a second grouping of local
wells. A groundwater monitoring well was placed in this layer. The borehole was
extended into bedrock, found (as predicted by Dr. Gerber) at about 129.5 m depth.
2.3. The Permit to Take Water process put in place a rigorous daily water monitoring
program for water handling procedures, with weekly reporting mechanisms. SLR
reviewed these results as they became available. Water quantities were much
lower than anticipated, and very little ground water contribut ion was seen. SLR
conducted several site visits and reported that water handling procedures were
operating as anticipated with no obvious signs of vegetative distress or
uncontrolled discharge.
2.4. The deep Thorncliffe aquifer, and the thin embedded sand layer in the Newmarket
host many local wells. These aquifers appear to get their water from a greater
distance to the north, probably the Oak Ridges Moraine. The deep wells are
protected by the thick low permeable Newmarket Till, as anticipated by Hydro One ,
and are not at risk from the Transformer Station. This interpretation does not
appear to have been accepted by Dr. Cherry and the residents.
2.5. The more shallow Mackinaw wells derive their water locally, and not from the
moraine. This is based on their depth, and the now documented tritium levels in
the two sampled wells from this layer. Based on the water well records, wells
tapping this layer are present along Winchester Road, and along Langmaid road,
but none exist south of the TS site. Further to this, cored boreholes drilled by
Stantec show this layer is not present west and south of the site. The presence of
a strong groundwater divide exists between the site and the closest Mackinaw
wells in the Farewell tributary near Langmaid Road. SLR concludes those wells
are not at risk, and has suggested further monitoring will confirm this.
2.6. The ground and surface water monitoring program is comprehensive and typical of
other programs in similar settings. The addition of regular surface water flow rates
would be of benefit in settling discussion on water depletion, but is not mandated
by the MOECC.
Municipality of Clarington
Report PSD-041-17 Page 4
2.7. The latter half of 2016 was very dry with very little groundwater recharge. Many
wells in the study area experienced water shortages and two homeowners asked
SLR to review the Stantec well reports. These reports essentially reported results,
and concluded that the dry year was the reason for the problems. They
unfortunately did not provide evidence as to why the Clarington Transformer site
was not the problem. SLR conducted their own analysis of the data, including an
assessment of water levels in the direction of the site and found that soil moisture
loss was sufficient to cause the problem. The more heavily affected wells were
found to have the smallest recharge areas. Similar to Stantec, but having
examined the issue in more detail, SLR concluded the site was not to blame for
the well problems.
2.8. The G360 research group conducted some tritium sampling and analysis on local
wells, using funds provided by Clarington for this purpose. They have found the
presence of tritium (an indicator of age and not a contaminant) in the s hallow wells
as anticipated, and also in some of the deeper wells. SLR previously showed this
could come from the moraine to the north by de ep pathways. It could also come
from the surface via insecure well casings. Some surficial contaminants like salt
and bacteria are also present at depth. Dr. Cherry maintains that it could also be
from a leaky aquitard, and has recommended further triti um testing in the aquitard,
particularly on the site, as there are no private wells in the aquitard. SLR is of the
opinion that the first two mechanisms (or a combination) are the most likely, and
cites the high difference in water pressures across the aquitard as a demonstration
that vertical leakage through fractures is not very likely. In summary, SLR
maintains that the wells are not at risk from the Transformer Site. SLR supports
further tritium/helium testing to help understand this.
3. Concurrence
Not applicable.
4. Conclusion
4.1 The purpose of retaining a peer review consultant was to assist with understanding
the technical information and to have an independent advisor monitor the practices
and methodologies being employed during the construction of the Clarington
Transformer Station. To date, the observations, recommendations and
conclusions by Mr. Usher of SLR Consulting (Canada) Ltd have required additional
work by Hydro One and their consultants to demonstrate that the conclusions of
the Environmental Assessment and Permit to Take Water are reasonable and
conservative.
4.2 Council and residents were concerned for the safety of private residential wells in
the vicinity of the transformer construction and Farewell Creek. The transformer
construction is not effecting or putting residential wells at risk.
4.3 Much has been learned about the hydrogeology of the site over the past few years
providing additional scientific knowledge for the G360 researchers, and the Oak
Ridges Moraine Groundwater Program.
Municipality of Clarington
Report PSD-041-17 Page 5
5. Strategic Plan Application
Not applicable.
Submitted by: Reviewed by:
David J. Crome, MCIP, RPP Curry Clifford, MPA, CMO
Director of Planning Services Interim CAO
Staff Contact: Faye Langmaid, Manager of Special Projects, 905-623-3379 ext. 2407 or
flangmaid@clarington.net
Attachments:
Attachment 1 – Clarington Transformer Station Peer Review (to be circulated under
separate cover)
The following is a list of the interested parties to be notified of Council’s decision:
Brad Bowness, Hydro One
Clint Cole, Enniskillen Environmental Association
Drs. John Cherry and Beth Parker, G360, University of Guelph
Dr. Rick Gerber, Oak Ridge Moraine Groundwater Program
Chris Darling, CLOCA
Steven Usher, SLR Consulting (Canada) Ltd
DJC/FL/tg
I:\^Department\LDO NEW FILING SYSTEM\PLN Planning Files\PLN 26 Ontario Hydro\PLN 26.14.1 Hydro One Sub-Station, Enfield\peer review\Staff Reports\PSD-041-
17.docx