Chapter A - Introduction - City of Pickering

Comments in white are satisfied.
Comments in orange background are not satisfied or are new comments.
Comments in blue background can be addressed at the NFSSR stage.
Comments in yellow are deferred due to need for hydrology model.
APPENDIX A. TRCA COMMENTS ON SEATON MESPA DECEMBER 2011; MESPA TEAM RESPONSE FEBRUARY 2013
# Section #
Page # in
PDF TRCA Comment Action Required
65. 7.6.3.1 180 Tables B7.9 and B7.10 contradict each other with We believe water balance is required for these
respect to which wetlands require water balance, wetlands. Confirm.
e.g. U2, U8, G12, G13.
66. 7.6.3.1 183 Table B7.9 states that there is no specific water
balance for UA4/5 because there is mitigation to
upstream and downstream wetlands. However, it
may not work this way and therefore further
analysis is required. With respect to UB3-1, how
can the catchment change if there is no proposed
development?
67. 7.6.3.2 184 Based on a review of the GIS database, some of
the Category B wetlands have been incorrectly
categorized given development is proposed within
the catchments. These include the wetland at D8-
3, the wetland NE of SWMF #70, and the wetland
east of WV1.
68. 7.6.3.3 185 Table B7.10 states in several places that
increased flow volumes will not be detrimental to
the wetland functioning; however, an assessment
of how this increased flow may impact on flooding
and adjacent development is required. Similarly,
increased volumes may also have implications on
adjacent upland communities (e.g. W7-3, WV3:
increased volumes may impact FOD7-2).
69. 7.6.3.3 185 Table B7.10 states that there are a number of
wetlands where no water balance is required
because the features are mainly groundwater-fed.
However, the water balance assessment
examined surface water contributions only. There
needs to be a marriage between groundwater and
surface water modeling to ensure that any
recharge areas feeding these wetlands will be
maintained. Changes in surface water
contributions to these features may also affect
water levels and should be considered.
70. 7.6.3.3 191 It is stated in Table B7.10 with respect to U5 that
a water balance is not required because this
woodland and wetland will be largely impacted by
a Brock Road realignment. However, due to the
proposed revisions to the Hwy 407 interchanges,
this wetland and woodland will no longer be
impacted.
71. 7.7.2 195 6 years of data is not appropriate for the feature
based water balance assessment. Given the
availability of data for the area, the assessment
should include a larger data set and include more
recent years of record.
Provide further analysis or clarification.
Reassess these wetlands as category D.
Provide additional hydrologic analysis on flooding
extents in areas where increased flow volumes are
proposed, and provide an assessment of
implications to the developable area and adjacent
vegetation communities.
Provide both groundwater and surface water
modeling analysis. Bring groundwater information
together with monitoring data into one table,
including geotechnical water level information.
Provide a groundwater depth map. Look at the
PRMS assessment locally, not globally, in areas
where the wetlands are groundwater fed.
Provide water balance for this wetland and
woodland.
Update assessment to include more relevant and
larger data set.
Consulting Team’s Response
April 27, 2011
In Table B7.9, the wetlands are identified by the
reach on which they occur. In Table B7.10,
other wetlands have been given a specific
identification number. Therefore in Table B7.9,
there are wetlands on Reach U2, Reach U8,
Reach G12 and Reach G13. In Table B7.10, the
references are to Wetland U2, Wetland U8,
Wetland G12, and Wetland G13. There is no
contradiction.
The drainage area for the downstream wetland
U9 includes the entire drainage area for the
wetland on reachesUA4 and UA5. The water
balance for U9 therefore encompasses the
reaches on UA4 and UA5.
With respect to the wetland on Reach UB3-1,
there is proposed development in the catchment
area (there is an error on Table B-7.9).
The wetland on Reach D8-3 and the wetland NE
of SWMF 70 on Reach DD4 do have
developable area in their catchments and will be
assessed as a Category D wetland.
We believe you mean wetlands to the west and
not east of WV1. These wetlands also have a
small area of developable land within the
catchment and will be assessed as a Category D
wetland.
Under review. To be discussed at upcoming
technical meetings.
The water balance for wetlands was surface
water based (Qualhymo) where those wetlands
are primarily sustained by surface water flows.
For wetlands primarily sustained by groundwater
flows, the impact analysis was addressed by the
PRMS and Modflow. Further efforts to refine the
presentation of the model results will be made
and further discussion of the wetlands water
sources will be provided. A depth to water table
map will also be provided as noted in Comment
7. With respect to the PRMS assessment, refer
to response to Comment 14.
Wetland and woodland water balance
assessments will be completed.
Revisions to datasets as discussed with TRCA
will be used, and will include representative dry
and wet years in consultation with the TRCA.
Action Taken
MESPA December 2011
Additional clarifying text is added to the MESPA,
explaining the naming of wetlands. (Section
B8.3.3)
The text in Table B8.8 (formerly Table B7.9) is
clarified and corrected.
These wetlands are reclassified having
development in their surface catchment and are
reassessed as required in Section B8.3.3.3 and
Table B8.9 of the MESPA.
Where peak flow controls are recommended,
increased runoff volumes will not impact the extent
of flooded areas.
MESPA is revised and updated with regard to
groundwater and wetlands and stream base flow, in
Section B4.7.
The MESPA is revised; see Section B8.3.3.3 and
Table B8.9.
Information provided in the MESPA is updated and
explained. The same six years of data was used
for the erosion assessment as well as the water
balance assessments. See Section B5.9.3.
Noted.
TRCA Comment on MESPA
The issue raised was pertaining to where
stormwater will be outlet to the various wetlands
undergoing water balance analysis and how this
may change from one to the next. However, the
resilience of the wetlands may not warrant
further analysis.
Noted.
Similarly on page 173, it is identified that wetland
U7 will not have a water balance, but it was felt
that the additional water would expand and
enhance the wetland. Also note that it will be
impacted by Brock Road realignment. We are
unsure whether there will be impacts to the
future Brock Road works by adding water to this
wetland? To be addressed at the NFSSR stage.
This section indicates that there will still be a 7%
change in groundwater contribution to wetlands
and streams. Figure B4.20 indicates that
drawdown will be as much as 4-5 m in some
areas. These areas correspond to sensitive
streams and wetlands. More work will need to
be done at the NFSSR stage to further mitigate
these impacts with LID measures. To be
addressed at the NFSSR stage.
Comment addressed.
See Comment #32 related to the erosion
assessment.
Team Response
February 2013
No response required.
To be addressed in the NFSSR for
Neighbourhood 20.
This has been addressed in the revised
MESPA in Section B4.7.4.
See the response to comment 32.
PAGE 15 February 2013