HomeMy WebLinkAboutDTS-08-032 - Alder Strasburg Creek Watershed Study & Upper Strasburg Creek Watershed Plan UpdateREPORT
Report To: DTS Committee, Chair - Christina Weylie
Date of Meeting: March 3, 2008
Submitted By: K. Grant Murphy, P.Eng., Director of Engineering
Prepared By: Binu J. Korah, P.Eng., Manager of Development Engineering
Ward(s~ Involved: 4 -South Ward
Date of Report: February 07, 2008
Report No.: DTS 08-032
Subject: Alder Strasburg Creek Watershed Study and Upper Strasburg
Creek Watershed Plan Update
RECOMMENDATION:
That the Alder Creek Watershed Study and Upper Strasburg Creek Watershed Plan
Update, prepared By CH2MHill and North-South Environmental Inc., dated January, 2008
be received and further;
That the Alder Creek Strasburg Watershed Study and Upper Strasburg Creek Watershed
Plan Update be adopted and approved in its entirety.
BACKGROUND:
The Alder Creek Watershed is a tributary of the Nith River, and the total drainage area is
approximately 81.2 square kilometres km2). Eighty percent of this watershed is located in the
Township of Wilmot, with the remainder located in the City of Kitchener and the Township of
Blandford-Blenheim. The majority of the watershed is primarily agricultural, with some rural
development and aggregate extraction. A portion of the Alder Creek subwatershed within
Kitchener has been designated as City Urban Area in the Regional Official Plan.
The Strasburg Creek Watershed drains approximately 14 km2 to Schneider Creek,
approximately 2 kilometres upstream of its confluence with the Grand River see attached map).
The watershed is located entirely within the City of Kitchener. The upper portion of the
Strasburg Creek subwatershed, which is the subject of this report, drains an area of
approximately 4 km2 west of Fischer-Hallman Road. The upper subwatershed is primarily
agricultural and aggregate extraction. Several residential developments have been constructed
recently and a large portion of the subwatershed has been designated as City Urban Area in the
Regional Official Plan.
Previous studies
Phase 1 of the Alder Creek Watershed Study was completed by the Grand River Conservation
Authority (GRCA) in 2001 and describes the overall watershed processes and identifies
watershed issues that should be addressed in Phase 2 of the Watershed Study. The Regional
Municipality of Waterloo (Region) and GRCA also completed the Alder Creek Groundwater
Study in 2003 to develop a better understanding of groundwater flow systems in the watershed.
The Strasburg Creek Master Watershed Plan was completed in 1991 for the City of Kitchener
by Paragon Engineering and established management objectives to guide future development
in the watershed. The Watershed Plan assumed that the upper watershed would be developed
and positively drained in the traditional manner. As the upper subwatershed started to develop,
it became apparent that the original assumptions on how the upper subwatershed would be
graded and drained should be revisited and an update to the Watershed Study was required.
The important contribution of the upper subwatershed on the Regional municipal wells was also
unknown at the time of the 1991 Plan.
Current study
The City of Kitchener, the Region, and the GRCA initiated the Alder Creek Watershed Study
and Upper Strasburg Creek subwatershed Plan Update therein referred to as the Study) in
2003. The GRCA was the Project lead on this project. The two watershed areas are adjacent
to one other and have recognized interrelationships between groundwater systems and surface
water systems. Therefore, study of both watersheds has been carried out together.
The overall purpose of the Watershed Study is to develop management strategies that will
support the long-term preservation and protection of the existing natural features within the
study area, while permitting development to proceed on lands where deemed appropriate.
The Study included the following major components, an Alder Creek Watershed Management
Plan, an Upper Strasburg Creek Management Plan, a Natural Heritage Strategy and a
Comprehensive Environmental Impact Study. A companion document, the Upper Strasburg
Creek Class Environmental Assessment, was also completed for the Fischer-Hallman Road
culvert to resolve floodplain and major flow control issues for the upper watershed under
existing conditions. This document is the subject of a separate staff report.
The Management Plans for both watersheds include a groundwater protection plan and a
stormwater management plan. Groundwater management plays an important role in these
subwatersheds as they are located in the south-central portion of the Waterloo moraine, a
regionally significant groundwater recharge area for the Region of Waterloo's municipal well
fields. Precipitation infiltrating the Upper Strasburg Creek subwatershed directly recharges the
unconfined Mannheim Aquifer. The gravel pits in the area contribute about 70% of the total
water reaching the eastern Mannheim Wells K25 and K29.
The key water management recommendations are:
the existing infiltration/recharge rates shall be maintained or enhanced in the watersheds
to ensure the water balance is maintained
water quality of the groundwater will be managed through reasonable use criteria for
chloride application, development restrictions and best management practices
the Region should revise the Well Head Protection Area mapping as determined through
the updated groundwater modeling to the south east of Municipal Wells K25 and K29.
the dispersed nature of the depression storage areas in the hummocky topography and
their function as infiltration sources shall be maintained during and after grading
operations
the form namely the pit bottoms) and the recharge function of the gravel pits in the
Upper Strasburg Creek subwatershed shall be maintained to ensure that the maximum
amount of water is recharged to the groundwater and the Regional supply wells
stormwater quality and quantity targets are set for both Alder Creek and Strasburg Creek
a comprehensive stormwater management plan is required as part of any official plan
amendment in the Upper Strasburg Subwatershed to demonstrate how the individual
targets and recommendations of the Study will be achieved.
A Natural Heritage Study was undertaken and natural areas were identified and assessed.
Wetlands within the Upper Strasburg Creek were evaluated. Core Areas were identified which
meet the criteria for designation as a Regional Environmental Sensitive Policy Area (ESPA}.
Satellite Areas were also identified which are smaller natural areas that may not have as many
natural attributes as a core area, but provide important functions such as linkages, improving
forest cover, or as "stepping stones" between two natural areas where a complete linkage does
not exist.
A comprehensive Environmental Impact Study was completed which identifies specific issues
that are most likely to affect the natural heritage system, and provides mitigation measures in
the Alder Creek Watershed and Upper Strasburg Creek Subwatershed.
The key natural heritage recommendations are:
the Region should give consideration to designating as new ESPA's identified cores
areas
minimum 30 metre buffer is recommended around natural features within the Core Areas
a 30 metre buffer is recommended around Satellite areas or non-provincially significant
wetlands. Environmental reports submitted at the time of development will determine
the ultimate buffer around these features
small, isolated wetland pockets that are not part of a Core Area, Satellite Area or part of
a potential linkage should be avoided during development, however they may be
considered for removal in accordance with the GRCA Wetland Policy.
a 125 metre corridor/linkage is recommended along the length of Alder Creek to provide
a continuous north-south corridor in the Alder Creek Watershed and protect broad tracts
of habitat
CONSULTATION PROCESS
One Steering Committee oversaw both the EA and the Alder Creek Watershed Study and
Upper Strasburg Creek Subwatershed Plan update. Various Technical Committees were
established to discuss the groundwater, stormwater and natural heritage aspects of the study.
Committee Members included staff from the City of Kitchener, Regional Municipality of
Waterloo, GRCA, Ministry of Natural Resources, County of Oxford and the Township of Wilmot.
The first public meeting was held in July 2003. A public workshop on Alder Lake (New Dundee}
was held November 27, 2003. Another public meeting was held March, 2007. Extensive
consultation has occurred with the major landowners in the City of Kitchener with six meetings
being held over the 2006-2007 period. The Steering Committee has resolved most of the
issues raised by the stakeholders. While some outstanding concerns remain, it is the opinion of
the Steering Committee that the comments cannot be addressed at the subwatershed scale, the
position presented cannot be supported, or wording has been added to the Study to address
their comments. On January 25, 2008, the GRCA General Membership approved the Alder
Creek Watershed Study and Upper Strasburg Creek Watershed Plan Update.
CONCLUSION:
The City of Kitchener, Regional Municipality of Waterloo and the GRCA have completed the
Alder Creek Watershed Study and Upper Strasburg Creek Subwatershed Plan Update (see
attached Executive Summary of the report). The study develops management strategies that
will support the long-term preservation and protection of the existing natural features within the
study area, while permitting development to proceed on lands where deemed appropriate. The
Staff recommend that Council adopt and approve the Alder Creek Watershed Study and Upper
Strasburg Creek Watershed Plan Update in its entirety.
Binu J. Korah, P. Eng.,
Manager, Development Engineering
K. Grant Murphy, P. Eng.,
Director, Engineering Services