Shirleys
Brook and Watts Creek Subwatershed Plan
(only 2 sections of the report - 7 and
8)
7.0 RECOMMENDED MANAGEMENT STRATEGIES
7.1 Approach to Strategy Development
7.1.1 Introduction
This section discusses the development of a subwatershed plan for the
Shirley’s Brook and Watts Creek Subwatersheds. The
recommended Subwatershed Plan consists of six different, but
interrelated management strategies, each comprised of a series of
management measures/actions designed to: protect and enhance the
Subwatershed natural features and ecological functions; restore those
features/functions that have been degraded; and guide future
development in a manner that will ensure the long-term health of the
environment.
The evolution of the overall Subwatershed Plan was based on the goals
and objectives previously described in Chapter 4.0. As well, it
is important to recognize that the management strategies address both
existing as well as preventing future problems.
As previously outlined in Chapter 4.0, there are a number of issues to
be addressed within the subwatersheds including:
Flooding and Erosion;
Lack of a Comprehensive SWM Strategy;
Degraded Surface Water Quality;
Degraded Fish and Aquatic Habitat;
Loss of Terrestrial Habitat and Linkages;
Groundwater Supply and Quality Constraints.
To resolve many of these issues, public sector initiatives and
resources will be required. In some circumstances, it may be
possible to resolve an issue through a co-operative approach with the
private sector. However, it is expected that the prevention of
additional problems can largely be accomplished through the land
development process.
To address both existing and potential future issues, a set of
recommended management strategies were developed which include:
Natural Area Management;
Flood Management;
Erosion Management;
Groundwater Quality and Quantity Management;
Agricultural and Rural Land Management; and
Urban Stormwater Management for New Development.
Also presented are comments on Kanata’s current Development Guidelines.
7.1.2 Environmental Assessment Process
7.1.2.1 Provincial EA Process
It was anticipated at the onset of this project that some components of
the management strategy may be subject to approval under the
Environmental Assessment Act, specifically Phases I and II of the
Municipal Engineers Association (MEA) Class Environmental Assessment
for Water and Wastewater Projects which is to include: problem
identification and the identification and evaluation of alternative
solutions. Alternative solutions are strategic alternatives to
solve the problem. The Class EA classifies projects according to
three “schedules” based on the type of project and the requirements for
approval. “Schedule A” projects are limited in scale and have
minimal adverse effects. They can be implemented without further
assessment under the Class EA process. “Schedule B” projects have
the potential for some adverse effects and the proponent is required to
undertake a screening process which ends at Phase II (i.e. evaluation
of alternative solutions). “Schedule C” projects have the
potential for more significant environmental effects than Schedule B
projects and must follow the full Class EA process (Phases 1-5).
The Municipal Class EA applies to both the public and private sector
(in some limited circumstances through Regulation 345/93). Given
the greater expectation that the private sector fund municipal
infrastructure, it is expected that the private sector will have a full
role in the implementation of the recommended facilities identified
through the subwatershed study. Schedule A and B private sector
projects are exempted and individual private sector EAs are subject
only if specifically designated. Schedule C private sector
projects are subject to the Class EA unless the project is in an
approved development plan.
It is noted that during the preparation of this subwatershed study
(1998- early 1999), a new MEA Class EA document was also being
developed. For the most part, proposed changes to the Class EA as
identified in the July 1998 draft document do not significantly change
the manner in which alternatives are to be developed and evaluated with
respect to this subwatershed plan. In the event that the
facilities proposed are not built within a 5 year period, the planning
process as undertaken under this Class EA will need to be reviewed and
confirmed. One proposed change in the Class EA Schedules is the
expectation that projects that gain approval through the Planning Act
(i.e. are included within an approved development plan), must still
meet the intent of the Class EA that includes following EA planning
principles and process as outlined in the Class EA.
Projects identified as part of this subwatershed study that would be
subject to the Class EA process include:
Schedule C Projects
Retention/detention facility or infiltration system for the purpose of
stormwater control, where chemical or biological treatment (including
constructed wetlands) or disinfection is included, including outfall to
receiving water body.
(Note: The new draft Class EA now excludes constructed wetlands.)
Schedule B Projects
New stormwater retention/detention ponds and appurtenances or
infiltration systems where all such facilities are not shown on an
approved development plan and which are needed to service new
development provided for in an approved development plan which are
required for existing development and includes outfall to receiving
water body.
(Note: The new draft Class EA deletes the reference to approved
development plans - see above comments though.)
It is intended that the subwatershed study fulfill Phase I (Problem
Identification) and Phases II (alternative solutions) of the Class EA
process for the identified applicable projects. As well, the
Class EA for Municipal Water and Wastewater Projects indicates that the
following five key principles of environmental planning should be met:
consult with affected parties;
consider all aspects of the environment;
consider a reasonable range of alternatives;
systematically evaluate the net environmental effects of each
alternative considered; and
provide clear, complete documentation.
The following describes how these principles have been addressed within
the subwatershed study.
Consultation
Consultation requirements have been satisfied through the preparation
of this subwatershed study (Refer to Section 2.0) and key consultation
events have included two public open houses, public notifications and a
notice of completion (to be submitted).
Consider All Aspects of the Environment
As part of the subwatershed study, an inventory and description of
existing environmental conditions was prepared (see Chapter 3.0).
These existing conditions were recognized in preparing the set of
subwatershed management strategies.
Alternatives and Effects Evaluation
Problem identification was based on proposed development conditions
within each catchment area. Based on the hydrologic analysis of
proposed land use conditions as specified in the Region’s Official
Plan, and the identified protection targets for each catchment/reach, a
determination is made as to the type and extent of stormwater
management that will be required. To address the identified
“problems”, alternatives were developed. Alternatives considered
(including the “do nothing” alternative) and evaluated were based on a
hierarchal or treatment train approach that included the following
components:
Source and conveyance control; and
End-of-pipe control.
It is recognized that where suitable subsoils exist, such as the
alluvial deposits within the lower reaches of the Shirley's Brook
Subwatershed, source and conveyance control infiltration measures can
result in a number of benefits and are therefore preferred for the
following reasons:
Water quality treatment/enhancement of urban stormwater, including
mitigation of potential thermal impacts to receiving watercourses;
Reduction of the volume of urban runoff, thereby reducing increases in
peak flows and streamflow velocities (i.e., flooding and erosion
impacts);
Contribution to the maintenance of local recharge conditions; and
Possibly, reduction in the size, number and complexity of stormwater
management facilities required.
However, a majority of the subsoils within the study area are not
conducive to infiltration based measures thus limiting the selection of
alternatives available to address the identified stormwater management
issues. In addition, implementation of infiltration measures,
even in the lower reaches of Shirley’s Brook cannot satisfy the
management targets alone, therefore, recommendations constitute a
combination of control measures.
Section 7.7 provides a summary by catchment area of the potential
alternatives and recommended measures to address stormwater management
for proposed development areas. Other components/ recommendations of
this subwatershed strategy are not subject to the Class EA process
(i.e. natural area restoration activities).
Provide Clear Complete Documentation
The following sections present the proposed subwatershed management
strategy. It is noted that Appendix A includes a set of
factsheets that summarizes key findings for each catchment area.
7.1.2.2 Federal EA Process
Although it is expected that the initiatives outlined in this
subwatershed study would not trigger the Canadian Environmental
Assessment Act (CEAA), it is possible that development activity
could. As an example, instream work that would require DFO
approval under the Federal Fisheries Act, is considered a CEAA
trigger. The developer would then be responsible for the
preparation of a CEAA screening document. It is also noted that
although the NCC, as a Crown corporation, is not required to follow the
CEAA process, it is their policy that CEAA screenings be prepared for
projects that affect their land. As a result, this could be
another “trigger” for CEAA within the subwatersheds.
The need for CEAA triggers from development activity should be
monitored by the MVCA through their development review process.
7.2 Management Strategy #1 - Natural Area Management
7.2.1 Introduction
This section outlines recommendations regarding the level of protection
that should be assigned to the identified natural heritage areas
(terrestrial and aquatic) located within the Shirley's Brook and Watts
Creek Subwatersheds. The Provincial Policy Statement is based on
a 2 level protection/ management system whereby natural features are to
be designated as either “Category 1 - No Development Lands” or
“Category 2 - Development Subject to Study Lands”. Areas to be
designated as “Category 1 - No Development Lands” include:
Significant wetlands located south and east of the Canadian Shield; and
Areas containing significant portions of habitat of endangered and
threatened species;
Areas to be designated as “Category 2 - Development Subject to Study
Lands” include:
Areas of fish habitat;
· Significant wetlands in the Canadian Shield:
Significant woodlands;
Significant valleylands south and east of the Canadian Shield;
Significant wildlife habitat;
Significant areas of natural and scientific interest; and
Adjacent lands to significant wetlands south and east of the Canadian
Shield and significant portions of the habitat of endangered and
threatened species.
The Ottawa-Carleton Official Plan is based on a 3 level protection
system as it includes an additional “no development/minor
encroachment” designation which applies to areas designated “Natural
Environment Area B”. The current City of Kanata Official Plan
contains a 2 level natural heritage features protection framework of
“no development/no encroachment” and “development subject to
study”. All natural heritage features, including significant
wetlands, are placed in a “development subject to study”
designation. The “no development/no encroachment” designation is
acquired through the development approval process.
The following presents the recommendations for the designation of
natural areas within the two subwatersheds as well as the management
strategy for the protection and/or enhancement of terrestrial and
aquatic habitats.
7.2.2 Category 1 - No Development Lands
The following describes the areas identified within the two
subwatersheds that are considered “Category 1 - No Development Lands”.
7.2.2.1 Significant Wetlands Located South and East
of the Canadian Shield
Wetlands are defined as lands that are seasonally or permanently
covered by shallow water, as well as lands where the water table is
close to the surface. In either case, the presence of abundant
water has caused the formation of hydric or saturated soils and has
favoured the dominance of either hydrophytic or water-tolerant plants
(OMNR/OMMA, 1992). In many cases, wetlands provide important
ecological functions related to biological and hydrological processes,
such as fish and wildlife habitat, surface and groundwater connection,
flood storage, and nutrient retention and removal.
The current City of Kanata Official Plan identifies Class 1-3 wetlands
(Schedule A) (now considered as “significant wetlands”) which are
located in a variety of land use designations. As the Official
Plan dates prior to the Provincial Policy Statement (1997), a
distinction between those located on the Canadian Shield and those
located south and east is not made. The Region Official Plan
identifies the former classified Provincially Significant Wetlands
(PSW).
As shown on Figures 3.3a and 3.3b (Refer to Chapter 3.0), significant
wetlands (south and east of the Canadian Shield) with the study area
that are recommended for protection from development include:
Area W3 and W5 - located in the southeast corner of the Watts Creek
Subwatershed area just south of Highway 417 (Stony Swamp); and
Area S26 and W17 - located in the northeast corner of the Shirley's
Brook Subwatershed (Shirley's Bay).
7.2.2.2 Areas Containing Significant Portions of
Habitat of Endangered and Threatened Species
Significant portions of the habitat of endangered and threatened
species include the portion(s) of habitat that is essential to
sustaining or expanding the species' population. Endangered
species are native species listed in the Regulations under the
Endangered Species Act, that are at risk of extinction throughout all
or a significant portion of their Ontario range if the limiting factors
are not reversed. Threatened species are native species that are
at risk of becoming endangered if the limiting factors are not reversed
(Province of Ontario, 1996).
No areas have been identified within the Shirley's Brook and Watts
Creek Subwatersheds that contain endangered and threatened species.
7.2.3 Category 2 - Development Subject to Study Lands
The following identifies areas subject to additional study in the event
that they are under some form of future development pressure and have
been organized by natural feature type as defined in the Provincial
Policy Statement. Additional study is required to assess the
impacts of development on a specified natural heritage feature or
system. In order for development and site alteration to be
permitted, the study will need to demonstrate that there will be no
negative impacts on the natural features or ecological functions for
which the area is identified. These studies can be facilitated by
the preparation of an Environmental Impact Study (EIS) or form part of
an Environmental Management Plan (EMP) for a development area. It
should be noted that the Region is currently finalizing its
Environmental Impact Statement Guidelines. These Guidelines have
evolved as a result of numerous meetings with biologists, planners,
developers, landowners and other interested parties.
7.2.3.1 Areas of Fish Habitat
Fish habitat is defined as the spawning grounds and nursery, rearing,
food supply and migration areas on which fish depend directly or
indirectly in order to carry out their life processes. Fish
include fish, shellfish, crustaceans, and marine animals at all stages
of their life cycle.
Development Setbacks
Neither Kanata or the Region's Official Plan identifies areas of fish
habitat. Through the efforts of this subwatershed study, fish
habitat areas have been identified and classified in terms of
their condition and value. Section 3.3 previously described the
results of this analysis. The stream reaches and habitat
classification are illustrated in Figure 3.2a and Figure 3.2b (Refer to
Section 3.0).
Table 7.1 refers to the aquatic resources along the reach as indicated
in the title.
There are a total of 24 reaches identified within the two
subwatersheds. Of this, 12 reaches have been identified as high
priority for protection/enhancement. Five of the reaches simply
need to be preserved in their existing state and include Shirley’s
Brook, reaches 6, 8 and 13, and Watts Creek reaches 2 and 10.
Appropriate development setbacks are essential to maintain these
habitats.
To protect, maintain and enhance the fish and aquatic habitats, a
minimum 15 m riparian buffer area, measured on both sides of the
watercourse from centreline, is recommended for Type 2 and Type 3
habitats; and a 30 m riparian buffer area is recommended for Type 1
habitats. Given that the streams within the study area are
predominantly warm water, a minimum 15 m buffer area is considered
adequate for most areas. In certain areas designated for urban
development, the preparation of an Environmental Impact Study (EIS) may
be required to assess an adjacent natural area, prior to site plan
approval. For these areas, a number of scenarios are possible,
including:
Table 7.1 Summary of Constraints and Opportunities for
Aquatic Resources of Shirley’s Brook/Watts Creek Subwatershed
(7 pages)
46. There may be an opportunity to enhance certain
degraded sections of the stream in exchange for a reduction in the
buffer width.
47. The presence of a large woodlot in the vicinity
of the stream may require that the buffer be increased to a width which
preserves the woodlot.
Set back distances will be established based on specific criteria which
may vary according to site conditions. Criteria used in
determining appropriate setback distance may include (but not be
limited) the following:
condition of stream reach through proposed development area;
nature of proposed development;
nature of vegetation through development area;
presence of any other significant natural features; and
current land use of development area.
The riparian buffer areas are recommended as a guide in the development
of suitable protection and restoration initiatives. The actual
buffer dimensions should be based on criteria established through a
site-specific assessment of the local conditions, as well as input from
relevant agencies (e.g. MVCA, OMNR). It should integrate such
aspects as groundwater seepage, geomorphology, streamside vegetation
and opportunities for stormwater management that best fit the specific
site characteristics for habitat protection/restoration.
Aquatic Habitat Protection/Restoration
A total of nine high priority Type 2 and 3 habitat reaches have been
recommended for restoration. These include Shirley’s Brook
reaches #3, 4, 7, 9 and 10 and Watts Creek Reaches #3, 5, 6 and 7 (See
Figure 3.2a and 3.2b). Table 7.1 provides a summary of fish
habitat preservation and enhancement recommendations. In general,
natural areas which, to date, are not impacted by urban development or
agriculture have been designated high priority for preservation.
Some severely impacted areas have also been designated high priority to
indicate immediate targets for restoration. Medium and low
priority areas include reaches which are somewhat impacted or offer
little opportunity for long term restoration (e.g. agriculture reaches).
The emphasis of stream and aquatic habitat restoration is to improve
the overall physical structure of the stream channels and bordering
shorelines while restoring the stream's natural morphological
characteristics. Stream rehabilitation techniques are to be
employed to achieve a relatively stable equilibrium of erosion and
deposition along degraded reaches. Physical improvements to the
aquatic habitat are necessary to help achieve stream stability (from
the effects of erosion) and enhance ecological function.
A significant component of these initiatives is the replanting of
streamside vegetation, removal of in-stream barriers and reduction of
(untreated) stormwater inputs from upstream areas. The
initiatives would serve to further enhance the existing fish habitat
and help improve water quality in the downstream reaches.
The following measures should be considered in undertaking aquatic
habitat restoration initiatives:
Natural channel rehabilitation in areas that have been channelized
and/or artificially hardened;
Stabilization of currently eroding streambanks, preferably using
natural channel design techniques and natural materials, such as root
wads, live log crib walls, willow brush bundles or live willow stakes;
Restoration and enhancement of stream bed structure, through selective
placement of gravel, boulders (vortex rock weirs), deflector logs and
lunker structures. Natural channel design techniques will be
selected based on a detailed assessment by a fluvial geomorphologist to
determine the fluvial characteristics of specific stream reaches;
Improvement of low flow characteristics, through the restoration of
natural sinuosity characteristics and the use of deflector structures,
as well as the removal of anthropogenic debris;
Rechannelization, where appropriate, using natural channel design
techniques and bioengineering materials (coconut fibre fabric, live
willow stakes) and reinstating a regular riffle pool complex;
Eliminate, remediate or bypass instream barriers such as blocked
culverts, or other migration barriers to allow easier movement of all
aquatic fauna;
Replanting of vegetative buffer zones using native woody plant species
to stabilize streambanks, improve groundwater regime, provide shade and
increase vegetative diversity along shorelines, as well as enhance
terrestrial habitats;
· Restriction of livestock access to
watercourses by constructing fences or other means;
· Consideration of opportunities to
integrate/create/enhance fish habitat as part of new development (i.e.,
construction of artificial wetlands for stormwater management and
habitat creation); and
· Reduce/mitigate impacts associated with
inputs of urban stormwater and combined sewer overflows.
Fish habitat can also be enhanced through the rehabilitation of natural
stream morphological characteristics as described in Section 7.4.
It will be important to develop detailed restoration plans. For
those reaches to be enhanced that are part of a development area, there
would be an opportunity to restore the reach by the developer (e.g.
Reach 10 that is located within the KRP lands). For those reaches
within existing built-up areas, restoration efforts will need to be
initiated by the City/MVCA with potential assistance from the local
community.
7.2.3.2 Significant Wetlands in the Canadian Shield
There exists a number of significant wetlands (e.g. S2 South March
Wetlands or K10) on an outcrop of Canadian shield that serves as a
headwater area to Shirley’s Brook. These wetlands are largely
contained within lands designated as NEA(B) in the Regional Official
Plan and as “Marginal Resource” in the Kanata Official Plan. No
further protection initiatives are therefore required.
Figures 3.3a and 3.3b (at end of Chapter 3.0) illustrates the location
of the above noted wetland Natural Areas.
7.2.3.3 Significant Woodlands
Woodlands are defined as treed areas that provide environmental and
economic benefits such as erosion prevention, water retention,
provision of habitat, recreation and the sustainable harvest of
woodland products. Woodlands include upland and lowland forests,
swamps and early to late successional fields.
The City of Kanata and the Region Official Plans were reviewed to
determine the designations of the woodlands within
subwatersheds. Natural areas that are currently designated
for preservation (i.e. natural environment areas (NEA) and
Greenbelt Rural (GR)) have been recognized to have environmental
value. However, it is important to remember that natural areas
located within the “urban” designated areas (i.e. General Urban Area
(GUA)) also play an important role from an ecological/aesthetic
perspective as they provide the following functions:
i) They provide settings for naturalized parks which
foster a public appreciation for an understanding of ecological
processes that occur within wetlands and forests.
ii) They provide habitat for local wildlife such as
raccoon, red squirrel, grey squirrel, chipmunk, cottontail and skunk
and also provide “islands” of habitat during the fall and spring
migration. For example, wet forests (swamps) may provide breeding
habitat for American toads and wood frogs in the spring, but these
species may be found in drier locales during the summer.
iii) They provide specific “corridors” or linkages
for local animal populations that may move from one area to another
during the spring, summer and fall. For example, migratory birds
including many waterfowl stop over in the Shirley's Bay area before
moving further north or south.
It will be important to preserve as many natural areas located within
the non-environmentally designated areas that is possible. As
previously explained in Chapter 3.0, a quantitative analysis of each
woodland areas was undertaken in order to identify those woodlands that
are of most significance and should be assigned some level of
protection. While the quantitative analysis has identified high
scoring natural areas, lower scoring areas should be considered for
preservation especially if they are in close proximity (i.e. < 750
m) to larger environmentally designated (NEA) areas or if they are
located along tributaries, or the main branch of Shirley's Brook,
Kizell Drain or Watts Creek.
Table 7.2 presents by subwatershed, for each identified natural area,
recommendations for 1) Preservation and 2) Enhancement, as well as
identifying the priority areas. Priority rankings refer to both
preservation and enhancement activities. Natural areas are
identified by a letter and number combination. For example, W5
refers to the fifth site in the Watts Creek subwatershed. Figures
3.3a and 3.3b (at end of Section 3) illustrates the location of each
natural area.
Table 7.2 Summary of Natural Feature Constraints and
Opportunities for
Shirley's Brook/Watts Creek Subwatershed
(13 pages)
As indicated earlier, two distinct corridors provide a linkage for
wildlife movement from natural areas south and west of Kanata to the
Ottawa River. The first named the Shirley's Brook/Kizell wildlife
corridor is located in the western section of Kizell Drain and
Shirley's Brook. It has a hub composed of Units S1 to S5.
The quantitative analysis (Table C.28 in Appendix C) shows that the
core of this hub (S1 and S2) scored very high (356 and 425) and covers
a substantial portion of the subwatershed. While S3, S4 and S5
are smaller and had lower scores, they too are in close proximity to
the core, and from a purely qualitative basis, should be included as
they can easily be linked to the larger areas.
In examining existing planning designations for these natural areas,
four have a NEA designation while S5 has a general Urban
designation. From a review of Table 7.2, areas S1 and S3 have
been assigned a high potential for the long term. S4, although is
in a NEA designation, was given a medium potential due to the high
incidence of bedrock outcrops that limits its rehabilitation
opportunities. S5 was given a low potential mainly due to the
existing GUA designation, however, it does have high potential within
the Shirley's Brook stream corridor where development would likely be
minimum.
In looking at other natural areas (i.e. S13 to S26) that complete the
western wildlife corridor, the scores (see Table C.28) range from 68
for S25 to 168 for S13. While these areas may have limitations
for wildlife habitat on an individual basis, their close proximity to
one another and other natural features such as watercourses, hedgerows,
etc., does provide an extension of the habitats found within the
wildlife hub (S1 to S5) and along the Ottawa River.
In reviewing Table 7.2, the units S13 to S26 have been assigned low to
medium potential with the exception of S24 (high potential).
These areas are considered to be important “stepping stones” to the
Ottawa River, however, they are gradually being developed for low
density development due to the General Rural Area designation.
The second named the Watts Creek Wildlife Corridor is located mainly
within the Watts Creek Subwatershed, and is situated on the height of
land along the eastern boundary in the south and along Watts Creek in
the north. The core of this corridor also contains designated NEA
areas.
Of the total 52 natural areas identified in the subwatershed, 21
natural areas have been identified as high priority for
protection/maintenance. Most of these areas are within
“non-development” designated lands (e.g. Natural Environment
Area). Six natural areas are either entirely or partially
designated for development (Natural Features K2, K4, K9, S1, S2 and
S24). It is noted that K2 and K4 are important for the
maintenance of the eastern wildlife corridor.
For those natural areas that are protected through their current
designation, recommendations are on maintenance/restoration
activities outlined in Table 7.2. For those areas that are
privately owned, landowner co-operation is required. Land
stewardship mechanisms, as presented in Table 8.2, are recommended.
The six natural areas that are not protected with an appropriate
designation are under the most threat. It is recommended that the
City of Kanata/MCVA examine each of these areas to determine
opportunities that might be available for their protection. Table
8.2 presents a number of securement mechanisms that could be used to
ensure that these areas are preserved.
Preservation of existing natural areas is the preferred option as most
natural areas have an established floral and faunal community.
Some maintenance may be required (i.e. Woodlot Management Plan) if the
natural system has undergone a recent change, but most require little
help from man.
Woodland Area Preservation Principles are:
Rehabilitation should be directed towards healthy, self-sustaining,
interconnected woodland ecosystems that integrate water
infiltration/stream flow management;
Initial regeneration planting may utilize species such as white birch,
larch, poplar, white cedar, ash, soft maple and cedar followed by
plantings of cherry, basswood, sugar maple, beech and hickory;
Woodlands should be managed to provide distinct overstorey, shrub layer
and understorey communities that provide diverse habitat for the areas
wildlife population. They should also be attractive to migratory
species that frequent the area;
Provision and restoration of woodland corridors of at least 100 m wide
will improve corridor functions for species and will improve interior
forest conditions; and
Provision of tall treed hedgerows no more than 200 m apart in
agricultural areas will improve habitat connectivity and reduce the
negative impacts of high winds. Removal of incompatible
non-native species that have potential to out compete native species
will improve the representativeness of the natural habitats.
Enhancement/restoration of existing natural areas can be successful but
is expensive and time consuming particularly if starting with a
landscape situation that is extensively degraded or that is still in
agricultural production. When planning any enhancement project,
the following general principles should be followed:
Allow natural regeneration to occur as much as possible;
Preference should be given to native species of local provenance.
These species are pre-adapted to the local conditions and already
constitute the genetic biomass supporting the areas wildlife; and
In areas where non-native woody or herbaceous vegetation predominates,
some form of eradication should occur to avoid plantings that at
maturity have little ecological usefulness. Aggressive non-native
woody species include common buckthorn, Austrian Pine, Norway maple,
scots pine, and black locust.
In Table 7.2, some of the opportunities for the natural areas suggest
that “a woodlot management plan would benefit this natural area to
ensure good health in the long-term”. The following generic
woodlot management plan could be applied to all areas, and modified
where necessary:
Unsafe Trees - For isolated or portions of woodlots that have been
preserved in residential developments (i.e. W1,W2,
W6,K8,S6,S8,S9,S12,S18,S19,S20,), it is paramount that the trees within
these areas be maintained in a safe condition so that they do not
become a liability. While the maintenance of every tree in
a woodlot is expensive, priorities should be set to monitor trees that
are within 20 metres of walkways. For example: trees that have
unsafe limbs or appear sick (i.e. delay in emergence, 50% or more of
canopy is dead) should be removed. It is recommended that trees
that are felled, should be left in-situ where possible, as the logs,
branches and leaves provide cover and food for woodlot
inhabitants. In addition, attempting to remove felled logs can
damage the understorey.
Walkway maintenance - Creating walkways within a woodlot can increase
opportunities for nature interpretation and appreciation, but the
design of the walkway can, in some cases, be a detriment to the
woodlot. For example, asphalt walkways are not recommended, as
the construction method usually requires some form of grading and
placement of gravel followed by a layer of asphalt. During this
process, surface feeder roots and anchor roots can be damaged or
removed and deeper underlying roots may die due to the lack of
oxygen. It is recommended that either woodchips or pea gravel be
used to “pave” walkways. Both materials are relatively
economical, permeable (i.e. allows water and air exchange to the roots)
and still allows all users (including wheelchairs) to use the pathways.
Control of aggressive native and non-native species - including
riverbank grape (Vitis riparia), Norway maple (Acer platanoides),
garlic mustard (Alliaria petiolata), common buckthorn (Rhamnus
cathartica) and dog-strangling vine (Cyanchum rossicum) can out-compete
existing native species and should be controlled where possible.
The control of woody species (i.e. wild grape, buckthorn, buckthorn)
can be accomplished by using selective herbicides or by severing main
stems at ground-level. Herbaceous weeds (i.e. garlic mustard,
dog-strangling vine) are best controlled with a selective herbicide
prior to flowering.
Edge management - The intrusion into a woodlot for development purposes
will result in the potential for edge effects including wind-throw (or
blowdown), sunscald of thin-barked trees and/or increased light levels
reaching the understorey. Wind-throw is usually more common in
areas where the soil is wet and tree species are shallow rooted.
This condition is more severe when the edge is exposed to prevailing
winds. Trees that are prone to this condition include white
cedar, red maple, silver maple, red ash and white ash. While
preventing trees from blowing over is difficult to do, planting water
tolerant shrub species in their place will restore some habitat that
has been lost.
The following provides an overview description of the woodlots
identified within the study area.
Kizell Drain
Eight of the ten natural areas within Kizell Drain are either within
the General Urban Ara (GUA) designation (K2, K3, K4, K5, K7), Business
Park (BP) (K8, K9) or Town Centre (TC) (K6), while only two (K1, K10)
are within environmentally designated areas including Greenbelt (GR) or
NEA.
It is interesting to note that all the natural areas that are within
the General Urban Area (with the exception of one (K7)), are adjacent
to the Kizell Drain or other tributary and are within 750 m of a
natural environment area. It is believed that four of these areas
(K2 to K5) create a southerly extension to the Shirley's Brook/Kizell
wildlife corridor as these are immediately adjacent to the core NEA
areas. These areas also had high scores and all serve as an
important buffer to the Kizell Drain.
It is suggested that any development within the K4 area be limited as
this area provides an important linkage between the NEA areas located
along the Golbourn Forced Road area and those located along the Kizell
Drain.
Watts Creek
With respect to Watts Creek, twelve of seventeen identified natural
areas are situated within the Natural Environmental Area (W3, W4, W5,
W10, W11, W12, W13, W14, W16, W17) or Greenbelt Rural (W9, W15).
These areas form the core habitat areas for the Watts Creek Wildlife
Corridor and link the main portion of the Stony Swamp provincially
significant complex with the Ottawa River. The key areas
include: W10 which encompasses the Nepean tent and trailer camp;
W14 which is situated along Watts Creek within the Department of
National Defence lands; W17 which is located at the mouth of Watts
Creek, and W3, W4 and W5 which include some of the NCC Greenbelt
trails. While areas W12 and W13 were small and had lower scores,
they also provide a key linkage within the central portion of the Watts
Creek wildlife corridor.
While most of these areas did have high overall scores, relatively
minor disturbances and do have some degree of environmental protection,
it was noted in earlier sections that overall the Watts Creek
Subwatershed is approaching critical levels when it comes to forest
resources. Therefore, it is critical that the existing NEA and GR
areas are protected during future official plan amendment applications.
Shirley's Brook
In the Shirley's Brook Subwatershed, six areas are identified within a
Natural Environment Area. These include S1, S2, S3, S4, S6 and
S26. The first five areas form core habitat for the Shirley's
Brook/Kizell wildlife corridor and include those areas with the highest
overall scores (S1 and S2). These areas are dominated by uplands
forests (sugar maple/white ash/beech and hemlock) but also have
extensive wetland areas.
In summary, a review of the scoring of natural areas found that some of
the larger natural areas such as S1, S2, W3, W4, W5 and W10 and S26
that scored high on a quantitative basis are within a designated
natural environment area (NEA), however, others that scored equally
high (K2, K5, K6) were located in a general rural area or business
park. Clearly, it is important to recognize that some valuable
natural areas still remain in non-environmentally designated areas and
that efforts should be made to preserve as much of the high scoring
areas as possible as well as lower scoring areas that are in close
proximity to these areas.
7.2.3.4 Significant Valley Lands South and East of
the Canadian Shield
Valleylands are defined as natural areas that occur in a valley or
other landform depression that has water flowing through or standing
for some period of the year. Valleylands include naturally vegetated or
potentially revegetated areas of ravine, river and stream corridors
situated within the physical boundaries of the valley landform (i.e.
below the top of bank).
Valleylands are important natural resources within a subwatershed and
form a natural water collection system. They contain and connect
woodland areas and provide essential ecological functions such as fish
and wildlife habitat and movement, hydrologic/hydrogeologic flow
connection, nutrient and sediment transport, floodplain storage, and
water temperature moderation. They have been and will likely
continue to be important in the maintenance of remnant indigenous flora
and fauna.
Given the topography and current land use conditions within the
Shirley’s Brook/Watts Creek Subwatershed, there are limited areas that
could be considered valleylands. In many parts of the study area,
agricultural activity or development extends to the edge of
watercourses. Notwithstanding, there are several moderate
valleyland areas as identified on Figures 3.3 and 3.3b (Refer to
Section 3.0). The boundaries of these valleylands are considered
to be represented by the existing Fill Line (or top of bank) as defined
through the 1989 floodplain mapping. It is noted that as the
floodplain mapping is to be updated, the limits of the Fill Line may
change.
The boundaries of the valleylands/fill line shown on Figure 3.3a and
3.3b are approximate. MVCA floodplain mapping should be referred
to for the exact boundary.
Opportunities for restoration and possible enhancement include:
rehabilitate steep slopes and top-of-bank areas impacted by erosion
through stabilization of severely eroded slopes and revegetation of
barren areas;
restore valleyland tree coverage by expanding and rehabilitating
vegetation situated in valleylands.
In areas that are still under agricultural production, encourage
farmers to implement Best Management Practices (as discussed in Section
7.6) to protect valleylands. Examples include:
retiring fields where the returns on crop yields are low and where the
risk to adjacent waterways/wetlands are high;
maintaining an appropriate buffer width between crop fields and
waterways/wetlands;
practising conservation tillage methods including no-fill, contour
farming, buffer strip cropping, cover crops and rotations;
creating water and sediment control basins to control surface runoff
along drainage ways;
maintaining tile drains on a regular basis especially where they enter
watercourses; and
preventing livestock from entering watercourses or reducing access to
certain areas with appropriate substrate modifications.
In areas of urban development, the protection of the vegetation
adjacent to, and within valleyland is critical as it reduces the risk
of sedimentation within the watercourse. Best Management
Practices (as discussed in Section 7.7) to consider when developing
adjacent to a valleyland may include:
installing and maintaining sediment fences and bale check dams prior
and during the construction period;
restricting access of equipment in valley lands; and
prohibiting stockpiling of soils within valley lands during
construction.
7.2.3.5 Significant Wildlife Habitat
Significant wildlife habitat within the subwatersheds is assumed to
include and be covered by the other natural heritage areas of fish
habitat, valleylands and woodlands. No significant wildlife habitat has
been specifically identified outside of these other natural heritage
areas. Additional areas may become evident as habitat
improvements and restoration are implemented in specific locations.
7.2.3.6 Significant Areas of Natural and Scientific
Interest (ANSI)
The Kanata Official Plan makes reference to one ANSI (earth science)
that is an exposed sedimentary rock formation in the Queensway corridor
immediately east of Terry Fox Drive. This area is surrounded by
significant development and is adjacent to Highway 417.
7.2.3.7 Adjacent Lands to Significant Wetlands and
Significant Portions of the Habitat of Endangered and Threatened Species
The Provincial Policy Statement is not specific as to what these
adjacent lands should include and various guidelines for set back or
buffer distances have been suggested by the MNR in the past. For
the identified significant wetlands, it is suggested that the
distance from the disturbance to the edge of the wetland be determined
through the preparation of an Environmental Impact Study (EIS) to
ensure that there is no loss of wetland function.
7.3 Management Strategy #2 - Flood Management
The formulation of a strategy to manage areas susceptible to hazards is
premised on recognition that areas within the Shirley’s Brook and Watts
Creek Subwatershed are inherently susceptible to increased risk arising
from hazards associated with flooding, and that this risk may present
an unacceptable threat to human life or property. This requires
that areas susceptible to flooding be identified and that new
development or non-compatible land uses be required to locate in areas
outside of hazardous lands. In some instances, development and
site alteration may be permitted in certain areas of hazardous lands if
the hazards can be safety addressed, no new hazards are created, and no
adverse environmental impacts will result.
For the most part, many of the components necessary for the management
of flood hazard within the Shirley’s Brook/Watts Creek
Subwatershed are already in place. This includes: the
MVCA’s previously prepared flood line mapping of portions of Shirley’s
Brook, Watts Creek and the Kizell Drain to denote hazards associated
with flooding, and, relevant Official Plan policies and land use
schedules dealing with flood hazards within the respective OPs of the
City of Kanata and the Regional Municipality of Ottawa-Carleton.
The fundamental elements of the flood management strategy are provided
below.
7.3.1 Identification and Reduction of Flooding
Mapping of the flooding hazards within the Shirley's Brook/Watts Creek
Subwatershed has been previously prepared by MVCA. Flood plain
limits based on the 100-year storm have been delineated on the MVCA's
1:2,000 scale topographic based mapping.
Watercourse reaches that have been mapped include:
Shirley's Brook main branch, extending from Ottawa River 1,200 m north
of Goulbourn Forced Road;
Shirley's Brook Tributary 1, extending from main branch to March Road;
Shirley's Brook Tributary 2, extending from Tributary 2 to 400 m north
of March Road;
Watts Creek main branch, extending from Ottawa River to Eagleson Road;
Kizell Drain, extending from Watts Creek to the Beaver Pond; and
Kizell Drain Tributary, extending from Kizell Drain to Beaverbrook Road.
The following points are recommended to assist the municipalities and
the MVCA in managing hazardous areas associated with flooding:
Revise/Update Flood Plain Mapping: Recognizing the age of some of
the previous flood plain mapping and the more recent changes in land
use culvert improvements/replacements and new roadway construction, new
flood plain mapping should be prepared for Shirley's Brook (including
its principle tributaries) in order to more accurately define the
location and extent of hazardous areas associated with flooding.
Extend Flood Plain Mapping: Additional flood plain mapping should
be prepared for the upper reaches of the Shirley's Brook tributaries
(i.e. 1 and 2) to identify any flooding hazards upstream of March Road.
Reduce Flooding Impacts Associated with New Development: New
development should include stormwater management facilities to provide
water quantity control (i.e., flooding) of urban runoff to minimize the
potential for increasing flooding impacts in Shirley's Brook, Watts
Creek and the Kizell Drain. A discussion of the recommended urban
stormwater management measures for new development within the
subwatersheds is provided in Section 7.7.
Hydraulic Structure Improvements: Review of previous studies and the
MVCA's flood plain maps identified several structures (see below) with
inadequate capacity to pass the 100-year storm peak flows. In
some instances, this may have a direct impact on the flood
susceptibility of private lands and/or dwellings, since the resulting
flood levels upstream of these structures result in an increase to the
extent of the land area flooded. Consequently, hydraulic
structure improvements including enlargement and/or replacement of
existing bridges and roadway culverts should be considered as part of
any structural upgrading works initiated by the Municipality.
Table 7.3 lists the structures identified as presenting an opportunity
to reduce flood hazards through hydraulic improvements.
Assess Flooding Hazards to New Development, Site Alteration or Land Use
Change: The following points are recommended to assist the
municipalities and the MVCA in reviewing development applications in or
adjacent to natural hazard areas associated with flooding:
i) For areas where flood lines have been mapped, the
flood line should be used by the MVCA to assess the hazards associated
with flooding. If the MVCA feels that site-specific information
is required to assess the potential flooding impacts associated with a
development proposal, the proponent of the development proposal shall
be required to prepare a hydrotechnical study that conforms to the
items listed in point iii).
TABLE 7.3
SUMMARY OF OPPORTUNITIES FOR
HYDRAULIC STRUCTURE IMPROVEMENTS
Catchment No. (Refer to Figure 3.6) Hydraulic
Structure Location Description of Flood Susceptible
Area (Refer to Figure 3.9)
Shirley's Brook
SB-1 March Road S4 -
Tributary 1 upstream of March Road
SB-5 CN Rail S2 - Main
branch upstream of CN Rail
SB-5 DND entrance S1 - Main
branch downstream of 4th Line Road
Watts Creek
WC-1 Chimo Drive W5 - Main
branch across Chimo Drive
WC-4 Sewer-laneway W4 -
Main branch across and upstream of sewer-laneway
WC-5 CN Rail W3 - Main
branch upstream of CN Rail
WC-5 Carling Avenue W2 -
Main branch upstream and east of Carling Avenue
WC-5 Sandhill Road W1 -
Main branch upstream of Sandhill Road
Kizell Drain
KD-3 Hertzberg Road K4 -
Tributary of Kizell Drain upstream of Hertzberg Road
KD-3 CN Rail K3 - Tributary
of Kizell Drain upstream of CN Rail
KD-2 Carling Avenue K1 -
Main branch upstream of Carling Avenue
ii) For areas where no flood lines have been mapped
and the MVCA feels that site-specific information is required to assess
the potential hazards associated with flooding, the proponent of the
development proposal shall be required to prepare a study to define the
hazardous lands associated with flooding. If the development
proposal is such that additional information is required to assess the
potential flooding impacts, the proponent of the development proposal
shall be required to prepare a hydrotechnical study that conforms to
the items listed in point iii).
iii) Pursuant to the Provincial Policy, development
and site alteration proposed in hazardous lands associated with
flooding must demonstrate that all of the following can be achieved:
a) the hazards can be safely addressed, and the
development and site alteration is carried out in accordance with the
established standards and procedures listed in point iv);
b) new hazards are not created and existing hazards
are not aggravated;
c) no adverse environmental impacts will result;
d) vehicles and people have a way of safely entering
and exiting the area during times of flooding, erosion and other
emergencies; and
e) the development does not include institutional
uses or essential emergency services or the disposal, manufacture,
treatment or storage of hazardous substances.
iv) All technical and planning related issues
pertaining to delineation of the flooding hazards and the technical
assessment of impacts thereof should adhere to the procedures, methods
and technical standards requirements defined in the Province's "Flood
Plain Planning Policy Statement - Implementation Guidelines" and
accompanying "Technical Guidelines" (MNR, 1988) and the MVCA's, "Fill,
Construction and Alteration to Waterways" regulations.
v) Any hydrotechnical studies conducted under points
i) or ii) shall recognize and be consistent with the methodologies and
findings established in the hydrologic investigations conducted as part
of this Study.
7.3.2 Policy Recommendations
The fundamental elements of the strategy includes the following policy
basis:
(i) Pursuant to the Provincial Policy, the
municipalities of the City of Kanata, City of Neapean and the
Regional Municipality of Ottawa-Carleton should establish appropriate
land use planning controls, designations and mechanisms in their
respective Official Plans to prohibit/restrict development in hazardous
areas associated with flooding and permit development subject to
conditions in areas defined as less hazardous. The actual limits
of the hazardous lands along river and stream systems impacted by
flooding should be based on the flood hazard limits defined by the
regulatory flood standard, established as the one hundred year
(100-year) flood.
In addition to relying on the 100-year flood lines, Fill Lines should
be used when considering development or redevelopment along a
watercourse. The purpose of these Fill Lines are to provide an
additional setback beyond the flood limits, where environmental
hazards, such as steep bank or meander belt are present. Before
any filling or development is permitted outside the flood line but
inside the fill line, an engineering study will have to be undertaken
to determine the potential effects of development on the hazards.
The findings of the investigation, recommended measures and the long
term effects of the proposed development on the watercourse and the
riparian environment should be submitted to for approval to the
Conservation Authority.
(ii) The municipalities and/or the MVCA may request
that detailed hydrotechnical studies be prepared by proponents of
development proposals in order to identify and fully assess the
site-specific hazards associated with flooding.
The following describes the specific aspects of the strategy.
7.4 Management Strategy #3 - Erosion Management
Changes in the configuration of watercourses occur naturally regardless
of changes in flow regime or alterations in channel planform (see
Section 5.4 for further discussion). Rather than inhibiting these
processes, they should be recognized as natural and be allowed to
continue. In catchment areas with identified future development,
changes in landuse may alter the hydrologic regime of the watercourses
that are situated within them. Management of watercourses within
the Shirley’s Brook/Watts Creek Subwatersheds must consider the
controls and modifiers of channel form and function in addition to
existing and potential future erosion concerns. As such,
Management Strategy #3 draws upon a geomorphic understanding of the
watercourses and on the results of hydrologic modelling.
7.4.1 Drainage Network
Low-order tributary channels serve an important function within any
drainage network. During precipitation events, water from
surrounding land areas begin to fill these channels until there is
sufficient volume to cause the water to flow. The lag time
between the onset of precipitation and the downstream flow of water in
the low-order streams lengthens the duration of the storm hydrograph
and attenuates peak flow. The efficiency with which water and
sediment are routed through a subwatershed is further determined by
drainage density. Channel configurations continually adjust to
the hydrologic regime of the drainage network, therefore it is
recommended that low-order tributary channels, where possible, be
protected in order to maintain the drainage density within the
subwatershed.
The hydrologic features within the watershed and along the watercourses
serve specific functions. For example, ponds in the headwater
areas provide a source of baseflow during low-flow conditions and
attenuate surface runoff during precipitation events, thereby
moderating the storm hydrograph. Given the important function
within the subwatersheds, and especially in headwater areas,
consideration should be given to protecting existing ponds. It is
recommended that future development ensure that the ponds and wetland
areas remain part of the drainage network, where possible, and that the
storage volume of the feature is maintained.
Groundwater contributions to baseflow are important, particularly
during dry periods with little precipitation. Baseflow disperses
sediment from local channel boundary erosion and is important to
maintain aquatic habitat. Given this, it is recommended that
contributions to baseflow from groundwater recharge be maintained under
future development conditions.
7.4.2 Channel Protection and Restoration
When the planform of a watercourse is changed through modifications to
land use, then adjustments will be made by the channel, over a period
of time, to regain a natural planform configuration. Excessive
erosion of channel banks often accompanies this re-adjustment process
since the stream power has been temporarily increased within the reach
and the development of meanders requires changes to the channel
banks. This results in decreased bank stability and substantial
sediment being contributed to the channel. To avoid these
adjustments and to limit interference with natural processes, the
following recommendations are made:
adjustments to channel length within a reach should be minimized;
the meander belt width should be used as a guide to determine future
development limits;
to ensure that the channel is functionally connected to its floodplain,
a minimum entrenchment ratio should not be below 4;
limit the number of watercourse crossings where possible; and
undertake in-stream works at locations shown in Figures 7.1a and 7.1b
(end of Section 7) in order to stabilize the channel and restore
natural functions. This work should follow the principles of
natural channel design.
Where livestock have direct access to the channel, bank erosion and bed
scour occurs. Specifically, the trampling of the channel boundary
increases the volume of sediment that enters the channel. In
addition, the structure of the channel bed (e.g. pools and riffles),
which is already poorly defined given the cohesive characteristics of
the watercourses, is destroyed by livestock trampling. Both
factors also have an adverse effect on water quality and aquatic
habitat (see Section 7.6). In order to protect the structure of
the channel bed and banks, and improve water quality of watercourses
within agricultural areas, it is recommended that livestock access to
the channel be controlled and managed.
Currently, riparian vegetation is poorly or not well established along
the stream corridors. By enhancing the diversity and quality of
the riparian zone, bank stability will increase. Increased bank
stability will reduce the rate of streambank erosion. The
riparian zone acts as a buffer between a watercourse and the
surrounding land area. As a buffer, sediment from adjacent land
becomes trapped rather than being deposited directly into the
channel. Coarse woody debris, derived from riparian zone
vegetation is often an important component within a channel as it
increases channel roughness, thereby reducing flow energy. As a
result, it is recommended that riparian zones be maintained and
restored to include well vegetated with dense herbaceous plants and
grasses as well as with native species.
7.4.3 Erosion Control Through Stormwater Management
Urbanization within a subwatershed may result in changes to the
magnitude and shape (i.e. duration) of the runoff hydrograph within a
receiving watercourse. These changes may impact the natural
geomorphic processes operative within a watercourse system, leading to
excessive erosion. Through the use of urban stormwater management
practices, particularly with respect to infiltration measures and
extended detention storage facilities, it becomes possible to
effectively minimize impacts to streambank erosion. For a more
detailed discussion on the stormwater control requirements for erosion
control, see Section 7.7.2.
7.4.4 Development Policy and the Meander Belt Width
Given that the migration of watercourses (as discussed in Section 3)
may compromise the integrity of any property or structure situated
within the identified meander belt, recognition of the meander belt
width by the City, the Region, and MVCA as a natural hazard area will
ensure that future development is not impacted by the natural
meandering process of a watercourse. In addition, protection of
the watercourse system through the implementation of a meander belt
width to limit future development will ensure a continued, unimpeded
function of the natural system.
The limits of the meander belt will most often extend beyond the
aquatic habitat development set-backs and are generally contained
within, or coincident with the regulatory floodplain. Meander
belt widths may extend beyond the floodplain in limited areas resulting
from active channel erosion of the valley wall. Therefore, it is
recommended that the meander belt widths, identified on Figure 7.2a and
7.2b (at the end of this chapter) be designated a natural hazard
feature within the Shirley's Brook/Watts Creek Subwatershed.
7.4.5 Summary
Implementation of the subwatershed-wide recommendations outlined above
will facilitate future development while maintaining the natural
geomorphic function of the watercourse systems within the
Shirley’s Brook/Watts Creek Subwatersheds. Additional benefits
may also include the protection and enhancement of aquatic habitat and
wildlife within adjacent stream corridors. It is recommended
future development adjacent to sensitive stream corridors may be
subject to additional analysis, through the preparation of an
Environmental Management Plan (EMP), to establish detailed design
criteria and refine the recommendations outlined in the subwatershed
management strategy using site-specific information. A
subwatershed monitoring program is also recommended (Refer to Section
8) to record the performance of the erosion management measures
implemented as part of existing and future development. Specific
information including erosion/deposition rates, stormwater management
performance and assessment of instream works can be used to establish a
better understanding of the geomorphic processes within the Study Area
and assist in developing more effective management measures.
7.5 Management Strategy #4 - Groundwater Quality and
Quantity Management
Groundwater quality and quantity management recommendations have been
made with respect to:
the protection and enhancement of recharge and discharge areas;
the reduction of groundwater impacts associated with agricultural and
rural areas;
the regulation of groundwater withdrawals; and
maintaining existing levels of groundwater recharge.
These recommendations are discussed as follows:
Suitable development constraints for the protection of bedrock
groundwater regime were established by Raven Beck Environmental Ltd.
(1994) as part of a water resources study completed for the City of
Kanata rural area. These recommendations included the following:
Lot Sizing
That development on terrain directly underlain by Precambrian bedrock
be restricted to recommended minimum lot size of 4 ha.
That development on terrain underlain by the Nepean/March/Oxford
Formations be based on recommended minimum lot size of 0.8 ha.
The exception to this lot size is in the area immediately adjacent to
the Ottawa River where a recommended minimum lot size of 2 ha is
suggested.
Development in areas with more than 5 m of protective (low
permeability) overburden material could accommodate lot sizes of 0.8 ha
or less. However until the suitability of smaller lot sizes is
confirmed through a site-specific hydrogeologic study, a lot size of
0.8 ha is recommended.
In addition to constraints regarding lot sizing, recommendations
regarding well construction, private sewage disposal, and development
in hydrogeologically sensitive areas were also established to preserve
groundwater quantity and quality as presented below.
Well Construction
For individual lots, septic systems should be located down gradient
with respect to water supply wells with a minimum separation distance
of 60 m between any septic system and well.
It is recommended that water well records, completed during
installation, be forwarded to MOE as per current regulation. Well
installation inspection on a site-specific basis may be considered
during the submission of a building permit application subject to the
hydrogeological sensitivity of the area. Inspection may be
carried out by either the City, MVCA or MOE based upon specific
municipal or agency concerns.
In areas with highly mineralized aquifers (i.e. excessive salt), the
location and depth of a fresh water aquifer as well as the water
quality is to be verified for future considerations. Any existing
wells within the proposed area are tested and abandoned, using standard
procedures, if the water supply is found to contain excessive
quantities of salt. The use of groundwater source heat pumps
within these areas should only be considered after careful evaluation
of potential impacts.
Use of On-Site Sewage Systems
The City of Kanata encourage the use of alternative sewage systems
which treat sewage prior to discharge.
It is recommended that septic system inspection be completed by the
MVCA during construction and on a regular basis thereafter (5 year
cycle), preferably during the spring high water table period.
Homeowners with failing systems should be required to bring their
systems up to standards within a specified time frame.
Development in Hydrogeologically Sensitive Areas
Future industrial and commercial activities with the potential to
contaminate the groundwater should not be located upgradient of
existing and future domestic supply wells.
It is recommended that the groundwater quality and quantity measures,
summarized above, be incorporated in the future development
planning process for the rural areas of the Shirley's Brook/ Watts
Creek Subwatershed in order to ensure the protection of
hydrogeologically sensitive features and guide future development
within the rural areas to minimize any potential impacts.
7.6 Management Strategy #5 - Agricultural and Rural
Land Management
With approximately 44% of the Subwatershed remaining in some form of
agricultural and rural land use for the foreseeable future, formulation
of an effective agricultural and rural land management strategy has
been recognized as an important aspect of the overall Subwatershed
Plan. Proper management of farming and rural land use activities
and the lands upon which they are conducted is central to the
environmental health of the Subwatershed, just as environmental quality
is essential to sustainable agriculture. Table 7.4 summarizes the
catchment areas containing agricultural and rural land uses which are
also shown on Figure 3.6a and 3.6b (Refer to Section 3).
Farmers, along with the rural community are stewards of the land.
They act as land managers responsible for the rural environment (just
as Municipalities and urban residents assume responsibility for the
urban environment). As such, the process of agricultural and
rural land management is of a farm or landowner-specific nature and
left to the actions of the individual. Many environmental
concerns cannot be addressed by individual landowners initiatives
alone. Some require government co-ordination, education programs,
community co-operation and financial assistance.
TABLE 7.4 SUMMARY OF AGRICULTURE AND RURAL AREAS WITHIN SHIRLEY'S
BROOK/WATTS CREEK SUBWATERSHED
Subwatershed Catchment Areas General
Location
WC-1 Nepean, East of Eagleson Road
WC-3 Nepean, Headwaters of Watts
Creek
WC-4 Nepean, Headwaters of Watts
Creek
SB-1 Western headwaters of Shirley’s
Brook
SB-2 Western headwaters of Shirley’s
Brook
SB-5 Northern headwaters of Shirley’s
Brook
SB-7 Northern headwaters of Shirley’s
Brook
The development of an agricultural and rural land management strategy
includes the identification of standard mitigative and restoration
measures (such as Stormwater Management Practices) to minimize the
potential impacts associated with agricultural practices and rural
development, as well as protecting and restoring waterways, streamside
vegetation, woodlots and wetlands. The strategy includes the
identification of existing government programs, participating agencies
and potential funding mechanisms available to assist farmers and the
rural community with implementation.
If properly planned, co-ordinated and implemented in an integrated
manner with the other Subwatershed management programs (i.e.,
rehabilitation and restoration), agricultural and rural land management
initiatives can contribute significantly to the maintenance and
restoration of natural ecosystems and associated resources including
wildlife and fisheries. It is imperative to recognize however,
that the present day agricultural and rural land activities, and the
communities that support them are intrinsic to the existing
environment. In lieu of this, it must be stressed that the
environmental needs of the Subwatershed (i.e., protection of
groundwater recharge areas, environmental buffers for fish habitat
protection, reforestation, and natural corridor restoration) must
recognize, and be balanced with the needs of the farming/rural
community.
7.6.1 Management Practices
There are a variety of management practices that embody a wide range of
alternative measures directed at minimizing the potentially adverse
impacts associated with current agricultural practices. These
measures emphasize: soil conservation to reduce soil loss due to wind,
gully, sheet or rill erosion; water management to protect and conserve
surface and groundwaters, and maintenance of septic systems; and,
forestry and habitat management to restore and enhance the ecological
integrity in wetlands, woodlands and waterways.
Best Management Practices include both structural and non-structural
measures, and practical guidelines and techniques for managing soil and
water related problems associated with agricultural and rural land use
activities. Table 7.5 summarizes the rural best management
practices, benefits, suitability within the study area and requirements
to assure efficient implementation. Many of the management
measures presented in Table 7.5 are drawn from research and on-farm
experience gathered by government agencies and farm groups, published
in a series of information booklets for Ontario Farmers. The
publications discuss strategies and recommendations for incorporating
management measures dealing with soil and nutrient management, water
management, livestock and poultry waste management, field crop
production, horticulture crops, and farm forestry and habitat
management.
TABLE 7.5 SUMMARY OF RURAL BEST MANAGEMENT PRACTICES
Management Alternative Benefit
Suitability/Requirements
Source and Conveyance Control
Disconnection of Tile Drains ·
decreased runoff quantity to receiving system; increased infiltration
· runoff detainment · decreased risk of surface water
contamination (i.e., bacteria, excess nutrients)
· retrofit applications (in Shirley’s Brook only area tile
drained is along Fourth Line Road. In Watts Creek lands located
east of Hertzberg Road between Carling Drive/ CNR and
Corkstown Rd. are tile drained)
Proper Manure Handling and Storage ·
decreased runoff quantity to receiving system · decreased risk
of ground and surface water contamination (i.e., bacteria, excess
nutrients) · storage can be costly to
construct and land consuming, depending on the size of the operation
and method best suited to the farm · depending on method used,
can cause persistent odours · liquid storage facilities can
present health and safety hazards · retrofit or new
development
Proper Fertilizer Handling and Storage
· decreased risk of ground and surface water
contamination · retrofit or new development
· requires dry, solid area for storage and adequate spill
containment
Effective Manure and Fertilizer Application
· decreased risk of ground and surface water contamination
(i.e., bacteria, excess nutrients) · requires
organization, planning, and soil and manure testing
Prevention of Livestock Access to Surface Water
Resources · reduced stream erosion and
sedimentation · decreased risk of surface water contamination
(i.e., bacteria, excess nutrients) · very
limited use in the study area · requires installation of some
type of watering device · may require construction of a stream
crossing to allow livestock access to lands on both sides of water
· retrofit or new development
Water Well Protection · decreased risk
of groundwater contamination (i.e., bacteria, excess
nutrients) · requires adequate location away
from pollution sources and regular testing · retrofit or new
development
Proper Disposal of Dead Animals and Hazardous Wastes
· decreased risk of ground and surface water
contamination (i.e., bacteria, chemicals) · decreased health
risk · requires hazardous waste disposal
site
Proper Fuel Storage · decreased risk of
ground and surface water contamination · decreased health
risk · requires proper storage facilities
with spill containment and regular inspections · retrofit or new
development
Proper Pest Management · decreased risk
of ground and surface water contamination ·
requires organization, planning, and record keeping
Effective Tillage Strategies ·
decreased runoff quantity to receiving system; increased infiltration
· runoff detainment · decreased risk of surface water
contamination (i.e., chemicals, excess nutrients) · reduced
erosion and downstream sedimentation ·
requires organization, planning, and record keeping · may
require specialized or modified equipment
Proper Planning of Trips Over Fields ·
decreased runoff quantity to receiving system; increased infiltration
· runoff detainment · reduced erosion and downstream
sedimentation · requires organization and
planning
Effective Planting Strategies ·
decreased runoff quantity to receiving system; increased infiltration
· runoff detainment · reduced erosion and downstream
sedimentation; improved water quality ·
requires organization, planning, and record keeping · depending
on strategy implemented, can create some inconvenience in working
fields due to trees between crops or alternating rows of different
crops
Effective Field Surface Drainage ·
decreased runoff quantity to receiving system; increased infiltration
· runoff detainment · reduced flood risk · reduced
erosion and downstream sedimentation; improved water
quality · can be costly to construct,
depending on method chosen, design and field area ·
collection/outlet system components requires regular maintenance to
prevent sediment accumulations
Windbreaks, Shelterbelts and Natural Fencerows
· reduced wind erosion and downstream
sedimentation · results in decreased acreage
· may delay crop drying, harbour nuisance animals and/or
conflict with tile drains
Marginal/Fragile Land Retirement ·
decreased runoff quantity to receiving system; increased infiltration
· runoff detainment · reduced erosion and downstream
sedimentation · can involve moderate cost
if reforestation is implemented, but water quantity and quality
benefits will be increased, along with value as a forested natural
area
Grassed Swales/ Waterways and Roadside Ditches
· potential for decreased runoff quantity to receiving system;
increased infiltration · runoff detainment · reduced
erosion and downstream sedimentation: improved water
quality · can increase mosquito breeding
· results in decreased acreage · retrofit or new
development
Drop Pipe Inlets/Rock Chute Spillways ·
reduced erosion and downstream sedimentation
· can involve moderate construction costs · retrofit or
new development
Channel/Outlet Protection · reduced
erosion and downstream sedimentation · can
involve moderate construction costs · retrofit or new
development
End of Pipe Control
Sediment/Water Control Basins · can
provide water quantity control · potential for downstream
erosion control · potential for spill control · improved
water quality due to settling · can involve
moderate construction costs · potential for sediment
re-suspension · can increase mosquito breeding · requires
regular maintenance to prevent sediment accumulation/ clogging ·
results in decreased acreage · retrofit or new
development
Filter/Buffer Strips · potential for
decreased runoff quantity to receiving system; increased infiltration
and evapo-transpiration · runoff detainment · erosion
protection and reduced downstream sedimentation; improved water
quality · moderate cost to establish ·
results in decreased acreage · may require regular maintenance
to prevent sediment accumulation · retrofit or new
development
7.6.2 Assistance Programs
Numerous government programs are available to assist farmers and rural
landowners to reduce erosion of agricultural lands, reduce nutrient
loadings, reduce or prevent livestock pollution, improve water quality,
and promote forestry and habitat management.
The programs promote sound resource management that conserves soil,
water and wildlife. They are generally administered by the MVCA,
OMAFRA, MOEE, OMNR and Agriculture Canada. Some programs are
co-sponsored by private associations such as the Ontario Soil and Crop
Improvement Association, the Ontario Federation of Anglers and Hunters,
the Ontario Cattlemen's Association, and Ducks Unlimited Canada.
Many of the programs provide both financial (grants, rebates and low
interest loans) and technical assistance (fact sheets, consultation,
and plan review).
A list of available programs include:
Ontario Environmental Farm Plan Incentive Program (through Ontario Soil
and Crop Improvement Association);
Structural Erosion and Tree Planting Program (through the MVCA);
Management Forest Tax Rebate Program (through OMNR);
Community Fisheries/Wildlife Involvement Program (through OMNR);
Ontario Land Care (through Ducks Unlimited Canada);
Environmental Partners Fund (through Environment Canada); and
Regional Rural Clean Water Program.
7.7 Management Strategy #6 - Urban Stormwater
Management
7.7.1 Urban Stormwater Management
The current practice of stormwater management advocates a hierarchy of
preferred Stormwater Management Practices (SWMP's) as outlined in the
updated (Draft) Stormwater Management Practices Planning and Design
Manual (MOE, 1998):
i) Source and Conveyance (system)
Controls.
ii) End of pipe Controls.
iii) Miscellaneous Controls.
Source controls should be considered first in the hierarchy in a manner
that is balanced with the other two measures in terms of environmental,
social and economic impact, costs and benefits. The “source
control first” approach in stormwater management should only be
implemented after benefits and environmental/social impacts and costs
are considered and compared to those associated with conveyance and
end-of-pipe measures.
The EA process requires the consideration of the “do nothing”
alternative. As shown in Section 5.0, a “do nothing” alternative
would increase peak flows, runoff volume, and pollutant loading
to receiving watercourses from increased urban development. This
would create an increased risk to safety, health hazards,
property and environmental damages. As a result, the “do nothing”
alternative described in Section 5, was not considered to be an
acceptable alternative.
A list of the latest techniques used to control urban runoff including
a detailed description and applicability within the Shirley's
Brook/Watts Creek Subwatershed is presented in Appendix G.
It is important to note that the ultimate selection of SWMPs is
dependent on the site-specific and in some instances, reach-specific
characteristics, sensitivities and serviceability issues present within
the study area. As well, the selection of the appropriate
alternative(s) must be based not only on technical consideration such
applicability and cumulative effects, or on economic consideration
reflecting long term operation and maintenance costs but also on
acceptability by the public.
7.7.2 Stormwater Control Requirements
Water Quality Control
The treatment of urban stormwater quality is typically accommodated
through end-of-pipe extended detention storage, complimented by source
and conveyance control measures. However, consideration should be
given to extensive use of source and conveyance given the potential
benefits including recharge to groundwater, erosion control and peak
flow attenuation:
Groundwater recharge is particularly important in maintaining shallow
groundwater inputs which lead to shorter low flow detention in
receiving watercourses; reduced cost of sewer infrastructure;
reduced end-of-pipe size and erosion control; a potential
reduction in severe infrastructure costs; and size of end-of-pipe
facilities.
A subsequent review are carried out in order to determine the benefits
of infiltration based measures within the Shirley's Brook/Watts Creek
Subwatershed. Subsurface soil conditions within the development
areas generally indicated a low potential for infiltration with the
exception of catchment areas SB-4, SB-5, SB-6 and KD-2. Soils
within these catchment areas were identified as having higher
infiltration capacity, and therefore, infiltration based measures are
recommended for implementation based on site-specific sub-surface
investigation carried out as part of detailed studies for future
development.
Recommended water quality treatment requirements for Shirley's
Creek/Watts Creek Subwatershed, as shown on Table 7.6, were based on
end-of-pipe storage volumes obtained from the Draft MOE Stormwater
Management Practices Manual, reproduced in Table 6.2.
Table 7.6 Summary of Recommended Catchment Area Water
Quality/Quantity Requirements for Future Urban Development Within
Shirley's Brook/Watts Creek Subwatershed
(1 page)
Table 7.6 summarizes future development areas for each catchment,
average percent imperviousness based on the Regional Official Plan,
level of required water quality protection, average unit water quality
volumes for each catchment area, and minimum permanent pool and
extended detention volumes required to address water quality for each
catchment area.
Unit water quality volumes are expressed over the entire catchment area
and require refinement using Table 6.2 based on site-specific land
use. It is important to note that potential reductions of
end-of-pipe storage requirements through implementation of infiltration
based source and conveyance measures has not been considered in the
preparation of Table 7.6. This can be attributed to the
uncertainties with respect to operation and maintenance considerations
and longevity of these types of SWMPs. However, this does not
preclude future use of these measures within the study area. It
is recommended that these measures be maximized, where possible, to
compliment end-of-pipe facilities and, potentially reduce storage
requirements in those areas identified above, subject to additional
site-specific investigations.
Stream Erosion Control Requirements
In order to evaluate the needs of erosion control for future urban
development within the Shirley's Brook/Watts Creek Subwatershed, a
hydrologic assessment was carried out using continuous hydrologic
modelling (Refer to Section 5.4). Geomorphic information
including critical threshold and bankfull flows, collected at several
cross-section locations throughout the study area, were also utilized
in the analysis. Average annual duration and frequency of
occurrence for a range of flows were assessed under various development
conditions including:
Current land use conditions;
Future land use conditions without SWM controls; and
Future land use conditions with SWM including extended detention water
quality treatment and 100-year flood control.
In general, flows from uncontrolled urban development increase in
frequency and duration over existing conditions as a direct result of
urbanization. As the magnitude of flow increases, reflecting less
frequent events, the impacts to frequency and duration are less
significant. Under future conditions with implementation of
extended detention, the frequency of peak flows are reduced.
However, duration at low flows increases as a direct result of
additional runoff volume from increased impervious areas. As
flows increase, the duration and frequency of flows diminish to
existing levels.
Results of the analysis have been summarized on Table 7.7 and presented
graphically in Figure 7.3 to Figure 7.7. Based on a review of the
information, it is apparent that under existing conditions, the streams
within the Study Area react fairly slowly to minor rainfall events, as
seen by the low number of exceedances for small discharges. In
order to protect a watercourse from increased erosion resulting from
urban development, critical threshold flow targets were determined at
several key locations through geomorphic analyses (refer to Section
5.4, Table 5.6). The duration and frequency of controlled future
flows should not exceed critical threshold flows in order to minimize
potential impacts to channel erosion. From the graphs, it is
clear that several sites experience erosion frequently, due to low
critical flow thresholds. This is confirmed through field
investigations which revealed current erosion conditions resulting from
channel alterations and previous effects of beaver activity within the
Study Area.
A review of proposed development conditions without stormwater
management controls indicates that the critical flow thresholds for
erosion are exceeded frequently. Further, peak flows increase
dramatically in both magnitude and frequency, suggesting that several
locations would experience substantial erosion. A graphical
comparison presented in Figure 7.3 to Figure 7.7 indicates that
implementation of water quality extended detention storage reduces the
magnitude of future flows such that the critical thresholds for erosion
along the respective reaches are generally not exceeded. The
duration of flows lower than the critical flows will tend to increase
over the existing durations in some reaches, regardless of SWM.
However, the depth of these flows is typically only 10 cm to 15 cm,
which will not directly impact channel erosion, but may contribute to
some weathering of the channel boundary.
A review of critical threshold flows indicates that water quality
extended detention requirements provide adequate erosion protection for
a majority of the watercourse reaches within the subwatershed
area. Durations of flow, at or above calculated thresholds,
determined at several key locations, were generally at or below
existing levels. Therefore, further extended detention storage
above water quality requirements is not required for erosion protection
with the Shirley's Brook/Watts Creek Subwatershed. For control of
the 2 to 100 year peak flows, see recommendations under Flood
Control. Excessive duration of low flows above the water quality
Table 7.7 Comparison of Duration and Frequency of
Flows for Existing and Future Land Use Conditions
(3 pages)
requirements may result in potential impacts to the stability of the
receiving streams given the cohesive nature of the in-stream soils
found within the study area. To ensure that erosion impacts from
future development are minimized, it is recommended that proposed
storage facilities be constructed off-line and placed at strategic
locations to minimize both downstream and local catchment erosion to
receiving watercourses.
The channel boundary materials in most reaches of Shirley's Brook and
Watts Creek are characterized by cohesive sediment (i.e. clay and
silt). As discussed in Section 5.4.3, geochemical weathering is
an important process in the erosion of cohesive sediment. Thus,
the duration of flow within a channel is an important factor in the
determination of channel bank and bed erosion.
The selection of the stormwater control requirements require a careful
balance of erosion control and water quantity/quality
considerations. The issue is how to minimize the weathering of
cohesive channel boundary material, while satisfying the need for water
quality and quantity control.
From the assessment completed for the subwatershed study, results from
field work and various empirical analyses, revealed that several
reaches within Shirley's Brook and one section of a reach within Watt's
Creek had cohesive channel boundary material, which was predominantly
clay. These sites were located in Catchments SB-4 and SB-5,
within Shirley's Brook and WC-5 within Watts Creek. The hydraulic
analyses for the determination of a critical flow, where erosion of the
channel boundary would occur, at these sites yield fairly high values,
which would be expected given the physical nature (strength, smooth
surface) of the material. However, it is also known that these
cohesive materials are susceptible to physical weathering, especially
from wet-dry cycles. Unfortunately, the quantification of the
weathering processes is difficult if not impossible. Attempts to
find a published laboratory value for a weathering and/or erosion rate
were not successful.
With this understanding, a stormwater management strategy was developed
that would reduce the amount of channel adjustment and erosion to the
impending increase in flow volumes. This was largely accomplished
through implementing traditional stormwater management
techniques. An initial concern was the effect of frequent, small
precipitation events that currently produce little or no runoff.
Through urbanization, these same precipitation events would result in
substantial runoff and consequently, more flow through receiving
channels, which would increase the number of wet-dry cycles and
therefore likely lead to greater weathering. Through the proposed
stormwater management analysis, the discharge values (well below the
critical threshold) from these minor precipitation events will have a
minimal impact on increased flow depths (<5 cm to 10 cm), which
would be expected to have little effect on the channel.
The stormwater management analysis of the larger flows (>15 mm of
rain), with detention for quality and quantity treatment shows that the
controlled flows do not exceed the hydraulic critical thresholds for
erosion, but these extended flows would be conveyed through the
channel, with greater depth, thereby leading to more weathering.
However, if outflows from stormwater management facilities are not
controlled for less frequent events (i.e. 2 to 100 year), the frequency
and duration of the flows could be reduced to approach pre-development
conditions, but the resulting uncontrolled flow would exceed existing
peak flow, and could create a potential liability and hazards
downstream.
Therefore, it is recommended that the larger flows (2 to 100 years)
should be controlled to pre-development conditions for flood and
erosion. During the catchment level EIS the alternative of less
control of larger flows and its effect on channel weathering should be
investigated, especially in Catchments SB-4, SB-5 and WC-5.
Flood Control
A common element in the management of urban stormwater runoff is the
need for flood control. The goal of flood control is to
provide protection of downstream riparian owners against existing and
the potential increased flood risk caused by future development.
To address this risk, alternatives may include: flood control through
the use of traditional end-of-pipe storage facilities designed to
maintain post-development peak flows from new developments to existing
levels for the 2 year to 100 year storm event; and a combination of
in-stream channel and/or structural improvements to accommodate
unattenuated increases in peak flows from future development.
The use of end-of-pipe storage facilities are a recommended method of
flood control for urban development within Shirley's Brook/Watts Creek
Subwatershed. However, the use of in-stream and/or hydraulic
structure improvement is not precluded from future implementation
within the subwatershed given that an additional impact assessment is
carried out. This may be considered as a subwatershed-wide
alternative during the preparation of updated flood plain mapping or on
a site-specific basis as part of an Environmental Management Plan (EMP)
required for new development.
Table 7.6 summarizes the minimum flood control volume required to
maintain post development flows to predevelopment levels for each
catchment area based on ROP future land uses. These volumes serve
as a guide for reviewing agencies during submission of detailed
Stormwater Management Plans.
7.7.3 Stormwater Management Practices
Stormwater Management Practices consist of a number of recommended
measures to mitigate potential adverse effects associated with urban
stormwater runoff. These measures can be incorporated on
individual lots (source control), as part of the conveyance system and
at the end of pipe, to treat water quality, provide stormwater erosion
and peak flows and control spills.
Table 7.8 summarizes the recommended SWMPs considered most appropriate
for application within each catchment area for the Shirley’s Brook and
Watts Creeks Subwatersheds. Recognizing that the subsoils
underlying many of the catchments within the Subwatersheds are not
conducive to infiltration measures and the relatively large size of the
planned development areas themselves, source controls alone would not
achieve minimum stormwater management requirements, therefore, a
standard approach including end-of-pipe storage complimented with
source and conveyance controls is envisioned to be a requirement for
most development areas.
Collectively, the function of end-of-pipe storage is to provide water
quantity control (i.e., peak flow control for flooding and streambank
erosion) and water quality treatment of urban stormwater runoff.
The use of a limited number of strategically located facilities is
favoured for both environmental and practical considerations.
Experience indicates that a reduced number of multi-purpose regional
facilities achieve a higher standard of performance in terms of water
quality treatment, while also minimizing maintenance and operational
requirements once constructed. Generally, the economics of
multi-purpose regional facilities are more favourable, resulting in a
cost-effective use of available lands.
It is important to note that measures identified in Table 7.8 are
provided to assist in the preparation of more detailed stormwater
management planning strategies for proposed development within each
catchment area. Specifically, they are intended to serve as a
guide for the developer proponent, the City and the review agencies
(e.g. MVCA and MOE) in the preparation, review and approval of
Stormwater Management Plans and Reports. The detailed design and
siting of the SWMPs,
Table 7.8 Summary of Recommended Stormwater
Management Practices
(4 pages)
including the size, type and number of end-of-pipe facilities is highly
dependant on the site-specific constraints and opportunities associated
with future development areas which only become evident and can be best
addressed during the subdivision planning process.
It is expected that this next level of planning and design occur at or
close to a catchment area level of detail. As it is likely that
any one catchment area will involve more than one landowner, it is
anticipated that collaboration will be required among developers in
preparing a Stormwater Management Plan. Further details regarding
expectations in developing the stormwater management plan for proposed
developments are presented in Section 8.3.3.
The recommended types of measures presented in Table 7.8 should be
considered for the treatment/control of urban stormwater and are not
meant to preclude the use of alternative measures subject to municipal
or regulatory agency approval.
Equally important to point out, is that, although the measures
identified in Table 7.8 have been adopted, in principle by the City,
the Region and the MVCA (i.e., they are acceptable as the minimum
requirements in an overall stormwater management strategy), final site
approval is still required.
In this regard, it is not the intent of this Report to imply that a
guarantee of approval has been established for any specific location,
size, or type of stormwater measure. All stormwater management
concepts must be approved by the City of Kanata, as part of to the plan
review process. In addition, all stormwater management ponds will
require a Certificate of Approval (COA) under the Ontario Water
Resources Act, which will require formal approval by the MOE.
7.7.4 Retrofitting Existing Urban Areas
Approximately 27% of the Watts Creek Subwatershed and 11% of Shirley's
Brook Subwatershed comprises urban land uses respectively with the
majority of urban development serviced by municipal storm sewers that
collect and convey surface runoff to outfalls located along the
watercourses. The incorporation of stormwater management measures
as a means of retrofitting the existing urban areas is
recommended to improve water quality conditions in the receiving
tributaries and mitigate the existing impacts relating to urban
development.
The following stormwater management alternatives are recommended as the
basis for formulating a strategy to retrofit existing urban areas.
An inventory of the existing urban storm drainage system should be
completed to identify the "micro-drainage" system associated with the
existing developed areas. The inventory would identify storm
sewer outfall locations, catchment areas, storage facilities, drainage
patterns and houses with roofleader downspouts connected to storm or
sanitary sewers.
Water quality samples should be taken at each storm sewer outfall
during one wet weather event and one dry weather event (if feasible) to
identify any possible sources of upstream pollutants such as faecal
bacterial, hydrocarbons, etc. which could indicate a sanitary sewage
cross-connection or pollutant source. If observed, a follow-up
program of sampling, smoke and/or dye-testing could be undertaken to
locate any improper/illegal connections or sources of pollutants.
Existing park and open space areas could be modified to incorporate
stormwater management measures, including infiltration (if suitable
subsoils exist) as a means of groundwater recharge and/or water quality
treatment of surface runoff.
Where possible, retrofit existing flood control ponds into multiple
purpose facilities to include baseflow augmentation, water quality and
erosion control functions.
During road and/or sewer reconstruction, measures such as infiltration
trenches and/or grassed swales should be integrated in the road
right-of-way where feasible.
Existing municipal maintenance programs should be reviewed and
modified, where applicable, to increase the frequency of street
sweeping, catchbasin sump cleanout and flushing of storm sewers.
Buildings (mainly commercial and industrial) identified with roofleader
downspouts connected to storm or sanitary sewers should have the
downspouts redirected to discharge onto grassed areas and shallow
ponding areas via splash pads to encourage infiltration and evaporation.
Consideration should be given to the limited use of oil and grit
separators for specific urban uses such as service stations and
commercial/industrial parking areas, as a means of spill control to
prevent hazardous chemicals from entering surface waters.
7.7.5 Erosion/Sediment Control for Construction Sites
An important aspect to consider during urban construction within the
study area is the control of erosion and sediment. Construction
activities such as clearing, stripping and grading exposes soil to
precipitation and to surface water runoff. If uncontrolled, these
activities could create significant increases in sediment loadings to
receiving watercourses draining the subwatersheds. This, in turn,
may lead to the impairment of water quality and degradation of the
natural environment.
In order to address this issue, a set of recommended measures to
minimize erosion and sediment during construction activities has been
included in Appendix I.
7.8 Design Guidelines for Future Development
To complement the recommended measures outlined in the previous
sections, a set of design recommendations are provided for future
development proposals, to ensure development conforms to the intent of
the urban stormwater management strategy. This section includes a
discussion of recommended sizing, design and maintenance guidelines for
stormwater management ponds.
Site Drainage and Servicing Guidelines
The proper design of the on-site storm drainage system associated with
new development is required to ensure standardization within the City
of Kanata. Adherence to the City’s Municipal Design &
Construction Standards for Sewers, Watermains & Roads should be
maintained to ensure an adequate level of service, facilitate storm
drainage and minimize on-site flooding impacts (such as flooding of
buildings, roads and parking lots). The principles governing the
design of the major and minor systems should follow Provincial
guidelines outlined in the Urban Drainage Design Guidelines (MNR, et
al., 1987c). Accordingly, the following recommendations should be
considered in the design of subdivision services:
The stormwater management system should recognize the dual drainage
concept;
The minor system should be based on the 2-5 year return period storms
depending on the type of development;
The major system should be based on the 100 year storm;
Storm sewer surcharges for all minor storms should be avoided;
For major storms, storm sewer surcharges should be limited to
approximately 3 cm above curb level;
Basement sewer connections should be set at least 50 cm above the 100
year hydraulic grade line;
Proper grading of the site properties and roadways should be ensured to
provide a continuous flow path for the major system flows;
Flow depths on the roadways should be checked (upon finalization of the
grading plan) to ensure that vehicular access can be maintained and
buildings are not flooded during severe storm events; and
Ponding depths in parking lot areas should be checked to ensure that
nuisance flooding is avoided during frequent storm events.
Stormwater Management Pond Guidelines
To ensure the successful implementation and general acceptance of
stormwater management facilities, consideration must be given to
safety, aesthetics, maintenance and design details.
To assist the development proponents and the City of Kanata in the
design, implementation and operation of these facilities, a set of
recommendations have been developed and include:
Design Features
Facility designs should follow the general design guidelines as
outlined in the draft "Stormwater Management Practices Planning and
Design Manual" prepared by MOE.
A geotechnical investigation should be carried out at proposed pond
locations to assess the suitability of the site with respect to
groundwater levels, bedrock and slope stability concerns (where
applicable).
The end-of-pipe facilities should be treated as complementary landscape
features, enhancing the adjacent natural features, parklands or the
general landscape.
· A landscape plan should be prepared for each
end-of-pipe facility. In addition to aesthetics, shading
provided by plantings around the facility will assist in minimizing of
thermal impacts of outflows in the receiving watercourse.
· A planting plan should be prepared for each
end-of-pipe facility to complement and enhance its quality control
functions. Plant species should be selected to meet the wide
gradient in soil moisture conditions anticipated in and around the
ponds.
· An access road to each end-of-pipe facility
should be provided. In addition, a maintenance strip should be
included around the perimeter of the pond to allow for maintenance and
operational activities such as grass mowing and the removal of trapped
debris.
· All end-of-pipe facilities should be
constructed with a sediment forebay to trap larger particle near the
inlet of the pond. In general, the sediment forebay should be no
more than one third of the pond surface area and should have a minimum
length to width ratio of 2:1.
· An access road extending into the sediment
forebay should be incorporated into the pond side slopes to facilitate
removal of accumulated sediment by mechanized equipment.
· Maximum side slopes of five horizontal to
one vertical should be provided for wet ponds and artificial wetlands
below the permanent pool.
· Consideration should be given for terraced
grading around the perimeter of the pond extending up from the water's
edge of the permanent pool, based on accessibility, maintenance and
safety considerations.
· All ponds should have a minimum length to
width ratio of 3:1.
· Public information initiatives should be
undertaken to promote public awareness of the operational aspects,
environmental objectives and safety awareness of the ponds.
During storm events, rapid fluctuations in water levels may occur which
could pose some risk to public safety. Therefore, the ponds
should not be viewed as recreational facilities, and activities other
than passive uses should be discouraged. Often these type of
facilities are enclosed by chain link fencing to prevent public
access. Measures such as terraced grading, strategic plantings to
restrict public access, warning signs and public awareness, are
generally sufficient to provide a level of safety such that fencing is
not required. In this regard, the City of Kanata should consider
the level of precaution required and assess the need for fencing.
Construction Phasing
The construction phasing and implementation of the end-of-pipe
stormwater management facilities is anticipated to proceed as
follows. Where a stormwater management facility is proposed to
accommodate a single development area, the design and construction of
the facility would proceed concurrently, as part of the individual
Draft Plan of Subdivision.
Where a regional facility is proposed to service a larger development
area comprising several proponents, alternatives may include the
following:
· A proponent developer(s) could purchase the
land or lease agreement to construct the facility.
· The City could purchase the land or
establish a purchase-lease to construct the facility and then seek
appropriate compensation from the developers via lot levies.
· The individual developer(s) wishing to
proceed could construct a temporary facility on their own lands to
subsequently treat the stormwater on-site until development proceeded,
necessitating the need for the regional facility to be built.
Ownership
All end-of-pipe facilities, once constructed, will be assumed,
maintained and operated by the City of Kanata, for those facilities
located within the City boundaries.
Operation and Maintenance
To ensure that the end-of-pipe stormwater management facilities
continue to operate as designed, the following recommendations are
provided to assist the City in planning for the maintenance and
operation of the facilities. The recommendations are general in
nature considering that there may be slight variance in maintenance
requirements for each end-of-pipe facility depending upon whether it is
an artificial wetland, wet pond or dry pond.
· Embankment side slopes should be mowed a
minimum of 8-12 times per year.
· The pond should be inspected annually
(during wet weather operation) to assess performance and
operation. Embankment stability, erosion, sediment and debris
accumulation, and inlet clogging should be noted.
· Debris and litter, particularly floatable
debris around the riser pipe should be removed.
· Incidence of embankment slumping and/or
erosion should be remediated by regrading, revegetating and/or
placement of rip-rap.
· Accumulated sediments should be cleaned-out
approximately once every 10 years. The frequency of clean-out may
vary depending upon the characteristics of the contributing drainage
area and should be assessed through the annual inspections.
City of Kanata Stormwater Planning and Design Standards
To ensure the infrastructure designs can be readily designed, approved,
constructed, and maintained, it is recommended that the City of Kanata
in co-ordination with other regional municipalities update its
stormwater management planning and design standard drawings and
specifications. The ability to quantify the
cost-effectiveness of source controls, including ability to reduce the
quantity and improve the quality of run-off should be part of the study.
Addressing the standards in co-ordination with the other municipalities
will ensure a consistency for designers and contractor that will
minimize the long-term costs (life-cycle-costs) incurred by the
developer and municipality and ultimately the home-owner and tax-rate
payer.
Support for this initiative is available from the Region and Ministry
of Environment.
It is recommended that the City of Kanata’s Design Manual dealing with
drainage should be reviewed and updated to reflect the Shirley’s
Brook/Watts Creek Subwatershed Study recommendations. For example
the Lot Drainage Design Guidelines 3.2.1 which specify minimum slopes
for yard surfaces and swales should be revised to permit minium slopes
less than 1.5 %. Similarly, Drawing No. KSD-230.01 illustrating
Grading Requirements and Drawing No. KSD-230.04 Grade Control Plan
Requirements should be made compatible with the recommendations within
the subwatershed study.
7.9 Current Development Proposals
There are a number of development proposals currently in progress
within the Shirley’s Brook/Watts Creek Subwatershed. Numerous
studies (e.g. SWM Plans, EIS’s, EMP’s) are being completed or have been
previously submitted for review and approval in support of these
development plans. The criteria and concepts presented within
these studies may vary from specific recommendations outlined in this
Subwatershed Study. Notwithstanding, the current Federal,
Provincial and municipal policies and guidelines, which form the basis
for which the subwatershed strategies were developed, must still be met
in order to obtain appropriate municipal and regulatory agency
approvals.
In light of this, it is recommended that municipal and regulatory
agencies continue to review current development plans underway within
the subwatershed on a site specific basis, using current policy and
guideline documents. Future development activities subsequent to
the adoption of the Shirley’s Brook/Watts Creek Subwatershed Study
should incorporate subwatershed recommendations as outlined in this
document.
8.0 IMPLEMENTATION STRATEGY
8.1 Introduction
This section presents the Implementation Strategy which has been
designed to maintain and improve the health of the subwatersheds by
implementing the recommended management strategies as presented in
Section 7.0.
It is important to recognize that the Subwatershed Strategy can only be
phased in gradually over time. Strategy components such as Urban
Storm Water Management will occur only when land development
proceeds. Other initiatives, such as habitat restoration, are not
necessarily linked to land development and could be initiated as funds
become available. It is expected that the implementation of the
Subwatershed Plan will extend over a number of years and in many
respects needs to be viewed as an ongoing long-term initiative.
This includes regular updating of the Subwatershed Plan to ensure that
it remains relevant.
To implement the recommendations made in this subwatershed study and to
fulfil its goals and objectives, assistance will be needed from a
number of stakeholders including: government agencies; the development
community; the public and interest groups. This implementation
strategy has been organized on the basis public sector and
private sector initiatives. With respect to public sector, it is
expected that most initiatives will require co-ordination led through
by either the City of Kanata, the Region, MVCA and the NCC for
initiatives on their property. The City of Nepean will also have
a role through the approval of developments within their
boundaries. What agency assumes the lead role will depend on the
specific initiative. Further assistance, including funding, may
be required from provincial agencies. Table 8.1 presents a
summary, by strategy component, of the key implementation
recommendations that are based on the Subwatershed Strategy presented
in Section 7.0. Table 8.1 also presents implementation
mechanisms, and recommended lead agencies as well as funding
responsibilities. The remaining sections provide subsequent
details regarding the recommended initiatives.
Table 8.1 Recommended Implementation Strategy
8.2 Public Sector Initiatives
8.2.1 Introduction
The following provides a summary of the recommended key public sector
initiatives that are to be undertaken in order to fulfil the objectives
of this subwatershed study. Also identified are the parties that
are to be involved in the implementation of the initiative as well as
an outline of required actions.
8.2.2 Natural Area Management
The Natural Area Management recommendations as they relate to the
public sector include 1) Official Plan changes; and 2)
protection/restoration initiatives as described below:
Initiative #1 - Natural Area Management Policy Changes
An audit of Kanata’s current Official Plan was conducted to determine
the extent to which its environmental policies address the matters of
provincial interest articulated in the Provincial Policy Statement as
well as the extent to which the policies conform to the Region’s
Official Plan. Through this audit, a number of policy actions
have been recommended as presented in Appendix F.
Action: The City of Kanata is to consider the
recommended Official Plan policy changes in the development of their
new Official Plan.
Initiative #2 - Protection/Restoration of Aquatic Habitat
The subwatershed study has identified and classified fish and aquatic
habitat by stream reach (see Figure 3.2a and 3.2b at end of Section
3.0). High quality habitat (Type I) is to be protected from
future development through an appropriate development setback based on
the habitat type as well as criteria suggested in this Plan (see
Section 7.2.3.1).
Action: The City of Kanata is to ensure that
developers are aware of the recommended aquatic development setbacks.
Also recommended in this Subwatershed Plan are the areas of poor
aquatic habitat that are to be restored. These areas have been
prioritized (see Table 7.1) and recommendations made as to what
restoration efforts should entail. Habitat restoration
should be considered as one of the key priorities of this subwatershed
strategy. As previously noted, opportunities for restoration may
develop as a result of land development proposals. The KRP lands
are a good example of this, as the section of creek that flows these
lands is highly degraded. Stream restoration efforts could be
tied into the proposed golf course. Discussions with developers
should occur early to ensure that restoration efforts are tied into the
overall site plan.
For stream reaches that are not included in proposed development areas,
restoration efforts will require landowner permission. Either the
City or MVCA are best suited to co-ordinate these initiatives.
Action: The City/MVCA should work with developers
where proposed development lands include reaches of degraded aquatic
habitat. For other priority areas, the City/MVCA should develop
site specific action plans with the assistance of landowners and local
interest/community groups. For federally owned lands, the NCC is
to lead the initiative. These action plans will need to detail
required in-stream works as well as cost estimates so that appropriate
funding can be raised.
Initiative #3 - Protection/Restoration of Terrestrial Habitat
Recommendations have been made for the protection as well as
enhancement of significant woodlands within the subwatersheds.
These recommendations recognize the presence of two wildlife corridors
that run through the study area. In order to maintain these
corridors, a number of individual woodlots will require to protection.
Woodland/wetlands have been prioritized for protection/enhancement (see
Table 7.2). There are some priority areas that are currently not
protected from development. These include (K2, K4, K9, S1, S2 and
S4). Obtaining these properties may be required to assure their
protection. Securement mechanisms for the protection of the
natural areas and wildlife corridors are presented in Table 8.2.
Available mechanisms include:
Planning Act;
Land acquisition; and
Land stewardship.
· Table 8.2 Possible
Securement Mechanisms for Protecting Natural Features/Areas in the
Shirley's Brook/Watts Creek Subwatershed
(8 pages)
For those natural areas that are protected through their current
designation, recommendations on maintenance/restoration are outlined in
Table 7.2. Privately owned lands will require landowner
co-operation.
Action: The City of Kanata should embark on a program
to secure the priority woodland/wetland areas. These lands may be
secured through land dedication as lands are developed or if necessary,
through purchase or means of securement. As there are presently
no mechanisms to prevent the clearing of these areas by landowners,
this initiative should be acted upon as soon as possible. As
well, for those woodlands that are degraded, with landowner
co-operation/incentives, these areas should be enhanced. It is
assumed that lands under federal ownership would be appropriately
managed by the NCC.
8.2.3 Flood Management
The following flood management initiatives have been recommended:
Initiative #4 - Revise/Update and Extend Flood Mapping
Recognizing the most recent changes in the subwatersheds, the MVCA is
to embark on a program to update the floodplain mapping.
Additional floodplain mapping should be prepared for the upper reaches
of the Shirley’s Brook tributaries (i.e. 1 and 2) to identify potential
flooding hazards upstream of March Road.
Action: Update and extend floodplain mapping for both
Shirley’s Brook and Watts Creek.
Initiative #5 - Hydraulic Structure Improvements
A number of bridges/culverts have been identified that have inadequate
capacity to pass the 100 year storm peak flows (see Table 7.3).
Improvements such as enlargement/replacement of these structures should
be undertaken.
Action: Hydraulic structure improvements should be
undertaken as part of road structure upgrade works.
Initiative #6 - Flood Policy Updates
To reflect the update floodplain mapping, the City of Kanata, City of
Nepean and the Region shall designate the hazard lands appropriately
through updates/amendments to their Official Plans.
Action: The local and Region Official Plans are to be
updated/amended to recognize changes to the floodplain once the
floodplain mapping is updated.
8.2.4 Erosion Management
Initiative #7 - Erosion Prevention Works
A number of areas along the watercourse reaches have been identified as
being susceptible to erosion (Refer to Figures 7.1a and 7.1b at end of
Section 7.0). Through natural channel design measures, it is
recommended that channel restoration works be undertaken at these
locations in order to stabilize the channel and restore natural
functions.
As well, special care shall be taken to protect headwater and on-line
ponds recognizing the important hydrologic function they serve (source
of water during low flow conditions).
Action: The City/MVCA should work with developers to
restore channels where proposed development lands include reaches
susceptible to erosion. For other areas, the City/MVCA should
develop site specific action plans with the assistance of landowners
and local interest/community groups.
Initiative #8 - Policy Update to Reflect Meander Belt
Meander belt widths were delineated within major watercourse and
tributary areas of the Shirley's Brook/Watts Creek Subwatershed.
In light of the ongoing natural process of migration expected to occur
within the identified limits of the meander belts, it is recommended
that these areas be designated as natural hazard areas.
Action: The local and Region Official Plan are to be
amended to incorporate the limits of the meander belt for areas
identified within the Shirley's Brook/Watts Creek Subwatershed.
These areas are to be designated as natural hazard lands and regulated
appropriately through the Region, City and MVCA.
8.2.5 Groundwater Quantity and Quality Management
Initiative #9 - Policy Changes
Recommendations to protect groundwater supplies from future development
in rural areas, as presented in Section 7.5, need to be adopted by the
City of Kanata in the form of policy.
Action: The City of Kanata should consider the
adoption of the groundwater management recommendations when updating
their Official Plan.
8.2.6 Agriculture and Rural Land Management
Initiative #10 - Farmer/Landowner Education
A number of agricultural and rural best management practices have been
recommended in the Subwatershed Study Report (Refer to Table
7.5). These recommendations include mitigative and restoration
measures to minimize potential impacts associated with agricultural
practices and rural development, as well as protecting and restoring
waterways, streamside vegetation, woodlots and wetlands. For the
most part, these initiatives can only be undertaken by the
landowner. These recommended measures should be promoted by the
MVCA taking advantage of the various provincial and federal rural
assistance programs that are available (see Section 7.6.2).
Action: The MVCA is to promote agricultural and rural
best management practices.
8.2.7 Urban Storm Water Management
Many of the recommendations presented within the Urban Storm Water
Management Strategy relate to storm water control requirements and
suitable management practices for new development. Although the
City/MVCA needs to be aware of these recommendations, they have the
greatest implications for developers and are examined in Section 8.3.
There are, however, a number of initiatives relating to the
retrofitting of existing urban areas that will need to be led by the
City of Kanata including.
Initiative #11 - Existing Urban
Storm Drainage System Inventory
An inventory of the existing urban storm drainage system should be
completed to identify the "micro-drainage" system associated with the
existing developed areas. The inventory would identify storm
sewer outfall locations, catchment areas, drainage patterns and houses
with roofleader downspouts connected to storm or sanitary sewers.
Action: City of Kanata to undertake an inventory of
the “micro drainage” system for developed areas.
Initiative #12 - Storm Sewer
Outfall Water Quality Sampling
Water quality samples should be taken at each storm sewer outfall
during one wet weather event and one dry weather event (if feasible) to
identify any possible sources of upstream pollutants such as faecal
bacterial, hydrocarbons, etc., which could indicate a sanitary sewage
cross-connection or pollutant source. If observed, a follow-up
program of sampling, smoke and/or dye-testing could be undertaken to
locate any improper/illegal connections or sources of pollutants.
Action: Region should initiate a water quality
sampling program with City assistance (see Section 8.2.9).
Initiative #13 - Identifying
Opportunities to Retrofit Parks and Open Spaces
Existing park and open space areas could be modified to incorporate
source and conveyance, stormwater management measures, including
infiltration (subject to suitable subsoils, bedrock and water table
levels) as a means of groundwater recharge and/or water quality
treatment of surface runoff. Also, storage facilities may be
considered including landscaping, to provide further water quality
treatment and control benefits.
Action: City to identify opportunities for
retrofitting of parks and open spaces.
Initiative #14 - Integrate Source
Control Measures During Road/Sewer Reconstruction
During road and/or sewer reconstruction, measures such as infiltration
trenches and/or grassed swales should be integrated in the road
right-of-way where feasible.
Action: City to ensure that these integration
opportunities are pursued.
Initiative #15 - Retrofit Buildings
with Roof Leaders Connected to Storm/Sanitary Sewers
Buildings (mainly commercial and institutional) identified with
roofleader downspouts connected to storm or sanitary sewers should have
the downspouts redirected to discharge onto grassed areas and shallow
pond areas via splash pads to promote infiltration and separation.
Action: City to encourage retrofitting of buildings
with roof leader connections to storm/sanitary sewers.
Initiative #16 - Consider the
Requirements for Oil/Grit Separators for Storm Sewers Draining
Commercial Areas.
Consideration should be given to the limited use of oil/grit separators
for specialized commercial areas (i.e. service stations, parking lots
and loading areas) and as a means of spill control to prevent hazardous
chemicals from entering surface waters.
Action: City to advise an appropriate use of oil/grit
separators.
Initiative #17 - Municipal Maintenance Program Review
Existing municipal maintenance programs could be reviewed and modified
where feasible to increase the frequency of street sweeping, catchbasin
sump cleanout and flushing of storm sewers.
Action: City to undertake a review of existing
municipal maintenance program.
8.2.8 Community and Corporate Involvement
In order to develop a workable Implementation Plan, there must be
continuous dialogue with the public to ensure that the plan is not only
accepted, but willingly adhered to. Although much of the
Subwatershed Plan deals with issues such as land use planning and
development servicing, which must be addressed at the municipal level,
the continued input of individuals and groups is vital to the effective
incorporation of the agricultural and rural land use management
measures and certain aspects of the monitoring program. Many
elements of these strategies are voluntary, and require the active
participation of the public to achieve the desired results.
The following summarizes key community/corporate initiatives that
should be advanced through the co-ordinated efforts of the City and
MVCA:
Encourage community and corporate involvement though public awareness
building programs;
Encourage communities to become involved in natural area restoration
efforts with the assistance of local interest groups;
Introduce land stewardship programs through the preparation of
Conservation Farm Plans and landowner initiatives to incorporate
agricultural/rural best management practices for soil conservation,
chemical management, waste management, forestry and habitat management;
and
Incorporate information on local watersheds and the methods of
environmental rehabilitation in local school curricula.
8.2.9 Monitoring
Successful implementation of the Subwatershed Plan will require
monitoring of many of the implementation components to ensure that the
goals and objectives of the Plan are being achieved.
The monitoring program involves the collection, interpretation and
assessment of observations, field measurements, biotic sampling and
analytical analyses of different facets of the environment, which can
be used as indicators of the health or status of the subwatershed
resources. Monitoring includes both seasonal, annual or long-term
assessments as well as periodic re-evaluations of the overall
Subwatershed Plan.
Monitoring of the Shirley’s Brook and Watts Creek Subwatersheds is
required to:
Confirm/establish trends relating to the overall health of the
ecosystem, and complete/progress the understanding of the hydrologic
(i.e. surface and groundwater interactions) and ecological functions.
Allow for the continued examination of the health/resiliency of the
ecosystem using the present subwatershed data as a baseline for
comparative assessment. This will facilitate assessments of land
use change (e.g. development), rehabilitative/restoration measures
(e.g. reforestation, stream rehabilitation), and the operational
performance of SWMPs (e.g., artificial wetlands, wet ponds, etc.) in
order to adopt new technologies as they arise.
· Provide the quantitative and qualitative
means to measure/assess how well the Subwatershed goals and objectives
are being achieved by identifying which environmental targets are being
met.
Data collection and education are equally important to the success of
the monitoring program. Where possible, public input should be
solicited and incorporated into the monitoring database.
Information should be compiled by one lead agency. The
Conservation Authority (MVCA) is recommended for this role, given their
extensive local knowledge. Monitoring reports should be compiled
and updated periodically and the results disseminated to the City of
Kanata/ the Region and pertinent agencies including the NCC, MNR, MOE
and OMAFRA.
The recommended monitoring program, its various elements and parameters
to be monitored is discussed below. The program consists of a
wide variety of parameters, many of which can be monitored at different
levels of detail, and at different frequencies. In many
instances, only certain parameters may need to be monitored to give
insight into the environmental health of the Subwatershed.
For example, sampling of the aquatic community (e.g. benthos and fish)
may provide a more economical means to appraise the overall ecosystem
health than an extended program of water chemistry sampling.
Then, if the aquatic community indicates a problem, additional, more
detailed sampling (i.e., water chemistry, stream morphology) could be
initiated to pinpoint the problem.
This Study recognizes that, in many instances, financial and personnel
constraints may limit the actual scope of the monitoring program that
is implemented. The frequency of monitoring recommended under
water quality, aquatic and terrestrial resources and storm water
facilities has been selected in view of the rate of development
expected in the watershed. The following outlines the proposed
monitoring programs:
Water Quality
The objective of a surface water quality monitoring program is be to
measure the environmental health of the subwatershed and assess the
impacts of development on it.
In order to achieve this objective, a comprehensive surface water
quality monitoring program is proposed that incorporates both water
chemistry sampling and analysis along with in situ measurements.
Water chemistry sampling should be performed 2 -3 times every three
years at locations where new developments are expected to impact the
water quality. Wherever possible, for comparison purposes, these
locations should coincide with locations where a significant amount of
historical data has been accumulated (see Table C-6 in Appendix
C). Sampling should be conducted between April and November and
carried out during both dry and wet weather events.
Water chemistry analysis should include a range of parameters including:
· general chemistry parameters (TDS, pH,
conductivity, alkalinity);
· nutrients (ammonia, TKN, nitrate, nitrite,
phosphate, total phosphorus);
· bacteriological indicators (Escherichia
coli, total and fecal coliforms);
· major ions; and
· trace constituents.
Along with the water chemistry analysis, in situ parameters such as
temperature, dissolved oxygen, pH, and conductivity should be measured.
In addition, water quality monitoring should include a benthic
invertebrate sampling program to be conducted in May and September on a
bi-annual basis. Results from this program would provide a long
term profile of water quality in the area.
A quality assurance and quality control (QA/QC) program should be
applied to both field and laboratory components of the surface water
quality monitoring program.
Aquatic Resources
Updated assessments of the fish community along various reaches of the
subwatershed would provide baseline information to assess future
performance of in-stream restoration works.
Any future works to improve channel morphology and streambank
restoration should be monitored annually and after major storm events,
for a period of 3-5 years after implementation.
Terrestrial Resources
Compare general changes in vegetated areas and natural corridors every
5 years using updated aerial photographs and ground truthing.
Maintain a record of features or species of concern.
Encourage (through MVCA and the City) public involvement of individuals
and local naturalists clubs. This would include monitoring of
human impacts on the terrestrial ecosystem such as stream shoreline
alterations or tree removals, as well as natural impacts such as bank
slumping or streambank erosion.
Maintain an update on the status of the Greenway System and its various
components.
Streamflows
Periodically estimate streamflows at selected locations, as required,
using current meters (electronic or mechanical) to measure streamflow
velocities and cross-sectional data (surveyed or estimated) to measure
flow area. This data is required for accurate geomorphologic
calculations during stream restoration.
Stream Form/Morphology
The objective of a geomorphic monitoring program is to increase the
understorey of channel processes (i.e. erosion rates), monitor the
effectiveness of channel rehabilitation works and to assess the impacts
associated with changes in flow/sediment regimes on the channel
morphology within the Shirley's Brook/Watts Creek Subwatershed.
The following provides recommendations to assist in the development of
a Stream Form/Morphology monitoring program and include:
On an annual basis the first three years and subsequently for high flow
events thereafter (i.e. 5-year flow), obtain:
Collect cross-sectional dimensions (at bankfull discharge) and measures
of channel relation to the floodplain (i.e. entrenchment) at the ten
established monitoring sites (although the channel may shift, an
increase in cross-sectional area is not desirable, entrenchment should
not increase)
Sample the substrate material (pebble count and grain size analysis)
Measure erosion/deposition rates at erosion pins and scour chains; note
and measure presence/removal of depositional bars.
Every two/three years, conduct a detailed survey of the channel bed
morphology and note changes in planform (decrease in channel length is
not desirable).
Surface and Groundwater Supply
Initiate a subwatershed-specific database of both surface and
groundwater taking permits and incorporate any existing information
collected by MOE through the MVCA as a means to monitor the types and
quantities of water usage within the subwatershed;
Compile a subwatershed-specific database of private and public sewage
systems; and
Ensure that the recommended monitoring initiatives be undertaken in
partnership between MVCA, MOE and local Health Units.
Storm Water Management Facilities: Pilot Project
Consider monitoring of a planned storm water (end-of-pipe) facility
(e.g. artificial wetland or wet pond) as a pilot project to assess its
operational performance with regard to urban storm water
control/treatment. Before selecting the type of facility and
location, a brief review of local and Ontario wide ongoing pilot
projects should be undertaken.
Ideally, monitoring would take place over a period of 2 to 3 years and
consist of:
- continuous measurements of rainfall depth, surface
runoff flows entering and discharging from the facility, and water
levels in the facility for a minimum of 5 storm events/yr;
- flow weighted water quality chemistry sampling of
urban storm water runoff entering the facility, in the facility (if
applicable) and discharging from the facility for a minimum of 5 storm
events/yr;
- water chemistry sampling should include a range of
typical PWQOs for urban storm water including temperature, dissolved
solids, turbidity, bacteria, dissolved oxygen, nutrients, metals,
alkalinity and hardness, and conductivity (Urbonas, 1995);
- sediment quality sampling for contaminants and
particle size distribution of accumulated sediments deposited in the
facility, once per year;
- flora and fauna community mapping (where wetland
component is included) should be done annually.
Storm Water Management Facilities: Routine Maintenance
Maintain monitoring of all storm water management facilities to ensure
proper operation. Once assumed, the municipality would be
responsible for the following:
- removal of trash, floatable debris and blockages
(as required);
- clean out of deposited sediments (once every 10-15
years);
- adjustment/maintenance of inlet and outlet control
structures (once every 2-3 years);
- vegetative (re)planting (as required) and grass
cutting (as required) for dry ponds;
- repair of inlet/outlet scouring and/or embankment
erosion (as required)
8.3 Implications for Developers
8.3.1 Benefits of the Subwatershed Plan
One of the most important aspects of the approvals process for land
development is to ensure a level of fairness and certainty in the
requirements of the various government review agencies.
Incorporating the principles of subwatershed planning in this process
is one way of achieving this in a cost-effective and timely
manner. In fact, the adoption of subwatershed planning principles
is already playing an increasing role in land development elsewhere in
the province. It has been recognized that planning within a watershed
context provides a basis for the successful integration of existing
natural systems with proposed urban land uses. It also
provides the basis for the next level of detail required in the
development proposal, that is, the servicing needs.
But perhaps more important than ensuring that a process is in place for
reviewing development proposals is the benefit of having all
stakeholders “buy in” to the environmental basis for
planning on a subwatershed basis. If, for example, it becomes
routine to identify environmental constraints and opportunities as the
first step in developing a subdivision plan, then the best
mix of stormwater management practices can be developed which both
preserves and enhances environmental features while meeting technical
needs. Other innovative strategies for the development can also
be discussed at these early stages, and tradeoffs can potentially be
made which satisfy all parties. Detailed planning can then
proceed with a high level of certainty that the final development
proposal will be accepted and approved. Some of these innovative
strategies could include:
preservation of designated environmental features within the plan by
allowing residential density changes which make if feasible for the
owner to develop the site from a cost point of view;
restoration of degraded valley systems as part of an overall
environmental management plan for the site, thereby allowing the
delineation of buffers to be based on environmental quality rather than
on a pre-set distance from the top of bank of centre of the stream;
encouraging the plan to incorporate green space preservation in
corridors or adjacent to “green “ uses such as parks and schools.
This process will ensure that good decisions are made early enough in
the process to satisfy the developer, the municipality and government
review agencies, and the public.
It is also recognized that there are many development applications “in
process” throughout the subwatersheds. The
recommendations/strategy in this plan are not to be viewed as a new set
of “rules” as the strategy has been developed based on existing
provincial and federal legislation.
For these “in process” development plans, the City of Kanata would like
to work with developers so that development plans are consistent with
the subwatershed strategy as much as is realistically possible
recognizing the point at which the development plan is.
8.3.2 Recommendations to be Recognized
The subwatershed study has developed a number of recommendations that
will need to be considered in developing land within the Shirley’s
Brook and Watts Creek Subwatersheds. The Fact Sheets (Appendix A)
are a summary of the key findings of this study presented by catchment
area. The appropriate Fact Sheet should be examined in initiating
a development plan.
The following presents a summary of the key findings/recommendations of
this study which the development community needs to recognize:
8.3.2.1 Natural Area Protection
No development is permitted in Natural Areas W3 and W5 (Stony Swamp)
S26 and W17 (Shirley’s Bay). These areas are currently protected
through Official Plan designations.
Appropriate setbacks for watercourses shall be recognized based on the
habitat type (see Figure 3.2a and b) as well as the criteria presented
in Section 7.2.3.1.
The harmful alteration or destruction of fish habitat cannot occur
without approval under the Federal Fisheries Act and the preparation of
a fish compensation plan.
Low order streams shall be preserved, where possible, and not enclosed.
· For Type 3 (i.e., poor) habitat reaches
(particularly the high priority areas presented in Table 7.1),
opportunities to restore these reaches as part of development proposals
shall be investigated.
High priority woodlands (Refer to Table 7.2 and Figures 3.3a and b)
should be protected as much as possible.
Environmental Impact Studies shall be prepared (Individual EIS based on
Region EIS Guidelines or as part of an EMP) in situations where natural
heritage features located in the subwatersheds are potentially affected
by development. These areas include:
Areas of fish habitat;
Significant wetlands;
Significant woodlands;
Significant valley lands;
Significant areas of natural and scientific interest; and
Adjacent lands to significant wetlands south and east of the Canadian
Shield (Stony Swamp and Shirley’s Bay).
These natural areas are presented in Figures 3.2 and 3.3 (at end of
Section 3.0) and described in Section 7.2.3.
8.3.2.2 Flood Control
The following flood control measures shall be recognized. Section
7.3.1 of this report should be reviewed for further information.
No development and no fill should be located in the 100 year flood
plain (to be based on updated floodplain mapping);
Development or fill within the regulated flood and fill lines is
subject to approval by MVCA and the City, and may require a
hydrotechnical to determine impacts and measures to eliminate any
environmental hazard;
· Runoff from new developments should control
the peak flows for the 2 to 100 year event to pre-development levels;
and
Where no flood lines are available, the 100 year flood line should be
defined and development or fill should be kept outside the computed
line.
8.3.2.3 Groundwater Protection
A number of recommendations regarding well construction, private sewage
disposal and development in hydrogeologically sensitive areas have been
made (see Section 7.5). Among these that will need to be
recognized in developing rural areas include:
Lot sizes underlain by Precambrian rock should be restricted to minimum
lot size of 4 ha. Any reduction in size below the minimum should
be based on a groundwater study.
Minimum lot size located in the Nepean/March/Oxford Formation should be
0.8 ha. Any reduction in size below the minimum should be based
on a groundwater study.
Individual lot septic systems should be located downgradient with
respect of water supply wells with a minimum distance separation of 60
m.
8.3.2.4 Urban Storm Water Management
Recommendations for the management of stormwater from developed areas
have been made in this Subwatershed Study. The following is to be
considered in developing a stormwater management plan for new
development:
that a hierarchy source, conveyance and end-of-pipe measures are to be
considered;
the unit storage volumes (m³/s) required to provide minimum water
quality protection for each catchment where development is proposed
(see Table 8.3);
Table 8.3 Summary of Recommended Water
Quality/Quantity Requirements for End-of-Pipe Storm Water Management
Facilities
(1 page)
the recommended types of storm water management practices/facilities by
catchment area which recognize underlying subsoils (see Table
8.4). These recommended management practices/facilities are to be
considered as the minimum requirements;
guidelines for: 1) Site Drainage and Servicing; and 2) Storm Water
Management Pond.
8.3.3 The Next Steps
This Subwatershed Study provides an initial basis or starting point for
developers in preparing their development plans. Stormwater
management measures recommended in this plan should be considered as
the minimum requirements for the treatment/control of urban storm
water. Alternative measures can be used assuming that they
provide the same or higher level of control. As well, the
detailed design and siting of the SWMPs, including the size, type and
number of storage facilities is highly dependent on the site-specific
constraints and opportunities associated with each development plan
which is only becoming evident during the development and plan design
process.
It is expected that each development proponent is required to prepare a
detailed Stormwater Management Plan as part of a larger Environmental
Management Plan and Servicing Study (EMPSS) that discusses how storm
water generated from the proposed development area will be managed in
accordance to the intent of the Subwatershed Plan.
This EMPSS study is to address the needs for stormwater management and
sanitary and water servicing for the proposed development taking into
account the environmental constraints and opportunities on the
site. The integrated environmental analysis required for the
EMPSS considers all of the natural and technical elements that will
provide for quality development in the City of Kanata.
The Consultant shall develop a stormwater management plan (SWMP) that
provides adequate flexibility for integration with adjacent development
and redevelopment areas, assists in the establishment of open space
linkages, identifies opportunities and constraints to development, and
details location and area requirements for stormwater management
facilities, as well as restoration and enhancement opportunities.
The purpose of the SWMP is to demonstrate the conformance of the
proposed future development with the Shirley’s Brook/Watts Creek
Subwatershed Plan.
Table 8.4 Summary of Potentially Applicable SWMPs
(6 pages)
The Stormwater Management Plan shall include:
the proposed drainage scheme for the development;
the proposed storm water management practices that will be incorporated
into the system, including their numbers, size and locations;
the proposed methods for minimizing erosion and sedimentation during
construction; and
the compatibility of the proposed works with the Urban Storm Water
Management Strategy.
It is noted that the majority of soils within the planned development
areas situated within the Watts Creek Subwatershed are not conducive to
SWMPs that rely on infiltration. Infiltration measures may be
possible in specified areas in the northeast portion of the Shirley’s
Brook Subwatershed. Notwithstanding as part of the initial site
investigations for development proposals, exploratory field works
should be conducted to determine site specific soil
characteristics. Boreholes and/or test pits should be used to
confirm the permeability of the native soils, subsoil conditions (i.e.,
depth to bedrock, etc.) and identify site areas where infiltration
techniques are possible. If the results support the use of
infiltration techniques, then one or a combination of the measures
recommended in Section 7.7 should be incorporated into the site
drainage plan.
Other considerations to be taken into account in developing the
Stormwater Management Plan include:
· All storm sewers and internal drainage
systems should be sized in accordance with the City of Kanata design
standards, without accounting for any flow attenuation achieved by
on-site measures such as ponds, rooftop and/or parking lot storage.
· A fundamental component of an urban drainage
system is the provision of an adequate major system flow route.
Therefore, attention must be given to proper grading of the roadways
and the incorporation of flow easements where necessary to ensure a
continuous flow route to a safe outlet. In this regard,
consideration must be given to:
maintaining the existing drainage pattern;
providing a continuous overland flow route to safe outlets;
minimizing flow depths along roadways; and
minimizing ponding depths in parking areas.
· To minimize the potential for flooding,
erosion and environmental problems, every attempt should be made to
preserve the existing drainage pattern.
· Due to the erosion sensitive nature of the
valleylands, every effort should be made to minimize the number of
storm sewer outlets. And, all outlets should be designed to
minimize outlet velocities to non-erodible levels (i.e., typically
<1.0 m/s) and/or provide adequate protection measures for energy
dissipation such as storm sewer headwalls with chute block aprons,
gabion mats, and/or rip-rap.
· Concurrent with the preparation of
individual Storm Water Management Plans is the preparation of an
erosion and sedimentation control strategy for the construction phase
of each development. Any site specific erosion problems should be
identified in the storm water management report, together with
appropriate remedial works. Appendix I of this Report presents and
describes several suitable measures which can be drawn from to
formulate a control plan.
· As part of the Environmental Management Plan
and Servicing study, the consultant shall provide information on
existing environmental conditions and prepare constraint mapping
to delineate the Regulatory Flood Plain, valley slopes, land uses,
hydrologic features, vegetation communities, habitat linkages and
aquatic conditions.
To assist developers in preparing the Stormwater Management Plan, a
sample Terms of Reference is contained in Appendix J for an
Environmental Management Plan and Servicing Study.
8.3.4 Approvals
The contents of this Subwatershed Plan have been agreed to, in
principle, by the City, the Region, MVCA and the NCC and is to serve as
the guideline/standard for future development in the subwatershed.
However, it is not the intent of the Plan to imply that a guarantee of
approval has been established for any recommended environmental and/or
drainage related works carried out through the implementation of the
Subwatershed Plan. All proposed activities carried out within the
subwatershed area remain subject to applicable approvals and permits
secured through various municipal and regulatory agencies (i.e. DFO,
MOE, MNR, MVCA, OMAFRA, NCC, RMOC and The City of Kanata).
A summary of applicable Federal and Provincial Acts, including
mandating agencies, that are commonly administered to regulate
permitting and approval processes for environmental and drainage
related works include:
Federal Fisheries Act, DFO and MVCA (Level 2 Agreement);
Navigable Waters Act, Transport Canada;
Environmental Assessment Act, MOE;
Ontario Water Resources Act, MOE;
Conservation Authorities Act, MVCA; and
Drainage Act and Tile Drainage Act, OMAFRA.
8.4 Funding, Costing and Scheduling
Many of the proposed initiatives in this subwatershed study,
particularly those to be initiated by the public sector, will
require some form of funding. The form of funding is dependant on
the site specific issues (e.g. land ownership) relating to the
initiative. Some of the initiatives can be paid for through the
development approval process. Others, such as for example,
increasing public awareness of the importance of the City’s Natural
Features, will need to be funded through other means. Many of the
subwatershed strategy recommendations, particularly proposed physical
works, need to be taken to the next level and a detail strategy
developed at the site level in order to develop costing estimates.
Implementing all of the recommendations in this strategy at once is
clearly cost prohibitive. For those initiatives that are not
development driven, priorities will need to be established with
community input. The following provides some further thoughts on
costing for each of the major strategy components.
Policy Initiatives
Policy and regulatory initiatives, such as the incorporation of the
recommendations into the City’s Official Plan, are clearly be the
responsibility of the City of Kanata. And will involve costs
primarily related to staff time.
Natural Habitat Restoration
Initiatives relating to aquatic and terrestrial habitat
restoration can be funded through a variety of means including: the
public sector (e.g. City of Kanata, RMOC, MVCA, MNR); by the
development community; and by landowners/community groups. The
group to fund the initiative clearly depends on where the restoration
work is to take place. For restoration work in areas that are to
be developed, opportunities would likely exist through the development
approval process for the developer/landowner to cover the costs or at
least a portion of them. As an example, golf course developments
provide an excellent opportunity to improve habitat of watercourses
that flow through the subject lands.
Natural Area Protection
Often the protection of terrestrial areas requires their purchase or at
least the transfer to public ownership as part of the development
approval process. This subwatershed plan has identified priority
natural areas that should be protected. Many of these areas are
privately held and are designated for development. As these areas
come “on stream” for development, it will be necessary to investigate
possible funding mechanism to ensure their protection. For
natural areas on private land but not under development pressure,
various incentives (i.e. tax) and funding public programs are available
to encourage landowners to maintain natural areas. These
opportunities should be investigated for such lands.
Flood Management
Recommendations have been made to update and extend the current
floodplain mapping for Shirley's Brook/Watts Creek Subwatershed.
Funding to carry out this initiative will be required from the MVCA
and/or the City of Kanata. Hydraulic structure improvements, will
be facilitated through roadway improvement projects.
Responsibility for funding to complete these works will vary depending
on the classification of road (i.e. City, Regional, Provincial).
Erosion Management
Recommendations have been made where in-stream works should be
undertaken to further prevent erosion problems in the study area.
Most of these sites are located on private land and will require
landowners permission. For those sites located in areas to be
developed, these initiatives could be undertaken as a condition of
development. For those areas not subject to development, these
works will need to be funded by either the City/MVCA , community groups
or possibly the landowner with incentives (see land stewardship
mechanisms presented in Table 8.2).
Groundwater Quality
No major groundwater works are proposed as part of this subwatershed
study. Groundwater supplies are to be protection through land
development policies as recommended in this study.
Agricultural and Rural Land Management
Most of the recommendations relating to Agricultural and Rural
management need to be initiated by the landowner. It is expected
that the MVCA would lead public awareness building programs to
encourage good land management practices. There are a number of
provincial programs to encourage good management by farmers.
These have been described in Section 7.6.2.
Urban Storm Water Management Practices
The recommended stormwater management measures basically come in two
forms: 1) those that can be applied to existing developed areas (i.e.
retrofit) and 2) those intended for “greenfield” development. For
initiatives in existing developed areas, many would need to be funded
by the public sector (e.g. storm outlet water quality
monitoring). On-site source control initiatives require the
co-operation of landowners, and therefore, there exists opportunities
for residents to participate in such programs that can significantly
off-set potential costs. Public awareness building is key to such
initiatives.
For the funding of stormwater management facilities for new development
areas, more flexibility typically exists. To begin with, all stormwater
management facilities to serve new development will be funded by
the developer. Depending on the location and timing of the
required facilities, opportunities such as development charges, front
end agreements and partnerships are possible mechanisms to assist in
the funding of these initiatives. The mechanisms that are
ultimately used will need to be developed in the context of the site
specific circumstances and will need to be negotiated between the
developers/landowners involved. There are no criteria or
frameworks available to suit all circumstances. It is expected
that a sub-basin stormwater management plan (funded by the landowner or
group of landowners) will have been developed which would
identify the location and sizing of the proposed stormwater management
facilities. This will provide some guidance as to how the
facilities can be funded (see Section 8.3.2).
Typically, the first developer into the area would be responsible for
the facility. This facility could be funded either by the
developer who would front end the costs and then recover these costs
through development charges. Alternatively, the developer
could form an agreement with the other developers/landowners to pay for
the facility. Once constructed, the City will assume ownership
and be responsible for operation and maintenance of the facilities.