Appendices related to Part D to this guide
Appendix D1: Wetland EIS evidence of “reasonableness”
Under the Regulation, applicants may seek an exception from the prohibition on development within a provincially significant southern wetland or a provincially significant coastal wetland for the construction, installation or expansion of a transmission or distribution line, or the expansion of an existing transformer station, distribution station or transportation system, provided the EIS report requirements of part V, subection 37 (2) are met, including subparagraph 37(2)(a)(v) which requires an explanation for why it is not reasonable for the project location to be entirely outside the wetland.
Note, in the case of the construction, installation or expansion of a transmission or distribution line, an applicant’s explanation will be considered to be in accordance with this Guide where it is demonstrated that the wetland can be spanned, without the placement of infrastructure within the wetland boundary. In such cases, an assessment of alternatives to determine ‘reasonableness’ is not required.
Minor encroachments for specified development types, where the applicant has demonstrated that alternatives for avoiding encroachment into the wetland are unfeasible, may be allowed where the least impactful and most easily mitigated development approach has been selected. Wherever possible, renewable energy projects should be located entirely outside provincially significant southern and coastal wetlands.
The attestation required as part of the application for a REA must confirm the EIS report required under subsection 37 (2) was prepared in accordance with this Guide. The EIS report must include the applicant’s explanation for why it is not reasonable for the project location to be entirely outside provincially significant southern and coastal wetlands.
To be in accordance with this Guide, when providing an explanation in the EIS report for why it is not reasonable for the project location to be entirely outside provincially significant southern or coastal wetlands, applicants must include:
- an assessment of alternatives which contains evidence that alternatives to development within the wetland(s) are unfeasible
- a description of how the proposed development approach meets the requirement to be the least impactful and most easily mitigated approach
Proposals for encroachments into provincially significant southern and coastal wetlands, even proposals which are minor in nature, have the potential to be controversial and generate considerable concern within the local community. Where such encroachments are proposed, applicants should expect that the rationale for encroachment into the wetland, and determination that alternatives are unfeasible, will be subject to considerable agency and public interest. Applicants proposing encroachment into provincially significant southern or coastal wetlands will need to place a particular emphasis on the evidence which demonstrates that alternatives are unfeasible.
The below tables outline requirements for alternatives which must be assessed, associated determinations of unfeasibility, and supporting evidence, as well as development approaches which must be considered for least impact, where alternatives are determined to be unfeasible. To establish an explanation in the EIS report under section 37(2)(a)(v) of the Regulation for why it is not reasonable for the project location to be outside provincially significant southern or coastal wetlands, the applicant must meet these requirements. While the tables outline the most common alternatives to be assessed for each potential development type, they are not exhaustive and the applicant may identify additional alternatives.
| Alternative | Determination that alternative is unfeasible | Supporting evidence |
|---|---|---|
| Span the wetland | Landscape constraints prevent construction/installation of a line which spans the wetland (for example, span is too wide) | Letter describing rationale for determination that spanning not feasible and qualifications of person making the determination (for example, engineer) |
| Route line outside wetland boundaries | Permission not granted by landowner(s) to route line entirely outside wetlands; and Landscape constraints prevent routing line outside wetlands (that is, high concentration of wetlands in the area); or Construction/installation of route outside wetlands would remove or significantly impact another significant natural feature; or Consideration and balancing of other land use and siting considerations | Description of efforts to gain access to routes on private land outside wetlands; and Map of identified wetlands and transmission/distribution options, which shows location outside wetlands is not possible; and Impact/benefit analysis which assesses and compares impact of each potential development alternative |
| Conduct horizontal directional drilling to bury line under wetland | Horizontal directional drilling is not possible due to distance or nature of substrate | Letter describing rationale for determination that drilling not feasible and qualifications of person making the determination (for example, engineer) |
Where the alternatives in table App-D1 (above) are determined to be unfeasible, development approaches may include:
- expansion within wetland boundary limited to upgrading existing transmission/distribution line (without increasing disturbed area)
- construction/installation within wetland boundary limited to existing surveyed, developed, and maintained infrastructure corridor (for example, municipal right of way, pipeline corridor, railway corridor) or existing transportation system as defined in the Guide
- construction/installation of a new transmission or distribution line within wetland boundary
| Alternative | Determination that alternative is unfeasible | Supporting evidence |
|---|---|---|
| Locate transformer/distribution station outside wetland boundaries | Permission not granted by landowner(s) to use existing transformer/distribution station outside wetlands; or Construction/installation of transformer/distribution station outside wetlands would remove or significantly impact another significant natural feature; or Consideration and balancing of other land use and siting considerations | Description of efforts to gain access to existing transformer/distribution station on private land outside wetlands Impact/benefit analysis which assesses and compares impact of each potential development alternative |
Where the alternatives in table App-D2 (above) are determined to be unfeasible, development approaches may include:
- transformer/distribution station proposed for expansion within wetland boundary meets the definition of “existing transformer station or distribution station” as outlined in the Guide
- the proposed expansion maintains a capacity and disturbed area similar to that for which the existing transformer/distribution station was constructed
| Alternative | Determination that alternative is unfeasible | Supporting evidence |
|---|---|---|
| Route project access outside wetland boundaries | Permission not granted by landowner(s) to route project access entirely outside wetlands; and Landscape constraints prevent routing project access outside wetlands (that is, high concentration of wetlands in the area); or Construction/installation of project access outside wetlands would remove or significantly impact another significant natural feature; or Consideration and balancing of other land use and siting considerations | Description of efforts to gain access to routes on private land outside wetlands Map of identified wetlands and project access options, which shows location outside wetlands is not possible Impact/benefit analysis which assesses and compares impact of each potential development alternative |
Where the alternatives in table App-D3 (above) are determined to be unfeasible, development approaches may include:
- transportation system proposed for expansion within wetland boundary meets the definition of “existing transportation system” as outlined in the Guide
- the proposed expansion maintains a capacity similar to that for which the existing transportation system was constructed
The proposed expansion is scaled only to allow use of the existing transportation system in its current form (that is, does not add length, create branches, parking areas, turn around areas, and more)
Appendix D2: Alternative wetland assessment
Go to section C4.1 for information about when this assessment can be applied. This approach is intended to ensure that relevant wetland attributes are identified and sensitivity of wetland characteristics or functions to negative effects of development are documented to support EIS requirements. The applicant is required to gather sufficient information to assess key wetland characteristics and ecological functions to inform preparation of the EIS. Table App-D4 below is based on information contained within the OWES manuals and in some cases, the OWES manuals are to be consulted for additional explanation.
The assessment and EIS report must be prepared as follows:
- Collect data and perform analysis to obtain an understanding of the wetland characteristics and ecological functions outlined in the table below. Data collection will be mainly through desktop procedures (for example, aerial photograph interpretation) or field visits as part of the Site Investigation.
Document the information collected and analyzed through the assessment and append to the EIS. For each wetland characteristic and ecological function in the table below the applicant must provide:
- a determination of presence or absence (where applicable) to inform the site investigation (column 3 in the table below)
- information required to inform the EIS (column 4 in the table below) including:
- an in-depth analysis of the characteristic or ecological function and its role within the broader landscape
- a description of the degree of sensitivity to potential negative environmental effects of development
- a description of methodology and rationale for arriving at determinations
Applicants should provide text descriptions for all analysis and determinations. The level of analysis should provide information sufficient to be used for preparation of an EIS.
- Prepare an EIS report according to procedures in section D2. When preparing the EIS report, the applicant must ensure that for each characteristic and ecological function in the table below, the information obtained during the assessment is addressed when identifying and assessing potential negative environmental effects as well as proposing mitigation and monitoring.
| Characteristic/function | What it indicates | Information required as part of the site investigation | Information required to Inform the EIS |
|---|---|---|---|
| Wetland size (ha) | Wetland size can be a proxy for species abundance, ecosystem or biological diversity, and carbon storage potential (for example, large areas are more likely to sustain higher levels of species abundance or diversity or store higher amounts of carbon). | Wetland size is baseline information about the wetland features at the project location. | Description of the relationship between wetland size, ecological functions or biodiversity values, and how these may be vulnerable to potential negative effects of the proposed development. |
| Wetland type | Indicator of rarity in the landscape (for example, marshes are typically rare in Northern Ontario, while bogs and fens are rare in Southern Ontario). Indicator of carbon storage potential (for example, peatlands actively accumulate peat and are considered a carbon sink). | Wetland type | Description of how wetland type influences hydrological characteristics, patterns, biodiversity, ecological functions and sensitivity to alteration. |
| Site type | The position of a wetland in a landscape predicts certain ecological functions, such as flood attenuation and pollutant or sediment transfer (for example, headwater wetlands are important for sediment removal). Wildlife habitat may be adversely impacted by changes to vegetation cover and variety (for example, introduction of invasive phragmites). | Site type | Description of how site type influences hydrological characteristics, patterns, biodiversity, ecological functions and sensitivity to alteration. |
| Habitat diversity | The variety of different vegetated and non-vegetated (for example, open water) habitats is a predictor of biodiversity. Vegetation types, density and variety may be impacted by changes in hydrology. | Description/characterization of the type of vegetated and non-vegetated (for example, open water | Description of vegetated and non-vegetated habitat diversity at the project location and sensitivity to potential negative effects from the proposed development. |
| Proximity to other wetlands | Provides an indicator of habitat connectivity and the potential for an activity to disrupt species movement patterns or access to resources or habitat. | Map and/or description of other wetland features within the catchment boundary. Note: this is a landscape-scale metric and not limited to the project location. | Description of hydrological and ecological connectivity of wetland(s) within project location to others within the study area, and sensitivity to potential negative effects of development. |
| Species rarity | Rare species and the habitats they depend on may be disproportionately impacted by an activity. Changes to vegetation cover, habitat diversity, or hydrology may be more difficult to mitigate for vulnerable species. | Provincially tracked plant or animal species known to depend directly or indirectly on the wetland(s) at the project location, based on Records Review or field studies conducted as part of the Site Investigation. | Assessment of vulnerability of the species to potential negative effects of development. |
| Significant features and habitats | Wetland wildlife habitats may be more adversely impacted by an activity. Changes to vegetation cover, habitat diversity, or hydrology may be more difficult to mitigate if it affects sensitive or rare habitat. | Presence of significant wildlife habitats (for example, colonial waterbirds, winter cover, waterfowl staging and/or moulting areas, waterfowl breeding, migratory passerine, shorebird, or raptor stopover area) or other significant habitat features provided by the wetland(s) at the project location, including fish habitat as defined under the Fisheries Act. | Assessment of vulnerability of the habitats or habitat features to potential negative effects of development. |
| Flood attenuation | Provides an indicator of potential negative impacts from changes in water levels and the duration, magnitude, and frequency of water level fluctuations. | Map and/or description of the other surface water features within catchment boundary. Note: this is a landscape-scale metric and not limited to the project location. | Description of hydrological characteristics of the catchment area, particularly related to flood hazards, the hydrological role(s) and function(s) provided by the wetland(s) at the project location, and sensitivity to development impacts. |
| Water quality | Provides an indicator of potential negative impacts from changes in water chemistry (for example, nutrients, metals, sediments and more). | Map and/or description of land uses and potential pollution/contamination pathways within catchment boundary (for example, discharge areas). Note: this is a landscape-scale metric and not limited to the project location. | Description of land uses within the catchment area and the role and function(s) potentially provided by the wetland(s) at the project location in reducing adverse impacts to water quality. |
| Shoreline erosion control | Potential risk of flooding and sedimentation characteristics and functions for shoreline wetlands. | Note presence or absence of any shoreline wetlands. | If shoreline wetlands are present, describe ecological values and functions provided by these wetlands, and vulnerability to potential negative effects of development. |
| Groundwater recharge | Hydrological pathways and resilience of the wetland to changes in hydrology. | Description of soil classes and topography within project location. | Description of groundwater recharge potential of the wetland(s) based on soils, typography and hydrological characteristics, and sensitivity of this function to negative effects of development. |
Appendix D3: Common characteristics and ecological functions of natural features
Below are the most common considerations for specific natural features. To ensure that an EIS takes into account all considerations necessary to address negative environmental effects, applicants will need to refer to field work undertaken during previous NHA stages and the determination of existing environmental conditions.
| Natural feature | Common EIS considerations |
|---|---|
| Wetlands |
|
| ANSIs |
|
| Significant woodlands |
|
| Significant wildlife habitat |
|
| Sand barrens, tallgrass prairies, savannahs |
|
| Alvars |
|
| Natural feature | Common EIS considerations |
|---|---|
| Wetlands |
|
| Significant ANSIs |
|
| Significant woodlands |
|
| Significant wildlife habitat |
|
| Sand barrens, tallgrass prairies, savannahs and alvars |
|
Appendix D4: Summary of potential negative environmental effects and mitigation
| Potential physical effects | Potential effects on functions and features | Some possible mitigation measures |
|---|---|---|
| loss of shade, possibly resulting in increased water temperatures | increase in water temperatures beyond the tolerance of cold- and coolwater fish species changes in fish species composition and abundance; drying up of refugia due to increased evaporation | maintain as much riparian vegetation as possible to maximize shading; plant appropriate native species (of local stock if possible) |
| reduced inputs of leaves, twigs and insects to waterbodies | reduced food supply for aquatic life, including fish | maintain or restore as much riparian vegetation as possible to provide a food supply |
| reduced bank stability and ability to trap sediment from upland areas; increased erosion, sedimentation and turbidity | decreased photosynthesis, loss of productivity, loss of fish habitat (for example, spawning areas), loss of food organisms, and avoidance of areas by fish; changes in fish species composition and abundance | maintain or restore riparian vegetation; develop and implement an erosion and sediment control plan before removing vegetation; stabilize banks where necessary |
| reduced stability of sensitive landforms; increased erosion of landforms | loss of all or part of earth science feature, valleyland and more | avoid removing vegetation on sensitive landforms |
| loss or disturbance of riparian wildlife species | reduced cover and food supply for species such as otter, mink, beaver and wintering deer; loss of habitat for species requiring both aquatic and terrestrial areas; interruption of riparian corridors | maintain or restore riparian vegetation and adjacent forests where they exist maintain important wildlife areas (for example, cover, nesting habitat, movement corridors) |
| Potential physical effects | Potential effects on functions and features | Some possible mitigation measures |
|---|---|---|
| increased erosion, sedimentation and turbidity; decreased shade, cover and diversity of vegetation | decreased photosynthesis, loss of productivity, loss of fish habitat, loss of food organisms, and avoidance of areas by fish; changes in fish species composition and abundance; smothering of upland and wetland vegetation | maintain or restore vegetative buffers; develop and implement an erosion and sediment control plan before removing vegetation |
| Potential physical effects | Potential effects on functions and features | Some possible mitigation measures |
|---|---|---|
| loss of vegetation and wildlife habitat or loss of significant portions of habitat; loss of successional habitat | direct loss of habitat (for example, winter cover, vernal pools, nesting trees, important food sources); reduction in habitat (for example, woodland habitat for area-sensitive birds) below a critical level; habitat fragmentation | identify and avoid or protect critical components of wildlife habitat (for example, winter cover, vernal pools, grasslands that support indicator species, hibernation sites, migration staging areas, nesting trees); leave a buffer around significant features and habitats of significant species |
| loss of vegetation and wildlife habitat or loss of significant portions of habitat; loss of successional habitat | greater exposure of wildlife to predation and parasitism | design the project to avoid or, where that is not possible, minimize loss of vegetation, particularly in edge habitats |
| loss of vegetation and wildlife habitat or loss of significant portions of habitat; loss of successional habitat | increased vulnerability of the site to invasion by non-native species | revegetate with native species after development to enhance habitat |
| loss of vegetation and wildlife habitat or loss of significant portions of habitat; loss of successional habitat | decreased biodiversity | avoid fragmenting forests and severing linkages; consider restoration and planting projects to restore high edge-to-interior ratio |
| loss of natural linkages and corridors for animal movement | isolation of species; loss of biodiversity | leave a buffer around habitats of significant species; identify important animal movement corridors; avoid eliminating corridors |
| disturbance of wildlife species | disturbance of concentrations of wildlife (for example, deer yards, bird nesting colonies) due to noise produced by clearing activities or other human activities | time activities to avoid wildlife disturbance; leave a buffer area around sensitive species |
| loss of rare plant species and communities | loss of species, specialized habitats and overall biodiversity | avoid disturbing habitats of rare plant species and communities; establish appropriate buffers |
| reduced stability of landforms composed of unconsolidated material (for example, eskers, moraines, dunes) | reduced integrity of landform and loss of significance, or loss of earth science area of natural and scientific interest (ANSI) |
| Potential physical effects | Potential effects on functions and features | Some possible mitigation measures |
|---|---|---|
| increased erosion, sedimentation and turbidity; increased inputs of nutrients and contaminants to waterbodies and wetlands; increased soil compaction | decreased photosynthesis, loss of productivity, loss of fish habitat, loss of food organisms, avoidance of areas by fish, lethal or sublethal toxic effects on aquatic life; changes in fish species composition and abundance; changes in wetland plant communities | maintain or restore vegetative buffers; develop and implement an erosion and sediment control plan; control access and movement of equipment and people; designate areas for equipment storage; time activities to avoid sensitive periods of habitat use (for example, spawning); minimize the area and duration of soil exposure schedule grading to avoid times of high runoff volumes (spring and fall) |
| changes in natural drainage, including elimination of streams, and increased or decreased surface runoff; increased or decreased stream flows | loss of fish habitat (for example, water, spawning areas) and food organisms; changes in fish species composition and abundance; changes in wetland plant communities; reduction in hydrologic functions of wetlands including impacts to flood attenuation and conveyance functions; channel erosion and changes in geomorphology | minimize changes in land contours and natural drainage; maintain streams (permanent and intermittent) and timing and quantity of flows |
| changes in soil moisture, tree cover and species composition of vegetation | loss of important wildlife species or habitat | minimize vegetation removal and changes in land contours and natural drainage; develop a tree conservation plan to encourage retention of trees where possible |
| disturbance of wildlife, particularly sensitive species | reduced numbers of species or abundance of a species | identify sensitive species before beginning the work; design grading to avoid disturbing sensitive species; conduct work at a time that is least disturbing to sensitive species |
| alteration or destruction of landforms composed of unconsolidated materials (for example, kames, eskers, sand dunes) | loss of an earth science ANSI, valleyland and more | avoid grading areas containing significant landform features |
| Potential physical effects | Potential effects on functions and features | Some possible mitigation measures |
|---|---|---|
| increased erosion, sedimentation and turbidity; increased inputs of nutrients and contaminants to waterbodies | decreased photosynthesis, loss of productivity, loss of fish habitat, loss of food organisms, avoidance of areas by fish; changes in fish species composition and abundance | maintain vegetative buffers; develop and implement an erosion and sediment control plan; time activities to avoid sensitive periods of habitat use; re-establish vegetation as soon as possible |
| disposal of large amounts of water required by dewatering activities | increased erosion, sedimentation and flooding of waterbodies or intolerant vegetation | install a temporary storage basin to allow water to infiltrate, or use permanent storm management facilities |
| disturbance of wildlife, particularly sensitive species | reduced abundance of species | identify sensitive species before beginning the work; conduct work at a time that is least disturbing to sensitive species |
| alteration of identified significant rock types, fossil assemblages or landforms by tunnelling or blasting | loss of significant earth science values | identify and avoid significant earth science features when planning and installing services minimize the amount of disturbance |
| hydrological changes (for example, changes in water levels as a result of rerouted water flow) | changes in vegetative communities and fish and wildlife assemblages; reduction in groundwater recharge | conduct appropriate studies to determine how to maintain the existing hydrological regime; design underground facilities (for example, seepage collars, trenches) to minimize effects on groundwater flows |
| fragmentation of natural areas | fragmentation of habitat by corridors through wetlands; reduction or elimination of area-sensitive species; increased nest predation and parasitism; introduction of non-native species | avoid forest fragmentation; if services must go through forests, route the corridor through edges instead of the interior |
| Potential physical effects | Potential effects on functions and features | Some possible mitigation measures |
|---|---|---|
| increased erosion, sedimentation and turbidity; increased inputs of nutrients to waterbodies and wetlands | decreased photosynthesis, changes in productivity, loss of fish habitat, loss of food organisms, avoidance of areas by fish; changes in fish species composition and abundance; loss of stream channel stability; changes in plant communities | maintain or restore vegetative buffers; prevent erosion, sedimentation and nutrient inputs through use of best management practices |
| water contamination by oils, gasoline, grease and other materials | lethal or sub-lethal toxic effects on aquatic life and vegetation | prevent water contamination through good best management practices |
| increase in impervious surfaces; increased surface runoff and reduced infiltration and groundwater discharge; reduced stream baseflows and upwelling; loss of vegetation resulting in increased water temperatures | loss of fish habitat (for example, water, spawning areas for brook trout); changes in fish species composition and abundance; changes in wetland vegetation communities; drying of wetlands | maintain or provide vegetative buffers; control quantity and quality of stormwater discharge using best management practices, implement infiltration techniques to the maximum extent possible |
| loss of vegetation, especially at forested edges barriers to animal and plant movement | loss or fragmentation of wildlife habitat; loss of biodiversity; introduction of non-native species of plants and wildlife; increased predation and parasitism on native wildlife interruption of functional connections | maintain a sufficient buffer between buildings and significant features such that trees do not present a hazard to buildings; ensure a threshold level of habitat is maintained for sensitive wildlife species (for example, area-sensitive species) ensure that important animal movement corridors are not lost; develop alternate corridors, cover and more where possible |
| disturbance of wildlife loss of wildlife (for example, mortality due to collisions with buildings) | avoidance of the area by wildlife species gradual attrition of certain wildlife populations | identify species sensitive to disturbance and time construction to avoid periods of habitat use appropriate building design to prevent/minimize mortality |
| Potential physical effects | Potential effects on functions and features | Some possible mitigation measures |
|---|---|---|
| realignment of stream channels; changes in water velocity | barriers to fish movement; downstream erosion or sediment deposition; separation of stream from floodplain | maintain existing stream channel if possible, or realign using natural channel design (accompanied by replanting plan using native vegetation); use bridges to span stream; time construction to avoid sensitive periods of habitat use (for example, spawning) |
| increased erosion, sedimentation and turbidity | decreased photosynthesis, changes in productivity, loss of fish habitat, loss of food organisms, avoidance of areas by fish; changes in fish species composition and abundance; changes in wetland vegetation | minimize width of right-of-way; develop and implement an erosion and sediment control plan, revegetate as soon as possible |
| loss of riparian vegetation | loss of habitat for certain wildlife species (for example, loons, ducks, reptiles and amphibians); increased water temperatures exceeding the tolerance of coldwater and coolwater fish species | minimize width of right-of-way; time construction to avoid sensitive periods of habitat use (for example, nesting, spawning); re-plant vegetation |
| obstruction of lateral flows in wetlands | significant alterations in wetland vegetation communities; potential change of wetland type; changes in wildlife populations | install adequate culverts and gravel base to maintain flow of surfacewater and shallow groundwater |
| interruption of linkage along a watercourse | increased roadkill as animals cross roads to follow a watercourse | identify wildlife use of linkage and size passage under road accordingly (information on cryptic species that use linkage will likely not be obtainable, so knowledge of wildlife most likely present must be used) |
| attraction of nesting turtles and other wildlife to roadsides and roads | roadkill | build roadside wings to keep turtles off roads; build underpasses with funnel fencing to direct turtles and other wildlife; develop alternate egg laying sites. |
| pollutants from roads | introduction of heavy metals, oils and grease from vehicles increased levels of salt from de-icing | collect and treat road runoff in stormwater management facilities use of vegetated swales to capture pollutants |
| barriers to wildlife movement | interrupted wildlife movement along watercourse | extend bridges beyond watercourse shorelines to allow wildlife passage |
| Potential physical effects | Potential effects on functions and features | Some possible mitigation measures |
|---|---|---|
| increase in impervious surfaces; increased surface runoff and stream peak flows; reduced infiltration, baseflows and upwelling | loss of fish habitat (for example, water upwelling/spawning areas for brook trout); changes in fish species composition and abundance; changes in wetland vegetation communities | minimize area of paved surfaces; design roads to promote infiltration; promote infiltration galleries and other infiltration devices, maintain or provide vegetative buffers; control quantity and quality of stormwater using best management practices |
| increased erosion, sedimentation and turbidity from increased peak flows; increased inputs of nutrients and contaminants to waterbodies and wetlands | loss of fish habitat; lethal or sub-lethal toxic effects on aquatic life; changes in wetland vegetation communities and productivity | minimize area of paved surfaces; design roads to promote infiltration; promote infiltration galleries and other infiltration devices, maintain or provide vegetative buffers; control quantity and quality of stormwater using best management practices |
| increased water temperatures | loss of coldwater and coolwater fish species where water temperatures exceed their tolerances | minimize area of paved surfaces; design roads to promote infiltration; promote infiltration galleries and other infiltration devices, maintain or provide vegetative buffers; control quantity and quality of stormwater using best management practices |
| loss of wildlife habitat |
|
|
|
|
|
| Potential physical effects | Potential effects on functions and features | Some possible mitigation measures |
|---|---|---|
| reduced groundwater discharge; reduced stream baseflows and upwelling; increased water temperatures |
|
|
| Potential physical effects | Potential effects on functions and features | Some possible mitigation measures |
|---|---|---|
|
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Buffers
The physical separation of a project from natural feature boundaries using vegetated protection areas is one of the most widely used mechanisms for reducing (that is, buffering) negative effects on natural features. Lands to be set aside from development and kept in a vegetated state are commonly referred to as “buffers.”
Buffers can contribute substantially to the protection of wetlands, woodlands, and other natural features. Appropriate widths for buffers vary depending on the sensitivity and functions of the natural features.
Buffers must be determined and rationalized on the basis of their ability to protect natural features and their associated functions. Whenever possible, buffers should be composed of species native to the geographic area (ecodistrict).
Buffers are not treated as extensions of the natural feature; therefore, if a buffer is allowed to become wooded, the natural feature boundary is not extended to include it. The buffer may serve a number of functions, some of which are not appropriate in a natural feature (for example, site maintenance activities) and such management is allowed to occur.
Wetland buffers
Buffers can be maintained or established to mitigate some potential negative environmental effects to natural features and their ecological functions. Vegetated buffers can be used to mitigate potential negative environmental effects to wetlands.
Wetland buffers can be critical for protection of wetland areas. Recommended widths may vary depending on the functions of the wetland and the nature of the project. Buffers must be determined and rationalized on the basis of their ability to protect the wetland and its associated functions.
Effective buffer widths may vary depending on the wetland functions, location and project design. For example, buffer widths of as little as 10 metres have been shown to be effective for the attenuation of nitrates and phosphorus in runoff, as long as the buffer ground surface is relatively flat and composed of dense vegetation that can filter and attenuate runoff.
Adjacent to a mature forested wetland, buffers calculated on tree height can allow for trees at the edge of the wetland to fall without damaging adjacent structures. Thus, demand is less for removal of dying trees from the wetland edge, as is the consequent degradation. In this case a buffer distance of 30 metres may be appropriate.
ANSI buffers
Buffers can be maintained or established to mitigate some potential negative environmental effects to natural features and their ecological functions. Buffers may be effective in relation to other natural features found within an ANSI, such as wetlands and woodlands.
Woodland buffers
Buffers can be maintained or established to mitigate some potential negative environmental effects to natural features and their ecological functions.
Buffers are recommended around woodlands to protect the structural integrity of vegetation along the edge, as well as to minimize impacts on woodland functions. Appropriate buffers may vary with the location and character of a woodland and the nature of proposed project. Some of the services that buffers may provide include:
- protection of root zone of edge trees
- reduction in the effects of hydrological changes from project construction
- area where trees and limbs can fall without causing damage (tree fall zones)
- filtering of contaminants
- extension of edge, thus increasing potential for woodland interior conditions to develop
- protection for wildlife use
A minimum 30 metres vegetated buffer zone around significant woodlands is recommended
Significant wildlife habitat buffers
Effective buffers for significant wildlife habitat vary depending on the specific habitat being protected. Proposed buffers should be based on the potential negative environmental effects of the proposed project. Also applicable is the significant wildlife habitat mitigation support tool, a tool to describe wildlife habitat, identify potential negative environmental effects that may affect the habitat and provide mitigation measures for an applicant to consider when working in or within the adjacent lands from a significant wildlife habitat.
Footnotes
- footnote[1] Back to paragraph Go to OWES section 1.1.2 for descriptions.
- footnote[2] Back to paragraph Go to OWES section 1.1.3 for descriptions.
- footnote[3] Back to paragraph Go to OWES section 1.2.6 for more details.
- footnote[4] Back to paragraph Go to OWES section 3.4 (southern manual) or 3.5 (northern manual) for more details.