3 EXISTING CONDITIONS
3.1 Socio-Economic
3.1.1 Land Use Land use designations within the Bayview Avenue Class EA study area reflect the York Region, City of Markham and Town of Richmond Hill Official Plans, as discussed in Chapter 2.
Within the City of Markham portion of the Bayview Avenue study area the existing land use is generally well established neighbourhoods with low density residential dwellings, pockets of medium density townhomes and newer high density high rise condominiums.
In Richmond Hill the existing land use is generally well-established and predominantly low-density residential dwellings, with commercial plazas along the Bayview Avenue frontage at major intersections and certain mid-block locations. Infill and redevelopment has typically consisted of medium density housing such as townhomes and low rise buildings. Current areas of new and redevelopment / infill include:
Bayview Creek; Mission Hill; Ambler Lane; Sapphires of Bayview Hill; Observatory Hill; Genuine Lane (off of Briggs Avenue); and Tao Condominium. These developments, highlighted on Exhibit 3-1, include low rise condominiums, townhomes and urban / stacked townhomes. The trend towards higher density redevelopment in the Bayview Avenue corridor has been evident over the past 10-12 years with the townhomes at Briggs Avenue and Blackmore Avenue (Bristol Court).
Two areas of intensive growth / redevelopment are identified in relatively close proximity to Bayview Avenue.
The Richmond Hill / Langstaff Gateway is designated by the Province’s’ Growth Plan and an Urban Growth Centre (UGC) and as an Anchor Mobility Hub in the Metrolinx’s Regional Transportation Plan (RTP). The area straddles Highway 407
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-1 Environmental Study Report | WSP | MMM Group | August 2017
between Bayview Avenue and Yonge Street (Exhibit 2-8). When fully developed, the Centre will have a population of approximately 48,000 residents and 31,000 employees. The Yonge-Steeles Corridor Secondary Plan area is generally located along the west side of Yonge Street between Steeles Avenue to south of Langstaff Road (Exhibit 2-9). The Secondary Plan contemplates mixed use re-development of this area, provides the development framework for intensification and sets out the required transit-oriented mixed use development that encourages walking and cycling. It also contains supporting policies for the introduction of rapid transit service from the Richmond Hill / Langstaff Gateway UGC to the Finch Avenue subway station. At build-out, the Secondary Plan area is projected to accommodate a residential population of 9,660 people and 4,500 new jobs in the South Area and a population of 760 people and 800 new jobs in the North Area. Bayview Avenue is an important community, cultural and spiritual hub of the surrounding Thornhill and Richmond Hill communities. There are numerous community features (institutions, community centres, places of worship etc.) that are directly accessible / serviced by Bayview Avenue. These are highlighted on Exhibits 3-1 and 3-2.
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-2 Environmental Study Report | WSP | MMM Group | August 2017
Exhibit 3-1: Community Features – Elgin Mills Road to Langstaff Road
Bayview Avenue – Elgin Mills Road to Langstaff Road • Toronto Montessori School, Kinderschool Nursery, Richmond Hill Christian Academy, • Bayview Avenue is 6 lanes from Langstaff Road to High Tech Road and transitions to 4 lanes Bayview Avenue Secondary School, John Vanier Catholic High School north of Bantry / Briggs Avenue • Anjuman-E-Burhani -Toronto Jamat • Connection to Highway 7 and Highway 407 • St. George Antiochian Orthodox Church • Mix of residential, commercial and institutional land uses • Richmond Hill Christian Community Church • Mix of low, medium and high density dwellings • St. Paul’s Lutheran Church • Numerous redevelopments and infill areas, the largest of which are the Richmond Hill / Langstaff Gateway Urban Growth Centre and Observatory Hill. Others include: Bayview • Our Lady Queen of the World Church Creek, Mission Hill, Ambler Lane, Sapphire of Bayview Hill, Tao and Genuine Lane. • St. Christopher’s Anglican Church • Numerous commercial plazas • German Mills Creek crossing • Existing right-of-way ranges from 31 m to 44 m • Rouge River tributary crossing
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-3 Environmental Study Report | WSP | MMM Group | August 2017
Exhibit 3-2: Community Features – Langstaff Road to Steeles Avenue
Bayview – Langstaff Road to John Street
• Mix of residential and institutional land use with one commercial development at Bayview Lane Plaza (other commercial development nearby on John Street) • Mix of low, medium and high density dwellings • Road right-of-way ranges from 33 m to 70 m • Thornhill Community Centre (Bus Hub) • Glynnwood Retirement Residence • Shouldice Hospital and associated Heritage Building immediately adjacent to Bayview Avenue • Fire Station and Water Pumping Station at Green Lane • Thornlea Secondary School • Bayview Reservoir/Park • Bayview Avenue bridge across the CN Rail line (Richmond Hill GO Line)
Bayview – John Street to Steeles Avenue
• Predominantly residential neighbourhood with one commercial development (Longo’s Plaza) • Predominantly low density dwellings with some pockets of medium to high density • Road right-of-way ranges from 23 m to 52 m (23 m at CNR Bridge) • Bayview-Steeles Bus Loop • East Don River Crossings (2) • Existing / historic flooding issues in John Street area • Cham Shan Temple • Imam Mahdi Islamic Centre • Temple Har Zion • CNR Bridge
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-4 Environmental Study Report | WSP | MMM Group | August 2017
3.2 Cultural Environment
3.2.1 Archaeology A Stage 1 Archaeological Assessment was undertaken in support of the Bayview Avenue Class EA study. The report is included in Appendix C.
The Stage 1 assessment was undertaken for Bayview Avenue and areas adjacent that were considered as having some potential to be impacted by the study. The Stage 1 assessment included a background study and visual assessment to determine the potential of the subject corridor for recovering archaeological resources.
The Bayview Avenue right-of-way has been subject to significant disturbance related to the construction of the road, utility installation, and residential and commercial development. The right-of-way has been landscaped, built up, or ditched. Sidewalks are present on both sides of the road, and traffic lights and telephone poles have been installed. Furthermore, a large portion of the study corridor has been previously disturbed by the construction of multiple subdivisions.
The MTCS’s Ontario Archaeological Sites Database was consulted to determine whether any archaeological assessments had been previously conducted within the limits of, or immediately adjacent to the study area. Nine (9) reports document work within 50 metres of the study area, of which only seven were available for review (Table 5). These sites have been found through archaeological assessments undertaken in support of the previous land and infrastructure developments. Descriptions of the sites are available in Appendix C.
The MTCS’s Ontario Archaeological Sites Database was consulted to determine whether any registered or known archaeological resources are located within 1 kilometre of the study area. Thirty-five (35) sites have been documented within 1 km of the study area, only three of which are located within the limits of the current study area (Appendix C). An additional two sites, Pristline site (AlGu-131) and the Strasser Findspot 1 site (AlGu-146) are located within 50 metres of the study area. Descriptions of the sites found within and immediately adjacent to the study area are in Appendix C, and specify their current development status.
The Stage 1 assessment resulted in the identification of multiple features of archaeological potential within the study area. Most prominent are the historic roadways (Bayview Avenue, Steeles Avenue, John Street, Green Lane, Highway 7,
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-5 Environmental Study Report | WSP | MMM Group | August 2017
16th Avenue, Major Mackenzie Drive, and Elgin Mills Road), the previously documented archaeological sites within (no longer extant) and adjacent to the study area, the presence of the Rouge and Don Rivers and their tributaries, and the presence of well drained soils. Numerous heritage features are also present within the study area including historic dwellings, laneways, mills, schools, and a factory, as well as one designated and three listed heritage properties situated within or immediately adjacent to the study area. The presence of these heritage features indicates there is a distinct archaeological potential for encountering archaeological sites associated with the occupation of the study area by both PreContact peoples and early settlers.
However, twentieth century use of the study areas has led to extensive and deep land alterations in portions of the study areas. The property inspection demonstrated that approximately 95.8% of the study area has been subject to deep and extensive land alterations that have removed archaeological. Disturbances are related to the construction of Bayview Avenue, numerous roadways, and traffic, sewer, and utility infrastructure associated with housing and commercial developments located on the east and west sides of Bayview Avenue. No further archaeological assessment is required within these areas.
Approximately 0.2% of the study area was assessed as low and wet, and does not require further assessment.
Finally, approximately 4% of the study area still holds archaeological potential and will require further assessment should these areas be within the construction envelope. Areas of archaeological potential include forested greenspace and parklands.
Based on the Stage 1 assessment, the following recommendations are made:
The portions of the study corridor located along Bayview Avenue that have been previously disturbed by road work and traffic and utility infrastructure do not hold archaeological potential and require no further assessment. Additionally, the portions of the study corridor that are currently comprised of subdivisions and residential roads no longer hold archaeological potential and require no further assessment. The remainder of the study corridor contains archaeological potential and requires a Stage 2 archaeological assessment prior to any ground disturbing activities:
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o Since the portion of the study area containing archaeological potential is located within manicured parklands or in woodlots, ploughing is not feasible. As a result, it is recommended that the portions of the study corridor containing archaeological potential be subject to a test pit survey as per Section 2.1.2 of the Standards and Guidelines for Consultant Archaeologists (MTCS 2011:31).
3.2.2 Built Heritage and Cultural Heritage Landscapes A cultural heritage resource assessment was carried out to identify built heritage resources and cultural heritage landscapes within the Bayview Avenue study area. The Cultural Heritage Assessment Report (CHAR) is provided in Appendix D summarized below:
The field survey of the Bayview Avenue study corridor was completed in May 2015. A description of the identified cultural heritage landscapes (CHL) and built heritage resources (BHR) identified during the field survey are listed in Appendix D and include a site number, resource category, resource type, location, description and digital photograph. It is noted the Thornhill Heritage Conservation District (HCD) is located to the west of Bayview Avenue (west of the Don River Bridge on John Street). Nine Cultural Heritage Landscapes (9) and twelve Built Heritage Resources have been identified within the study area. Of the nine Cultural Heritage Landscapes:
o A portion of the Ladies Golf Club of Toronto property in proximity to Yonge Street that includes the clubhouse is situated within the Thornhill Heritage Conservation District and, therefore, designated under Part V of the Ontario Heritage Act. This area is located well away from Bayview Avenue. o The west portion of the Dunlap Observatory which includes the buildings and notable landscape features has been designated by the Town of Richmond under Part IV of the OHA, By-Law 100-09. This portion of the property is located well away from Bayview Avenue. The portion of the property fronting Bayview Avenue is currently under development. o The remaining CHLs are not included on the Town of Richmond Hill’s Inventory of Buildings of Architectural and Historical Importance included or the City of Markham’s Register of Properties of Cultural
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Heritage Value or Interest and include features such as bridges/ culverts, waterscapes and roadscapes. Of the twelve Built Heritage Resources:
o Three properties have been designated by the City of Markham under Part IV of the OHA (7070 Bayview Avenue – James Murray House; 288 John Street – John Welsh House; 8127 Bayview Avenue - Carl Reesor James House). o One property is listed on the City of Markham’s Register of Properties of Cultural Heritage Value or Interest (7716 and 7750 Bayview Avenue – C. George McCullagh House / Shouldice Hospital). o One property is listed on the Town of Richmond Hill’s Inventory of Buildings of Architectural and Historical Importance (8763 Bayview Avenue – George Quantz House).
3.3 Natural Environment The natural environmental assessment, carried out in support of the Bayview Avenue Class EA study, is provided in Appendix E and summarized in this section.
3.3.1 Previous Field Inventory As part of the background data review, TRCA provided ecological data on July 31, 2015. These data included results of surveys undertaken by TRCA and MNRF, as well as those undertaken by Ecoplans (now WSP/MMM) in 2006 (as part of a previous Class EA study in a portion of the current study area). Where appropriate, previous work has been incorporated into the natural heritage review for the current Class EA study.
TRCA provided all available flora and fauna observation records for the study area which included date, location, type of data, comments, and recorder. The data include observations between 1996 and 2014 collected with a variety of survey methods including; vascular plant inventory, incidental observations, and amphibian calling surveys. Additional species were detected within this dataset where more extensive property access was available within the adjacent lands during survey. It is of note that some records are ~ 20 years old and may no longer reflect current habitat conditions.
MNRF Records – MNRF provided all existing available Species at Risk (SAR) and fish collection records for within the study area. This data has also been incorporated
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into the Natural Heritage Report (Appendix E), as summarized in this section of the ESR.
3.3.2 Field Surveys Field investigations were completed to assess aquatic and terrestrial resources in 2015. These surveys were carried out to confirm and enhance information available from existing documentation. Field surveys were focused with the limits of the Bayview Avenue road right-of-way from Steeles Avenue to Elgin Mills Road. Representative site photographs were taken during field visits and some are provided in Appendix E.
Table 3-1: Summary of Field Surveys
SURVEY SURVEY METHODOLOGY DATES Vegetation Classification, mapping and evaluation of vegetation communities within July 15 and Assessment the study area using a modified version of the Ecological Land August 8, 2015 Classification (ELC) for Southern Ontario (Lee et al. 1998).
A botanical inventory was undertaken within the study area. This was deemed appropriate to survey for any plant Species at Risk that may occur in the area and to identify the majority of flora that occurs on the site. Assessment focused on within the right-of-way. The adjacent areas within 120 m were delineated by data provided by TRCA or air photo interpretation. Fish Habitat Survey focused on the aquatic features within the right-of-way and May 19, 2015 Assessment approximately 50 m up and downstream of the road crossings (where accessible). Where watercourse was not accessible beyond the right-,
aquatic features were documented based on a visual assessment from the right-of-way. Included documenting substrates, habitat characteristics, cover, geomorphic details, channel dimensions, riparian habitat, specialized habitats, evidence of groundwater inputs, fish observations. Fish Fish community sampling was completed at water crossing locations within September 22, Community the right-of-way using a backpack electrofisher and dip net. 2015 Breeding An avifaunal inventory, breeding and habitat assessment was undertaken. June 15, and July Birds Survey The level of breeding bird evidence observed was recorded following 3, 4 2015 standard criteria established by the Ontario Breeding Bird Atlas (OBBA). Breeding Amphibian calling (breeding) activity was not assessed as part of this study Not Undertaken Amphibian as previously collected data were deemed suitable to identify suitable Surveys breeding habitat of the species.
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-9 Environmental Study Report | WSP | MMM Group | August 2017
SURVEY SURVEY METHODOLOGY DATES General Supplemental observations of herpetofauna, mammals, and insects were June 15, and July Wildlife recorded during all field visits. All observations made during the field 3, 4 2015 Surveys surveys were recorded, including sightings of species, as well as evidence of use (e.g. browse, tracks / trails, scat, burrows, and vocalizations). Wildlife habitat potential (SWH and SAR) was also evaluated during field surveys
3.3.3 Vegetation Survey Approach A vegetation community assessment and botanical inventory was undertaken on July 15 and August 8, 2015 within the study area. For portions of properties outside of the right-of-way, vegetation communities were characterized using existing available information from previous studies (ELC mapping provided by TRCA), air photo interpretation, or by roadside survey (closest available vantage point).
The scope of vegetation surveys and analyses included the following:
Classification, mapping and evaluation of vegetation communities within the study area using the Ecological Land Classification (ELC) for Southern Ontario (Lee et al. 1998); Vegetation community significance was evaluated using Natural Heritage Resources of Ontario: Vegetation Communities of Southern Ontario (Bakowsky 1996) and vegetation community significance listed on the NHIC website at the time of report preparation. A vascular plant species list was prepared based on the botanical inventory work (Appendix C); and Plant species status was was evaluated using the rankings within The Vascular Plants of Halton Region (Halton Natural Areas Inventory 2006) for regional significance; the Rare Vascular Plants of Ontario, Fourth Edition (Oldham and Brinker 2009) for provincial significance; the current Species At Risk in Ontario List (MNRF, May 2014) for Ontario species at risk; and, the Species At Risk Act (Schedules 1 and 3), for species at risk in Canada.
3.3.4 Fish and Fish Habitat Survey Approach Field investigations of aquatic features were conducted on May 19, 2015. All watercourses and drainage features crossing Bayview Avenue within the study area were assessed and habitat mapped within the right-of-way and approximately 50 m upstream and 50 m downstream of Bayview Avenue, where accessible. Where not
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accessible, aquatic habitat features were visually assessed and mapped from within the right-of-way.
In total, four main water crossing locations were identified for assessment; BS-1, BS-2, BS-3, and BS-4. Two additional drainage features BS-1a and BS-2a associated with the four main features were also assessed as part of the study. Watercourse assessments included noting of the following habitat parameters (where applicable):
Flow condition, clarity, general gradient and velocities; Channel dimensions and general character; Morphology (e.g., riffles, pools); Cover opportunities (i.e., woody debris, undercut banks, boulders, aquatic vegetation); Substrate type; Bank height, character and stability/evidence of erosion; Riparian vegetation; Any observations of fish presence and/or barriers to fish movement; Potential specialized and important habitat areas including potential spawning habitat, good nursery cover, holding habitat (deeper refuge pools); Evidence of groundwater discharge or indicators; and Disturbances and habitat limitations Fish community sampling was completed at each water crossing within the right-of- way using a backpack electrofisher and dip net on September 22, 2015.
3.3.5 Wildlife Survey Approach Wildlife surveys were conducted on June 15, and July 3 and 4, 2015 and included: breeding avifauna surveys, wildlife habitat assessment for Species at Risk (SAR) and potential Significant Wildlife Habitat (SWH), collection of general wildlife and habitat information, and visual survey of existing wildlife passage structures. The surveys were carried out within the right-of-way. Adjacent lands were generally assessed in terms of vegetation characteristics and potential for wildlife habitat based on visual assessment from the right-of-way, recent air photo interpretation, and background information. As extensive wildlife surveys have been undertaken within the study area previously, results of these surveys have been reviewed and
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incorporated where appropriate for the purposes of this study. This includes wildlife observation records provided by TRCA on July 31, 2015.
3.3.6 Avifauna Avian surveys were conducted to gather breeding bird data and to evaluate the study area for avian habitat potential. Breeding bird surveys were undertaken on June 15 and July 3, 4, 2015 and were conducted during appropriate weather conditions (low wind, no precipitation) and timing (surveys beginning around sunrise during the breeding bird season). The surveys included visiting each feature twice (at least 10 days apart) and recording all visual and audible observations as well as the level of breeding bird evidence following standard criteria and protocols established by the Ontario Breeding Bird Atlas (OBBA). Bird species observed during surveys are listed in Appendix E.
3.3.7 Wildlife Habitat Assessment and General Observations An assessment of existing habitat was undertaken to consider potential use for Species at Risk (SAR) and Species of Conservation Concern (SCC) known to occur within the vicinity of the study area. This included searches for cavity/snag trees and open building structures that may provide suitable roosting/maternity habitat for SAR bats. Existing habitats were also screened for potential as Significant Wildlife Habitat (SWH) as defined in Ecoregion 7E SWH Criterion Schedule (MNRF 2015). Existing structures such as bridges and culverts were also surveyed to document any bird nesting or other wildlife use (e.g. using culverts as a movement corridor). Supplemental observations of birds, herpetofauna, mammals, and insects were recorded during all field visits. These observations were recorded, including sightings of species, as well as evidence of use (e.g. browse, tracks / trails, scat, burrows, and vocalizations). Other wildlife observations are listed in Appendix E.
3.3.8 Surface Drainage and Watershed Characteristics The study area lies within two watersheds, Rouge River and Don River. The northern portion of the study area (from Elgin Mills to Major Mackenzie Drive East – approximately 2 km in length) is located within the Rouge River Watershed. One crossing, BS-1, is considered a headwater tributary of the Rouge River. The remaining 8.2 km south of Steeles Avenue East is located within the Don River Watershed, encompassing crossings BS-2, BS-3, and BS-4. Both watersheds are within the jurisdiction of the TRCA.
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Four (4) water crossings are present along the Bayview Avenue right-of-way. For the purposes of this study these crossings are identified in the Natural Heritage Report (Appendix E) as BS-1 to BS-4, from north to south. Crossing BN-1, a Rouge River Tributary, originates from a storm sewer outfall ~150 m west of Bayview Avenue and flows easterly across Bayview Avenue just south of Elgin Mills Road East. Crossing BN-2, German Mills Creek, flows southeasterly across Bayview Avenue at the intersection of Bantry Avenue. Crossing BN-3, the East Don River, and BN-4, a tributary of the East Don River convey surface flows southeasterly across Bayview Avenue just north of Steeles Avenue.
Two additional drainage features are also present within the right-of-way. These features include BS-1a and BS-2a. Feature BS-1a is a branch of feature BS-1 (Rouge River Tributary). The feature is piped upstream of Bayview Avenue and approximately 20 m east of Bayview Avenue, the feature becomes an open channel for ~ 60 m before it is then piped for another 50 m, finally draining into the main channel of BS-1. Feature BS-2 is a small tributary of German Mills Creek (BS-2), located in the immediate vicinity of the BS-2 crossing. This feature drains from a small SWM facility located on the east side of Bayview Avenue. Surface water drains from the facility via a pipe westerly under Bayview Avenue, where it opens up into a channel for ~40 m before connecting with German Mills Creek.
3.3.9 Environmentally Designated Areas Several natural heritage features and overlapping designated areas are present within the Bayview Avenue study area. These include:
East Don River – Located in the southern portion of the study area, crossing Bayview Avenue at two locations north of Steeles Avenue. Rouge River Tributary – Located in the northern portion of the study area, crossing Bayview Avenue just south of Elgin Mills Road. German Mills Creek – Located in the middle of the study area crossing Bayview Avenue north of the 407 Toll Route; Policy designated areas include:
York Region Official Plan (2010) – Natural features designated as part of the Regional Greenlands System (including Regionally Significant Woodlands). Designations are consistent with ORMCP. Town of Richmond Hill Official Plan (2010) – Designations are consistent with ORMCP.
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-13 Environmental Study Report | WSP | MMM Group | August 2017
TRCA Regulation 166/06 Lands - natural and hazardous areas (e.g., areas in and near watercourses and floodplains). Endangered Species Act (2007) – The study area reach of the Rouge River Tributary identified as Redside Dace Recovery Habitat and is protected under the ESA (2007).
3.3.10 Vegetation Land use within the study area is primarily residential development with few areas of natural and culturally-derived vegetation. Larger areas of natural vegetation in the form of forests, woodlands, and wetlands occur along stream corridors. The majority of the forested land within the study area consists of Cultural Woodland and Deciduous Forest with small sections of Thicket Swamp. Within the existing road right-of-way, the majority of the habitat is comprised of manicured lawns, as well as residential and municipal plantings. Grassy cultural meadow communities, which are dominated by non-native, tolerant forbs and grasses, also make up a portion of the road right-of-way.
3.3.10.1 Vegetation Communities Vegetation communities are delineated on Exhibits 4-3 to 4-13, provided in Appendix E and described below. TRCA ELC mapping for the study area has been incorporated into the descriptions. ELC communities provided by TRCA, which are located within the right-of-way have been field confirmed or adjusted appropriately, communities present outside of the study remain as provided from TRCA.
Dry – Moist Old Field Meadow Type (CUM1-1) Units: 1B1, 2, 5B, 7C, 8, 9, 10, 11, 12, 13, 14A, 16, 17, 19B and all roadside areas
Old Field Meadow habitat is widespread throughout the study area, often occurring within the right-of-way, and typically comprised of early successional, disturbance- tolerant species. These old-field communities include a dense layer of herbaceous ground vegetation, and are characterized by an open herbaceous layer of common ‘old-field’ species such as, Red Fescue (Festuca rubra), Awnless Brome (Bromus inermis ssp. inermis), Common Milkweed (Asclepias syriaca), Tall Goldenrod (Solidago altissima), Garden Bird’s-foot-trefoil (Lotus corniculatus), Kentucky Bluegrass (Poa pratensis ssp. pratensis), Creeping Wild Rye (Elymus repens), Orchard Grass (Dactylis glomerata), Wild Carrot (Daucus carota), and Chicory (Cichorium intybus). Common, native aster (Symphyotrichum) species that flower in late summer, such as New England Aster (S. novae-angliae) and Panicled Aster (S.
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lanceolatum), were observed along the right-of-way. Along the right-of-way, small patches of Common Reed, Cattail Mineral Shallow Marsh Type (MAS2-1) and Reed Canary Grass Mineral Meadow Marsh Type (MAM2-2) were interspersed within the drainage ditches.
Silver Maple Deciduous Plantation (CUP1-5) Unit: 21B
These plantations consist primarily of mid-age Silver Maple (Acer saccharinum) trees with a portion of American Elm (Ulmus americana), Black Cherry (Prunus serotina), younger Green Ash (Fraxinus pennsylvanica), and Common Buckthorn (Rhamnus cathartica) interspersed. In the understory and ground layer Garlic Mustard (Alliaria petiolata), Common Buckthorn, Northern Red Current (Ribes rubrum), Siberian Squill (Scilla siberica), and Lesser Periwinkle (Vinca minor) are predominant. Communities where field or roadside confirmation was possible indicate some variability in age and composition.
Scotch Pine Coniferous Plantation Type (CUP3-3) Units: 22
These plantations are young to mid-aged communities of densely planted Scotch Pine (Pinus sylvestris) with Black Walnut (Juglans nigra), and American Elm interspersed. Occasional edge species near the roadside of the plantation include, Manitoba Maple (Acer negundo), Staghorn Sumac (Rhus typhina), and Common Buckthorn. Ground flora is comprised of cultural meadow “old field” species near the edges. Some understory regeneration is occurring.
Dry-Moist Exotic Deciduous Woodland (CUW1) Units: 6A, 7A, and 18
Cultural woodlands are typically created when an area is highly disturbed. Canopy cover ranges from 30 to 60% and is typically made up of regenerating native and non-native species, which spread likely from an adjacent woodlot or from residential plantings. The units mentioned above are dominated by non-native species, such as Black Locust (Robinia pseudoacacia), Northern Catalpa (Catalpa speciosa), Common Buckthorn, Multiflora Rose (Rosa multiflora), Norway Maple (Acer platanoides), Scotch Pine, Siberian Elm (Ulmus pumila), and English Hawthorn (Crataegus monogyna). Native species include Red-osier Dogwood (Cornus sericea), Green Ash, Black Walnut, Honey Locust (Gleditsia triacanthos; planted), Staghorn Sumac, Eastern Red Cedar (Juniperus virginiana), and Manitoba Maple. The understory / ground flora consists of cultural meadow species, as well as regenerating or dispersed seeds from neighboring communities.
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Deciduous and Coniferous Cultural Hedgerows (TAGM5) Units: 1A, 2, and the right-of-way
These units typically consist of narrow rows of naturally occurring (native or non- native) or planted tree species situated along property boundaries or within agricultural fields; however, in this instance planted street trees have been included within this category. Within this study area tree species include Amur Maple (Acer ginnala), Manitoba Maple, Norway Maple, Sugar Maple (Acer saccharum var. saccharum), Freeman's Maple (Acer ×freemanii), Common Hackberry (Celtis occidentalis), Honey Locust, White Ash (Fraxinus americana), Black Walnut, Kentucky Coffee-tree (Gymnocladus dioicus), Common Apple (Malus pumila), Amur Honeysuckle (Lonicera maackii), Norway Spruce (Picea abies), Colorado Spruce (Picea pungens), Scotch Pine, Common Lilac (Syringa vulgaris), Little-leaf Linden (Tilia cordata), and Siberian Elm. Unit 1A included just Scotch Pine in the hedgerow, while unit 2 contained Scotch Pine and Norway Maple. Understory varies relative to canopy cover, but often consists of cultural meadow ‘old-field’ species.
Dry-Fresh Sugar Maple Deciduous Forest Type (FOD5-1) Units: 14B, 15
Sugar Maple is the dominant species in both the canopy and subcanopy of this community type. Additional species within the canopy include: Bitternut Hickory (Carya cordiformis), American Elm, and American Basswood (Tilia americana). The subcanopy / understorey layer consisted of Honeysuckle Species (Lonicera sp.), Common Apple, Choke Cherry (Prunus virginiana), Staghorn Sumac, and Riverbank Grape (Vitis riparia). The ground layer was not visible for unit 14B; however, within unit 15’s understory Common Boneset (Eupatorium perfoliatum), Enchanter's Nightshade (Circaea lutetiana ssp. canadensis), Herb-robert (Geranium robertianum), Wild Red Raspberry (Rubus idaeus ssp. strigosus), Bittersweet Nightshade (Solanum dulcamara), Tall Goldenrod, and Creeping Bellflower (Campanula rapunculoides) were observed. The edge along unit 14B has had a recent disturbance and has no “edge” habitat. Cultural meadow extends up to the dripline of this unit. Unit 15 is located kitty-corner to unit 14B, and it appears as if the two units were connected prior to land development in the area.
Dry-Fresh Sugar Maple - Basswood Deciduous Forest Type (FOD5-6) Unit: 4C
This forest community is mid-age to mature, and is dominated by Sugar Maple with various associates. The assemblage consists of Sugar Maple with Northern Red Oak (Quercus rubra), American Elm, and American Basswood as the most abundant canopy trees. The patchy understory is comprised of mainly Green Ash, Manitoba Maple, Bell’s Honeysuckle (Lonicera ×bella), and Choke Cherry. The ground flora Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-16 Environmental Study Report | WSP | MMM Group | August 2017
was not visible during the 2015 field visit, but TRCA includes Tall Goldenrod in their species list for this community.
Fresh - Moist Willow Lowland Deciduous Forest Type (FOD7-3) Units: 4A, 5A, 6B, 19A, 20B, and 24B
These lowland forest communities occupy valley slopes and bottomlands and are dominated by willow species, such as White Willow (Salix alba), Peach-leaved Willow (Salix amygdaloides), and Hybrid Willow (Salix ×sepulcralis). In addition, less dominant species include: Silver Maple, Manitoba Maple, American Elm, Eastern Cottonwood (Populus deltoides), European Alder (Alnus glutinosa), Common Hackberry, and Green Ash. Where visible, understory shrubs include Common Buckthorn, Honeysuckle (Lonicera sp.), Common Apple, and Red-osier Dogwood. The ground flora is indicative of moist to wet soils, and includes species such as Great Angelica, Spotted Joe-pyeweed (Eupatorium maculatum), Reed Canary Grass (Phalaris arundinacea), One-row Watercress (Rorippa microphylla), Stinging Nettle (Urtica dioica), Garlic Mustard, Enchanter’s Nightshade, and Field Horsetail (Equisetum arvensis).
Fresh-moist Black Walnut Lowland Deciduous Forest Type (FOD7-4) Units: 24B, 25
Observed along East Don River corridor at the southern end of the study site, this community type consists of riparian vegetation and introduced species from the surrounding residential areas. Canopy cover can be quite dense in areas. Black Walnut is the dominant species in the canopy with Manitoba Maple, American Elm, and willow species (Salix sp.) abundant as well. The understory and ground layer contain species such as Garlic Mustard, Enchanter's Nightshade, Clover-root (Geum urbanum), European Swallow-wort (Cynanchum rossicum), Bell's Honeysuckle, Thicket Creeper (Parthenocissus vitacea), and Choke Cherry
Fresh - Moist Exotic Lowland Deciduous Forest Type (FOD7-9) Unit: 21D
This disturbed community is fairly young and contains predominantly weedy species. Canopy is sparse (closer to a woodland), while the subcanopy and understorey are dense with Common Buckthorn. Overstorey species include Siberian and American Elm, Black Locust, Eastern Cottonwood, Norway Maple, Manitoba Maple, European (Fraxinus excelsior), Green, and White Ash, as well as Black Walnut. In addition to Common Buckthorn, a combination of native and non-native species makes up the understorey and ground layer. These species include: European Swallow-wort, European Spindle-tree (Euonymus europaeus), Clover-root, St. John's-wort,
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-17 Environmental Study Report | WSP | MMM Group | August 2017
(Hypericum perforatum), Purple Loosestrife (Lythrum salicaria), Thicket Creeper, Reed Canary Grass, Allegheny Blackberry, (Rubus alleghaniensis), Broad-leaved Goldenrod, (Solidago flexicaulis), Smooth Goldenrod, (Solidago gigantea), Stinging Nettle, and Riverbank Grape.
Dry-Fresh Black Walnut Deciduous Woodland Type (WODM4-4) Units: 4B, 23
Black Walnut is the dominant species in the canopy of this community with Manitoba Maple, and ash species as co-dominant. The canopy cover is generally less than 60%. This community is along the edge of a forested area in unit 4B and is the remnant of a forested area that was previously more substantial (prior to road construction) for unit 23. Both, however, are found along stream corridors. Understory and ground flora have a relatively high percentage of native species for such a disturbed community type. Invasive species include Norway Maple, honeysuckles, Common Buckthorn, and Siberian Elm in the canopy / understory, as well as Garlic Mustard, Dame’s Rocket (Hesperis matronalis), and Woods Bluegrass (Poa nemoralis).
Fresh-moist Manitoba Maple Deciduous Woodland (WODM5-3) Units: 3, 20A, 21A
Within the study area, these communities are found along forested edges that abut the right-of-way. Units 3 and 20A are located along stream corridors, while unit 21A is adjacent to a moist Silver Maple Plantation. Canopy cover is generally less than 60%. This community type contains mix of native and non-native species in areas that display signs of recent disturbance. The species assemblage includes successional species that are typically found within moist to wet areas, as well as residential, planted trees where these communities come in contact with property lines. The canopy cover is generally < 60% and is dominated by Manitoba Maple. Reddish Willow (Salix xrubens) is nearly as abundant as Manitoba Maple in unit 20A, while until 21A includes Common Buckthorn as abundant. The understory is made up of cultural meadow and hydrophilic species such as St. John’s-wort, Purple Loosestrife, and Reed Canary Grass.
Forb Mineral Meadow Marsh Type (MAM2-10) Unit: 1B2, Roadside ditches along right-of-way
This community type consists of predominantly forb species with very little woody vegetation (typically <10% cover). In this case, the only woody species is Crack Willow (Salix ×fragilis). The ground layer contains species that are often found in moist soil, such as; Spotted Joe-pyeweed, Broad-leaved Cattail (Typha latifolia), and
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-18 Environmental Study Report | WSP | MMM Group | August 2017
Cultural Meadow species. These communities are most often present in association with bottomlands in isolation or in association with wooded features. Where they border wooded communities, these communities are known to often contain abundant snag trees, however, in this study area, there were no snags recorded.
Common Reed Mineral Shallow Marsh Type (MASM1-12) Unit: 1A
This community is located at the northern portion of the study area near the intersection of Bayview and Elgin Mills. It is surrounded by Cultural Meadow on all sides. The dominant species within the marsh is Common Reed (Phragmites australis ssp. australis) with no other species observed.
Cattail Mineral Shallow Marsh Type (MAS2-1) Unit: 5C and small patches along the right-of-way
These small, shallow marsh communities are dominated by cattail species, predominately the non-native Narrow-leaved Cattail (Typha angustifolia), but also Broad-leaf Cattail, and Blue Cattail (Typha ×glauca). Within the study area, they are found in small patches along the roadside in drainage ditches, in bottomlands, and along watercourses. Hydrophytic shrubs and trees may occur sporadically, and other herbaceous associates include Reed Canary Grass, Common Reed, willows (Salix sp.), Yellow Rocket (Barbarea vulgaris), Spotted Jewelweed (Impatiens capensis), Cursed Crowfoot (Ranunculus sceleratus), Bittersweet Nightshade, and sedges (Carex sp.).
White Cedar - Hardwood Organic Mixed Swamp Type (SWM4-1) Unit: 4D
During the 2015 MMM field survey, this community was not visible from the right-of- way. Therefore, TRCA ELC data were not confirmed. TRCA described the community as a mature forest community with White Cedar (Thuja occidentalis) occurring as the dominant species in the canopy. Additional canopy species include Black Ash (Fraxinus nigra), Yellow Birch (Betula alleghaniensis), and Balsam Poplar (Populus balsamifera). Species in the subcanopy and understory include: Red-osier Dogwood, Cranberry Viburnum (Viburnum opulus), Marsh Marigold (Caltha palustris), Spotted Jewelweed, Ostrich Fern (Matteuccia struthiopteris), and Sensitive Fern (Onoclea sensibilis).
Willow Mineral Swamp Thicket Type (SWT2-2) Unit: 6D
These communities appear to be dominated by shrubby vegetation including Sandbar Willow (Salix interior), Heart-leaved Willow (Salix eriocephala), Red-osier Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-19 Environmental Study Report | WSP | MMM Group | August 2017
Dogwood, Choke Cherry, and Common Buckthorn. The ground cover included cultural meadow species in combination with hydrophytic species, such as Field Horsetail, Spotted Jewelweed, and Purple Loosestrife.
Pondweed Submerged Shallow Aquatic (SAS1-1) Unit: 6C
This community contains water with a depth of less than 2 m that is not ephemeral. The dominant species within the standing water is Sago Pondweed (Stuckenia pectinata) with abundant Broad Waterweed (Elodea canadensis). Along the edges of the pond, Narrow-leaved Cattail, Common Reed, Creeping Thistle (Cirsium arvense), and White Avens (Geum canadense) were observed.
Open Water Aquatic (OAO) Units: 7B, 19C, and 21C
This type has a water depth of over 2 m, which is typically too deep for any submergent plant to gather light. An occasional floating-leaved plant may pass through, but this type typically does not contain vegetation. Therefore, no plant list is provided.
3.3.10.2 Floristic Inventory Plant lists for each vegetation community type are provided for communities where a reasonable level of observation of community strata was possible from the roadside / community edge or within the right-of-way. In some cases, communities were observed from a distance or had high edge density which reduced visibility – in these cases only the primary canopy and edge species could be observed. As such, plant lists should not be taken as exhaustive lists, but rather as a general characterization of the vegetation types that make up each community.
Survey Results
In total 166 plant species were recorded from within the study area including species from the 2015 field surveys, including species provided by TRCA. A Vascular Plant List is provided in Appendix F. Of the identified species, 82 (49%) are native, and 84 (51%) are non-native. Key findings include:
One (1) unconfirmed Butternut (S3?; END) tree SAR identified through background sources was observed within the study area during field surveys. This species was located outside of the right-of-way, which made identification uncertain. This specimen will not be impacted by the road improvements.
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-20 Environmental Study Report | WSP | MMM Group | August 2017
Honey Locust (S2) was observed throughout the study area. However, these trees had obviously been planted, and are thus not considered to be of concern. Thirty (30) species are listed as regionally significant by the TRCA. This includes one species ranked L1 (Regional Concern), six species listed as L3 (Regional Concern), and 23 species ranked as L4 (Urban Concern).
o Species of Regional Concern included Great Angelica (L3), Strawberry Goosefoot (Chenopodium capitatum; L3), Quebec Hawthorn (Crataegus submollis; L3), Broad Waterweed (L3), Butternut (L3), White Spruce (Picea glauca; L3), Red Pine (Pinus resinosa; L1). However, the White Spruce and Red Pine trees may have been planted. o The remaining 23 regionally significant species are ranked as L4 species (Urban Concern), the majority of which are confined to and protected by the valleys along stream corridors. Six (6) species listed as regionally rare in York Region were observed and included: Broad-glumed Brome (Bromus latiglumis; R5), Quebec Hawthorn (R1SR), River-bank Wild-rye (Elymus riparius; R5), Black Walnut (R), Eastern Red Cedar (R4), Virginia Creeper (Parthenocissus quinquefolia; R4). All observations of regionally rare species were outside of the right-of-way. Coefficient of Conservatism (CC)1 values range from 0 (low habitat sensitivity) to 8 (high habitat sensitivity) with the majority (91%) of native species ranging between 0 and 6 (moderate habitat sensitivity). The one species that has a CC value of 8 (Common Hackberry) was only found planted as a street tree along Bayview Ave.
TRCA Records
Records of 165 vascular species from within the study area were provided by TRCA. The data included observations between 2001 and 2014 made by TRCA and MNRF. A Vascular Plant List is provided in Appendix E. Of these species, two could not be identified beyond genus due to an absence of identifying characteristics. Of the identified species, 81 (49%) are native, and 84 (51%) are non-native. Key findings include:
1 Value of 0 to 10 based on plants degree of fidelity to a range of synecological parameters: (0-3) Taxa found in a variety of plant communities; (4-6) Taxa typically associated w ith a specific plant community but tolerate moderate disturbance; (7-8) Taxa associated with a plant community in an advanced successional stage that has undergone minor disturbance; (9-10) Taxa w ith a high fidelity to a narrow range of synecological parameters (Oldham et al., 1995). Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-21 Environmental Study Report | WSP | MMM Group | August 2017
Fifty-one (51) of the 165 species were not recorded during the 2015 surveys. This variation is likely a result of TRCA and MNRF having additional access to adjacent lands. It is of note that some records are ~15 years old and such species may no longer be longer present within the area. No plant SAR or SCC were identified through existing TRCA records. The majority of species observed have S-ranks2 of S5 (Secure in the province) or are unranked, while about 4% are listed as S4 or S4? (Apparently Secure). Seven (7) of the 113 species are listed as regionally significant (Regional Concern) by the TRCA. This includes one species ranked L1 and seven species listed as L3. Coefficient of Conservatism (CC)3 values range from 0 to 9 with the majority (86%) ranging between 0 and 6.
3.3.11 Wildlife
3.3.11.1 Avifauna Survey Results
Forty bird species were observed within the study area. A full species list is provided in Appendix E. A summary of key results, including level of breeding evidence, is highlighted below:
Bird species observed were predominantly common, generalist, and urban- adapted; including species associated with a variety of habitats:
o Forest edge (most prevalent habitat type; species found include American Robin [Turdus migratorius], Northern Cardinal [Cardinalis cardinalis] and Song Sparrow [Melospiza melodia]);
o Forest interior (limited to portions of riparian corridors, which are at most 60 m from the edge; species found include Cooper's Hawk, Hairy Woodpecker, Red-breasted Nuthatch and White-breasted Nuthatch);
2 Refer to plant list legend in Appendix D for an explanation of S-Ranks. 3 Value of 0 to 10 based on plants degree of fidelity to a range of synecological parameters: (0-3) Taxa found in a variety of plant communities; (4-6) Taxa typically associated w ith a specific plant community but tolerate moderate disturbance; (7-8) Taxa associated with a plant community in an advanced successional stage that has undergone minor disturbance; (9-10) Taxa w ith a high fidelity to a narrow range of synecological parameters (Oldham et al., 1995). Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-22 Environmental Study Report | WSP | MMM Group | August 2017
o Wetland/aquatic (limited to riparian features and man-made ponds at golf course; species found include Canada Goose [Branta Canadensis], Mallard [Anas platyrhynchos], and Wood Duck [Aix sponsa]);
o Grassland/field (limited availability in Feature 1; species found include Savannah Sparrow and Killdeer [Charadrius vociferous])
Of the 40 bird species observed, 35 species were recorded as having some `breeding`4 evidence in features located adjacent to the right-of-way.
Two (2) SAR bird species listed as Threatened provincially and afforded protection under the ESA (2007) was observed within the study area: Barn Swallow (Hirundo rustica) and Chimney Swift (Chaetura). Barn Swallow was observed in 2015 only as a foraging visitant (no breeding evidence or nests observed) around Features 5 and 6 over the baseball fields as well as Feature 17, adjacent to the right-of-way. Chimney Swifts were observed as foraging visitants above Feature 21. There may be suitable nesting habitat in surrounding buildings (chimneys) or in tree cavities within forested areas; however, no nesting activity or suitable nesting habitat was noted within the right-of-way.
One (1) SCC bird species observed within the study area: Eastern Wood Pewee (Contopus virens (federally and provincially listed as Special Concern). The species was observed in 2015 with probable breeding evidence in Feature 15, adjacent to the right-of-way.
Thirty-seven (37) of the 40 species are considered Regionally Significant by the TRCA. This includes two species ranked L3 (Regional Concern). These species were all observed outside of the right-of-way.
TRCA Records
An additional five bird species were recorded within the study area according to the TRCA records. This includes Cooper’s Hawk (Accipiter cooperii), Hairy Woodpecker (Leuconotopicus villosus), Northern Flicker (Colaptes auratus), Ruby-throated Hummingbird (Archilochus colubris), and Wood Duck (Aix sponsa).
4 Breeding birds include species for which any level of breeding evidence w as recorded (i.e. possible, probable, confirmed; or `observed` where some potential for local breeding exists) Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-23 Environmental Study Report | WSP | MMM Group | August 2017
3.3.11.1.1 Herpetofauna Survey Results
General wildlife observations within the study area did not result in observation of any herpetofaunal species.
TRCA Records
TRCA herpetofauna records were obtained through calling amphibian and general observation. Three amphibian species were identified in the study area through the TRCA records. Species included: American Toad (Anaxyrus americanus), Green Frog (Lithobates clamitans) and Spring Peeper (Pseudacris crucifer). The TRCA data also included observation of one reptile in the study area: Eastern Gartersnake (Thamnophis sirtalis sirtalis). All of these species are relatively common throughout southern Ontario and expected to occur in the study area due to the presence of wetland and other aquatic habitats. A summary of available TRCA herpetofauna data is provided in Appendix E.
3.3.11.1.2 Mammals Survey Results
Mammal observations, including sightings and evidence of use (e.g. browse, tracks / trails, scat and burrows) were recorded during all field surveys. Targeted searches for suitable bat maternity roosting habitat (cavity/snag trees, open structures) was also undertaken within the right-of-way.
In total, five (5) common and expected mammal species were recorded in the study area: Grey Squirrel (Sciurus carolinensis), Groundhog (Marmota monax), Red Squirrel (Sciurus vulgaris), Raccoon (Procyon lotor), and White-tailed Deer (Odocoileus virginianus). All of these species are relatively common throughout southern Ontario and expected to occur in the study area. A complete list of species is found in Appendix D. No SAR or SCC mammals were found in the area and all species have a provincial S-Rank of S4 or S5 (secure). Habitat conditions found in the study are likely to support a number of other mammal species commonly found in this region.
Four bat species including Little Brown Bat (Myotis lucifugus), Northern Long-eared Bat (Myotis septentrionalis), Tri-Colored Bat (Perimyotis subflavus), and Eastern Small-Footed bat (Myotis leibii) have potential to occur within the study area. These species are provincially listed as Endangered and are afforded protection under the
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-24 Environmental Study Report | WSP | MMM Group | August 2017
ESA (2007). Results of searches for cavity/snag trees and open building structures that may provide suitable roosting/maternity habitat for SAR bats indicated that no suitable habitat is present within the right-of-way. Potential roosting habitat for SAR bats does occur within adjacent forested areas where cavity/snag trees are present.
TRCA Records
Two (2) additional species were recorded through the TRCA records: Eastern Cottontail (Sylvilagus floridanus) and Eastern Chipmunk (Tamias striatus). These species are relatively common throughout southern Ontario and expected to occur in the study area.
3.3.11.2 Lepidoptera and Odonates Survey Results
Any presence of Lepidoptera (butterflies and moths) and Odonates (dragonflies and damselflies) was recorded in the course of detailed breeding bird surveys and general wildlife observations. One (1) Odonate species was recorded: Ebony Jewelweed (Calopteryx maculata). This species is common in Ontario (S-Rank of S5) and no SAR Lepidoptera or Odonates were found in the study area.
Monarch (Danaus plexippus), which is provincially and federally listed as Special Concern, was not found in the study area during field surveys - however, there is potential habitat for this SAR species where fields with Common Milkweed occur.
TRCA Records
No additional insect records were available within the TRCA data.
3.3.11.3 Wildlife Movement Corridors/Passages Field investigations did not indicate any areas of obvious high-use large / medium- sized mammal movement corridors or road crossing points within the study area. Generally, opportunities for wildlife movement within the area are limited due to the highly urbanized surrounding land use.
Overall, no key locations of wildlife movement have been identified, the Don River crossings likely provide some movement opportunity for medium to large sized mammals as well as for herpetofauna.
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-25 Environmental Study Report | WSP | MMM Group | August 2017
3.3.12 Watercourses and Fish Habitat A summary of the fish and aquatic habitat characteristics at each of the four water crossing locations is presented below. No key habitats were identified and no provincial or federal SAR were observed or collected during the field surveys. The Rouge River Headwater Tributary (BS-1) which crosses Bayview Avenue just south of Elgin Mills Road East is designated as recovery habitat for Redside Dace (Clinostomus elongates) (MNRF Correspondence, 2015). Redside Dace are Endangered provincially and as such they and their habitat are afforded protection under the Endangered Species Act (2007).
3.3.12.1 BS-1 (Rouge River Tributary) Habitat Characterization
This coldwater headwater tributary of the Rouge River originates approximately 200 m upstream (west) of Bayview Avenue in a residential neighborhood, daylighting from a storm sewer outlet. The tributary flows in a south-easterly direction through a defined channel, crossing Bayview Avenue via a concrete box culvert 3.0 m wide and 1.0 m high.
Upstream (west) of Bayview Avenue
Channel morphology is predominantly comprised of flats as this reach has been highly altered and hardened with large concrete slabs along the channel bed. Average bankfull widths and depths were measured at 3.5 m and 0.5 m, respectively. Upstream banks are relatively steep, composed of silt and measure approximately 2.0 m high. Riparian vegetation consists of mixed forest approximately 7 -10 m extending on either side of the channel bank. In-stream cover in the form of concrete slabs and sparse overhanging vegetation and undercut banks provide cover to approximately 10% of the wetted area within the assessed reach. No in-stream vegetation was observed at the time of survey. A dense tree canopy provides shading to the entire wetted surface. No groundwater seepage indicators were identified within the upstream reach.
Within Bayview Avenue Right-of-Way
Within the culvert, channel morphology consisted of moderate gradient riffle habitat. The average wetted width and depth was 2.5 m and 0.05 m, respectively. Substrates consisted mainly of cobble with some gravel and silt.
Downstream (east) of Bayview Avenue
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-26 Environmental Study Report | WSP | MMM Group | August 2017
To the east of Bayview, the watercourse bends sharply to the south and flows parallel to Bayview Avenue (approximately 4 m from the shoulder of the road) for approximately 50 m before bending again sharply to the east. Channel morphology extending from the right-of-way to approximately 50 m downstream consists mainly of alternating low-to-moderate gradient pool and riffle habitat. Wetted width and depth within the pool habitat averages 2.5 m and 0.31 m, respectively, with substrates dominated by sand with sparse silts, cobble and gravel. Within the riffles, wetted width and depth averages 0.85 m and 0.05 m, respectively. Substrates within the riffles are dominated by cobble with sparse sand and gravel. Bankfull width and depth are consistent throughout the reach and average 4.5 m and 0.65 m respectively. The left upstream bank is relatively steep (approximately 2.0 m high), composed of silt and cobble and transitions into the road embankment further downstream where the watercourse runs parallel to Bayview Avenue. The right upstream bank is more gradual (0.8 m high), transitioning into a Fresh-Moist Willow Lowland Deciduous Forest riparian area. Some erosion is evident on both banks downstream of the right-of-way. In-stream cover in the form of rocks / boulders and sparse overhanging vegetation and woody / organic debris provides cover to approximately 25% of the wetted area within the assessed reach. There was no instream vegetation at the time of survey. A dense tree canopy provides shading to approximately 90% of the wetted surface. No groundwater seepage indicators were identified within the downstream reach.
Fish Community
Two Brook Stickleback (Culaea inconstans) were captured during electrofishing surveys on September 22, 2015. Fish community assemblage within this reach is expected to be comprised of tolerant warmwater baitfish. MNRF fish collection records from 2009 indicate that six additional species were recorded in several stormwater management (SWM) ponds located downstream within 2 km. These species include; Creek Chub (Semotilus atromaculatus), Goldfish (Carassius auratus), Pumpkinseed (Lepomis gibbosus), Brown Bullhead (Ameiurus nebulosus), Fathead Minnow (Pimephales promelas) and Black Crappie (Pomoxis nigromaculatus).
The Rouge River Fisheries Management Plan (FMP) (MNRF & TRCA, 2010) identifies the crossing as being located within Fisheries Management Zone 1 which focuses on stormwater management and maintaining water balance (see Section 4.1.1.1 in the Rouge River FMP for management direction in Zone 1).
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-27 Environmental Study Report | WSP | MMM Group | August 2017
It is important to note that this section of the Rouge River is designated as recovery habitat for Redside Dace as indicated by MNRF (email communication 2015), as such is afforded protection under the ESA (2007). The species historically occupied the watercourse.
3.3.12.2 WBS-1a (Rouge River Tributary) Feature BS-1a is a branch of feature BS-1 (Rouge River Tributary). The feature is piped upstream (west) of Bayview Avenue to approximately 20 m east of Bayview Avenue (outside of right-of-way) where the feature becomes an open channel for ~ 60m before it is then piped again for another 50 m, finally draining into the main channel of BS-1. Fish species assemblage, if present, is likely similar to that of the Rouge River Tributary.
3.3.12.3 WBS-2 (German Mills Creek) Habitat Characterization
German Mills Creek (BS-2) is a coolwater watercourse that flows through the study area in a south-easterly direction via a defined channel, crossing under the intersection of Bayview Avenue and Bantry Avenue on a diagonal through three large open bottom concrete box culverts, each measuring approximately 7.5 m wide by 3.0 m high and 25 m long.
Upstream (west) of Bayview Avenue:
Channel morphology consists of low gradient flat and pool habitat as the watercourse meanders through a Narrow-leaved Cattail Mineral Shallow Marsh. Immediately upstream of the culvert opening, a pool measuring approximately 15 m in width and up to 1.0 m in depth is present. Flows through the western-most culvert were inhibited by a large woody / organic debris jam at the culvert entrance. Flows through the eastern-most culvert were inhibited by a vegetated island bar in the channel. Substrate within the pool is dominated by muck with some silt and detritus. Bankfull width and depth were unmeasurable given the wetland habitat on both sides of the channel. Instream cover is sparse, consisting of rocks / boulders surrounding the vegetated island and overhanging cattails / Phragmites sp. upstream of the pool. No groundwater seepage indicators were identified within the upstream reach.
Downstream of Bayview Avenue
Channel morphology consists of low gradient flats, transitioning to a pool approximately 30 m downstream where the channel narrows. A vegetated island bar
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-28 Environmental Study Report | WSP | MMM Group | August 2017
is located immediately downstream of the centre culvert. Wetted width at the time of survey transitioned from 22.5 m within the flat habitat between culvert wingwalls to 3.5 m in the pool habitat downstream. Wetted depths averaged 0.2 m within the flats and 0.7 m within the pools. Substrates within the flats are dominated by muck with some silt. Within the pools, substrates are dominated by silt with some cobble and sparse muck. Bankfull width and depth within the channel downstream were measured at 15 m and 0.65 m, respectively. There are no defined banks immediately downstream of the culverts. Banks within the defined channel reach downstream are gradual, well vegetated and composed of silt. The right upstream bank measured slightly higher at 3.0 m compared to the left upstream bank which was measured at 1.75 m. No erosion was evident downstream of the culvert. In-stream cover consists of some woody / organic debris accumulation at the culvert and overhanging vegetation within the defined channel downstream, covering <5% of the wetted area. No in-stream vegetation was observed at the time of survey. The tree canopy provides shading to <5% of the wetted surface and only at the far downstream end. Riparian vegetation consists of grasses and a Fresh-Moist Willow Lowland Deciduous Forest on top of the right upstream bank. No groundwater seepage indicators were identified within the downstream reach.
Fish Community
Electrofishing surveys conducted immediately upstream of the Bayview Avenue crossing yielded collection of four (4) fish species; Creek Chub, Blacknose Dace (Rhinichthys atratulus), Bluntnose Minnow (Pimephales notatus) and Fathead Minnow. All generally tolerant warm/coolwater baitfish species. Electrofishing Downstream (east of Bayview Avenue), electrofishing surveys yielded the same four species with the addition of Brook Stickleback.
Within the Don River Watershed Plan – Implementation Guide (TRCA 2009), crossing BS-2 is located within Fish Management Zone 4. Near term target species within this zone include: Northern Redbelly Dace (Chrosomus eos), Johnny Darter (Etheostoma nigrum), Mottled Sculpin (Cottus bairdii) and Rainbow Trout (Oncorhynchus mykiss) [migratory].
3.3.12.4 WBS-2a (German Mills Creek Tributary) Just north of the German Mills Creek crossing (BS-2), a drainage channel (crossing BS-2a, see Figure 3-5 in Appendix A) contributes flow to the main channel at a confluence approximately 5 m upstream of the easternmost culvert (west of Bayview Avenue). This drainage channel is 40 m long and daylights from a drainage outlet
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-29 Environmental Study Report | WSP | MMM Group | August 2017
which pipes surface flows from a stormwater management (SWM) facility located to the east of Bayview.
Stream morphology within this open drainage channel is moderate gradient riffle habitat with two scour pools created by armourstone >0.5 m in height. These structures function as significant barriers to fish migration. Wetted with and depth within the drainage channel averages 4.0 m and 0.2 m, respectively, although the scour pools are significantly deeper. Substrates are dominated by cobble within the riffles and sand within the pools. Armourstone banks upstream transition to natura l silt banks about halfway downstream. Riparian vegetation consists of a Fresh-Moist Willow Lowland Deciduous Forest bordering both banks. No groundwater seepage indicators were identified within the drainage channel.
3.3.12.5 WBS-3 (East Don River) Habitat Characterization
This coldwater reach of the East Don River flows in a south-easterly direction through a defined channel, crossing perpendicularly under Bayview Avenue via a bridge structure with a span width of approximately 12 m and a deck width of approximately 30 m. Approximately 40 m downstream of Bayview Avenue, the river bends sharply to the south, meandering through a residential neighborhood before re-crossing Bayview Avenue in a south-westerly direction 725 m further downstream (at crossing BS-4).
Upstream of Bayview Avenue
Channel morphology is dominated by low gradient pool habitat with riffles immediately upstream of the bridge. Wetted width is fairly consistent upstream and measured 5.0 m at the time of survey. Maximum depth within the pool was 0.93 m and averaged approximately 0.4 m in the riffle immediately upstream of the bridge. Substrates within the pools were dominated by cobble with some sand and sparse boulders. Substrates within the riffles were also dominated by cobble with some gravel and sparse silts. Bankfull width and depth are consistent throughout the reach and average 10.25 m and 1.25 m, respectively. The left upstream bank is relatively steep (approximately 7 m high), composed of silt and contains boulder protection for approximately 50 m upstream. Significant erosion exists above the rock protection up to the top of the embankment. The right upstream bank is vertical, consists of silt and is approximately 1 m in height. No erosion was evident on the right upstream bank. In-stream cover in the form of woody / organic debris, rocks / boulders and sparse overhanging vegetation provides cover to approximately 60% of the wetted
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area. There was no instream vegetation at the time of survey. Tree canopy provides shading to approximately 15% of the wetted surface. No groundwater seepage indicators were identified within the upstream reach.
Within Bayview Avenue Right-of-Way
Channel morphology is low gradient run habitat with a deep (approximately 1.0 m) pool immediately downstream of the right-of-way. The wetted width spans the entire span width of the bridge which is approximately 12 m. Wetted depth within the right- of-way averages approximately 0.6 m and substrates consist of a mixture of gravel and cobble. Substrate along the south side of the channel consists of approximately 0.5 m of accumulated muck.
Downstream of Bayview Avenue
Channel morphology is dominated by low-to-moderate gradient riffle habitat with a run leading into a pool at the downstream end. Wetted width is fairly consistent averaging 7.5 m at the time of survey with wetted depths measuring 0.25 m in the riffles and 0.52 m in the run. Substrates are dominated by cobble with some gravel within the riffles and a mixture of sand, gravel, cobble and sparse silt within run habitat. Bankfull width and depth are fairly consistent throughout and average 9.5 m and 1.2 m respectively. The left upstream bank is steep to vertical heading downstream, 1.5 m high and composed of silt and rip rap closer to the bridge. The right upstream bank is steep, 2.0 m high and is reinforced by rip rap approximately 35 m downstream where a newly constructed stormwater outlet drains to the watercourse. Moderate erosion was noted on both banks. Instream cover is plentiful downstream, consisting mainly of rocks / boulders with some undercutting of the right upstream bank, overhanging vegetation and woody / organic debris, covering approximately 70% of the wetted area. There was no instream vegetation at the time of survey. Tree canopy provides shading to approximately 20% of the wetted surface and consists mainly of a Fresh-Moist Willow Lowland Deciduous Forest on the left upstream bank. No groundwater seepage indicators were identified within the downstream reach.
Fish Community
Electrofishing surveys yielded Longnose Dace (Rhinichthys cataractae), Blacknose Dace, Johnny Darter, White Sucker (Catostomus commersonii), Creek Chub and Mottled Sculpin within and immediately upstream and downstream of the right-of- way.
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Crossing BS-2 is located within Fish Management Zone 4, as identified within the Don River Watershed Plan – Implementation Guide (TRCA 2009). Near term target species within this zone include: Northern Redbelly Dace, Johnny Darter, Mottled Sculpin and Rainbow Trout (migratory).
3.3.12.6 WBS-4 (East Don River) Habitat Characterization
This coldwater reach of the Rouge River flows in a south-westerly direction through a defined channel, crossing under Bayview Avenue on a skew through three large open bottom concrete box culverts. Approximately 25 m downstream, the river bends to the south, receiving flows from a tributary flowing southeast on the outside of the meander bend. The river flows south for another 25 m before flowing beneath Steeles Avenue East, approximately 40 m west of Bayview Avenue.
Upstream of Bayview Avenue
Channel morphology consists of low gradient run habitat, with riffles evident >50 m upstream. Wetted width is fairly consistent at 9.25 m, widening slightly as the river approaches the culverts. Maximum wetted depth averages 0.5 m throughout the reach. Substrates consist of a mixture of fine and coarse material with sand the most abundant. Bankfull width and depth are consistent throughout and were measured at 11.25 m and 1.0 m respectively. Both left and right upstream banks are steep-to- vertical and are approximately 1.5 m in height. Banks are composed of silt and clay and moderate erosion is evident on both banks. The right upstream bank has been reinforced with rip rap approximately 20 m upstream of the culverts. A vertical rip rap retaining wall at the southernmost culvert and at the south end of the river valley separates the floodplain from Bayview Avenue and adjacent development to the south. Instream cover is sparse, consisting of loose rip rap within the channel and a woody debris jam that is currently constricting flow to the northernmost culvert only. Tree canopy provides shading to approximately 75% of the wetted surface upstream and consists of a Fresh-Moist Manitoba Maple Lowland Deciduous Forest on both left and right upstream banks. No groundwater seepage indicators were identified within the upstream reach.
Downstream of Bayview Avenue
Channel morphology consists of moderate gradient riffle habitat separated by runs. Wetted width at the time of survey averaged 6.25 m within the riffles and 7.5 m within the runs. Wetted depths averaged 0.3 m within the riffles and 0.53 m within the runs.
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A small pool was observed at the tributary outlet on the outside of the meander bend. Substrates within the riffles are dominated by cobble with some sand and gravel. Within the runs, substrates are dominated by sand with some cobble. Bankfull widths ranged from 8.5 m in the riffles to 10.5 m within the runs. Bankfull depths were consistent throughout the downstream reach at 0.9 m. Both banks are steep, composed of silt and heavily stabilized by rip rap at the waterline. The left upstream bank measured slightly higher at 2.5 m compared to the right bank which was measured at 1.5 m. Moderate erosion was noted on the right upstream bank immediately downstream of the culverts. Instream cover consists of rocks / boulders (mainly rip rap), covering approximately 50% of the wetted area. There was no instream vegetation at the time of survey. The tree canopy provides shading to approximately 20% of the wetted surface. Riparian vegetation consists of approximately 15 m of lowland forest. No groundwater seepage indicators were identified within the downstream reach.
Fish Community
Electrofishing surveys yielded White Sucker, Blacknose Dace, Johnny Darter, Longnose Dace and Mottled Sculpin.
Crossing BS-4 is located within Fish Management Zone 4, as identified within the Don River Watershed Plan – Implementation Guide (TRCA 2009). Near term target species within this zone include: Northern Redbelly Dace, Johnny Darter, Mottled Sculpin and Rainbow Trout (migratory).
3.3.13 Species at Risk (SAR) The potential presence of Species at Risk (SAR) and Species of Conservation Concern has been undertaken through a comprehensive tabular screening to identify which SAR have reasonable potential to be present within the study area, based on known occurrences of the species and the habitats present.
The screening exercise involved developing a list of SAR known to occur within the vicinity of the study area or region from a review of various sources including: species indicated by MNRF and TRCA through correspondence, NHIC data extracted from online Biodiversity Explorer tool, MNRF Species at Risk website regional species list, and DFO SAR mapping.
Once the list of species was developed, each species known preferred habitat was then cross-referenced against habitats identified within the study area or adjacent lands, with consideration of species distribution and range, to determine the
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reasonable likelihood of the species being present. The likelihood of potential impacts and habitats was also evaluated (Chapter 8). SAR screening information is provided in Appendix E.
The species afforded protection under the ESA (2007) with potential for presence within the study area are:
Butternut; Barn Swallow and Chimney Swift; Little Brown Bat, Northern Long-eared Bat, and Eastern Small-Footed Bat; Redside Dace (recovery habitat Rouge River Tributary). Potential impacts to these species and their habitats is provided in Chapter 8.
3.3.14 Summary of Sensitivity and Significance A summary of ecological sensitivity and significance is provided below which considers the findings of the ecological surveys including: vegetation community, presence of rare/sensitive flora and faunal species, and presence of sensitive/ specialized habitats (e.g., SWH, spawning habitat, etc.). It also takes into account applicable environmental policy (e.g. ESA, Fisheries Act, etc.) as well as policy designations (e.g. Provincially or Locally Significant Wetland, Environmental Significant/Sensitive Areas, Significant Corridors, Areas of Natural and Scientific Interest). For the purposes of this report, sensitivity rankings of low, moderate, and high have been attributed to the identified natural heritage features present within the study area. These rankings are defined below:
High Sensitivity: sensitive to disturbance based on the rarity or significance of the feature or its functions, and/or are addressed by policies, legislation, or planning- related studies which prohibits site alteration to occur within or adjacent to them.
Moderate Sensitivity: some sensitivity to disturbance, significant features or functions may be present, may have policies/legislation or planning related designations that prohibit or restrict site alteration. Lower relative habitat and species diversity; lower relative numbers of rare species; typically smaller, more disturbed woodlands and / or cultural mosaics;
Low Sensitivity: limited sensitivity to disturbance, no significant features or functions present, limited applicable policies, typically already have existing disturbance from human activity. Common/ tolerant habitats with limited species diversity and few or
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no rare / specialized species; small, isolated, high level of disturbance from human activity.
In general, designated natural features such as woodlands, wetlands, SAR and SCC habitat, floodplains and watercourses provide some constraint the infrastructure changes contemplated in this Class EA study. Encroachment within these areas should be avoided or limited as much as possible, where feasible.
The primary areas of constraint within the Bayview Avenue study area associated with natural heritage features and functions include the following features. In general, there are no areas of high constraint within the study area as it is primarily urbanized. The following were identified as having moderate sensitivity:
Feature BS-1 – Rogue River Tributary - Redside Dace Recovery Habitat (ESA 2007) Feature 4 – Regionally Significant Woodlands, Rouge River Tributary Valley Feature 7 - Regionally Significant Woodlands, German Mills Creek Valley Feature 14 – Regional Greenlands System Feature 15 – Regional Greenlands System, Special Concern Species observation Features 19, 20, 21 – Regionally Significant Woodlands, East Don River Valley Features 23, 25 – East Don River Valley
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Exhibit 3-3: Designated Natural Features Overview
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Exhibit 3-4: Natural Environmental Features – Plate 1
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Exhibit 3-5: Natural Environmental Features – Plate 2
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Exhibit 3-6: Natural Environmental Features – Plate 3
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Exhibit 3-7: Natural Environmental Features – Plate 4
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Exhibit 3-8: Natural Environmental Features – Plate 5
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Exhibit 3-9: Natural Environmental Features – Plate 6
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Exhibit 3-10: Natural Environmental Features – Plate 7
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Exhibit 3-11: Natural Environmental Features – Plate 8
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Exhibit 3-12: Natural Environmental Features – Plate 9
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Exhibit 3-13: Natural Environmental Features – Plate 10
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3.4 Tree Inventory An Arborist Report and Tree Management Plan were prepared in support of the Bayview Avenue Class EA. The full report (Appendix F), provides an inventory for trees greater than 10 cm diameter at breast height (DBH), and for all trees that have been planted within 10 m of the roadway corridor with the potential to be impacted by the Preferred Plan (as described in Chapter 6). The inventory is summarized below. The assessment of impacts is summarized in Chapter 8 of this Environmental Study Report.
The inventoried trees within the Study Area were tagged and assessed based on their health and condition at the time of survey. The tree inventory was completed over five (5) days: August 17, 2016, August 31, 2016, September 1, 2016, October 7, 2016, and October 11, 2016. The following information was obtained for each tree:
Tree tag number; Tree species (common and scientific names – genus and species); Diameter at breast height (DBH); Tree condition (structure and vigour); GOOD - dead branches less than 10%; signs of good compartmentalization on any wounds, no structural defects. FAIR – 10-30% dead branches, size or occurrence of wounds present some concerns, minor structural defects. POOR – more than 30% dead branches, weak compartmentalization, early leaf drop, presence of insects or disease, major structural defects. DEAD – tree shows no signs of life. Evidence of insect or fungal infection; Evaluation of the dripline; General comments including structural integrity, significant lean, etc.; and, A picture of the tree for reference records. A total of 1636 trees were inventoried within the study area. A total of 1251 trees were individually tagged, and 385 trees were assessed but not tagged, due to barriers to access and/or private ownership. The species composition of inventoried trees for the Study Area is as follows:
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3 American Beech (Fagus grandfolia) 6 Lilac (Syringa vulgaris) 5 Amur Maple (Acer ginnala) 74 Little Leaf Linden (Tilia cordata) 76 Austrian Pine (Pinus nigra) 113 Manitoba Maple (Acer negundo) 40 Autumn Blaze Maple (Acer x freemanii 441 Norway Maple (Acer platanoides) ‘Jeffersed’) 4 Norway Spruce (Picea abies) 3 Balsam Fir (Abies balsamea) 21 Ohio Buckeye (Aesculus glabra) 2 Basswood (Tilia americana) 22 Red Oak (Quercus rubra) 1 Black Locust (Robinia pseudoacacia) 93 Red Pine (Pinus resinosa) 27 Black Walnut (Juglans nigra) 32 Scots Pine (Pinus sylvestris) 13 Bradford Ornamental Pear (Pryus calleryana ‘Bradford’) 1 Serviceberry (Amelancier sp.) 101 Siberian Elm (Ulmus pumila) 4 Bur Oak (Quercus macrocarpa); 43 Silver Maple (Acer saccharinum) 4 Celebration Maple (Acer freemanii) 39 Sugar Maple (Acer saccharum) 2 Cherry species (Prunus sp.) 4 Swamp White Oak (Quercus bicolor) 1 Choke Cherry (Prunus virginiana) 3 Tamarack (Larix laricina) 1 Cockspur Hawthorn (Crategus crusgalli inermis) 18 White Ash (Fraxinus americana) 35 Colorado Spruce (Picea pungens) 1 White Birch (Betula papyrifera) 27 Common Hackberry (Celtis occidentalis) 15 White Elm (Ulmus americana) 18 Crabapple species (Malus sp.) 5 White Mulberry (Morus alba) 1 Crack Willow (Salix fragilis) 127 White Spruce (Picea glauca) 1 Eastern Red Cedar (Juniperus virginiana) 10 White Willow (Salix alba x S. fragilis) 21 Eastern White Cedar (Thuja occidentalis) 4 Yew species (Taxus sp.). 4 Eastern White Pine (Pinus strobus) 2 Eucalyptus (Eucalyptus sp.) 1 Hawthorn species (Crategus sp.) 21 Hedge Maple (Acer campestre) 97 Honey Locust (thornless) (Gleditsia triacanthos var. inermis) 2 Horse Chestnut (Aesculus hippocastanum) 2 Juniper (Juniperus communis) 35 Kentucky Coffeetree (Gymnocladus dioicous)
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Of the 1626 trees inventoried, 964 were evaluated to be in good condition, 382 in good to fair condition, 161 were in fair condition, 40 were in fair to poor condition, 60 were in poor condition, 10 were in very poor condition, and 10 were dead. Refer to Appendix F for results of the tree inventory.
3.5 Hydrogeology An overview of hydrogeological conditions was prepared in support of this Class EA study. The report is provided in Appendix G and considers the findings of the Contamination Overview Study and the Geotechnical Investigation. Key aspects of the report are summarized below. Please refer to Appendix G for exhibits / graphics.
3.5.1 Physiography and Topography Most of the study area lies within the Peel Plain physiographic region, which consists of glaciolacustrine deposits over glacial till deposits (Chapman and Putnam, 2007).
The northern most extent of the study area, around the intersection of Elgin Mills Road, abuts the South Slope physiographic region, characterized by drumlinized till plains. In this area, the topography rises steadily upwards to the north where the Oak Ridges Moraine begins, approximately three kilometers north, near Stouffville Road. Both the Don River and the Rouge River have their headwaters where streams emerge at the base of the Oak Ridges Moraine southern slope. No part of the study area is within the Oak Ridges Moraine or the Greenbelt regulated areas.
Bayview Avenue generally slopes downward to the south throughout the study area. Within the specific study area, the elevations range from approximately 230 m AMSL in the northern most portion of the study area (Elgin Mills Road) to a low of approximately 145 m AMSL at the southern edge of the study area (Steeles Avenue – Don River Valley).
3.5.2 Regional Geology The total depth of overburden sediments within the study area is approximately one hundred to one hundred and fifty meters, whereby the total overburden thickness increases to up to two hundred meters towards the north (Oak Ridges Moraine). These units are described in detail in Appendix G and in the TRCA (2007 and 2009a) reports (refer to Appendix G for references). The typical geological sequence may vary from location to location such that not all of these units may be encountered at any given location. Deeper ravines, including the East Don River, also have incised into the overburden geological sequence, up to approximately 20 meters, exposing the upper
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overburden units (generally Lake Peel sediments, Halton Till, and in some areas Oak Ridges Moraine sediments) in the valley side walls.
Site-Specific geology was investigated by Thurber (2017) for the entire study area with twenty six boreholes drilled along the alignment in November 2016, with depths ranging from 1.5 to 15.8 meters deep. Deeper boreholes were completed in the vicinity of watercourse and railway crossings where structural works may be required to accommodate the proposed road and infrastructure improvements. Thurber (2017) generally encountered earth fill and sandy silty clay till along the alignment with localized zones of silty clay and sand to sandy silt. Petroleum hydrocarbons were detected in select soil samples collected in the vicinity of the East Don River Crossings and the CN Laureleaf railway crossing. The complete geotechnical report is provided in Appendix J.
3.5.3 Regional Hydrogeology There are four significant overburden aquifers within the area, as follows:
Shallow Aquifer (localized sandy lenses in Lake Peel deposits or Halton Till, and weathered Halton Till); Oak Ridges Moraine Deposits; Thorncliffe Aquifer; and Scarborough Aquifer. Localized shallow aquifers occur in deeper pockets of surficial sandy glaciolacustrine deposits as well as within localized sand lenses in the Halton Till, whereas the regionally extensive Oak Ridges Moraine Aquifer Complex occurs within the Oak Ridges Moraine deposits and the tunnel channels (TRCA, 2007 and 2009a). Shallow overburden groundwater water flow is generally horizontal (north to south according to the general topographic gradient in the region) and controlled by surface topography, as the Halton Till reduces vertical infiltration (TRCA, 2007), through some downward infiltration occurs nonetheless.
Groundwater water recharge rates are relatively low in the Peel Plain portion of the Rouge and Don River watersheds, because of the mostly fine grained nature of these sediments, as well as the underlying fine grained Halton Till.
Groundwater is widely used in the north parts of the Rouge River watershed through private water supply wells, generally beyond the limits of urban areas with municipal water servicing. In the Don River watershed, most of the watershed is now municipally serviced (water mains), such that only limited areas in the northern most portion are beyond
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municipal servicing. Therefore, over most of the watershed, groundwater is withdrawn primarily for remediation, dewatering, industrial and commercial use.
In the study area, municipal water is available and all buildings and developments, with very limited exceptions, are interpreted to use municipally provided water.
3.5.4 Site Specific Hydrology Thurber (2017) completed five of the twenty six boreholes as piezometers (near the watercourse and railway crossings) and measured groundwater elevations ranging from 142.7 to 225.0 meters above mean sea level in open boreholes and monitoring wells along the alignment. Monitoring wells constructed in proximity to specific road related structures (i.e. bridges and culverts), or areas of potential environmental concern, are listed in Table 3.1 of Appendix G. The following summarises the location and depth to groundwater in the monitoring wells installed along the road, and within the road alignment:
East Don River South Crossing (BH16-02): 1.9 m (December 2016), within a shallow sand aquifer potentially in hydraulic connection with the East Don River; East Don River North Crossing (BH16-04): 8.4 m (November 2016), within a thick silty clay glacial till deposit interbedded with a sand lens, whereby the sand lens may be in hydraulic connection with the East Don River; CN Laureleaf Subway (BH16-05): 3.3 m (December 2016), within a confined sand aquifer below a silty clay till deposit; German Mills Creek Bridge (BH16-11): 8.7 m (December 2016), within a confined sand aquifer below a silty clay till deposit; German Mills Creek Tributary Culvert (BH16-12): 5.7 m (December 2016), within a thick silty clay till deposit; extending downward from the bottom of road fill materials, and Rouge River Tributary Culvert #1 (BH16-26); 1.4 m (December 2016), within a thick silty clay till deposit extending downward from the bottom of road fill materials. Based on the Thurber (March 2017) borehole logs, as listed above, there is high potential for dewatering to be required at the East Don River South crossing (north of Steeles Avenue), East Don River North Crossing (between Proctor Avenue and Doncrest Drive), the German Mills Creek crossing (at Bantry Avenue), and the Rouge River Tributary #1 Culvert crossing (near Taylor Mills Drive), and low to moderate potential for construction
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dewatering to be required at the other structures where boreholes were advanced (CNR Subway near Laureleaf Drive).
3.5.5 Water Well Records There are approximately two hundred and fifty-nine MOECC water well records within the study area, with records from 1951 to 2016 and well depths from 1.4 to 98.5 meters and an average depth of 24.5 meters. It is interpreted that the older records are primarily for historical water supply wells, which are no longer in use and the recent records are for monitoring wells or dewatering wells. The locations of water well records are provided in Appendix G.
3.5.6 MOECC Permits-to-Take-Water There are approximately nine active Permits-to-Take-Water (PTTW) in the study area with the following uses:
One PTTW (No. 4678-8UJRJ3) is for surface and groundwater commercial golf course irrigation (Ladies’ Golf Club of Toronto Limited) 7859 Yonge Street, Richmond Hill; One PTTW (No. 2218-8KZJ7G) is for ongoing groundwater dewatering to stabilize a building foundation (Richmond Hill Christian Community Church, 9670 Bayview Avenue Richmond Hill). Noting their PTTW includes a second sources for construction dewatering; and Eight PTTWs are for groundwater and surface water construction dewatering. The locations are shown on Figure 3.2 and a summary is provided in Table 3.2 within the full report in Appendix G.
3.5.7 Source Water Protection The study area lies within the CTC (Credit Valley, Toronto and Region, Central Lake Ontario) Source Protection Region, specifically the Toronto and Region Source Protection Area (SPA).
The majority of the study area has low groundwater recharge with a few areas of increased recharge, interpreted where sandier pockets of Lake Peel sediments are present. There is area of moderate groundwater stress in the study area, south of Highway 407, within the East Don River watershed. There is variable groundwater vulnerability to surficial contamination in the study area, with several areas considered to
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have medium to high groundwater vulnerability. Groundwater vulnerability is related to rapid groundwater recharge as well as areas with a shallow water table.
The section of Bayview Avenue between Steeles Avenue and Elgin Mills Road does not pass through any municipal wellhead protection areas (WHPA) or intake protection zones (IPZ), however does pass through the well head protection area (WHPA) Q1/Q2 of moderate risk, established to protect groundwater recharge to regional aquifer units which are generally used as a source of groundwater.
3.6 Drainage and Stormwater Management As part of the Bayview Avenue Class EA, a Drainage and Stormwater Management Study was undertaken to: document existing drainage conditions, review the current policy framework, identify potential impacts of the Preferred Plan and recommend appropriate mitigation measures. The full report is provided in Appendix H. The existing conditions are summarized in this section. The drainage and stormwater design for the Preferred Plan is provided in Chapter 6 of this ESR.
3.6.1 Overall Drainage Pattern The study area includes Bayview Avenue and its adjacent catchment areas from Elgin Mills Road to Steeles Avenue. The study area is located in the headwater area of the Don River watershed and includes a small portion of the Rouge River watershed. Most of the lands within and adjacent to the study area generally drain from the north to the south to German Mills Creek and the East Branch of Don River (East Don River). The study area is located within the jurisdiction of the Toronto Region Conservation Authority (TRCA). The major watercourses within the study area are:
Rouge River tributary in the upper portion of the study area, shown as Crossing 34-10 B1710 German Mills Creek in the central portion of the study area, north of Langstaff Road, shown as Crossing 34-06 C0800 East Don River crossings in the south portion of the study area, shown as Crossings 34-02 B0800 (at Proctor Avenue) and 34-02 C0050 (north of Steeles Avenue), respectively. The Regulatory floodplain limits of the Rouge River, German Mills Creek and the East Don River have been defined by the TRCA and are provided in Appendix H.
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3.6.2 Storm Drainage Problem Areas Concerns were raised during public consultation meetings by residents of the Bayview Glenn and Grandview-Henderson neighbourhoods regarding existing flooding problems, problems with sanitary sewers along the East Don River in Bayview Glenn, untreated stormwater to the East Don River and erosion problems. Residents noted that the severe storm in August 2005 caused significant property damage and expressed concerns regarding the potential impacts of widening Bayview Avenue. Concerns have also arisen regarding flooding at Bayview Avenue and John Street intersection.
It was noted that major flows (surface flows) from Bayview Avenue spilled down Dunsinane Drive, west of Bayview Avenue, during the August 2005 storm. This overland flow apparently contributed to flooding problems along Dunsinane Drive.
The City of Markham has been leading the effort to address the flooding issues through its own studies (i.e. outside of the Bayview Avenue Class EA). York Region will ensure that the final Bayview Avenue design integrates with the City of Markham’s efforts in this area. The City of Markham studies are highlighted below and it is noted that implementation by the City is ongoing. For more information, please refer to the City of Markham website.
3.6.2.1 West Thornhill Stormwater Flood Control Implementation Strategy The West Thornhill Stormwater Flood Remediation Class EA study, initiated in 2008 and completed in August 2011, identified system improvements to increase capacity and reduce flood risks. The West Thornhill Flood Control Implementation Strategy, adopted October 2011, is intended to implement recommendations of the West Thornhill Stormwater Flood Remediation Class Environmental Assessment (Class EA Study).
The West Thornhill Stormwater Flood Remediation Class EA recommended solution includes storm sewer improvements within thirteen (13) separate networks that can be implemented independently of each other. Phasing of improvements will be based on prioritization of flooding risks and the need to coordinate storm system improvements with improvements to other services, particularly the wastewater (sanitary) system. The Phase 1 stormwater implementation area is within the Bayview Glen area and the Phase 2 implementation area is within the Grandview area. The schedule for Phases and stages of works within the Phases is contingent upon the availability of funding.
Beyond capital-intensive sewer capacity improvements, the Class EA recommended solution includes several low-cost elements such as the installation of inlet control devices and extensive roof downspout disconnection. Where these elements are not contingent
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on related storm sewer capacity improvements to convey additional flows, and where overland flow capacity is available, they may proceed in the short term.
3.6.2.2 Glynnwood Tributary Class EA The Glynnwood Tributary Class EA was initiated in 2012 and the City of Markham indicates that the Environmental Study Report has been prepared (October 2016) and is in the process of being finalized.
The Glynnwood Class EA found that the causes of extensive flooding as a result of the 2005 storm included:
Surcharge from the Thornhill Community Center (TCC) storm sewer system during major storms, this includes accumulation of surface runoff in low lying areas causing water to spill into the TCC (experiencing surcharging in the basement level). Surcharge of storm sewer located in the easement of Glynnwood Retirement Residence (GRR) access road causing flooding in the underground parking at GRR. Overland flows from Bayview Avenue spilling down GRR access road due to road grades, also spilling into the underground parking. Overloaded storm sewers. Additionally, within the area of the TCC and GRR, the Glynnwood Class EA found the following stormwater flow information pertinent to the Bayview Avenue Class EA:
Major system flows drain along the existing overland flow routes with the road drainage system on Green Lane, John Street and Bayview Avenue. There is a spill point at the GRR entrance road. The current model assumes that these overland flows are directed to the Glynnwood pond through the upper parking lot of GRR. The existing model did not contain the elevation / storage / discharge relationships for the Glynnwood pond. WSP modelled this relationship in the Glynnwood Class EA. Under the 100 year event the storm sewer in the TCC area and the entrance to GRR are surcharged. There is no outlet below the weir elevation at the pond. Pond storage has been determined to be sufficient to control stormwater runoff from the TCC and also for water quality control considerations assuming the
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-55 Environmental Study Report | WSP | MMM Group | August 2017
existing weir crest could be modified (Summary in Table 4.4 of the Glynnwood Tributary Class EA). The Glynnwood Tributary Class EA included the following recommendations:
Design and construction of a new storm sewer from Glynnwood Pond to Bayview Avenue (Phase 1); New storm sewer crossing of Bayview Avenue including upgraded catchbasins (Phase 2); and New storm sewer and catchbasins at the Thornhill Community Centre (Phase 3). In June 2012 the City of Markham initiated sedimentation clean-up and repairs to the pond, under easement / agreement with the Glynnwood Residence and Shouldice Hospital. The day to day operation of the pond still rests with Glynnwood Residence and Shouldice Hospital.
3.6.3 Bayview Avenue Minor Drainage The minor system for the Bayview Avenue consists of the road storm sewers and the contributing storm sewers from the external development areas. The minor drainage system design storm is a 10 year storm event. The Bayview Avenue minor drainage was assessed in this study as follows:
Hydrologic assessment – calculation of flows for the Bayview storm sewers and the contributing external catchments; Capacity assessment of the existing storm sewers; and Proposed storm sewer capacity assessment.
3.6.3.1 Storm Sewer Flows A combination of the Rational Formula and SWMHYMO hydrologic modelling were used to establish existing flows within the study area. The Rational Method was used to determine flows along Bayview Avenue. SWMHYMO along with ‘modified’ Rational Method were used to establish overland flows for adjacent lands contributing to the storm sewer system on Bayview Avenue. These flows were then used to assess the capacity of the existing storm sewer system.
For the SWMHYMO Method the hydrologic parameter included the 3-hour Chicago storm distribution from the Town of Richmond Hill.
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-56 Environmental Study Report | WSP | MMM Group | August 2017
Sewer Inflows from External Catchments
A total of 12 external catchments from existing developments were identified as contributing flows to the Bayview Avenue storm sewer along the entire study area. The locations and boundaries of these external drainage areas are shown in Appendix H. These areas range from 3.4 ha to 104.9 ha and were delineated based on available contour information. No detailed storm sewer information including sewer layout and sizes was available for these areas.
The flows for the external drainage areas were first generated within the SWMHYMO model for the 2-year through 100-year storm events (including the 10 year storm sewer design flow) using the 3-hour Chicago storm distribution from the Town of Richmond Hill. Since all of the external drainage areas are developed with larger amounts of imperviousness the StandHyd hydrograph method within the SWMHYMO model was used. These flows are summarized in Table 3-2.
Table 3-2: SWMHYMO Peak Flows for External Drainage Areas
Catchment Drainage 10- 25- 50- 100- 2-year 5-year Outlets To* ID Area (ha) year year year year
CA3 5.6 0.80 1.23 1.37 1.94 2.23 2.55 MH 2498 CA4 3.4 0.44 0.70 0.79 1.12 1.32 1.49 MH 2498 CA8 85.9 8.55 13.06 15.44 21.68 27.21 31.02 MH 2362 Outlets to CA9 11.2 1.05 1.65 1.86 2.68 3.14 3.65 Weldrick Road CA11 71.9 2.95 4.73 5.34 8.42 9.86 12.09 MH 2402 CA12 67.2 6.12 9.61 11.23 17.02 19.76 22.56 MH 2630 CA13 9.1 0.82 1.33 1.52 2.25 2.69 3.10 MH 2603 CA14 104.9 8.23 13.14 14.80 22.30 26.08 30.97 OF 361 CA18 6.4 0.87 1.36 1.53 2.20 2.53 2.91 MH 2889 No information CA20 31.5 2.63 4.10 4.68 6.56 7.69 8.80 on this section of storm sewer CA21 56.1 4.32 6.83 7.80 11.19 13.02 15.28 MH 2692 CA23 19.2 2.78 4.21 4.79 6.61 7.61 8.73 MH 2564
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-57 Environmental Study Report | WSP | MMM Group | August 2017
*all outlets are approximate due to incomplete storm sewer data.
As illustrated above, the above flows are very high. The 10-year peak flows range from 0.7 m3/s to 15.4 m3/s, which are not typical of storm sewer inflows.
The second storm sewer flow calculation method for external catchments included Rational Method with Time of Concentration calculated based on estimated longest section of the storm sewer for each catchment. The adjusted runoff coefficient C varied from 0.48 to 0.75 based on the existing land use for each catchment. The time of concentration varied from 17 to 58 minutes. This method resulted in an appreciable reduction in flows; however, the calculated peak flows were still significant, and when included in sewer calculation all of them were found to be in excess of the capacity of the Bayview storm sewer downstream of the external sewer inflows.
The third hydrology method was to specify the 10-year flow from each catchment such that it will match the lowest available capacity of the exiting Bayview Avenue storm sewer section that contains the particular catchment inflow. For example, Catchments C8 to C12 discharge to a single trunk sewer. The lowest available capacity in this sewer reach is 2.28 m3/s (the maximum available capacity in this reach is 6.56 m3/s).
The 10-year peak flows for the external catchments and the above discussed three flow calculation methods are summarized in Table 3-3.
Table 3-3: 10 Year Peak Flows for External Drainage Areas
Method 3 Method 1 Method 2 Drainage Based on Capacity of Catchment ID SWMYMO Rational Method Area (ha) Downstream Storm (m3/s) (m3/s) Sewer (m3/s)
CA3 5.6 1.37 0.98 0.02 CA4 3.4 0.79 0.62 CA8 85.9 15.44 7.38 CA9* 11.2 1.86 1.30 2.28 CA11 71.9 5.34 3.69 CA12 67.2 11.23 5.63 CA13 9.1 1.52 1.07 6.03** CA14 104.9 14.80 7.61
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-58 Environmental Study Report | WSP | MMM Group | August 2017
Method 3 Method 1 Method 2 Drainage Based on Capacity of Catchment ID SWMYMO Rational Method Area (ha) Downstream Storm (m3/s) (m3/s) Sewer (m3/s)
CA18 6.4 1.53 1.01 0.00 CA20 31.5 4.68 2.66 na CA21 56.1 7.80 4.22 2.05 CA23 19.2 4.79 2.17 0.22
* CA9 outlet the Bayview Storm Sewer System.
** Based on assumed sewer slope of 0.50% in this sewer reach As discussed above, several assumptions were made to establish storm sewer inflows from external catchments. Without detailed storm sewer information including any storage, other minor outlets within each catchment, sizes of existing storm sewers restricting flows downstream, etc., it is very difficult to provide reasonable estimates of the external catchments inflows.
Existing Storm Sewer Assessment
The existing storm sewers on Bayview Avenue were assessed using the standard storm sewer calculation Rational Method.
Some assumptions were made in terms of pipe slope and pipe size were the specific sewer information was not provided. Where the pipe slope was not available it was assumed that the grade of the sewer mirrored the grade of the road surface above it. All assumed information is shown in red on the calculation sheets. The following two sets of calculations are presented in Appendix H:
Scenario 1 – Bayview Avenue storm sewer without inflows from the above discussed 12 external catchments; Scenario 2 – Bayview Avenue storm sewer with inflows from the above discussed 12 external catchments using inflows presented in Method 3 based on available capacity of the downstream Bayview Avenue storm sewer. Results for Scenario 1 show the following:
That 43% of the length of the Bayview Avenue storm sewers are under sized during the 10-year storm event. See Appendix H for calculations.
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-59 Environmental Study Report | WSP | MMM Group | August 2017
This is however improbable due to the fact that there is no recorded flooding for any area other than the area of the Thornhill Community Center and Glynnwood Retirement Residence. Results for Scenario 2 show the following:
That most of the length of the Bayview Avenue storm sewers are under capacity during the 10-year storm event. This is however improbable due to the fact that there is no recorded flooding for any area other than the area of the Thornhill Community Center and Glynnwood Retirement Residence. The results indicate that a large portion of the existing Bayview Avenue storm sewer is under sized to convey the 10-year storm. While this may be the theoretical case, the historical accounts and site observations, indicate that the main area of concern is the known flooding at the Glynnwood Retirement Residence and Thornhill Community Center.
As discussed the storm sewer capacity results are subject to several assumptions which were made including the lack of storm sewer information for external catchments and the gaps in storm sewer information of the Bayview Avenue storm sewer as noted in the full report in Appendix H.
It should also be noted that although the current 10-year storm sewer design criteria for York Region is conservative, it is possible that some of the older existing storm sewers on Bayview Avenue and in external drainage areas were designed to a lesser standard (i.e. 2-year or 5-year).
3.6.4 Bayview Avenue Major Drainage The major system includes the overland flows and includes the four major crossings of the study area.
The major drainage is assessed in this study as follows:
Description of the existing four major crossings; Capacity assessment of the existing four major crossings; Assessment of impacts of extending of existing structures; and Assessment of required structure improvements to meet design criteria.
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-60 Environmental Study Report | WSP | MMM Group | August 2017
3.6.4.1 Major Crossings There are four transverse crossings of Bayview Avenue within the study area.
1) A tributary of the Rouge River crosses Bayview Avenue near Taylor Mills Drive North (Crossing 34-10 B1710). This crossing is comprised of a concrete 3050 x 960 mm culvert. The channel upstream is a channelized concrete and gabion- basket lined channel. The channel runs parallel to Bayview Avenue for approximately 50 m before turning east and meandering through a wetland.
2) German Mills Creek crosses Bayview Avenue at Briggs Avenue / Bantry Avenue north of Highway 407 (Crossing 34-06 C0800). The German Mills Creek culvert was replaced with a triple cell prefabricated culvert. Modelling was represented by 3 – 7300 x 3050 mm concrete arch culverts. The project was initiated by a private developer to advance channelization of German Mills Creek for land development. The project included hydraulic analysis, storm sewer modifications, downstream channelization and extensive erosion control measures as well as securing permits and approvals from the TRCA, MNRF and the Town of Richmond Hill. The design of the culvert is such that it now accommodates six lanes on Bayview Avenue and will be able to accommodate all proposed works without requiring extension or any modifications.
3) The East Don River runs south along the west side of Bayview Avenue and crosses just south of Proctor Avenue (34-02 B0800). This is a 14.7 x 3.5 m bridge structure.
4) A second crossing of the East Don River is located north of Steeles Avenue (34- 02 C0050) consisting of three - 4800 x 3600 mm concrete culverts. The flood elevation for the Regulatory Storm currently overtops the road at these crossings.
3.6.4.2 Hydraulic Analysis of Major Existing Major Crossings Current HEC-RAS modelling was obtained from the TRCA for all four crossings along Bayview Avenue. The models included the peak flows for events ranging from 2-year to the Regional Storm (Hurricane Hazel).
The following sections present the hydraulic assessment for the four structures. The hydraulic performance of each structure were evaluated in terms of the MTO HDDS which include the following:
Design Flow Criterion; Freeboard Criterion: Minimum and Desirable Freeboard;
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Relief Flow Criterion: The maximum depth of overtopping and the product of depth of relief flow and velocity; Soffit Clearance Criteria for Bridges and Open Footing Culverts; Headwater Depth/Culvert Rise (HW/D) Criteria for Closed Footing Culverts. The hydraulic modelling summary outputs for are provided in Appendix H.
3.6.5 Rouge River Tributary Crossing 34-10 B1710 Tables 3-4 and 3-5 summarize the HEC-RAS modelling output for the existing 3050 mm x 960 mm Rouge River Tributary crossing 34-10-B1710.
Table 3-4 presents the calculated water elevations for various flood events, Freeboard, Relief Flow and Flood Depth (HW/D). The design storm is a 50 year storm. No clearance criterion applies since it is a closed bottom culvert. The required HW/D ratio is 1.5 (culvert rise less than 3.0 m).
Table 3-5 shows whether the existing structure meets the applicable MTO hydraulic standards. As illustrated the existing structure:
Does not meet the 1.0 m required freeboard (minimum and desired); and Relief Flow depth exceeds the maximum allowable 0.30 m.
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Table 3-4: Existing Conditions for Rouge River Tributary Crossing 34-10 B1710
Structure 10- 25- 50- 100- Regional 2-year 5-year (Upstream Face) year year year year Storm
Water Surface Elevation 225.59 225.82 225.97 226.21 226.41 226.54 226.97
Energy Gradeline Elevation 225.63 225.86 226.02 226.25 226.45 226.54 226.97
Top of Road (low point) 226.46 226.46 226.46 226.46 226.46 226.46 226.46
Top of Road Freeboard (Min) 0.87 0.64 0.49 0.25 0.05 -0.08 -0.51
Top of Road Freeboard (desired) 0.83 0.60 0.44 0.21 0.01 -0.08 -0.51
Top of Road Velocity Na Na Na Na Na 0.32 0.93
Top of Road (Velocity x Depth) Na Na Na Na Na 0.03 0.47
Soffit Elevation 225.40 225.40 225.40 225.40 225.40 225.40 225.40
Flood Depth (WH/D) 0.2 0.44 0.59 0.84 1.05 1.19 1.64
Table 3-5: Drainage Criteria for Rouge River Tributary Crossing 34-10 1710 Meets Criteria Criteria Storm Event yes or no Top of Road Freeboard (Min) 50-year No
Top of Road Freeboard (Desired) 50-year No
Relief Flow (Max Depth over the roadway) Regional No
Relief Flow (Velocity x Depth) Regional Yes
Flood Depth (HW/D) (closed footing) 50-year Yes
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3.6.6 German Mills Creek Crossing 34-06 C0800 Tables 3-6 and 3-7 summarize the HEC-RAS modelling output for the existing triple 7300 x 3050 mm Concrete span Arch Culverts of the German Mills Creek crossing 34-06 C0800. It should be noted that larger structures with no road fill such as the German Mills structure can be classified as bridges which require 1.0 m clearance from the design water elevation compared to 0.30 m clearance for culverts. In this study, the existing structure was assumed to be a culvert structure.
Table 3-6 presents the calculated water elevations for various flood events, Freeboard, Relief Flow and Soffit Clearance. The design storm is a 100-year storm (span greater than 6.0 m). The required soffit clearance is 0.30 m. The HW/D criterion does not apply since it is an open footing structure.
Table 3-7 shows whether the existing structure meets the applicable MTO hydraulic standards. As illustrated the existing structure meets the applicable hydraulic criteria with exception of the 0.30 m soffit clearance. There is no overtopping during the Regional Storm.
Table 3-6: Existing Conditions for German Mills Creek Crossing 34-06 C0800
Structure 10- 25- 50- 100- Regional 2-year 5-year (Upstream Face) year year year year Storm
Water Surface Elevation 199.02 199.56 199.72 199.98 200.19 200.38 200.61
Energy Gradeline Elevation 199.03 199.59 199.76 200.04 200.26 200.46 200.17
Top of Road (low point) 202.00 202.00 202.00 202.00 202.00 202.00 202.00
Top of Road Freeboard (Min) 2.98 2.44 2.28 202 1.81 1.68 1.39 Top of Road Freeboard 2.97 2.41 2.24 1.96 1.74 1.54 1.29 (desired) Top of Road Velocity Na Na Na Na Na Na Na
Top of Road (Velocity x Depth) Na Na Na Na Na Na Na
Soffit Elevation 1.25 0.71 0.55 0.29 0.08 -0.11 -0.34
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Table 3-7: Drainage Criteria for German Mills Creek Crossing 34-06 C0800
Meets Criteria Criteria Storm Event yes or no Top of Road Freeboard (Min) 100-year Yes
Top of Road Freeboard (Desired) 100-year Yes
Relief Flow (Max Depth over the roadway) Regional Yes
Relief Flow (Velocity x Depth) Regional Yes
Soffit Clearance 100-year No
3.6.7 East Don River Crossings Tables 3-8 and 3-9 summarize the HEC-RAS modelling output for the existing 14.7 x 3.5 m bridge on the East Don River (34-02 B0800).
Table 3-8 presents the calculated water elevations for various flood events, Freeboard, Relief Flow and Soffit Clearance. The design storm is a 100-year storm (span greater than 6.0 m). The required soffit clearance is 1.0 m.
Table 3-9 shows whether the existing structure meets the applicable MTO hydraulic standards. As illustrated the existing structure meets the applicable Freeboards and Soffit Clearance, but does not meet the following:
Relief Flow criterion for depth of overtopping. The maximum allowable depth of overtopping is 0.30 m compared to calculated 1.21 m; and Relief Flow criterion for depth of overtopping x velocity. The calculated depth of overtopping x velocity is 0.84 m/s2, which almost meets the maximum allowable of 1.89 m/s2.
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Table 3-8: Existing Conditions for East Don River Bridge Crossing 34-02 B0800
Structure 10- 25- 50- 100- Regional 2-year 5-year (Upstream Face) year year year year Storm
Water Surface Elevation 149.52 149.65 149.80 149.94 150.00 150.10 153.57
Energy Gradeline Elevation 149.60 149.81 150.05 150.28 150.38 150.57 153.74
Top of Road (low point) 152.36 152.36 152.36 152.36 152.36 152.36 152.36
Top of Road Freeboard (Min) 2.84 2.71 2.56 2.42 2.36 2.26 -1.21 Top of Road Freeboard 2.76 2.55 2.31 2.08 1.98 1.79 -1.38 (desired) Top of Road Velocity Na Na Na Na Na Na 1.56
Top of Road (Velocity x Depth) Na Na Na Na Na Na 1.89
Soffit Elevation 151.60 151.60 151.60 151.60 151.60 151.60 151.60
Soffit Clearance 2.08 1.95 1.80 1.66 1.60 1.50 -1.97
Table 3-9: Drainage Criteria for East Don River Bridge Crossing 34-02 B0800
Meets Criteria Criteria Storm Event yes or no Top of Road Freeboard (Min) 100-year Yes
Top of Road Freeboard (Desired) 100-year Yes
Relief Flow (Max Depth over the roadway) Regional No
Relief Flow (Velocity x Depth) Regional No
Soffit Clearance (open footing) 100-year Yes
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Tables 3-10 and 3-11 summarize the HEC-RAS modelling output for Pre-development conditions for the East Don River Crossing 34-02 C0050. The existing structure comprises of triple 4800 x 3600 mm Concrete Culverts.
Table 3-10 presents the calculated water elevations for various flood events, Freeboard, Relief Flow and Flood Depth (HW/D). The design storm is a 50-year storm (less than 6.0 m span). No clearance criterion applies since it is a closed bottom culvert. The maximum allowable headwater depth (HW) ratio is 4.5 m (culvert rise between 3.0 m and 4.5 m).
Table 3-11 shows whether the existing structure meets the applicable MTO hydraulic standards. The results show that the structure meets the HW criterion, but does not meet the following:
Required 1.0 m Freeboard (Minimum and Desirable); Relief Flow for depth of flow. Calculated depth of overtopping for the Regional Storm is 2.6 m compared to maximum allowable 0.30 m; and Relief Flow for depth of flow x velocity of overflow. Calculated 2.51 m/s2 versus maximum allowable 0.80 m/s2. It should be noted that the major exceedance of the Relief Flow criteria is attributed to the existing structure on this watercourse downstream of Bayview Avenue. The structure at Steeles Avenue is severely undersized creating significant backwater conditions during major storm events at the lowest Bayview Avenue elevation. As a result, replacement of the existing Bayview Avenue culverts with larger structures while maintaining the undersized downstream structure will not have appreciable improvement to the Relief Flow at Bayview Avenue.
Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 3-67 Environmental Study Report | WSP | MMM Group | August 2017
Table 3-10: Existing Conditions for East Don River Culvert Crossing 34-02 C0050
Structure 10- 25- 50- 100- Regional 2-year 5-year (Upstream Face) year year year year Storm
Water Surface Elevation 146.59 146.84 147.17 147.56 147.77 147.92 151.29
Energy Gradeline Elevation 146.63 146.91 147.27 147.68 147.90 148.08 151.40
Top of Road (low point) 148.69 148.69 148.69 148.69 148.69 148.69 148.69
Top of Road Freeboard (Min) 2.10 1.85 1.52 1.13 0.92 0.77 -2.60 Top of Road Freeboard 2.06 1.78 1.42 1.01 0.79 0.61 -2.71 (desired) Top of Road Velocity Na Na Na Na Na Na 0.96
Top of Road (Velocity x Depth) Na Na Na Na Na Na 2.51
Soffit Elevation 148.20 148.20 148.20 148.20 148.20 148.20 148.20
Soffit Clearance 0.55 0.62 0.71 0.82 0.88 0.92 1.86
Flood Depth (HW) 146.59 146.84 147.17 147.56 147.77 147.92 151.29
Table 3-11: Drainage Criteria for East Don River Culvert Crossing 34-02 C0050
Meets Criteria Criteria Storm Event yes or no Top of Road Freeboard (Min) 100-year No Top of Road Freeboard (Desired) 100-year No
Relief Flow (Max Depth over the roadway) Regional No
Relief Flow (Velocity x Depth) Regional No
Flood Depth (HW/D) (closed footing) 100-year Yes
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3.6.8 Fluvial Geomorphic Assessment Geomorphic site investigations were completed on the Rouge River Tributary, located approximately 270 m south of Elgin Mills Road and two crossings of the East Don River.
The findings of the geomorphic site assessment are documented in Appendix H which also contains the Meander Belt Assessment report for the Rouge River Tributary. Site visits were conducted on November 28 and November 29, 2016 to assess the existing geomorphic conditions of the watercourses. The channels were walked within approximately 100 m up and downstream of Bayview Avenue. In every reach the bankfull channel width was measured and the dominant geomorphic function and process were identified. Flows were below bankfull during the site visits.
A summary of the field assessment is presented in Table 3-12 below. Detailed reach descriptions are presented in Appendix H. Many of the reaches appear to have been previously modified by development and/or road works. Modified reaches are generally stable or in the early stages of recovering a sinuous planform through lateral adjustment. The Rouge River Tributary upstream of Bayview Avenue daylights from a storm sewer and outlets into a heavily modified watercourse defined by a trapezoidal concrete channel. Downstream of Bayview Avenue, the Tributary runs parallel to the Bayview Avenue road embankment for approximately 70 m before meandering to the east into a deciduous woodlot.
In the southern part of the study area, the East Don River is a meandering watercourse; however its planform is straight in its approach and departure from both the north and south crossings. The channel has riffle-pool morphology in the vicinity of the both the Bayview Avenue crossings.
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Table 3-12: Summary of Geomorphic Assessment Approx. Crossing Bankfull Channel Process Substrate Drainage Name Width (m) Geometry Area (km²) Rouge River N/A N/A Straight Tributary 2.5 – 3.4 (concrete (concrete 0.54 (modified) Upstream channel) channel) Fine to medium Rouge River Lateral gravel with Straight Tributary 1.6 – 6.9 0.54 Adjustment sand and large (modified) Downstream cobble Straight in East Branch Silt, sand, Lateral approach and of Don River 6.5 – 10.2 gravel, with 51.1 Adjustment departure to 34-02 B0800 some cobble crossing Gravel with Straight in East Branch Lateral cobbles and approach and of Don River 6.6 – 7.1 51.6 Adjustment some silts and departure to 34-02 C0050 clays crossing
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