6 Preferred Plan

6 PREFERRED PLAN

The Preferred Plan for the widening of Bayview Avenue between Steeles Avenue and Elgin Mills Road is described in this Chapter and depicted on Plates 1 to 29, located at the end of the Chapter. The typical road cross-sections are shown in Exhibit 6-1.

The design plan and profile will be further refined during future detailed design. The implementation of the Preferred Plan will be carried out in a phased approach as follows:

 The construction of Bayview Avenue between Highway 7 and Major Mackenzie Drive is currently programmed to begin in 2020 per the 2017 10-Year Roads and Transit Capital Construction Program.  The improvements of Bayview Avenue between Steeles Avenue and Highway 7 is identified in the York Region TMP Map 17 to occur in 2022 to 2026. The 10-year Roads and Transit Capital Construction Program is subject to annual Council review and approval.

6.1 MAJOR FEATURES The Preferred Plan for Bayview Avenue between Steeles Avenue and Elgin Mills Road includes the following aspects:

 Widening Bayview Avenue to six through-lanes from Steeles Avenue to Elgin Mills Road for Transit/HOV;  Providing a continuous system of sidewalk on the west side and multi-use path on the east side of Bayview Avenue;  Widening CN Rail Overpass north of John Street to accommodate the proposed additional lanes, sidewalk and multi-use path;  Replacing the CN Rail Underpass south of John Street to accommodate the proposed additional lanes, sidewalk and multi-use path;  Implementing a drainage design that addresses the nominal increase in paved road surface, ensures appropriate water quality and quantity control and is consistent with City of Markham’s Glynnwood Tributary Class EA and West Thornhill Flood Remediation Class EA;  Implementing intersection improvements which includes extending turning lane storage lengths, and addition of dedicated southbound right-turn lanes where required;

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-1 Environmental Study Report | WSP | MMM Group | August 2017

 Optimizing traffic signal phasing;  Designing intersections compliant with Accessibility for Ontarians with Disabilities Act (AODA) with enhanced visual, aural and textural elements;  YRT consideration of upgrading/replacing transit shelters and amenities, consistent with YRT current standards; and  Streetscape / landscape enhancements, mitigation / replacement for street tree removals and other amenities (benches, gathering areas). It is noted that Bayview Avenue is already at six lanes between Langstaff Road and Bantry Avenue / Briggs Avenue. The lane marking through the Highway 407 interchange will be confirmed through consultation with 407ETR and the Ministry of Transportation during detailed design.

During detailed design, there will be future consultation with relevant technical agencies, utilities, stakeholder groups and affected property owners.

This Chapter should be reviewed in conjunction with Chapter 5 of the ESR which describes the approach to the Preferred Plan, and Chapter 8 which includes recommended mitigation measures and commitments to future work. While refinements may occur during detailed design, any changes should not alter the intent of the recommended undertaking or its components.

6.1.1 Design Criteria A 60 km/h design speed is applied for the widening of Bayview Avenue between Steeles Avenue and Elgin Mills Road. The design criteria were developed based on consultation with the York Region staff and are listed in Table 6-1. The design criteria will be finalized in consultation with the City of Markham and Town of Richmond Hill, specifically related to off road active transportation facilities and landscaping features.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-2 Environmental Study Report | WSP | MMM Group | August 2017

Table 6-1: Design Criteria

Design Criteria Design Standard Proposed

Road Classification UAD 60 UAD 60

Design Speed 60 km/h 60 km/h

Posted Speed 60 km/h 60 km/h

Minimum Stopping Sight 85 m 85 m Distance

Minimum Vertical Curve Kcrest curve – 10; Ksag curve – 8 Kcrest curve 16-25; Ksag curve 10-25 *

Maximum and Minimum 5 % (UAU @70 km/h) / 0.5% 6 % / 0.4% Vertical Grade

Minimum Horizontal Radius 150 m 150 m

4 inside lanes at 3.3 m 4 inside lanes at 3.3 m (General 2 curb lanes at 3.5 m for Transit/HOV Purpose Lanes) Pavement Width (per York Region TMP, Bayview 2 curb lanes at 3.5 m (Transit/HOV Avenue is identified as a Frequent Lanes) Transit Network corridor)

Median Width N/A Varies, up to 3.75 m

43 m (York Region Official Plan Map Right of Way Varies 33.9 m to 36 m 12)

Separated facilities (i.e. cycle tracks, Multi use path 3.0 m (or 2.4 m in Provision for Pedestrians raised bike lanes or multi-use path), constrained areas) and Cyclists per York Region TMP Sidewalk 1.5 m

*Existing Profile to be used to furthest extent possible

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-3 Environmental Study Report | WSP | MMM Group | August 2017

Exhibit 6-1: Typical Cross Sections for 36 m and 33.9 m Right-of-Way

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-4 Environmental Study Report | WSP | MMM Group | August 2017

6.1.2 Typical Road Cross Section While a full Official Plan Right-of-Way of 43 m is identified for Bayview Avenue in the York Region Official Plan, it is recognized that Bayview Avenue is a well-established corridor and is constrained in most areas throughout the project limits. As such, it would be impractical to provide design alternatives for a 43 m right-of-way at this time.

As discussed in Chapter 5, in order to minimize impacts to adjacent properties, a reduced 36 m right-of-way is proposed and in very constrained areas, a 33.9 m right-of-way is proposed (see Exhibit 6-1).

It is important to note, however, that the Region will look for opportunities to acquire the full Official Plan Right-of-Way as areas adjacent to Bayview Avenue redevelop. This is considered to be a long-term strategy and is beyond the scope of the current Class EA study. Table 6-2 summarizes the basic features of the typical cross sections.

Table 6-2: Features of Typical Cross Sections

Features 36 m Right-of-Way 33.9 m Right-of-Way

Urban or Rural Urban (i.e. curb and gutter) 4 General Purpose Lane at 3.3 m Lanes 2 Transit/HOV Lane at 3.5 m Median Centre turn lane at 3.3 m or raised median up to 3.75 m

Multi Use Path (East Side) 3.0 m 2.4 m

Sidewalk (West Side) 1.5 m Minimum boulevard on both Limited boulevard on one side Landscape Opportunity sides for landscaping and utilities only for landscaping and utilities

6.1.3 Horizontal Alignment and Road Cross-Section Elements By Section The horizontal alignment of Bayview Avenue generally follows that of the existing alignment and is shown on Preferred Plan Plates 1 to 29, at the end of this Chapter. The cross sectional elements through each section of Bayview Avenue are described in this section. This should be read in conjunction with reference to the typical cross section in Exhibits 6-1a and 6-1b.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-5 Environmental Study Report | WSP | MMM Group | August 2017

6.1.3.1 Steeles Avenue (10+000) to Fairfield Place / Whitelaw Court (10+300) – 36 m Right-of-Way While the southerly limit of the EA Study is at Steeles Avenue, the construction limit for the widening of Bayview Avenue begins approximately 100 m north of Steeles Avenue. The intersection of Bayview Avenue / Steeles Avenue is under the jurisdiction of the City of Toronto. Any potential future changes to this intersection will be part of a future study for Steeles Avenue.

This section of Bayview Avenue is currently at four lanes with an urban cross-section and will be widened to six lanes generally by the existing centreline to accommodate for the new Transit/HOV lanes. The existing right-of-way ranges between 36 m to 52 m. The raised median will be extended to just south of the condo complex at 7071 Bayview Avenue; this is to better manage the southbound left turn queue at the Steeles Avenue intersection.

Full move access to the condo complex at 7071 Bayview Avenue on the east side and the two residential properties on the west side will be maintained.

Access to the bus loop in the northwest quadrant of Bayview Avenue / Steeles Avenue will be modified to allow for southbound travelling buses to utilize the bus loop. Any modification to the bus loop (including bus stop locations) will be subject to further discussion amongst York Region, York Region Transit and Toronto Transit Commission.

As part of the widening, the existing sidewalk on the west side will be shifted to the west to allow for a wider boulevard of 3.75 m. On the east side, a 2.4 m multi-use path (adjacent to the curb) will be provided to minimize impacts to vegetation adjacent to Bayview Avenue. The 2.4 m multi-use path will transition to a 3.0 m multi-use path as it approaches Fairfield Place.

6.1.3.2 Fairfield Place / Whitelaw Court (10+300) to CN Railway Crossing (south of John Street at 11+120) – 33.9 m Right-of-Way This section of Bayview Avenue is currently at four lanes with an urban cross-section and will be widened to six lanes generally symmetrically by the existing centreline to accommodate for the new Transit/HOV lanes. The existing right-of-way ranges between 29 m to 49 m. A raised median will be provided north of Fairfield Place / Whitelaw Court to north of Steele Valley Road. Access to Steele Valley Road will be limited to right- in/right-out only. Drivers from Steele Valley Road wishing to travel on northbound Bayview Avenue may do so via Proctor Avenue / Bayview Avenue intersection. Similarly, residential properties east and west of Bayview Avenue through this section will be limited

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-6 Environmental Study Report | WSP | MMM Group | August 2017

to right-in/right-out only; U-turn is permitted at signalized intersections such as Proctor Avenue or at Fairfield Place. The existing right-in/right-out access to the plaza in the northeast quadrant of Bayview Avenue / Laureleaf Road will be reconstructed and maintained.

As part of the widening, the existing sidewalk on the west side will be shifted to the west between Whitelaw Court and Proctor Avenue to allow for a wider boulevard of up to 3.75 m. On the east side, a 2.4 m multi-use path (adjacent to the curb) will be provided up to the CN Railway crossing to minimize impacts to residential properties and vegetation adjacent to Bayview Avenue. Landscape features and signage to Cham Shan Temple, Imam Mahdi Islamic Centre and Temple Har Zion may be impacted due to the road widening; the signage will be relocated and replaced. A detailed landscape plan will be prepared during detailed design.

There will be some property requirements on four properties on the west side (7160 Bayview Avenue, 2 and 3 Steele Valley Road, Cham Sham Temple, and Temple Har Zion). Impacted property owners will be compensated based on fair market value subject to negotiation between York Region Realty Group and the property owner.

There are four (4) properties on the east side of Bayview Avenue (7165, 7175, 7195 and 7217 Bayview) which will have grading impacts on their properties with the proposed design. Detailed design shall review boulevard and multi-use path grading adjustments and/or the use of retaining walls to minimize these grading impacts.

Retaining walls are proposed along the frontage of Cham Shan Temple, Temple Har Zion and both sides of the Don River valley. The existing retaining wall on the east side of Bayview Avenue for the residential properties on Prescott Court (reversed frontage to Bayview Avenue) will be replaced and shifted to the east to accommodate the widening.

A retaining wall will be required along the east side of Bayview Avenue from north of 7227 Bayview Avenue to the east end of the culvert structure in order to minimize impacts to the woodlot area adjacent to the Don River.

6.1.3.3 CN Railway Crossing (11+120 to 11+160) The CN Railway structure over Bayview Avenue will be replaced to accommodate the widening of Bayview Avenue. See Section 6.2.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-7 Environmental Study Report | WSP | MMM Group | August 2017

6.1.3.4 CN Railway Crossing (11+160) to John Street (11+700) – 33.9 m Right-of- Way This section of Bayview Avenue is currently at four lanes with an urban section and will be widened to six lanes generally to the east to accommodate the new Transit/HOV lanes. The existing right-of-way ranges between 34 m to 38 m. A centre turn lane will be provided between the CN Railway crossing and just north of Harris Way to maintain full move access to local streets such as Barristers Court, Elm Ridge Acres Road, Thornlea Road and Harris Way. A raised median will be provided approaching John Street.

As part of the widening, the existing sidewalk on the west side will be shifted to the west between Barristers Court and John Street to allow for a wider boulevard of up to 3.75 m. On the east side, a 2.4 m multi-use path (adjacent to the curb) will be provided to minimize impacts to residential properties and vegetation adjacent to Bayview Avenue.

Auxiliary lane requirements and storage lane lengths for the John Street / Bayview Avenue intersection will be reviewed during detail design in coordination with the City of Markham.

6.1.3.5 John Street (11+700) to Langstaff Road (13+500) – 36 m Right-of-Way This section of Bayview Avenue is currently at four lanes with an urban cross-section and will be widened to six lanes generally to the east to accommodate the new Transit/HOV lanes. The existing right-of-way ranges between 33 m to 44 m. A centre turn lane will be provided to access the Thornhill Community Centre and Glynnwood Retirement Residence north of John Street. The existing right-in/right-out configuration at Royal Orchard Boulevard will remain the same as existing. Due to the long southbound left turn queue at the Bayview Avenue / Green Lane intersection, York Region recommends that the existing configuration at Royal Orchard Boulevard be maintained to ensure there is sufficient storage space for southbound left turn vehicles.

Raised median will be provided approaching Romfield Circuit / Willowbrook Road, approaching Dunsinane Drive, between Dunsinane Drive and Langstaff Road.

There will be some property requirements along the east side of Bayview Avenue at the Thornhill Community Centre, Fire Station (7801 Bayview Avenue), the condo complex at 7825 Bayview Avenue, Thornlea Secondary School and the Bayview Reservoir Park.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-8 Environmental Study Report | WSP | MMM Group | August 2017

Parking area at the Thornhill Community Centre and Thornlea Secondary School will be directly impacted as a result of the road widening. City of Markham and the York Region District School Board will have to be consulted during detailed design to determine the reconfiguration of the respective facilities.

The structure on Bayview Avenue north of John Street over the CN Railway / Metrolinx Richmond Hill GO Transit line will have to be widened to the east to accommodate the road widening. See Section 6.2.

6.1.3.6 Langstaff Road (13+500) to Bantry Avenue / Briggs Avenue (15+000) This section of Bayview Avenue is already an urban six lanes road. There is a full interchange at Highway 407. The lane marking through the Highway 407 Interchange will be confirmed through consultation with 407 ETR and the Ministry of Transportation during detailed design.

The existing Highway 407 Bridge is in good condition, therefore replacement of this structure is not being considered at this time. An existing sidewalk on both sides of the bridge facilitates pedestrian crossing and provides a connection to Highway 7, below. In the future, a multi-use path is proposed for the east side of Bayview Avenue however since there is not sufficient space on the existing Highway 407 Bridge to accommodate a multi-use path, cyclists will dismount and walk on the sidewalk. Consideration of widening the Highway 407 Bridge to accommodate a multi-use path will be subject to future consultation with 407ETR and MTO. Whether the design involves widening the existing bridge or constructing a new dedicated bridge for the multi-use path, the design will have to accommodate the future 407 Transitway, involve an assessment of bridge design alternatives, consider connection to VIVA at Highway 7, and directly involve 407ETR and MTO in the planning and approval process.

Access to Highway 7 from Bayview Avenue is via Creswick Road. A double northbound left turn is proposed to accommodate the high traffic volumes turning onto Highway 7.

Full move access to the condo complex at 8501 Bayview Avenue will be maintained. The gated access to the Toronto Montessori School is proposed to be closed.

6.1.3.7 Briggs Avenue / Bantry Avenue (15+000) to 16th Avenue (16+100) – 36 m Right-of-Way This section of Bayview Avenue is currently at four lanes with an urban section and will be widened to six lanes generally to the east to accommodate for the new Transit/HOV lanes. The existing right-of-way ranges between 36 m to 43 m. A centre turn lane will be

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-9 Environmental Study Report | WSP | MMM Group | August 2017

provided to access Pathlane Road, Ducan Road and Loredana Court south of 16th Avenue; otherwise, a raised median is provided throughout this section.

On the west side of Bayview Avenue, the existing sidewalk 1.5 m is largely maintained in its current location. On the east side, the existing sidewalk will be removed and reconstructed as a 3.0 m multi-use path.

There will be some property requirements along the east side of Bayview Avenue, just south of 16th Avenue.

Auxiliary lane requirements and storage lane lengths for the 16th Avenue / Bayview Avenue intersection will be reviewed during detailed design in coordination with the Town of Richmond Hill.

6.1.3.8 16th Avenue (16+100) to Weldrick Road (17+360) – 36 m Right-of-Way This section of Bayview Avenue is currently at four lanes with an urban cross-section and will be widened to six lanes generally by the centreline to accommodate the new Transit/HOV lanes. The existing right-of-way ranges between 34 m to 38 m. A centre turn lane will be provided between 16th Avenue and Fern Avenue to provide storage for southbound left turns at 16th Avenue and to Fern Avenue. A centre turn lane will also be provided to access Hillsview Drive and the Richmond Hill Christian Community Church. A new full move intersection will be provided opposite to Ardwold Gate to service the new development.

On the west side of Bayview Avenue, the sidewalk will be shifted to the west to accommodate the widening and the boulevard. On the east side, the existing sidewalk will be removed and reconstructed as a 3.0 m multi-use path. Detailed design will adjust boulevard grading and/or multi-use path or sidewalk alignments as required to eliminate any minor grading encroachments and ensure that the proposed work(s) are contained within the right-of-way through this section.

There will be some property requirements along the west side of Bayview Avenue (Richmond Hill Christian Community Church). The future David Dunlop development between Fern Avenue and Hillsview Drive will have to accommodate the Region’s proposed 43 m right-of-way as identified in the Official Plan.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-10 Environmental Study Report | WSP | MMM Group | August 2017

6.1.3.9 Weldrick Road (17+360) to Major Mackenzie Drive (18+180) – 33.9 m Right-of-Way This section of Bayview Avenue is currently at four lanes with an urban cross-section and will be widened to six lanes generally to the east to accommodate the new Transit/HOV lanes. The existing right-of-way ranges between 31 m to 40 m. A centre turn lane will be provided to access properties on the east side of Bayview Avenue north of Weldrick Road, properties on the west side of Bayview Avenue south of Elmwood Avenue and access to Elmwood Avenue. A raised median will be introduced north of Elmwood Avenue to prevent left turn moves to Old Markham Road; to reduce the traffic conflict in this area.

On the west side of Bayview Avenue, the sidewalk will be shifted to the west to accommodate the widening and the boulevard. On the east side, the existing sidewalk will be removed and reconstructed as a 2.4 m multi-use path. Detailed design will adjust boulevard grading and/or multi-use path or sidewalk alignments as required to eliminate any minor grading encroachments and ensure that the proposed work(s) are contained within the right-of-way through this section.

There will be some property requirements along the west side of Bayview Avenue between Palmer Avenue and Elmwood Avenue (private residences). The future development on the east side of Bayview Avenue north of Weldrick Road will be required to accommodate the Region’s proposed 43 m right-of-way as identified in the Official Plan.

6.1.3.10 Major Mackenzie Drive (18+180) to Taylor Mills Drive South (19+460) – 36 m Right-of-Way This section of Bayview Avenue is currently at four lanes with an urban cross-section and will be widened to six lanes generally to the east to accommodate the new Transit/HOV lanes. The existing right-of-way ranges between 33 m to 38 m. A centre turn lane will be provided to access Bayview Secondary School and St. Paul Lutheran Church south of Centre Street; Jean Vanier Catholic School and Our Lady Queen of World Church north of Crosby Avenue, as well as Cartier Crescent and Taylor Mills Drive South. A raised median will be provided between Centre Street and Crosby Avenue.

On the west side of Bayview Avenue, the sidewalk will be shifted to the west to accommodate the widening and the boulevard. On the east side, the existing sidewalk will be removed and reconstructed as a 3.0 m multi-use path. There will be some property requirements along the east side of Bayview Avenue from Our Lady Queen of World Church and Jean Vanier Catholic High School. During detailed design there will be future

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-11 Environmental Study Report | WSP | MMM Group | August 2017

consultation with representatives from Our Lady Queen of World Church and York Region Catholic District School Board to confirm mitigation measures.

Auxiliary lane requirements and storage lane lengths for the Major Mackenzie Drive / Bayview Avenue intersection will be reviewed during detail design in coordination with the Town of Richmond Hill.

6.1.3.11 Taylor Mills Drive South (19+460) to Elgin Mills Road (20+180) – 33.9 m Right-of-Way This section of Bayview Avenue is currently at four lanes with an urban cross-section and will be widened to six lanes generally to the east to accommodate the new Transit/HOV lanes. The existing right-of-way ranges between 36 m to 41 m. A centre turn lane will be provided between Windhurst Gate and Elgin Mills Road to provide access to the commercial plaza and residential properties on the west side of Bayview Avenue, Taylor Mills Drive North, Judlea Court and Alper Street.

The existing culvert crossing of Bayview Avenue for the Rouge River tributary will require widening to accommodate the proposed sidewalk and multi-use pathway. The tributary is considered Redside Dace contributing habitat and, as such, the length and type of widening is subject to review and coordination with MNRF in addition to hydrotechnical conditions and fluvial geomorphology recommendations regarding the stream alignment on the east side in particular, discussed further in Section 8.3.4. Subject to detailed design, the proposed sidewalk and multi-use pathway widths and/or alignments over the structure may be modified to reduce impacts to stream habitats.

Auxiliary lane requirements and storage lane lengths for the Elgin Mills Road / Bayview Avenue intersection will be reviewed during detail design in coordination with the Town of Richmond Hill. Improvements will be matched to ongoing Bayview Avenue improvements north of Elgin Mills Road (i.e. widening from 2 to 4 lanes).

6.1.4 Road Profile The profile of Bayview Avenue is likely to remain similar to existing conditions. Some localized profile adjustments where the roadway is reconstructed. These will be confirmed in detailed design. Section 6.1.8 refers to the preliminary geotechnical report wherein recommendations for repaving would have impacts on the profile of Bayview Avenue.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-12 Environmental Study Report | WSP | MMM Group | August 2017

6.2 Structures As part of the Bayview Avenue Class EA Study, the following structures along Bayview Avenue (from south to north) were inspected and the inspection reports can be found in Appendix I:

 East Don River Culvert north of Steeles Avenue (Structure # 34-02 C0050);  East Don River Bridge at Proctor Avenue (34-02 B0800);  CN Subway north of Laureleaf Road (34-02 B1200);  CN Overhead north of Royal Orchard Boulevard (34-04 B0650);  German Mills Creek Culvert at Bantry Avenue/Briggs Avenue (34-06 C0800) ; and  Rouge River Tributary Culvert south of Elgin Mills Road (34-10 B1710). A summary of the inspection of the above-noted structures, as well as the proposed improvements to the respective structure as part of the Bayview Avenue widening are included in this section of the ESR. Improvements at the watercourse crossings are informed by the structural inspections and the hydraulic assessment (Section 6.3 of the ESR). Ecological-based design criteria that considers species at risk at the Rouge River Tributary will be finalized during detailed design (discussed in Section and 8.3.2 and summarized below and in Section 6.3 of the ESR).

6.2.1 East Don River Culvert (34-02 C0050)

6.2.1.1 Existing Conditions The East Don River culvert crossing is located approximately 70 m north of Steeles Avenue. Constructed circa 1964, the existing structure is a triple cell reinforced cast-in- place concrete rigid frame box culvert. It has clear spans of 3.4 m, 4.3 m, and 3.4 m, an overall length of 42.7 m, and a 3.7 m opening height. The culvert was constructed on a 30° skew to the roadway with approximately 2.1 m of fill above. A precast concrete “Dura- Hold” retaining wall was constructed in 1998 along the west end of the culvert.

An inspection completed by MMM in November 2015 identified the culvert to generally be in good condition except for some localized concrete scaling along the waterline in each cell. Actively leaking construction joints with localized areas of concrete delamination were also noted in each cell.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-13 Environmental Study Report | WSP | MMM Group | August 2017

The culvert currently carries two northbound lanes and four southbound lanes (two through lanes, a left turn lane and a right turn lane) of traffic plus a sidewalk on each side over the East Don River.

The existing structure can accommodate the Preferred Plan without any widening. No substantial changes to the road cross-section are proposed in this location.

6.2.1.2 Geotechnical Investigations and Foundations Requirements A geotechnical investigation was carried out part of the study and the Geotechnical Report is provided in (Appendix J).

Subsurface conditions at the location of the structure typically comprise a pavement structure overlying dense to loose silty sand and stiff clayey silty sand till with Standard Penetration Test (SPT) ‘N’ value of 2 blows per 300 mm penetration, underlain by firm to stiff silty clay, very loose sand, then very stiff to hard silty clay with SPT ‘N’ values of 24 to 58. Should the structure require replacement, factored geotechnical resistances at Ultimate Limit States (ULS) and Serviceability Limit States (SLS) of 180 kPa and 120 kPa may be used for the preliminary design of spread footings founded on the stiff clayey silty sand till for a culvert extension. Alternatively, driven steel HP 310x110 piles may be used with geotechnical resistances of 1400 kN and 1200 kN at ULS and SLS respectively. Additional boreholes will be required to determine the required depth of the piles.

6.2.1.3 Hydraulic Assessment A hydrology and hydraulics assessment was completed as part of this study (Appendix H). The East Don River culvert currently does not meet the required freeboards and severely exceeds the Relief Flow depth and depth x velocity criteria. The high Relief Flow is caused by backwater of an undersized downstream structure on Steeles Avenue (see Section 6.3 of this ESR).

6.2.1.4 Proposed Rehabilitation The proposed culvert work involves concrete patch repairs on the soffit with form and pump methods, as well as repair of actively leaking cracks, voids, and construction joints by cleaning (flushing) and injecting with a polyurethane resin. If cracks, voids, and / or construction joints are wider than 5 mm, repair will instead comprise concrete or non- shrink grout patches.

The General Arrangement for the structure is provided in Exhibit 6-2.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-14 Environmental Study Report | WSP | MMM Group | August 2017

6.2.2 East Don River Bridge (34-02 B0800)

6.2.2.1.1 Existing Conditions The East Don River Bridge is located approximately 30 m north of Proctor Avenue. The existing structure is a single-span slab-on-girder bridge comprising a composite concrete deck supported by 12 lines of galvanized steel girders with semi-integral abutments. The substructure is comprised of two reinforced concrete abutments founded on timber piles. There are cast-in-place concrete retaining walls at all four corners. The bridge has an overall span of approximately 14.3 m and a total width of approximately 30.7 m. Original structural drawings, dated 1956, indicate that the structure previously comprised a reinforced concrete T-beam superstructure until the superstructure was replaced in 1998 with what is now existing.

As part of a study for the Markham Watercourse Erosion Restoration Implementation Plan, a gabion basket retaining wall was constructed in 2012 at the northeast corner of the structure extending the existing wingwall to stabilize the embankment and address erosion concerns.

There is a 300mm diameter watermain suspended from the deck.

An inspection completed by MMM in November 2015 identified the bridge to generally be in good condition, except for some vertical cracking in the abutments and parapet walls and localized cracking and staining in the soffit.

The existing bridge accommodates 2 through lanes and a right turn lane in each direction, a southbound left turn lane plus a sidewalk on each side.

6.2.2.2 Roadway The proposed structural cross-section including lane, shoulder and side clearance widths were established in accordance with the Ministry’s Geometric Design Standards for Ontario Highways (GDSOH) and Road Classifications. The proposed structure cross- section comprises the following from west to east:

 0.3 m parapet wall  2.0 m sidewalk  1.25 m shoulder  1 x 3.5 m Transit/HOV lane  2 x 3.3 m southbound lanes

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-15 Environmental Study Report | WSP | MMM Group | August 2017

 1 x 3.3 m southbound left turn lane  2 x 3.3 m northbound lanes  1 x 3.5 m Transit/HOV lane  0.5 m shoulder  2.88 m multi-use path  0.3 m parapet wall The existing structure can accommodate this cross-section without any widening.

6.2.2.3 Geotechnical Investigations and Foundations Requirements Subsurface conditions at the location of the structure typically comprise a pavement structure, soft silty clay, and a thin layer of very loose silty sand with Standard Penetration Test (SPT) ‘N’ values of 5 to 48 blows per 300 mm penetration, underlain by stiff to hard silty clay with SPT ‘N’ values of 2 to 67.

Should the structure require replacement, factored geotechnical resistances at Ultimate Limit States (ULS) and Serviceability Limit States (SLS) of 180 kPa and 120 kPa may be used for the preliminary design of spread footings founded on the stiff silty clay for a bridge widening. Alternatively, driven steel HP 310x110 piles may be used with geotechnical resistances of 1400 kN and 1200 kN at ULS and SLS respectively. Additional boreholes will be required to determine the required depth of the piles; however, these are not anticipated to exceed 15 m.

6.2.2.4 Proposed Rehabilitation The proposed work includes removal of the existing asphalt and waterproofing system, removal of the existing east sidewalk and parapet wall, concrete patch repairs to the deck surface, construction of a new east sidewalk and parapet wall, and a new asphalt and waterproofing system. The removal of the existing east sidewalk and parapet wall is necessary to accommodate the proposed cross-section.

It is recommended that a detailed condition survey be completed prior to detailed design to confirm the structure condition and proposed rehabilitation strategy.

The General Arrangement for the structure is included in Exhibit 6-3.

Meetings were held with Toronto and Region Conservation Authority (TRCA) in September and October 2016; TRCA will continue to be consulted during the detailed design process.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-16 Environmental Study Report | WSP | MMM Group | August 2017

6.2.3 CN Subway (34-02 B1200)

6.2.3.1.1 Existing Conditions The CNR Subway (mileage 18.1 York Subdivision) is located approximately 100 m north of Laureleaf Road and 500 m south of John Street.

The existing structure was constructed circa 1962 and is a single span through plate girder subway, carrying two sets of tracks over Bayview Avenue. It has a span length of approximately 27.4 m, a total width of approximately 9.3 m, and was constructed at a skew angle of approximately 35.8° to the roadway. The clear span between abutments is approximately 21.3 m (square). The existing deck is comprised of ballast on a steel deck plate supported by transverse floor beams. The existing substructure comprises two reinforced concrete abutments with retaining walls at each of the four corners.

An inspection was completed by MMM in November 2015. Significant findings from this inspection include: light corrosion throughout the exterior faces and bottom flange of the main girders and on the bottom flange and ends of the webs of the transverse floor beams, localized areas of light corrosion on the underside of the deck plate, and a few vertical wide to medium cracks with some discolouration near the bottom of the concrete abutments and retaining walls.

The subway currently accommodates two through lanes in each direction, a southbound left-turn lane and a sidewalk on each side.

As part of the proposed Bayview Avenue widening, the structure will need to be replaced to accommodate additional lanes and active transportation facilities.

6.2.3.2 Railway Horizontal and Vertical Alignment The horizontal alignment of the railway tracks at the existing bridge location is on a tangent as indicated on available drawings. The existing north and south track are spaced at 3.96 m on centres. The proposed spacing is 6.90 m on centres. Each track will be realigned to accommodate this increased spacing.

The existing vertical profile of the railway tracks is a constant grade of -0.50% throughout the length of the bridge, from east to west. The existing profile will be reviewed during the detailed design phase.

The existing minimum clearance above the roadway is approximately 4.6 m as indicated on the original structure drawings. The minimum clearance required under the proposed bridge will be 4.8 m in accordance with the GDSOH.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-17 Environmental Study Report | WSP | MMM Group | August 2017

6.2.3.3 Roadway The roadway cross section including lane, shoulder and side clearance widths were established in accordance with the Ministry’s Geometric Design Standards for Ontario Highways (GDSOH) and Road Classifications.

The proposed roadway cross-section below the structure comprises the following from west to east:

 1.5 m sidewalk  3.0 m buffer  0.5 m shoulder  1 x 3.5 m Transit/HOV lane  2 x 3.3 m lanes  Variable width concrete median / pier  2 x 3.3m lanes  1 x 3.5 m Transit/HOV lane  0.5 m shoulder  0.5 m buffer  2.4 m multi-use path

6.2.3.4 Geotechnical Investigation and Foundations Requirements Subsurface conditions at the location of the structure typically comprise a pavement structure, dark grey silty clay layer, and a thin layer of sand with Standard Penetration Test (SPT) ‘N’ values of 11 to 22 blows per 300 mm penetration, underlain by very stiff silty clay and stiff to hard silty sandy clay till with SPT ‘N’ values of 14 to 87, over a compact sand and silt layer with an SPT ‘N’ value of 26.

Factored geotechnical resistances at Ultimate Limit States (ULS) and Serviceability Limit States (SLS) of 450 kPa and 300 kPa may be used for the preliminary design of spread footings founded on the very stiff silty clay. Alternatively, driven steel HP 310x110 piles may be used with geotechnical resistances of 1400 kN and 1200 kN at ULS and SLS respectively. Additional boreholes will be required to determine the required depth of the piles; however, these are not anticipated to exceed 15 m.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-18 Environmental Study Report | WSP | MMM Group | August 2017

6.2.3.5 Proposed Structure The proposed structure will need to accommodate all of the proposed Bayview Avenue road cross-sectional elements including additional lanes and active transportation facilities (sidewalk / multi-use path). Consequently, the proposed structure comprises two single-track, two-span through plate girder (TPG) subways, each with a total length of 50.2 m. The individual span lengths of the through plate girders will vary between 21.81 m and 27.5 m. The new structure crossing would require a median pier due to the need for a longer span to accommodate all of the proposed Bayview Avenue cross-sectional elements.

Similar to the existing structure, the decks will comprise ballast on a steel deck plate supported by transverse steel floor beams, longitudinal steel stringers, and longitudinal steel plate girders. The superstructure depth below the base of rail defines the clearance under the bridge and the need to lower the profile of Bayview Avenue to accommodate the required clearance. This depth will be kept to a minimum to mitigate the cost of relocating and lowering utilities. The substructure comprises two common reinforced concrete abutments and one reinforced concrete pier for each structure in the median. The abutments would be constructed square to the centerline of the existing tracks, per CN requirements; however, the piers would be constructed along the same skew as Bayview Avenue (35.8°). 6.0 m long retaining walls would be provided at the northeast and southwest corners of the structure to retain the embankments. A trainman’s walkway would be provided along the south side of the south structure.

The General Arrangement for the structure is included in Exhibit 6-4.

The existing bridge pier and abutments are supported on spread footings. In addition to accommodating the proposed Bayview Avenue widening, the span lengths of the proposed structure account for the locations of existing foundations in order to avoid conflict during excavation and construction of the new abutments.

CNR has advised that they will confirm the new track alignment, track profile, and whether they would require protection for a third track on a new structure during detail design.

Meetings were held with CN in May and October 2016. CN will continue to be consulted during the detail design process to coordinate design / approvals and construction staging details.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-19 Environmental Study Report | WSP | MMM Group | August 2017

6.2.3.6 Construction Staging Due to number of geometric constraints adjacent to the existing structure, including residential properties, a commercial plaza, and a communications tower, it will not be feasible to implement a rail detour during construction. Therefore, construction of the proposed subway will need to be completed in-place. Temporary spans behind the existing abutments will be required for excavation and construction of the new abutments while maintaining rail traffic. Construction staging will be as summarized below:

1. Install piles to support temp spans during track blocks;

2. Temporarily stop rail traffic during a pre-arranged track block and remove sections of the track and ballast to facilitate the installation of temporary spans;

3. Install temporary 10 m deck plate girder (DPG) spans, reinstate tracks, and resume rail traffic;

4. Excavate and install lagging / struts / walers as excavation progresses for construction of concrete abutments;

5. Construct footings, abutments, and piers and backfill;

6. Temporarily stop rail traffic during a pre-arranged track block and remove track, ballast, and temporary DPG spans to facilitate erection of permanent TPG spans. Bayview Avenue will have to be closed during the removal and erection;

7. Erect permanent TPG spans;

8. Place precast ballast wall; subballast closure; ballast, ties, and rails; and

9. Resume rail traffic and complete excavation under permanent structure as required for Bayview Avenue.

The construction of the new piers / median will require lane restrictions/shifting on Bayview Avenue during construction. These restrictions will allow for only one traffic lane in each direction during the construction of the piers. Geometrically, construction of the piers will need to account for sheet pile protection around an excavation for the footings, as well as temporary barriers, standard edge distances to excavations beyond the barriers, footing width, and area required for construction equipment. Full closures of Bayview Avenue including sidewalks will be required during removal of existing and erection of the new TPG spans; the anticipated duration of these closures can be arranged in weekends.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-20 Environmental Study Report | WSP | MMM Group | August 2017

6.2.4 CN Overhead (34-04 B0650)

6.2.4.1 Existing Conditions Bayview Avenue is grade separated (road over rail) with the CN Railway, which is also utilized by the Metrolinx / GO Transit Richmond Hill line at the location of this structure. The CN structure (mileage 19.62 Bala Subdivision) is located approximately 280 m north of Royal Orchard Boulevard. The existing structure was constructed circa 1976 and is a six span post-tensioned solid concrete slab. It has a total deck length of approximately 139 m, a total width of approximately 19.3 m, and was constructed at a 25° skew to the railway. The substructure comprises two reinforced concrete abutments supported by steel H-piles and five reinforced concrete piers, each comprising five round columns, supported by spread footings. The structure was previously rehabilitated in 1995 with various concrete patch repairs to the concrete deck, soffit, curbs, sidewalks, abutment walls and wingwalls, new concrete parapet walls, new deck expansion joint assemblies, new asphalt drainage tubes and new waterproofing and asphalt paving.

The bridge accommodates two lanes in each direction plus a sidewalk on west side.

An inspection completed by MMM in November 2015 found the structure to be generally in fair to good condition. Significant findings included: vertical cracking and rust staining on the abutments, piers, and parapet walls; wet areas, staining, concrete delaminations, and spalling in the soffit; concrete disintegration on the northwest approach sidewalk; concrete spalling and cracking on the sidewalks; and cracking and wheel track rutting in the asphalt wearing surface.

As part of the proposed Bayview Avenue widening, the structure will need to be widened to the east to accommodate additional lanes and active transportation facilities.

6.2.4.2 Roadway The proposed centerline of Bayview Avenue will be offset to the east from the existing centerline. The structural cross section including lane, shoulder and side clearance widths were established in accordance with the Ministry’s Geometric Design Standards for Ontario Highways (GDSOH) and Road Classifications.

The proposed structure cross-section comprises the following from west to east:

 0.3 m parapet wall  1.6 m sidewalk

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-21 Environmental Study Report | WSP | MMM Group | August 2017

 Variable width shoulder  1 x 3.5 m Transit/HOV lane  2 x 3.3 m lanes  1.5 m concrete median  2 x 3.3 m lanes  1 x 3.5 m Transit/HOV lane  Variable width shoulder  2.7 m sidewalk  0.3 m parapet wall

6.2.4.3 Geotechnical Investigations and Foundation Requirements Subsurface conditions at the location of the structure typically comprise a topsoil layer over layers of very stiff silty clay till and compact silty sand with Standard Penetration Test (SPT) ‘N’ values of 17 to 26 blows per 300 mm penetration, underlain by a deep deposit of dense to very dense sandy silt till with SPT ‘N’ values of 36 to 101, over a silt layer with SPT ‘N’ values of 28 to 65.

Widening of the structure will require extension of the existing bridge foundations. Selection of a similar system to existing is recommended to maintain consistency of performance between the existing structure and proposed widening; i.e., steel H-piles at abutments and spread footings at the piers. Furthermore, footing extensions should be founded at the same levels as existing footings.

Factored geotechnical resistances at Ultimate Limit States (ULS) and Serviceability Limit States (SLS) of 300 kPa and 200 kPa may be used for the preliminary design of spread footings at the piers founded on clay till or silty sand. Higher values of 600 kPa at ULS and 400 kPa at SLS may be used for spread footings founded on dense to very dense sandy silt till. At the abutments, driven steel HP 310x110 piles may be used with geotechnical resistances of 1400 kN and 1200 kN at ULS and SLS respectively. Additional boreholes will be required to determine the required depth of the piles; however, these are not anticipated to exceed 10 m.

6.2.4.4 Proposed Widening/Rehabilitation Similar to the existing structure, the proposed widening will be a post-tensioned superstructure. Other alternatives, including precast concrete box girders were

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-22 Environmental Study Report | WSP | MMM Group | August 2017

considered; however, these were not carried forward due to limited vertical clearance above the existing railway tracks.

It will be necessary for the widened portion to be constructed independent of the existing structure and left for approximately 6 to 8 months to allow for creep and shrinkage effects due to post-tensioning. The widened portion would then be connected to the existing structure by a cast-in-place concrete closure strip.

Falsework will be required to construct the widenings. Based on the existing drawings, there is approximately 600mm depth available for falsework to provide a 6400 mm minimum vertical construction clearance over the CNR. However, the depth of falsework that will be required to span the existing CNR tracks would be much greater than the 600 mm available. One option is to detour one of the existing tracks such that intermediate supports could be placed between the two tracks thereby reducing the length the falsework would have to span and thus reducing the depth of falsework. Alternatively, the widening could be constructed at a higher elevation to accommodate the falsework and then be jacked down onto the bearings. This is the preferred solution due to the site constraint.

Rehabilitation of the existing structure will include removal of the existing asphalt and waterproofing system, concrete patch repairs to the deck surface, concrete patch repairs to the soffit and substructure using form and pump methods, and a new asphalt and waterproofing system.

It is recommended that a detailed condition survey be completed prior to detailed design to confirm the structure condition and proposed rehabilitation strategy.

The General Arrangement for the structure is included in Exhibit 6-5.

Meetings were held with CN in May and October 2016. CN will continue to be consulted during the detailed design process to coordinate design / approvals and construction staging details.

6.2.4.5 Construction Staging This alternative will likely require at least three traffic stages to maintain four lanes of traffic during construction. The widening would be constructed first while maintaining traffic on the existing structure, but shifted to the west side of the existing bridge to accommodate the construction zone. After sufficient time for creep and shrinkage effects in the widened structure, with pedestrian access maintained on the existing west sidewalk, to remove the existing railing and curb on the east side, complete concrete

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-23 Environmental Study Report | WSP | MMM Group | August 2017

patch repairs to the east side of the existing deck surface, construct the closure strip between the east widening and the existing structure, and paving. The four lanes of traffic and pedestrian access would then be shifted onto the widened structure and the east side of the existing bridge to complete concrete patch repairs to the west side of the existing deck surface and paving. The duration of these lane reductions and shifts will ultimately be dependent on the staging identified as part of detailed design.

6.2.5 German Mills Creek Culvert (34-06 C0800)

6.2.5.1 Existing Conditions The German Mills Creek culvert is located approximately 120 m south of Bantry Avenue / Briggs Avenue. Constructed circa 1991, the crossing is a triple cell precast concrete open footing arch culvert. Each cell has a length of approximately 250 m, clear span of 7.32 m, and an opening height of 3.05 m. The culvert is comprised of precast concrete “CON/SPAN” units except for approximately 75 m at its east end where it is comprised of cast-in-place concrete. Reinforced cast-in-place concrete cantilever retaining walls have been provided at all four corners.

From the east, the culvert crosses Bayview Avenue at approximately 41° skew to the roadway for approximately 75 m. The culvert then curves to the north and runs parallel to Bayview Avenue for approximately 150 m, crossing below Bantry Avenue. North of Bantry Avenue, the culvert then curves approximately 30° to the west for 25 m to its west end. There is approximately 2 m of fill above the culvert.

An inspection completed by MMM in November 2015 identified the culvert to generally be in good condition, except for a few small localized areas of concrete spalling. The proposed work involves concrete patch repairs on the soffit with form and pump methods.

Bayview Avenue is already 6 lanes through this area and therefore the structure can accommodate the proposed improvements.

The General Arrangement for the structure is included in Exhibit 6-6.

6.2.6 Rouge River Culvert (34-10 B1710)

6.2.6.1 Existing Conditions The Rouge River Tributary culvert is located approximately 260 m south of Elgin Mills Road. Constructed circa 1997, the existing structure is a single span reinforced cast-in- place concrete rigid frame box culvert. It has a length of 30 m, clear span of 3.0 m, and

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-24 Environmental Study Report | WSP | MMM Group | August 2017

an opening height of 1.25 m. The culvert was constructed at approximately 10° skew to the roadway with approximately 0.6 m of fill above the culvert. Reinforced concrete cantilever retaining walls have been provided at all four corners.

The structure currently accommodates two through lanes in each direction, a southbound left-turn lane and a sidewalk on each side.

An inspection completed by MMM in November 2015 identified the culvert to generally be in good condition, except for some cracking on the culvert walls, suspected concrete delamination, and suspected actively leaking cracks in the soffit.

As part of the Bayview Avenue widening, the culvert may need to be extended to accommodate the additional lanes and active transportation facilities.

6.2.6.2 Roadway The roadway cross section including lane, shoulder and side clearance widths were established in accordance with the Ministry’s Geometric Design Standards for Ontario Highways (GDSOH) and Road Classifications. The proposed roadway cross section above the culvert comprises the following from west to east:

 1.5 m sidewalk  0.5 m shoulder  1 x 3.5 m Transit/HOV lane  2 x 3.3 m lanes  1 x 3.3m left turn lane  2 x 3.3 m lanes  1 x 3.5 m Transit/HOV lane  0.5 m shoulder  0.5 m buffer  2.4 m multi-use path

6.2.6.3 Geotechnical Investigations and Foundation Requirements Subsurface conditions at the location of the structure typically comprise a pavement structure and firm to stiff silty sandy clay till with Standard Penetration Test (SPT) ‘N’ values of 5 to 13 blows per 300 mm penetration, underlain by a thick deposit of very stiff

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-25 Environmental Study Report | WSP | MMM Group | August 2017

to hard silty clay with SPT ‘N’ values of 14 to 50, over a cohesionless layer of compact sand and silt with an SPT ‘N’ value of 10.

Factored geotechnical resistances at Ultimate Limit States (ULS) and Serviceability Limit States (SLS) of 120 kPa and 80 kPa may be used for the preliminary design of a box culvert base founded on undisturbed native silty clay. Alternatively, an open footing culvert with spread footings may be used with geotechnical resistances of 375 kN and 250 kN at ULS and SLS respectively.

Backfill to the proposed culvert extension shall consist of free-draining, non-frost susceptible granular material conforming to OPS Granular A or B Type II requirements.

6.2.6.4 Hydraulic Assessment The design storm at this location is a 50-year storm. The existing structure does not meet the 1.0 m required freeboard. Additionally, the relief flow depth exceeds the maximum allowable 0.30 m. In order to improve hydraulic performance of existing crossings to meet the hydraulic standards, it is recommended, from a hydrotechnical perspective, that the culvert be twinned or replaced as discussed in Section 6.3 of this ESR.

6.2.6.5 Proposed Structure The Rouge River Tributary is protected habitat under the Endangered Species Act and therefore the design criteria and proposed structural design must include ecological considerations as well as hydrotechnical and structural inputs.

The Rouge River Tributary is protected habitat under the Endangered Species Act and therefore the final design criteria must extend beyond hydrotechnical to include the requirements of the Endangered Species Act (2007) and it regulations and ecological considerations. Based on these inputs, the following three replacement options were identified on a conceptual basis to carry forward for further review in detailed design. These are also discussed further in Section 8.3.2.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-26 Environmental Study Report | WSP | MMM Group | August 2017

 Option 2: Road alignment is shifted west to avoid the need for a channel realignment to the east of the road. This option would result in a ~ 4.25 m culvert extension to the west (upstream).  Option 3: A retaining wall is constructed along the east side of the road to avoid the need for channel realignment to the east of the road as well as a culvert extension. These options were reviewed with Toronto and Region Conservation Authority (TRCA) in September and October 2016, and the Ministry of Natural Resources and Forestry (MNRF) in October 2016. These options will be further refined and reviewed with agencies in detailed design and a structural design will be confirmed at that time.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-27 Environmental Study Report | WSP | MMM Group | August 2017

Exhibit 6-2: General Arrangement – East Don River Culvert (34-02 C0050)

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-28 Environmental Study Report | WSP | MMM Group | August 2017

Exhibit 6-3: General Arrangement – East Don River Bridge (34-02 B0800)

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-29 Environmental Study Report | WSP | MMM Group | August 2017

Exhibit 6-4: General Arrangement – CN Subway (34-02 B1200)

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-30 Environmental Study Report | WSP | MMM Group | August 2017

Exhibit 6-5: General Arrangement – CN Overhead (34-04 B0650)

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-31 Environmental Study Report | WSP | MMM Group | August 2017

Exhibit 6-6: General Arrangement – German Mills Creek Culvert (34-06 C0800)

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-32 Environmental Study Report | WSP | MMM Group | August 2017

6.3 DRAINAGE AND STORMWATER MANAGEMENT The Drainage and Stormwater Management Report is provided in Appendix H. Existing conditions are described in Chapter 3 of this ESR. The proposed design is summarized below.

6.3.1 Stormwater Management Design Criteria and Guidelines

6.3.1.1 SWM Criteria  SWM Quality Control Criteria: An Enhanced level of stormwater treatment was identified for the study area. This is the highest level of treatment (80% removal of total suspended solids) identified in the MOECC SWM Planning and Design Manual (2003).  SWM Quantity Control Criteria: As identified by TRCA, any localized increase in flows due to the proposed project should be controlled to pre development conditions for the 2 to 100 year design storms before discharging to the creeks. The proposed development will increase surface runoff. It needs both quantity and quality controls.  Additionally, TRCA requires that the equivalent of 5 mm of rainfall be retained on site. In this case, consideration was given for detaining 5 mm across the change in imperviousness, rather than considering the full area of the existing roadway.

6.3.1.2 Flood Impacts Floodline mapping was available for the Rouge River Tributary, German Mills Creek and the two crossings of the East Don River. It is recognized that floodline impacts could result from the widening of Bayview Avenue due to the loss of floodplain storage. Detailed design and mitigation measures will ensure that there would be no increase in flood risk to Bayview Avenue and adjacent upstream and downstream lands.

6.3.1.3 Water Crossing Structure Criteria The design and hydraulic performance criteria adopted in this study that relates to the crossing structure design includes design flows, minimum freeboard, allowable overtopping frequency, and soffit clearance. The following criteria were extracted from the MTO Highway Drainage Design Standards (2008):

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-33 Environmental Study Report | WSP | MMM Group | August 2017

 Design Flow Criterion: The 50 year design flow was used for sizing all required structures within the study reach with spans less than or equal to 6 m and the 100- year design flow was used for sizing structures with spans more than 6.0 m. (Standard WC-1).  Freeboard Criterion: Freeboard of a minimum 1.0 m for the Design Flow Water Surface Elevation to the top of road low point. (WC-2) Desired Freeboard – a minimum of 1.0 m for the Design Flow Energy Gradeline to the top of road low point. (Standard WC-2).  Relief Flow Criterion: The Maximum Depth over the roadway should be less than 0.3 m for the Regulatory Storm. Relief Flow (Velocity x Depth) should be less than 0.8 m2/s for the Regional Storm (WC-13).

6.3.1.4 Soffit Clearance Criterion  Bridges: The minimum soffit clearance for bridges located on urban arterials (from the design flow water surface elevation to the lowest soffit elevation) should be 1.0 m (WC-2)  Culverts with Erodible Bottom: The minimum soffit clearance for culverts with open footings (erodible bottom) should be 0.3 m. (WC-7)  Culverts with Closed Bottom (Box Culverts, WC-7): Culverts with diameter or rise (D) of less than 3.0 m the Headwater Depth to D (HW/D) ratio should be less than or equal to 1.5. Culverts with diameter or rise from 3.0 m to 4.5 m the Headwater Depth (HW) should be less than or equal to 4.5 m. Culverts with diameter or rise greater than 4.5 m the HW/D ratio should be less than or equal to 1.0.

6.3.2 Bayview Avenue Minor Drainage and Future Storm Sewer Capacity Assessment The increase in overall pavement due to the preferred Bayview Avenue widening / reconfiguration to six lanes is considered minimal. The additional pavement will have a minimal impact on existing storm sewer flows.

The post-development drainage catchments are shown in Appendix H. As illustrated, the drainage areas differ marginally from for existing conditions. Post-development storm sewer calculations for are included in Appendix H.

In light of the above data limitation for the existing storm sewers, it is recommended that detailed storm sewer information as well as detailed sewer inspections including CCTV be obtained for detailed design, particularly to establish the true inflows from the external

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-34 Environmental Study Report | WSP | MMM Group | August 2017

drainage areas to update this study’s existing storm sewer calculations and provide storm sewer design for the preferred widening alternative.

6.3.3 Proposed Conditions Hydraulic Assessment This section presents the hydraulic modelling results of extending selected existing structures and associated impacts on the hydraulic culvert performance and upstream water levels. The hydraulic HEC-RAS models for each crossing were updated to reflect the following proposed conditions. All extensions were the type and size as existing structures:

 Rouge River Tributary Crossing – 4.25 m extension on downstream side is considered for hydraulic assessment purposes;  German Mills Creek Crossing – no proposed changes to existing structure;  East Don River Culvert Crossing 34-02 B0800 – 2.3 m extension on downstream side is considered for hydraulic assessment purposes; and  East Don River Bridge Crossing 34-02 C0050 – no proposed changes to existing structure. Tables 6-3, 6-5, 6-7 and 6-9 show the results for the proposed Rouge River, German Mills, East Don River 34-02 B0800 and 34-02 C0050 structures, respectively. The bottom row of each table shows an increase in upstream water levels due to the structure extension.

Tables 6-4, 6-6, 6-8 and 6-10 show whether the proposed structures meet the hydraulic criteria. As illustrated, the structure extensions result in the following:

 Minimal increases in upstream water levels for 2 to the Regional Storm for the Rouge River 34-10 B1710 and the East Don River 34-02 B0800 structures. There is only 0.01 m increase and zero increase for the Regional Storm elevation for the Rouge River and East Don River 34-02 B0800 structures, respectively.  No increases in flood elevations for all storm events for the German Mills and the East Don River 34-02 C0050 structures.  No changes to the status of meeting/not meeting hydraulic criteria for each structure.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-35 Environmental Study Report | WSP | MMM Group | August 2017

Table 6-3: Post Conditions for Rouge River Tributary Culvert 34-10 B1710 - Extended 3050 x 960 mm Concrete Culvert

Structure 10- 25- 50- 100- Regional 2-year 5-year (Upstream Face) year year year year Storm

Water Surface Elevation 225.59 225.86 226.03 226.29 226.50 226.57 226.98

Energy Gradeline Elevation 225.61 225.86 226.03 226.29 226.50 226.57 226.98

Top of Road (low point) 226.46 226.46 226.46 226.46 226.46 226.46 226.46

Top of Road Freeboard (Min) 0.85 0.60 0.43 0.17 -0.04 -0.11 -0.52

Top of Road Freeboard (desired) 0.85 0.60 0.43 0.17 -0.04 -0.11 -0.52

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 0.48

Soffit Elevation 225.40 225.40 225.40 225.40 225.40 225.40 225.40

Flood Depth (HW/D) 0.02 0.48 0.66 0.93 1.15 1.22 1.65 Max Increase upstream of 0.02 0.04 0.06 0.08 0.09 0.03 0.01 structure

Table 6-4: Drainage Criteria for River Tributary Culvert 34-10 B1710

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

Max. Increase upstream of structure Regional Yes

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-36 Environmental Study Report | WSP | MMM Group | August 2017

Table 6-5: Post Conditions for German Mills Creek Culverts 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 (desired) 2.97 2.41 2.24 1.96 1.74 1.54 1.29

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 Clearance 1.25 0.71 0.55 0.29 0.08 -0.11 -0.34 Max Increase upstream of 0.00 0.00 0.00 0.00 0.00 0.00 0.00 structure

Table 6-6: Drainage Criteria for German Mills Creek Culverts 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

Max. Increase upstream of structure Regional Yes

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-37 Environmental Study Report | WSP | MMM Group | August 2017

Table 6-7: Post Conditions for East Don River Bridge 34-02 B0800

Structure 10- 25- 50- 100- Regional 2-year 5-year (Upstream Face) year year year year Storm

Water Surface Elevation 149.52 149.66 149.82 149.96 150.03 150.14 153.57

Energy Gradeline Elevation 149.61 149.82 150.06 150.30 150.40 150.59 153.74

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 2.70 2.54 2.40 2.33 2.22 -1.21

Top of Road Freeboard (desired) 2.75 2.54 2.30 2.06 1.96 1.77 -1.38

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 1.94 1.78 1.64 1.57 1.46 1.97

Max Increase upstream of structure 0.00 0.01 0.02 0.02 0.03 0.04 0.00

Table 6-8: Drainage Criteria for East Don River Bridge 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

Max. Increase upstream of structure Regional Yes

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-38 Environmental Study Report | WSP | MMM Group | August 2017

Table 6-9: Post Conditions for East Don River Culverts 34-02 C0050 - Extended Three 4800 x 3600 mm Concrete Culverts

Structure 10- 25- 50- 100- Regional 2-year 5-year (Upstream Face) year year year year Storm

Water Surface Elevation 146.59 146.83 147.16 147.56 147.77 147.92 151.29

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 1.86 1.53 1.13 0.92 0.77 -2.60

Top of Road Freeboard (desired) 2.06 1.78 1.42 1.01 0.79 0.61 -2.71

Top of Road Velocity Na Na Na Na Na Na 0.97

Top of Road (Velocity x Depth) Na Na Na Na Na Na 2.53

Soffit Elevation 148.20 148.20 148.20 148.20 148.20 148.20 148.20

Flood Depth (HW) 0.55 0.62 0.71 0.82 0.88 0.92 1.86 Max Increase upstream of 0.00 0.00 0.00 0.00 0.00 0.00 0.00 structure

Table 6-10: Drainage Criteria for East Don River Culverts 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) 100-year Yes

Max. Increase upstream of structure Regional Yes

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6.3.4 Structure Modification Considerations The hydraulic assessment results indicate that:

 The Rouge River Culvert 34-10 B1710 does not meet the required freeboards (actual desired and minimum -0.04 m compared to minimum required 1.0 m) and the depth of the Relief Flow (actual: 0.51 m and 0.52 m extended compared to maximum allowable 0.30 m).  The German Mills Creek Culverts 34-06 C0800 do not meet the minimum 0.3 m Soffit Clearance (actual: -0.11 m).  The East Don River Bridge 34-02 B0800 does not meet the Relief Flow depth (actual: 1.21 m compared to max. allowable 0.30 m) and Relief Flow depth x velocity (actual: 1.89 m/s2 compared to max. allowable 0.80 m/s2).  The East Don River Culverts 34-02 C0050 do not meet the required freeboards (actual min. 0.77 m compared to minimum required 1.0 m) and exceeds the Relief Flow depth and depth x velocity criteria, even more than the Upstream East Don River structure. The high Relief Flow is caused by backwater of an undersized downstream structure. In order to improve hydraulic performance of existing crossings to meet the hydraulic standards the following hydrotechnical improvements were analyzed:

 Rouge River Culvert 34-10 B1710 – provision of a second culvert for flood conveyance or a replacement with a larger structure to increase freeboard and reduce depth of Relief Flow.  German Mills Culverts 34-06 C0800 – no change to existing structure since only the Clearance Criteria is not met.  East Don River Bridge 34-02 B0800 – the impacts of the downstream structures were analyzed by removing the Steeles Avenue and East Don River Culverts 34- 02 C0050 to assess their impacts on flood elevations at the East Don River Bridge. Note: Removal of downstream structures did not show backwater effects on the East Don River Bridge.  East Don River Culverts 34-02 C0050 – Removal of the bridge at Steeles Avenue to assess its impact on flood elevations. Note: Removal of Steeles Avenue bridge showed improvement; however, not to the extent to meet the Relief Flow standards at the East Don River Culvert 34-02 C0050. The depth of Relief Flow decreased as a result of the Steeles Avenue bridge removal.

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6.3.4.1 Rouge River Tributary Crossing The existing Rouge River Tributary culvert 34-10 B1710 does not meet the required freeboards and the depth of the Relief Flow. In order to improve hydraulic performance of existing crossings to meet the hydraulic standards, it is recommended, from a hydrotechnical perspective, that the culvert be twinned or replaced.

 Option 1: Road alignment determined by “best fit” approach, widened from centerline on either side. This option results in a ~ 4.25 m culvert extension to the east (downstream) and the realignment of approximately 50 m of channel, extension of structure at crossing by 4.25 m. A permit under the ESA (2007) will be required with this approach.  Option 2: Road alignment is shifted west to avoid the need for a channel realignment to the east of the road. This option would result in a ~ 4.25 m culvert extension to the west (upstream).  Option 3: A retaining wall is constructed along the east side of the road to avoid the need for channel realignment to the east of the road as well as a culvert extension. Meetings were held with Toronto and Region Conservation Authority (TRCA) in September and October 2016, and the Ministry of Natural Resources and Forestry (MNRF) in October 2016. TRCA and MNRF will continue to be consulted during the detailed design process.

6.3.4.2 East Don River Bridge 34-02 B0800 A 30 m span bridge at the East Don River Bridge would be required to bring the Relief Flow depth and depth x velocity to acceptable levels. However, this solution is infeasible due to the constraints of the site. The bridge lies between two intersections 55 m apart. It is not possible to construct a 30 m bridge between these two intersections and allow for all safety factors. It should be noted that the extension of the existing structure does not make the hydraulic factors worse.

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6.3.4.3 East Don River Culverts 34-02 C0050 The existing East Don River Culverts do not meet the hydraulic criteria for freeboard and Relief Flood primarily due to backwater impacts from the undersized East Don River Bridge at Steeles Avenue located immediately downstream of 34-02 C0050.

A sensitivity analysis with the East Don River Bridge at Steeles Avenue removed showed that:

 The minimum freeboard increased from 0.77 m to 1.35 m  The Relief Flow depth decreased from 2.60 m to 0.785 m  The Relief Flow velocity x depth decreased from 2.53 m2/s to 0.94 m2/s Without the impacts of the East Don River Bridge at Steeles Avenue the existing structure would meet he required freeboard but not the Relief Flow depth and velocity x depth criteria. It should be noted, however, that both Relief Flow parameters would be greatly reduced from existing conditions should the East Don River Bridge at Steeles Avenue is removed. This is not a feasible option.

6.3.5 Stormwater Management This section summarizes the Drainage and Stormwater Management Report, provided in Appendix H.

6.3.5.1 Stormwater Management Objectives and Criteria In consideration of the current policy framework and storm drainage issues, previous drainage and storm water management studies, and relevant guidelines, storm water management objectives were identified as follows:

 Flood Control: Provide flood control storage as required to prevent an increase in existing peak flood flow rates to storm outlets and along the watercourses within and downstream of the study area.  Erosion Control: Provide storage of road runoff to prevent an increase in the erosion potential along the watercourses within and downstream of the study area and provide adequate erosion protection measures where required.  Water Quality: Treatment of the additional pavement area plus existing pavement where feasible, provide an ‘Enhanced’ Level of Protection (previously Level 1) as defined by the Ministry of the Environment’s 2003 SWM Planning and Design Manual (80% removal of total suspended sediments), minimize the potential for

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water temperature increases resulting from storm water management measures, provide spill control measures where feasible and incorporate measures to reduce winter use of salt and/or sand.  Stream and Valley Corridor Impacts: To the extent feasible, locate SWM facilities outside of the valley and stream corridor.  Floodplain Impacts: Ensure that the proposed works do not cause an increase in existing flood elevations as a result of increased flows, loss of flood plain storage, or loss of effective flood flow area.  Drainage Pattern: Maintain the existing drainage pattern and drainage outlets.

6.3.5.2 Drainage and Stormwater Management Constraints The stormwater management constraints for this project are summarized as follows:

 Limited right-of-way: The implementation of stormwater management measures may result in the need to acquire additional land. Lands adjacent to Bayview Avenue are largely established and there is limited opportunity to acquire property for stormwater management control.  Existing outlets: The stormwater management measures must be designed such that the existing stormwater outlets can be utilized.  Depth to the Oak Ridges Moraine Aquifer Complex (ORMAC): There may be limitations to the implementation of certain drainage and stormwater management measures due to the depth to the ORMAC along Bayview Avenue.  Dense soils: The dense soils of the Halton till limit the potential for infiltration measures

6.3.5.3 Best Management Practices Some of the applicable Best Management Practices (BMPs) for treatment of urban stormwater runoff include the following:

 Oil and Grit Separators (OGS) - are effective water quality treatment for storm sewer systems which do not require significant areas to be installed.  Stormwater Management (SWM) ponds (wet / dry / linear pond facilities) - for water quality and quantity treatment of larger drainage areas (i.e. min. 5 ha of drainage areas for wet ponds) where available land for the pond is available.

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 Low Impact Development (LID) measures such as infiltration trenches, permeable pavement, bioswales) - are most effective for water quality and quantity treatment where local soil have high permeability. The City of Markham does not endorse this practice so it will not be considered for this project. Discussions of enhanced swales (a basic LID measure that would not necessarily promote infiltration issues) with both the City of Markham and the TRCA should be undertaken at detailed design to ensure that Quality criteria can be met.  Grassed Swales - are effective measures of stormwater quality treatment in many applications. They provide an effective water quality treatment and can be accommodated within the road right-of-way. In order to achieve effective stormwater treatment, the grassed swales should have a minimum 0.75 m bottom width and maximum slope of 1%. The grassed swale should be designed to convey the peak flow with a velocity of less than 0.5 m/s and flow depth less than 0.25 m.  Underground storage including oversized storm sewers for stormwater detention are applicable for water quantity treatment where adequate surface detention storage cannot be facilitated due to lack of available space / existing infrastructure.

6.3.5.4 Stormwater Management Strategy for the Preferred Plan The most suitable BMPs for treatment of the runoff from Bayview Avenue within the study area are those which can be incorporated within the existing drainage system and do not require significant drainage areas. Consequently, OGS’s and grassed swales are the preferred measures for water quality treatment. Use of SWM ponds is desirable to achieve water quality as well as water quantity control, where sufficient area can be provided for the pond construction. A new SWM pond is currently being constructed on the David Dunlap Conservatory Lands. Another SWM pond is located on the Glynnwood Retirement Residence property. It is recommended that OGS’s are installed upstream of all SWM ponds within the study area. The least preferred BMP is an underground storage / oversized storm sewer primarily due to high construction and maintenance costs. Most of these BMP’s do not provide water quality treatment.

6.3.5.5 Impacts of Post-Development Road Runoff to Flood Flows at Major Crossings Due to the lack of storm sewer information for external catchments and the gaps in storm sewer information for the Bayview Avenue storm sewer, a detailed review and comparison of existing and future condition flows for the study area was not possible in this study. However, based on available information it can be stated that the proposed

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widening of Bayview Avenue will have negligible impacts on peak flows at each of the four major crossings. This qualification is based on the following considerations:

 Additional Pavement: The proposed road widening represents a relatively small increase in total pavement area within the study limits from 24.2 ha to 25.8 ha (an increase of 6.6%).  Lagging of hydrograph peaks: The runoff hydrographs from Bayview Avenue to each of the major crossings peak much earlier than the overall flood hydrographs at each crossing. Due to this lagging effect any increase in peaks in road runoff would be translated to zero or a very minor increase to the overall watercourse peak flow.

6.3.5.6 Implementation of the City of Markham Class Environmental Assessments As discussed in Section 3.6.2, the City of Markham has completed and is implementing two Class Environmental Assessments in the area:

 West Thornhill Stormwater Flood Remediation Class EA which includes:

o storm sewer improvements within thirteen (13) separate networks;

o The Phase 1 stormwater implementation area within the Bayview Glen area; o Phase 2 implementation area within the Grandview area; and o several low-cost elements such as the installation of inlet control devices and extensive roof downspout disconnection. Where these elements are not contingent on related storm sewer capacity improvements to convey additional flows, and where overland flow capacity is available, they may proceed in the short term.  Glynnwood Tributary Class EA which includes the following recommendations:

o Flows up to the 25 year storm event will be diverted to the Glynnwood Pond for water quality treatment. Prior to conveyance to the Pond, an oil/grit separator (OGS) will be installed to intercept heavier sediment particles, oil / grease and other debris before they are transported into the Pond;

o The existing storm sewer system up to its capacity will be used to convey a portion of the flows from major storm events; o Once the capacity of the existing storm sewer system is exceeded, the excess flows will be diverted to the main Glynnwood Pond via the new storm sewer relief sewer system.

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York Region will work with the City of Markham to ensure coordination between the Bayview Avenue widening and the City’s planned storm system upgrades.

6.3.6 Summary The proposed Bayview Avenue improvements include road widening to six lanes throughout the study area from Elgin Mills Road to Steeles Avenue. The proposed road widening represents an increase in total pavement area within the study limits is from 24.2 ha to 25.8 ha (an increase of 6.6%).

The assessments carried out in this study included analysis of the existing minor and major drainage systems, development stormwater management strategy for the study area, and recommendations for the proposed drainage improvements to accommodate the proposed road widening.

Minor System

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 theoretically correct, 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.

The storm sewer capacity results are subjected 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.

It is recommended that detailed storm sewer information be obtained for detailed design, particularly to establish the correct inflows from the external drainage areas to update this study’s existing storm sewer calculations and provide storm sewer design for the preferred widening alternative.

The increase in overall pavement due to the preferred Bayview Avenue widening option is only 6.6% of the total pavement area. As a result, the additional pavement will have a minimal impact on existing storm sewer flows.

Major System

The hydraulic HEC-RAS models for each crossing were updated to reflect the following proposed conditions. All extensions were the type and size as existing structures:

 Rouge River Tributary Crossing – 4.25 m extension on downstream side is considered for hydraulic assessment purposes;

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 German Mills Creek Crossing – no proposed changes to existing structure;  East Don River Culvert Crossing 34-02 B0800 – 2.3 m extension on downstream side is considered for hydraulic assessment purposes; and  East Don River Bridge Crossing 34-02 C0050 – no proposed changes to existing structure. The results of the HEC-RAS modelling were compared to the hydraulic criteria from the MTO Highway Drainage Design Standards for watercourse crossings. The criteria included minimum and desirable freeboard from the design flood elevation to the lowest pavement elevation, the soffit clearance for bridges, relief flow in terms of the depth of relief flow and velocity, and depth of flow at culverts. The results show the following:

 The Rouge River Culvert 34-10 B1710 does not meet the required freeboards (actual desired and minimum -0.04 m compared to minimum required 1.0 m) and the depth of the Relief Flow (actual: 0.51 m and 0.52 m extended compared to maximum allowable 0.30 m).  The German Mills Creek Culverts 34-06 C0800 do not meet the minimum 0.3 m Soffit Clearance (actual: -0.11 m).  The East Don River Bridge 34-02 B0800 does not meet the Relief Flow depth (actual: 1.21 m compared to max. allowable 0.30 m) and Relief Flow depth x velocity (actual: 1.89 m/s2 compared to max. allowable 0.80 m/s2).  The East Don River Culverts 34-02 C0050 do not meet the required freeboards (actual min. 0.77 m compared to minimum required 1.0 m) and exceeds the Relief Flow depth and depth x velocity criteria, even more than the Upstream East Don River structure. The high Relief Flow is caused by backwater of an undersized downstream structure. A sensitivity analysis was also carried out to determine what improvements to the proposed structures are required to meet the hydraulic criteria. However, solutions that would meet all criteria proved to be infeasible due to project constraints.

It is recommended that further analysis should be carried out during detailed design to confirm required improvements to proposed structures.

As discussed in Section 6.3.4 and Section 8.3.2 of this ESR, the Rouge River Tributary is protected habitat under the Endangered Species Act and therefore the final design criteria must extend beyond hydrotechnical to include the requirements of the Endangered Species Act (2007) and it regulations and other ecological considerations.

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Based on these inputs, three replacement options were identified to carry forward for further review in detailed design.

Fluvial geomorphology assessments of the four major crossings was also completed and is included in Appendix H.

Stormwater Management

The preferred stormwater management measures for treatment of the runoff from Bayview Avenue within the study area are those which can be incorporated within the existing drainage system and do not require significant drainage areas. Oil Grit Separators and grassed swales are the preferred measures for water quality treatment. Use of SWM ponds is desirable to achieve water quality as well as water quantity control, where sufficient area can be provided for the pond construction. A new SWM pond is currently being constructed on the David Dunlop Conservatory Lands. Another SWM pond is located on the Glynnwood Retirement Residence property.

It is recommended that OGS’s are installed upstream of all SWM ponds within the study area. The least preferred BMP is an underground storage / oversized storm sewers primarily due to high construction costs. Most of these BMP’s do not provide water quality treatment.

The most notable flooding area is that around the Glynnwood Retirement Residence. This flooding condition was addressed in the Glynnwood Tributary EA Document which made the following recommendations:

 Flows up to the 25 year storm event will be diverted to the Glynnwood Pond for water quality treatment. Prior to conveyance to the Pond, an oil/grit separator (OGS) will be installed to intercept heavier sediment particles, oil/grease and other debris before they are transported into the Pond;  The existing storm sewer system up to its capacity will be used to convey a portion of the flows from major storm events; and  Once the capacity of the existing storm sewer system is exceeded, the excess flows will be diverted to the main Glynnwood Pond via the new storm sewer relief sewer system Based on the available information it is considered that that the proposed widening of the Bayview Avenue will have no or negligible impacts on peak flows at each of the four major crossings.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-48 Environmental Study Report | WSP | MMM Group | August 2017

6.4 GEOTECHNICAL A preliminary geotechnical memo has been completed by Thurber Engineering and the memo is included in Appendix J of the ESR. The preliminary report provides guidance with respect to existing geotechnical conditions along the corridor, pavement design, foundation types for structure replacements and/or widenings and municipal services.

The recommendations will be reviewed during detailed design for practicality given the corridor constraints and the impact that raising the road profile would have on adjacent properties.

Additional geotechnical investigations are required for detailed design to confirm subsurface conditions and determine exact recommendations for bridge, culvert and grade separation structure foundations, excavations and embankment design in addition to dewatering requirements and soil contamination/environmental risk assessments.

6.5 STREETSCAPING The Streetscape Concept Plan is provided in Appendix K. The streetscape along an arterial corridor such as Bayview Avenue plays a prime role in defining the character of the corridor as well as the neighborhoods, municipalities and natural areas through which it runs. The reconfiguration of this long corridor provides the opportunity to establish a consistent visual language and rhythm throughout, while also allowing specific areas of interest such as key intersections and natural features to be highlighted through focused design efforts.

The conceptual landscape plans proposed for Bayview Avenue enhance the character of this street as well as improve the pedestrian and cyclist experience through the addition and improvement of active transportation infrastructure, boulevards, street trees, public art, and focused design in key areas such as intersections.

The following provides an overview outlining the general urban and landscape design principles and approaches, as well as site-specific treatments which are to be further developed into a detailed landscape plan during the future detailed design phase.

6.5.1 Protection of Existing Vegetation A variety of vegetated conditions can be found within the right-of-way throughout the study area. Although some vegetation will need to be removed to accommodate the road widening, where feasible existing vegetation in the right-of-way should be preserved to the greatest extent possible. Alignment of sidewalks and the multi-use path may be

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adjusted (within limits) to avoid removing or damaging significant mature trees; in some cases, the existing sidewalk alignment is retained in order to avoid the need for removal of existing street trees. Special attention should be given to preserving large, healthy mature trees both within and adjacent to the right-of-way, as well as vegetation within and in proximity of natural areas associated with the several stream/river crossings and woodlot areas along the corridor. Tree species, condition and age should be taken into account in decisions taken whether to remove or preserve specific trees. Grading should be avoided or minimized around existing vegetation and trees, and may require the use of retaining structures to avoid grading disturbance within the root zone.

Edge management measures will be incorporated into detailed design to protect retained areas of natural vegetation. TRCA has noted that climate change has the potential to exacerbate the spread of invasive species. Proper edge management should help to improve the resiliency of the forest by limiting the spread of invasive species along vulnerable edge habitat. TRCA’s Forest Edge Management Guidelines will be referenced, as appropriate, during detailed design.

6.5.2 Opportunities for Enhancements to Corridor Vegetation In addition to retaining and preserving existing vegetation, effort should be taken to enrich the corridor vegetation with the addition of plantings, notably trees, where feasible. All plantings should be non-invasive, hardy and drought-tolerant species, well-suited to roadside conditions and planted exclusively within the road right-of-way and within adjacent areas where vegetation is impacted from road development. In addition, plantings within any regulated areas should be native. In certain locations where there is insufficient space within the right-of-way for tree planting, there may be an opportunity to work landowners to plant trees on private property adjacent to the right-of-way. TRCA has indicated a preference for native species outside the TRCA regulated area as well.

Street trees should be planted at regular intervals along the corridor where sufficient rooting space is available. Ornamental trees should be planted at a higher density at key intersections and supplemented where appropriate with planting beds of native and ornamental shrubs and perennials to provide a sense of character and arrival. Plant species should be selected to provide year-round visual interest and should be sufficiently diversified so that monocultures are avoided. For street trees, a maximum of 15-20 trees of the same species are to be planted in a row within the right-of-way. In some locations, it may be desirable to work with private property owners who own land within the proposed area of grading impacts in order to come to a landscape solution that benefits both the property owner and the public using the corridor.

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Riparian planting in Redside Dace habitat will be determined through consultation with MNRF. Generally grasses are preferred in this habitat.

6.5.3 Boulevard Enhancement Boulevards are an important element in defining the streetscape of the corridor, providing valuable continuous rooting space for street trees as well as a buffer separating the sidewalk/multi-use trail and traffic lanes, enhancing safety for all users. In boulevards that are 3.0 m and wider, street trees placed 8.0 m on centre (for large form trees) Under overhead utility lines, smaller hydro-acceptable trees should be used, placed 6.0m on centre. Due to the length and suburban nature of the corridor, grass is a suitable ground cover for most boulevard areas.

6.5.4 Connectivity & Enhancement of Public Space Connectivity - The study area of Bayview Avenue is a main corridor linking neighborhoods, institutions and commercial areas, used not only by motorists but also by pedestrians and cyclists. As such, the landscape concept should seek to enhance connectivity for all users as they travel through the corridor. The landscape concept should capitalize on existing parks, parkettes and open spaces, integrating seamlessly with them where possible and providing connectivity to existing sidewalk and trail networks that meet or cross Bayview Avenue. Where there are long distances between street intersections, accessible shortcuts into adjacent neighborhoods should be considered to provide more frequent pedestrian/cyclist access points. Consideration should be given to formalizing existing paths indicating “desire lines” (for example, at the corner of Willowbrook Road and Bayview Avenue leading to Thornlea Secondary School); this may involve coordination with private property owners.

Gateways – As one travels through the corridor there are distinct transition zones between areas of different character; for example, travelling northbound, the John Street intersection marks the transition between a residential area and a commercial/community hub. Both the north and south terminus of the study area can also be considered “gateways”; at the southern terminus, Steeles Ave. marks the municipal boundary between North York and Markham; for those traveling from north of the study area, Elgin Mills Rd. E. marks a transition from a rural, agricultural character to an increasingly commercial and suburban character.

As part of the landscape plan, there are opportunities to mark the importance of these gateways with elements such as ornamental planting, sculpture, and signage. Special attention to the landscape at important gateways can provide visual and aesthetic

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interest, highlighting the character of an area. Exhibit 6-4 shows a design concept with ornamental planting and sculpture in the median near Steeles Avenue East, marking the transition into Markham and York Region. The existing signage identifying York Region and City of Markham could be upgraded to reflect the overall aesthetic.

Exhibit 6-7: Gateway Landscape Treatment on Bayview Avenue at Steeles Avenue

Intersections – Like gateways, intersections mark a transition and are by nature a place of congregation as motorists, pedestrians and cyclists gather and often pause at these nodes before travelling through them. From the point of view of landscape, intersections present a valuable opportunity to create usable public space and aesthetic improvements in the form of parkettes, site furniture, planting beds, ornamental trees, and even public art. Adjacent to the multi-use trail, seating areas and lookouts can provide resting space, increasing accessibility for a range of users. Significant intersections along the Bayview Avenue corridor have been identified in the landscape plan and degrees of conceptual landscape treatment have been proposed depending on the adjacent conditions and available space for landscape improvements. Notable intersections include the John Street intersection (see Exhibit 6-5), as well as intersections at Briggs Avenue and 16th Avenue, where there are valuable opportunities to tie into existing adjacent parkettes and open spaces.

Safety at intersections includes safety measures for all users. Prominent crosswalks and ample space for pedestrians and cyclists to pause at corners enhance both real and perceived safety. Special treatments, for example different paving patterns or a change in paving materials, can not only increase safety but also elevate the overall aesthetic appeal of the intersection.

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Exhibit 6-8: Enhanced Intersection at Bayview Avenue / John Street

Active Transportation – The inclusion of active transportation facilities are an essential part of the overall reconfiguration to Bayview Avenue. As the area surrounding the corridor densifies, there is a need to provide safe opportunities for people to leave the car at home and walk or cycle to their destination. An off-road, paved 3.0 m wide multi-use trail is proposed along the east side of Bayview Avenue in place of a standard on-road bike lane. The multi-use trail allows a more compact cross-section than that of a bike lane configuration and thus minimizes disturbance to adjacent properties as part of the widening. On the west side of Bayview, a standard 1.5 m wide sidewalk runs the length of the west side of Bayview, separated from the vehicular lanes by a 3.0 m wide vegetated boulevard in most locations. At intersections and crossings with existing path and trail networks, benches and other amenities can provide stopping and resting places for those traveling on foot or by bicycle.

Low-Impact Development (LID) – Opportunities to integrate LID measures for stormwater runoff reduction and infiltration may be explored during the detailed design phase. Properly sited and constructed, LID structures are not only highly effective in reducing runoff flows into storm sewer systems but they often contribute aesthetically to their surroundings as well as provide habitat value when they are planted with a diverse native mix of plantings. Bioretention areas, vegetated swales, and vegetated filter strips are a few examples of LID measures which could be integrated into the detailed landscape design within the right-of-way. The exact selection, design and placement of LID features within the right-of-way will depend on site-specific conditions (slope, available space, soils, relationship to streets, etc.). During the detailed design phase, the

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medians, boulevards, and vegetated areas between the sidewalk/multi-use trail and the right-of-way line should be considered as prime candidates for accommodating these features. Areas on private property that have been identified as potential landscape areas (for example, where construction and grading activities will take place outside the right- of-way), may also be suitable for LID measures.

6.5.5 Area-Specific Streetscape Design Please refer to Streetscape Concept plans provided at the end of this chapter.

6.5.5.1 Steeles Avenue Intersection This “gateway” intersection marks the entry into York Region (and into the study area) from the City of Toronto. The plan proposes improvements to the existing bus loop at this location, including amenities such as benches and bike racks. Bus loop improvements are subject to consultation with TTC, YRT and the City of Toronto. A section of wide median just north of the intersection allows potential space for public art and plantings within the median. Upgraded signage marking the gateway into Markham and York Region at this location should be considered.

6.5.5.2 East Don River, German Mills Creek and Rouge River Crossings At these crossings, vegetation disturbed by construction activity should be restored in the natural areas to the greatest extent possible, considering species for habitat value, as these serve as important riparian corridors. Signage, public art and/or an accessible observation “lookouts” can draw attention to the waterways below which may otherwise go unnoticed and provide an added educational benefit.

6.5.5.3 New CN Railway Bridge south of John Street The replacement of the existing CN Railway Bridge north of Laureleaf Road presents the opportunity to create a pedestrian-friendly, safe and aesthetically pleasing grade separation condition. Physical separation of pedestrians and automobiles can contribute to the safety of all users, while planting and unique abutment treatments like textured concrete can soften the mass of the structure. LID measures should be considered where there is space within the right-of-way, for example, at the intersection of Laureleaf Rd, as well as adjacent to the commercial plaza parking lot.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-54 Environmental Study Report | WSP | MMM Group | August 2017

6.5.5.4 John Street Intersection The John Street intersection marks a transition between a residential area and a community hub; as such, it is a prime candidate for enhancement as a public space with additional amenities like seating areas, ornamental planting beds and trees, and unique pavement treatments (see Figure 2). More generous space within the right-of-way at this intersection will likely be able to accommodate a more robust treatment of landscape and hardscape; it also may lend itself well to the integration of LID measures as part of the landscape. For example, ornamental planting beds may double as bioretention areas, planted with grasses and flowering perennials.

6.5.5.5 CN Bridge north of Royal Orchard Boulevard This bridge, which spans both Royal Orchard Boulevard and the Richmond Hill GO rail line, has a long approach and descent, which currently is bordered by a single narrow sidewalk on the west side directly adjacent to the vehicular lanes. The proposed multi - use trail and sidewalk will provide more space for cyclists and pedestrians to cross the bridge, and if space allows, a separation from the vehicular lanes could be provided. As trees and vegetation cannot be planted on the bridge itself, public art (in the median or on the sides) should be considered as a way to break up the monotony and provide an element of interest for those travelling over it. As this bridge is highly visible from much of the surrounding area, the addition of art and/or bright colours on the bridge can transform it into a distinctive landmark for the corridor.

6.5.5.6 Thornlea Secondary School and Bayview Reservoir Park The intersection of Romfield Circuit, Willowbrook Road and Bayview Avenue connects existing pedestrian trails and residential areas with Thornlea Secondary School and Bayview Reservoir Park. There is an opportunity to work with property owners to formalize existing “desire line” paths that cut diagonally across the slope towards the school, while enhanced intersection treatment and pedestrian amenities should be considered as this is a school zone. At Bayview Reservoir Park, increased vegetation is proposed along the street edge can take on an informal, “park-like” layout. At both the school and the park, there may be an opportunity to plant trees and other plantings on private property along Bayview Avenue to further improve the character of the street edge. Consideration should also be given to safety measures at the bottom of the slope near Bayview Avenue, as this is a popular winter sledding destination.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-55 Environmental Study Report | WSP | MMM Group | August 2017

6.5.5.7 Highway 407 and Highway 7 Overpasses The crossing of Bayview Avenue over Highways 407 and 7 results in two overpasses with several ramp connections. Safety for all users – particularly pedestrians and cyclists as they cross the ramps – is paramount, and the design of these crossings will impact their safety and effectiveness. Highly visible pavement markings such as crosswalks and cross-rides can alert drivers to the presence of cyclists and pedestrians. These overpasses are highly visible and provide a good opportunity to integrate public art, potentially on the sides of the bridges as well as in the medians on either end. Signage and art can also be used to bring attention to the Viva elevators as the transfer point between transit on Bayview Avenue and Highway 7, and the access points to these structures from Bayview Avenue should provide adequate maneuvering space for bicycles when entering/exiting the multi-use trail.

6.5.5.8 Bantry Avenue/Briggs Avenue and Bayview Avenue Intersection This area contains a mix of low, middle and high-density residential uses in proximity to commercial centres and open spaces, it is important to pay special attention to enhancing pedestrian infrastructure here. Landscape treatment at this intersection should take advantage of existing adjacent parkettes, parks and natural areas; these open green spaces may also be prime candidates for the integration of LID measures to deal with localized stormwater runoff. Visual and physical connectivity between the German Mills Creek path, Russell Farm Park and Bayview Avenue should be maximized with signage, clear trail connections and safe road crossings. A section of wider median just south of the intersection could support street trees and/or other plantings.

6.5.5.9 16th Avenue and Bayview Avenue Intersection This busy intersection is bordered to the north by two parkettes, which should be integrated into the landscape plans and are also, again, prime candidates for siting of LID structures. Linear LID measures such as filter strips and vegetated swales may be accommodated in boulevards, while extra space at the intersection may accommodate planted bioretention areas. To the south, enhancements to space within the right-of-way may include ornamental trees and planting beds. Distinctive crosswalk treatments at this location can serve both aesthetic and safety purposes.

6.5.5.10 Elgin Mills Road Intersection At the northern terminus of the study area, Elgin Mills Rd. E. marks the transition to a currently more rural/agricultural condition. Landscape and streetscape treatments here will need to be closely coordinated with the ongoing widening of Bayview Avenue north

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-56 Environmental Study Report | WSP | MMM Group | August 2017

of the study area from two lanes to four. This rapidly developing area will benefit from intersection landscape enhancements similar to other major intersections in the corridor, including special crosswalk treatments similar to those other intersections, and the integration of LID for localized stormwater management. The existing Beverly Acres Park is an important open space asset, and should be integrated into the overall landscape plan.

6.6 UTILITIES

6.6.1 Hydro (PowerStream) Currently, a set of utility (hydro) poles are located along the west side of Bayview Avenue within the study area. The design of the preliminary plan has considered the location of these hydro poles and attempted to accommodate their current alignment/location wherever possible to minimize the need to relocate them. The utility poles that require relocation as a result of the road widening can be shifted to the boulevard space on the west side of Bayview Avenue. Boulevard has been provided for this reason. The relocation of the existing poles will be coordinated as part of detailed design.

6.6.2 Gas (Enbridge) There are existing gas mains of various sizes and ages along the Bayview Avenue corridor. Depending on the location the existing plant may be in conflict with the proposed road widening and/or relocation of other infrastructure such as hydro poles, catchbasins etc. The relocation and/or protection of the existing gas mains will be coordinated as part of detailed design.

6.6.3 Telecom (Bell/Rogers) Existing Bell and Rogers infrastructure are largely overhead along the corridor, mounted on the existing hydro poles and as such would be affected by any hydro pole relocations. Detailed design will be required to identify any underground telecom conduits and/or infrastructure by subsurface utility investigation (minimum Level B) to establish horizontal and vertical alignments and potential conflicts with the proposed work(s). The relocation and/or protection of existing telecom along the Bayview Avenue corridor will be coordinated during detailed design.

6.6.4 Municipal Services There are minimal impacts to existing sanitary sewers and watermains along Bayview Avenue through the study limits. However, the age and condition of this infrastructure is

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-57 Environmental Study Report | WSP | MMM Group | August 2017

unverified and will be confirmed during detailed design by CCTV inspections and/or in coordination with the City of Markham and Town of Richmond Hill.

The Town of Richmond Hill has identified the following works to be completed during the Bayview Avenue widening:

 Bayview Avenue from 16th Avenue to Major Mackenzie Drive (MMD) - 200 mm CI WM Palmer Avenue to MMD East = +/- 660 m  Bayview Avenue between Hwy 7 to 16th Avenue - 300 mm DI WM Briggs to 16th Avenue = +/- 1,120 m  Bayview Avenue from MMD to Elgin Mills - 150 mm and 200 mm CI watermain = +/- 1,600 m  Bayview Avenue between Hillsview Drive to Weldrick - 200 mm CI and DI watermain = +/- 200 m  Bayview Avenue from 16th Avenue to MMD - 200mm VC sanitary Alper Street to MMD East = +/- 65 m  Bayview Avenue between Highway 7 to 16th Avenue - east side storm sewer – Briggs Avenue to 16th Avenue = +/- 155 m  All additional Storm and sanitary sewer within the right of way shall be reviewed via CCTV. Deficient areas shall be identified and repair method shall be recommended.  Any additional iron (DI & CI) watermain not identified above shall be replaced. The City of Markham has identified the watermain replacement at the following locations on Bayview Avenue:  300 dia. C.I. Watermain on the west and east side of Bayview Avenue from Steeles Avenue to approximately 2200 m north.  300 dia. C.I. Watermain on the east side of Bayview Avenue from 2200 m north of Steeles Avenue to John Street.  All perpendicular watermain connections (R.O.W.) from side streets on Bayview Avenue from Steeles Avenue to John Street. The City will be undertaking detailed design of the replacement/rehabilitation of the City’s watermain along this section of Bayview Avenue in 2017 with construction proposed in 2020. Coordination will be required between York Region and City staff during the design phase to confirm the location / alignment of the proposed watermain. The purpose of the

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-58 Environmental Study Report | WSP | MMM Group | August 2017

coordination is to avoid conflicts to proposed features from the Bayview Avenue widening which may affect future operations and maintenance activities conducted by City Waterworks staff.

As noted in Section 6.3.5.5 the City of Markham is implementing the West Thornhill Stormwater Flood Remediation and Glynnwood Tributary Class EA studies which involve upgrades to the existing storm water management system. York Region will work with the City of Markham to ensure coordination between the Bayview Avenue widening and the City’s planned storm system upgrades.

It is noted that some utilities and municipal services works will require separate permits under TRCA’s Ontario Regulation 166/06.

6.7 Traffic Signals and Illumination Existing signalized intersections on Bayview Avenue include from, south to north, Proctor Avenue, Laureleaf Road, John Street, Green Lane, Willowbrook Road/Romfield Circuit, Dunsinane Drive, Sycamore Drive/Romfield Circuit, Langstaff Road, ramp terminals at Highway 407, Creswick Road, High Tech Road, Bantry Avenue / Briggs Avenue, Blackmore Avenue / Springbrook Drive, 16th Avenue, Ardwold Gate, Weldrick Road, Palmer Avenue, Major Mackenzie Drive, Maramak Road, Centre Street, Crosby Avenue, Frank Endean Road / Windhurst Gate and Elgin Mills Road. New and modified signalized intersections would be constructed to fulfill Accessibility for Ontarians with Disabilities (AODA) requirements.

The proposed intersections would be illuminated. Illumination requirements will be determined during detailed design to meet the requirements of York Region.

6.8 PHASING AND CONSTRUCTION STAGING

6.8.1 Project Phasing The Region’s current capital program has funds allocated for construction for the section of Bayview Avenue between Highway 7 and Major Mackenzie Drive in 2020. The balance of the work along Bayview Avenue has yet to be included in the Region’s 10 year Capital Works planning.

Given this timeline, the project design for Bayview Avenue between Highway 7 and Major Mackenzie Road will commence immediately following the completion of the EA. Property and reference plans will be prepared for the property purchase process. Once

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-59 Environmental Study Report | WSP | MMM Group | August 2017

The Region gain ownership of the right-of-way utility relocation work, municipal servicing and road reconstruction can commence following detailed design.

CN Rail has indicated that work cannot occur on both grade separation structures simultaneously. As such, the replacement of the CN Rail structures should be phased separately or, if included in the same phase of construction, must be planned as a sequential program over several construction seasons.

Overall, the actual timing of improvements to different sections of Bayview Avenue will be dependent on traffic volume growth and the following factors will also affect the timing/staging of construction of the recommended undertaking:

 obtaining the necessary approvals;  obtaining the required funding;  acquiring the necessary land; and  designing the roadway in detail.

6.8.2 Construction Staging One of two widening scenarios is proposed for the various sections of Bayview Avenue; widening of the roadway to the east and widening of Bayview Avenue symmetrically about the existing centerline of the roadway. For each scenario it would be possible for four (4) lanes for traffic along Bayview Avenue to be maintained during construction for the majority of the corridor with some potential auxiliary/turning lane closures at intersections necessary on a temporary basis. Maintaining four lanes of traffic may require temporary constrictions of traffic lane widths and/or traffic shifts to allow for construction zones on one or both sides of Bayview Avenue. Temporary, short duration closures of Bayview Avenue to accommodate utility, sewer and/or municipal services work may be accommodated in off-peak hours and/or weekends provided municipal permits have been granted for atypical work times.

Works at structures require temporary lane restrictions/closures in order to facilitate construction in a practical and cost-effective manner. In the case of the CN Structure north of Laureleaf short duration closures of Bayview Avenue may be required for stages of construction on that structure.

Every practical effort will be made to maintain driveway access/egress during the proposed construction work(s). Driveways may require temporary closures for short

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-60 Environmental Study Report | WSP | MMM Group | August 2017

durations. If there are no alternative accesses available, half driveway width closures may be implemented.

A construction staging plan will be prepared during the detailed design phases of the project and the management of traffic and provision of temporary traffic provisions must be assessed in conjunction with the development of the detailed design, construction methodologies and materials and any planned approach to the work including permitting requirements and timing restrictions.

All plans for construction staging must consider the potential impacts on vehicular/cyclist traffic and pedestrians at all times during the construction contract. Detouring of traffic and closure of lanes and road segments must also be identified and communicated effectively with the public to ensure an efficient completion of the construction work and at a reasonable cost without significant impacts to area properties.

Construction staging in the vicinity of Highway 407 and/or Highway 7 should also consider impacts to ramp operations. Construction staging plans will require coordination and approval by 407ETR and MTO including analysis demonstrating anticipated impacts to traffic operations at the interchange.

6.9 PRELIMINARY COST ESTIMATE The preliminary cost estimate for the Preferred Plan is $114 M. An allowance for minor items (25%), construction indexing (5%) and contingency (30%) has been included in the road cost.

The breakdown of the preliminary cost estimate is provided in Tables 6-11 to 6-13. It should be noted that the estimated costs are preliminary only and would be updated during detailed design. The cost estimate below also includes cost items to accommodate for local municipal infrastructure that would be funded by the local municipality.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-61 Environmental Study Report | WSP | MMM Group | August 2017

Table 6-11: Preliminary Cost Estimate for Bayview Avenue – Steeles Avenue to Highway 407 / Highway 7

Steeles Avenue to Highway 407/Highway 7 3680 l.m. Station 10+000 to 13+680 Item Description Quantity Unit Est. Unit Price Cost Removals (incl. ex curb & gutter, sidewalks, driveways etc) 3680 l.m. $ 200 $ 736,000 Earth excavation, disposal and boulevard grading 3680 l.m. $ 600 $ 2,208,000 Road Construction Subgrade preparation and sub drains 3680 l.m. $ 75 $ 276,000 Granular "A" 23205 t $ 25 $ 580,125 Granular "B" 96910 t $ 20 $ 1,938,200 Base Asphalt SP19.0 27900 t $ 100 $ 2,790,000 Surface Asphalt SP12.5 14900 t $ 115 $ 1,713,500 Concrete curb and gutter 8500 l.m. $ 100 $ 850,000 Concrete sidewalk (1.5m wide, west side only) 3680 l.m. $ 125 $ 460,000 Multi-Use Path (2.75m avg. width, east side only) 3680 l.m. $ 175 $ 644,000 Concrete ramps and driveway restoration 3680 l.m. $ 100 $ 368,000 Storm sewer including catchbasins 3680 l.m. $ 450 $ 1,656,000 Municipal Services (Sanitary, Watermain) 3680 l.m. $ 250 $ 920,000 Boulevard restoration, Tree Planting, Streetscaping 33300 m2 $ 45 $ 1,498,500 Structural Culvert Replacement (north of Steeles Ave) 1 L.S. $ 3,500,000 $ 3,500,000 Retaining walls/fences/miscellaneous 1 L.S. $ 250,000 $ 250,000 Electrical (Signals/Lighting) 1 L.S. $ 1,575,000 $ 1,575,000 Traffic Staging/Detouring 1 L.S. $ 300,000 $ 300,000 Pavement Markings/Signage 1 L.S. $ 155,000 $ 155,000 Miscelleanous/Minor Items (25%) 1 L.S. $ 5,604,581 $ 5,604,581 CN Structures 1 L.S. $ 25,000,000 $ 25,000,000 30% Contingency + 5% Construction Indexing $ 15,911,372 Total $ 68,934,278 Pricing for Items is Approximate

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-62 Environmental Study Report | WSP | MMM Group | August 2017

Table 6-12: Preliminary Cost Estimate for Bayview Avenue – Highway 407 / Highway 7 to Major Mackenzie Drive

Highway 407/Highway 7 to Major Mackenzie Drive 4500 l.m. Station 13+680 to 18+180 Item Quantity Unit Est. Unit Price Cost Removals (incl. ex curb & gutter, sidewalks, driveways etc) 3160 l.m. $ 200 $ 632,000 Earth excavation, disposal and boulevard grading 3160 l.m. $ 200 $ 632,000 Road Construction Subgrade preparation and sub drains 3160 l.m. $ 75 $ 237,000 Granular "A" 19845 t $ 25 $ 496,125 Granular "B" 83160 t $ 20 $ 1,663,200 Base Asphalt SP19.0 23900 t $ 100 $ 2,390,000 Surface Asphalt SP12.5 12700 t $ 115 $ 1,460,500 Concrete curb and gutter 7300 l.m. $ 100 $ 730,000 Concrete sidewalk (1.5m wide, west side only) 4500 l.m. $ 125 $ 562,500 Multi-Use Path (2.75m avg. width, east side only) 4500 l.m. $ 175 $ 787,500 Concrete ramps and driveway restoration 3160 l.m. $ 100 $ 316,000 Storm sewer including catchbasins 3160 l.m. $ 450 $ 1,422,000 Municipal Services (Sanitary, Watermain) 3160 l.m. $ 250 $ 790,000 Boulevard restoration, Tree Planting, Streetscaping 28500 m2 $ 45 $ 1,282,500 Structural Culvert Extensions 1 L.S. $ 50,000 $ 50,000 Retaining walls/fences/miscellaneous 1 L.S. $ 200,000 $ 200,000 Electrical (Signals/Lighting) 1 L.S. $ 1,395,000 $ 1,395,000 Traffic Staging/Detouring 1 L.S. $ 330,000 $ 330,000 Pavement Markings/Signage 1 L.S. $ 160,000 $ 160,000 Miscelleanous/Minor Items (25%) 1 L.S. $ 3,884,081 $ 3,884,081 Retrofit Existing 407 and Highway 7 Structures for MUP Crossing 1 L.S. $ 3,500,000 $ 3,500,000 30% Contingency + 5% Construction Indexing $ 6,877,258 Total $ 29,797,666 Pricing for Items is Approximate

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-63 Environmental Study Report | WSP | MMM Group | August 2017

Table 6-13: Preliminary Cost Estimate for Bayview Avenue –Major Mackenzie Drive to Elgin Mills Road

Major Mackenzie Drive to Elgin Mills Road Station 18+180 to 20+200 2020 l.m. Item Description Quantity Unit Est. Unit Price Cost Removals (incl. ex curb & gutter, sidewalks, driveways etc) 2020 l.m. $ 200 $ 404,000 Earth excavation, disposal and boulevard grading 2020 l.m. $ 200 $ 404,000 Road Construction Subgrade preparation and sub drains 2020 l.m. $ 75 $ 151,500 Granular "A" 12705 t $ 25 $ 317,625 Granular "B" 53240 t $ 20 $ 1,064,800 Base Asphalt SP19.0 15300 t $ 100 $ 1,530,000 Surface Asphalt SP12.5 8100 t $ 115 $ 931,500 Concrete curb and gutter 4670 l.m. $ 100 $ 467,000 Concrete sidewalk (1.5m wide, west side only) 2020 l.m. $ 125 $ 252,500 Multi-Use Path (2.75m avg. width, east side only) 2020 l.m. $ 175 $ 353,500 Concrete ramps and driveway restoration 2020 l.m. $ 100 $ 202,000 Storm sewer including catchbasins 2020 l.m. $ 450 $ 909,000 Municipal Services (Sanitary, Watermain) 2020 l.m. $ 250 $ 505,000 Boulevard restoration, Tree Planting, Streetscaping 18200 m2 $ 45 $ 819,000 Structural Culvert Extensions 1 L.S. $ 150,000 $ 150,000 Retaining walls/fences/miscellaneous 1 L.S. $ 75,000 $ 75,000 Electrical (Signals/Lighting) 1 L.S. $ 900,000 $ 900,000 Traffic Staging/Detouring 1 L.S. $ 200,000 $ 200,000 Pavement Markings/Signage 1 L.S. $ 100,000 $ 100,000 Miscelleanous/Minor Items (20%) 1 L.S. $ 2,434,106 $ 2,434,106 30% Contingency + 5% Construction Indexing $ 2,922,140 Total $ 15,092,671 Pricing for Items is Approximate

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-64 Environmental Study Report | WSP | MMM Group | August 2017

6.10 PROPERTY REQUIREMENTS Significant efforts have been made during the Bayview Avenue Class EA to minimize property impacts, including:

 Minimizing the road cross-sections and associated rights-of-way to 36 m and 33.9 m (as discussed in Chapter 5);

 Recommending a flexible ‘best fit’ approach to road widening (as discussed in Chapter 5); and  Recommending design mitigation measures such as retaining walls to minimize the extent of grading in select locations, as depicted on the Preferred Plan. Retaining walls are proposed in the following locations in order to avoid / minimize property impacts:

 Station 10+560 to 10+680 (west side) at Cham Shan Temple;  Station 10+580 to 10+740 (east side) Don River valley;  Station 10+740 to 10+810 (west side) Don River valley;  Station 10+810 to 10+980 (east side ) residential properties on Prescott Court; reversed frontage to Bayview Ave;  Station 10+920 to 10+970 (west side) Temple Har Zion; and  Station 17+160 to 17+200 (west side) 9640 Bayview Avenue. Despite these measures to avoid property impacts, some sections of the Bayview Avenue corridor have very limited existing right-of-way and therefore some property will be required to accommodate the road widening.

The Preferred Plan will impact 30 private properties. Approximate property impacts are summarized in Table 6-14. The exact amount of property required at each property will be confirmed during detailed design. Impacts are limited to very minor edge encroachments. There are no direct impacts (i.e. displacement) to residences or commercial buildings. In some cases encroachment impacts will result in the removal of landscaped vegetation. Additional property will be required from lands approved for future development or currently being developed. It is assumed that, at these locations, the Region has acquired the road right-of-way per the Region’s Official Plan.

Easements will be required at approximately 8 other properties to accommodate grading or temporary construction works. The location and extent will be confirmed in detailed design.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-65 Environmental Study Report | WSP | MMM Group | August 2017

Table 6-14: Preliminary Property Requirements

Approximate Municipal Address / Location Property Requirement (ha) 1 7160 Bayview Avenue 0.013 ha 2 2 Steele Valley Road 0.029 ha 3 3 Steele Valley Road 0.03 ha 4 Cham Shan Temple (7254 Bayview Avenue) 0.014 ha 5 Temple Har Zion (7360 Bayview Avenue) 0.021 ha 6 Thornhill Community Centre and Thornhill Pumping Station 0.09 ha (5 John Street and 1 Green Lane) 7 Markham Fire Station (7801 Bayview Avenue) 0.031 ha 8 Condo complex (7825 Bayview Avenue) 0.041 ha 9 Thornlea Secondary School (8075 Bayview Avenue) 0.16 ha 10 Bayview Reservoir Park 0.156 ha 11 Toronto Montessori School (8569 Bayview Avenue) 0.019 ha 12 50 Robin Street 0.004 ha 13 Commercial plaza (9275 Bayview Avenue) 0.017 ha 14 9640 Bayview Avenue 0.003 ha 15 Richmond Hill Christian Community Church (9670 Bayview Avenue) 0.045 ha 16 9741 Bayview Avenue 0.01 ha 17 9785 Bayview Avenue 0.013 ha 18 9791 Bayview Avenue 0.012 ha 19 9860 Bayview Avenue 0.009 ha 20 9868 Bayview Avenue 0.005 ha 21 9874 Bayview Avenue 0.005 ha 22 9890 Bayview Avenue 0.005 ha 23 9900 Bayview Avenue 0.006 ha 24 9904 Bayview Avenue and 9912 Bayview Avenue 0.01 ha (same property) 25 Commercial plaza (northeast quadrant of Bayview Avenue / Major Mackenzie 0.034ha Drive, 1070 Bayview Avenue) 26 Bayview Secondary School (10077 Bayview Avenue) 0.085 ha 27 St. Paul Lutheran Church (10131 Bayview Avenue) 0.026 ha 28 TD Bank (10381 Bayview Avenue) 0.016 ha 29 Our Lady Queen of World Church (10411 Bayview Avenue) 0.044 ha 30 Jean Vanier Catholic High School (10475 Bayview Avenue) 0.068 ha

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-66 Environmental Study Report | WSP | MMM Group | August 2017

The Preferred Plan will result in the following changes to existing access:

 Accesses that will be closed are:

o South access at 8569 Bayview Avenue (Toronto Montessori School)

o South access at 8905 Bayview Avenue  Accesses that will change (i.e. by the introduction of a raised median) are as follows:

o The following will become right-in/right-out only: . 7160 Bayview Avenue . 7165 Bayview Avenue . 7175 Bayview Avenue . 7195 Bayview Avenue o Access to Steeles Valley Road will become right-in/right-out

o Access to Old Markham Road will become right-in/right-out

 Reconfiguration of parking areas will occur at:

o Thornhill Community Centre o Thornlea Secondary School o Bayview Secondary School

Possible changes to access of the underground parking area at the Cham Shan Temple (7254 Bayview Avenue) will be confirmed during detailed design.

6.11 Preferred Plan

The Preferred Plan is presented on the following plates.

Regional Municipality of York Bayview Avenue – Steeles Avenue to Elgin Mills Road 6-67 Environmental Study Report | WSP | MMM Group | August 2017