DEVELOPMENT SERVICES COMMITTEE
	TO:	Mayor and Members of Council
	FROM:	Alan Brown, Director of Engineering
	PREPARED BY:	same as above
	DATE OF MEETING:	September 21, 2004
	SUBJECT:	Pomona Mills Creek (Don River) Implementation Plan

RECOMMENDATION:

That the Engineering Department report entitled “Pomona Mills Creek (Don River) Implementation Plan” be received;

And that the Terms of Reference for a Task Force for the Pomona Mills Creek (Don River) Implementation Plan be endorsed;

And that the Director of Engineering be authorized to retain a consulting engineer to assist in the project management of the proposed implementation plan to an upset limit of $25,000;

And that such costs be funded from Account # 083 5350 4726 005

And that staff report back to Committee with updates as the work of the Task Force progresses.

And that the TRCA and Don Watershed Council be advised accordingly.

PURPOSE:

The purpose of this report is to provide an inventory of issues and priorities in the immediate vicinity of the Pomona Creek within the Town of Markham which are of concern to local communities, stakeholders (Don Watershed Council), the Toronto and Region Conservation Authority (TRCA) and the Town. In particular, the report focuses on issues identified in and near Pomona Creek, including discussions with the TRCA, the Toronto Ladies Golf Club (TLGC) and other stakeholders. Other areas of concern within the Don watershed in Markham may still be identified during the implementation plan and these may be raised and dealt through future plan updates in a later stage.

BACKGROUND:

The Don watershed within the Town of Markham is located between Yonge Street to the west, Woodbine to the east, Steeles to the south and Highway 7 to the north (See Figure 1). The watershed is located in the southwest corner of the Town and includes the lower portions of Upper East Don and German Mills Creek sub-watersheds which are mostly developed.

Pomona Creek is a tributary of the Don River which starts in Richmond Hill, west of Yonge Street. The streams flows southward across highway 407, across the Beaver Valley Stone property and into the Holy Cross Cemetery before reaching Kirk Drive and later Royal Orchard Park and Royal Orchard Boulevard.

The Don Watershed Planning document “Forty Steps to a New Don, 1994” identified the Don River as one of the most degraded urban rivers in the GTA and recommended a number of strategies to revitalize and regenerate the Don watershed. The future Don is envisioned as a revitalized urban river, flowing with life-sustaining water through regenerated natural habitats and human communities¹. The document emphasizes three general principles:

• Protect what is healthy
• Regenerate what is degraded
• Take responsibility for the Don

As a partner to the Don Watershed Council, the Town is committed to protect and regenerate Pomona Creek within the Don River watershed in Markham.

APPROACH

A number of important environmental issues that are in need of short and long term attention are identified through examination of prior studies, TRCA’s priorities, local community complaints and preliminary field assessment. They include:

• Fish barrier mitigation
• Stream bank erosion control
• Retrofit of Glynnwood pond and mitigation of Glynnwood Storm sewer surcharge
• Toronto Ladies Golf Course (TLGC) water management
• Implementation of recreational trail link
• Water quality of Don during wet-weather events
• Impacts of upstream developments in Richmond Hill

These issues with Pomona Creek can be grouped into three categories: typical issues of the Don watershed, local watershed issues within Pomona Creek and future development issues. Some of the issues such as fish barrier mitigation, stream bank erosion and water quality, are typical problems of the Don River. Other issues such as TLGC water management and Glynnwood site problems are local sub-watershed issues. As developments are proposed in the headwaters of the Don, the impact from the developments on the water quantity, quality and erosion needs to be evaluated.

In order to address all these environmental issues and verify the issues and priorities, a detailed Management Plan will be required. The Plan should adopt an integrated approach which includes the involvement of the TRCA, stakeholders, community interest group, staff and Council. The plan should provide management guidelines to improve water quality in the Don, environmental amenity and ecological integrity commensurate with the overall Don Watershed Regeneration Plan. Prior to the development of the management plan, some of the issues need to be further investigated to ensure the watershed’s long-term health and sustainability.

The implementation of the management plan will commence following approval by Markham Council in consultation with any community group and/or stakeholders who express interest in the plan, and subject to funding availability.

_______________________________

¹Executive Summary, Forty Steps to a New Don, TRCA

The TRCA, Don Watershed Council, MOE and community consultation will occur during the development of this plan to ensure that all community and landowner’s values are adequately considered in the long-term management objectives of the Don watershed within the Town. The implementation of this management plan and major works scheduled for the Don will occur in stages and in accordance with priority rating and fund availability.

A conceptual structure of the management plan is outlined in Figure 2 and illustrates the key steps and issues.

*TLGC: Toronto Ladies Golf Course

Figure 2: Town of Markham Don Watershed Management Plan Structure

DON RIVER ISSUES

Fish Barrier Mitigation

A number of weir structures are located in Pomona Creek within the Town boundaries. These structures have been acting as barriers to movement of fish and other animal and plant life of the region and also interfere with the normal transport of stream substrate. Figure 3 illustrates a fish barrier. Barriers to fish movement have been a problem in the Don River watershed for many years and will continue to be a problem in the future unless steps are taken to mitigate the impacts of existing barriers. Many in-stream barriers were identified through a limited field survey and approximately 12 in-stream weir structures are located in the Pomona Creek.

Figure 3: Typical Fish Barrier

The Forty Steps to a New Don recommends that the fish barriers within the Don should be replaced with fish friendly alternatives. As an example of barrier rehabilitation, the weir structure at Lawrence Avenue was modified in 1999 by reshaping the grade of the river. The weir is now fish passable. Similar modifications to weirs upstream will allow salmon to access the northern reaches of the East Don River in the Oak Ridges Moraine.

Prior to the development of the fish barrier mitigation strategy, an inventory of barriers within the Don is required. This was recommended by TRCA during the preliminary field assessment visit. The inventory would include spatial and topographic survey of each structure including relevant details, and upstream and downstream conditions. Such an assessment would be helpful in determining the cost and re-grading of the river during the development of management plan.

Stream Bank Erosion Control and Retaining wall/Culvert Rehabilitation

The preliminary field survey identified a number of eroding bank conditions along Pomona Creek (See Figure 4). In some stretches, erosion is significant, which poses risks to the existing culvers and the recreational trail. As part of the update of the Development Charges By-law (2004) an update of the background study for erosion works was completed. It outlined areas of the Don River which require stabilization. An implementation plan to prioritize the stabilization of watercourses in Markham is to be undertaken starting this fall and will be a factor in the implementation plan for the Don River and Pomona Creek. In some locations, gabion baskets are either displaced or in a poor condition. Figure 5 illustrates a retaining wall failure which could negatively impact the adjacent culvert structure.

Figure 4: Stream Bank Erosion

Figure 5: Retaining Wall Failure and Culvert Obstruction

Retrofit of Glynnwood Pond and Mitigation of Storm Sewer Surcharges

The Glynnwood pond is located near the northwest corner of John Street and Bayview Avenue. The pond is on lands owned by Shouldice Hospital and the Glynnwood senior citizen’s residence. Although the pond is privately owned, it receives runoff and sediments from a 60-hectare tributary area predominantly to the north and east of the pond, including private properties and public right-of-ways. In this regards, the Town completed a comprehensive drainage area and pond assessment and developed a plan to conduct sediment removal maintenance and shore erosion. In addition, a plan to alleviate the frequent sewer surcharge and flooding under the Glynnwood building was developed by the Town. This plan should be implemented in the near-term subject to negotiation with interested parties as to funding and future maintenance and liability obligations. The watercourse downstream of this storm sewer and Glynnwood pond is also experiencing accelerated erosion rates and should be stabilized with erosion control measures.

Toronto Ladies Golf Course Water Management

The Toronto Ladies Golf Course (TLGC) is located south of Royal Orchard Drive between Yonge Street and Bayview Avenue. Recently, the TLGC informed the Town that they are searching for irrigation water sources and are interested in working with the Town to find a viable solution. In addition, they are interested in evaluating the opportunity for establishing a north-south Town recreational trail link through the golf course alongside the Pomona Creek.

There may be opportunities to divert stormwater runoff from adjacent urban areas into TLGC from the Bayview storm sewer which otherwise outlets to the Glynnwood Pond. The runoff can be conveyed and stored within the TLGC property as an irrigation source. However, this alternative will require thorough analysis to assess grading, water quality, and funding perspectives.

Implementation of Recreational Trail Link

The Don River has been well used and appreciated by local residents as it enhances the community’s quality of life. The popular activities in the Don include walking and bird watching/nature appreciation. The Forty Steps to a New Don recommends that recreational trials should be constructed as a public access to the River. The recreational trail link that exists between Kirk Drive and Royal Orchard Boulevard can be extended south of Royal Orchard Boulevard through Ladies Golf Course. Prior to the planning of trail however, landowner assessment, and trail alignment design is required.

Water Quality

One of the main sources of water pollution in Pomona Creek and the Don within the Town is urban runoff. The quality of water within the Town depends on the upstream conditions and on the quality of runoff discharged. The preliminary visit identified potential locations for pond retrofit not previously identified as well as the need to further assess, through an inventory of storm sewer outlets, other locations. Furthermore, a drainage area assessment should be undertaken to assess runoff quantity and quality from the contributing watershed for input into the watershed regeneration plan.

Impacts from Upstream Development

The northern portions of Upper East Don and German Mills Creek sub-watersheds are not fully developed and the development is in progress. The impacts of these upstream developments on the Don should be assessed for existing and future conditions. Baseline water quality sampling and baseline flow monitoring can be considered and prioritized to assess future changes caused by development upstream.

PRELIMINARY PRIORITIZATION OF ISSUES

The following table has been prepared as a preliminary prioritization of issues that will be included in the Town of Markham Pomona Implementation Plan. A set of preliminary tasks are included for each of the issues.

Table 1: Prioritization of Issues

ISSUES and Objectives	Tasks	PRELIMINARY PRIORITY
Fish Barrier Mitigation	· Inventory of fish barriers · Conduct survey of barriers · Develop suitable fish friendly alternatives to barriers · Replace barriers and implement best alternative	High
Stream Bank Erosion Control	· Conduct survey to define stretches that need erosion control · Develop alternative erosion control measures · Stabilize retaining wall that need attention · Rehabilitate culverts	High
Cleaning Glynnwood Pond and Mitigation of Sewer Surcharge at Glynnwood site	· Removal of accumulated sediments · Replace gabion retaining wall at the forebay · Stabilize eroded banks · Investigate contributing drainage areas · Installation of inlet control devices in storm sewer serviced areas · Stabilization of outlet channel between pond and Don river	High
Toronto Ladies Golf Course Water Management	· Assess demand · Develop water source alternatives · Plan recreational link within the golf course	High
Implementation of Recreational Trail Link	· Assess implementation of recreational trail · Land owners assessment · Assess alternative routes	Moderate
Water Quality	· Create inventory of the storm sewer outlets · Assess potential pond retrofit locations · Evaluate stormwater management within the watershed · Evaluate downspout disconnection · Monitor water quality · Analyze runoff quality and quality	Moderate
Impact of Upstream Developments	· Assess upstream development conditions · Monitor base condition of river at the boundary of Richmond Hill and Town of Markham	Moderate

NEXT STEPS

As the above issues relate to Development Services and Community Services Commissions, external agencies (TRCA, MNR), property owners (Ladies Golf Club, Shouldice Hospital, Glynnwood Retirement Residence, etc.) and interest groups (Don Watershed Council)/property owners, it is recommended that a task group be established to assist Council in implementing the proposed tasks.

Terms of Reference for the task force and suggestions for its membership are enclosed as Attachment ‘A’.

FINANCIAL CONSIDERATIONS:

Subject to the recommendations of the task force funding requirements, possible funding sources and partners will be identified in subsequent reports to Council. In order to undertake the implementation plan, staff will require assistance from consulting engineers. Staff recommends that a consultant be retained at an upset limit of $25,000 to be funded from the Engineering Department Capital Account 083 5350 4726 005.

Subsequent reports will be submitted to Committee and Council outlining additional funding requirements for the implementation plan.

ATTACHMENTS:

Attachment A – Terms of Reference

Q:\Development\Engineering\REPORTS\2004\September\Don River Implementation Plan 090904 #2.doc

Alan Brown, C.E.T. Director of Engineering

Jim Baird, M.C.I.P., R.P.P. Commissioner of Development Services