Director of Planning and Development Services. Manager of Planning. Kevin Tryon, CET Manager of Engineering Development Approvals

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1 TOWN OF AJAX REPORT REPORT TO: SUBMITTED BY: PREPARED BY: General Government Committee Paul Allore, MCIP, RPP Director of Planning and Development Services Gary Muller, MCIP, RPP Manager of Planning Kevin Tryon, CET Manager of Engineering Development Approvals SUBJECT: Carruthers Creek Watershed Environmental Assessment WARDS: 2, 4 DATE OF MEETING: April 22, 2010 REFERENCES: n/a RECOMMENDATIONS: 1. That staff be authorized to prepare and release a Request for Proposals to qualified consultants to undertake an Environmental Assessment of the Carruthers Creek watershed with specific emphasis on flood remediation solutions for the Pickering Beach Neighbourhood; 2. That staff be authorized to hold a public open house on May 6, 2010 in order to provide information regarding the Carruthers Creek floodplain and the proposed Environmental Assessment to the general public; 3. That staff be directed to report back with a recommended consultant, costs and the necessary timeframes to complete the study. BACKGROUND: The purpose of this report is to recommend the initiation of an Environmental Assessment process for the Carruthers Creek watershed, in order to respond to recently identified areas of flood risk near the mouth of the Carruthers Creek. The Carruthers Creek watershed crosses the City of Pickering and the and encompasses approximately 3,830 ha in land area, It is approximately 20 km long and 3 km at its widest point and according to MNR information, the Carruthers Creek watershed is approximately 9.8% forested. The Lake Iroquois Shoreline is located near the 5th Concession Road and cuts across the Ajax-Pickering border. Unlike many of the Lake Ontario watersheds, the headwaters of Carruthers Creek are not on the Oak Ridges Moraine but is rather on the Halton Till Plain north of Highway 7 (See Figure 1).

2 Subject: Carruthers Creek Watershed Environmental Assessment P a g e 2 Carruthers Creek Watershed Environmental Assessment Figure 1 Carruthers Creek Watershed Land Use Planning and Development Services Date: April 22, 2010

3 Subject: Carruthers Creek Watershed Environmental Assessment P a g e 3 Approximately two thirds of Carruthers Creek is considered coldwater fish habitat (the middle and upper reaches) with one third classified as warmwater. Water quality conditions are generally good in comparison to other watersheds in the TRCA jurisdiction. A number of significant Natural Heritage Features exist within the Carruthers Creek watershed including: the Carruthers Creek Wetland Complex (Provincially significant, composed of 8 individual wetlands); the Salem Road Wetland Complex (locally significant, composed of 2 widely separated wetlands); the Rossland Road Wetland Complex (locally significant, composed of 3 individual wetlands); Carruthers Creek Forest (ESA No. 113) supports a mature forested stand of White Ash, Red Ash, Eastern White Cedar and Eastern Hemlock, that supports a high diversity of avian as well as flora species. Significant flooding along the Carruthers Creek watershed has been a rare event over the last century, with no recorded information available on flooding within the basin. Severe tropical storms, such as Hurricane Hazel in October of 1954, and heavy thunderstorms continue to be a threat to southern Ontario. Therefore, flood protection along the watercourse is a necessity to ensure that no new flood prone urban development takes place. Floodplain mapping along with hydrologic and hydraulic studies for the Carruthers Creek were originally completed in 1986, with the watershed hydrology and hydraulics recently updated in The Toronto and Region Conservation Authority (TRCA) has recently undertaken a comprehensive process to revise its floodplain mapping along a number of creek systems across its jurisdiction. Within Ajax, the TRCA has provided updated flood plain mapping for both the Duffins and Carruthers Creek watersheds as a component of TRCA s ongoing work to identify and protect flood vulnerable areas. This exercise is based on updated mapping and modeling techniques governed through the Ontario Ministry of Natural Resources. Description of Revised Maps There are three areas within Ajax which have been affected by the revised mapping (see Figure 2): Along the Duffins Creek, flooding concerns exist related to the Regional storm events (Hurricane Hazel), rain or snow events and ice jamming; Along the Millers Creek, immediately upstream of Highway 401, concerns are related to summer thunder storms, as well as tropical storms; Along the Carruthers Creek at Pickering Beach, flooding concerns exist related to Regional storm events (Hurricane Hazel), and rain or snow events (coinciding with spring thaws).

4 Subject: Carruthers Creek Watershed Environmental Assessment P a g e 4 Carruthers Creek Watershed Environmental Assessment Figure 2 Flood Vulnerable Areas Within Ajax Planning and Development Services Date: April 22, 2010

5 Subject: Carruthers Creek Watershed Environmental Assessment P a g e 5 This report focuses on the Carruthers Creek watershed, since it is within this area that changes in the flood plain mapping are most pronounced. Policy Context The Provincial Policy Statement (PPS) was issued under Section 3 of the Planning Act and came into effect March 1, The PPS focuses growth within settlement areas and away from significant or sensitive resources and areas which may pose a risk to public health and safety. The PPS provides policy direction on matters of provincial interest related to land use planning and development and sets the policy foundation for regulating the development and use of land. Section of the PPS directs that Development and site alteration shall not be permitted within areas that would be rendered inaccessible to people and vehicles during times of flooding hazards, erosion hazards and/or dynamic beach hazards, unless it has been demonstrated that the site has safe access appropriate for the nature of the development and the natural hazard. Development is prohibited in a floodway regardless of whether the area of inundation contains high points of land not subject to flooding. Section of the Durham Regional Official Plan indicates that the creation of a lot on land susceptible to flooding, erosion or any other physical or environmental constraint will be discouraged unless it can be clearly established that the proposed use does not adversely impact such constraints, in accordance with Policy Section of the Official Plan deals with the Protection of Lake Ontario and Water Resources and recognizes that land use planning and human activities have a direct impact on water quality that, in turn, affects the ecosystem, human health, the local economy and ultimately the quality of life in the Town. It indicates that it shall be the policy of the Town to protect surface water, the function of sensitive groundwater recharge and discharge areas, aquifers, headwaters and Lake Ontario, which is the source of the Town s drinking water. It indicates that stormwater quality and erosion control measures will be undertaken for all public and private development activities to protect Lake Ontario and valued surface water and groundwater resources. It also affirms that Ajax endorses watershed and sub-watershed planning studies to inform decision making concerning matters affecting vital water resources that sustain life. Rationale for Changes to the Floodline In early 2010, the was provided with updated floodplain mapping for Carruthers Creek, based on a Regional Storm event (i.e., Hurricane Hazel), prepared by the Toronto and Region Conservation Authority (TRCA) and R.J. Burnside & Associates Limited. The new flood lines are based upon updated topography, hydraulic modeling and hydrologic modeling. The Carruthers maps were approved in 2007 with 2002 to 2005 era topographic base maps. The Ministry of Natural Resources provides the basic technical framework for the flood plain mapping including the requirement that mapping be prepared to the Hurricane Hazel storm (Regional Storm) level.

6 Subject: Carruthers Creek Watershed Environmental Assessment P a g e 6 Carruthers Creek Watershed Environmental Assessment Figure 3 Comparison of TRCA Regulatory Flood Plains 1986, 2007, 2009 Planning and Development Services Date: April 22, 2010

7 Subject: Carruthers Creek Watershed Environmental Assessment P a g e 7 The updated mapping redefines the depth and extent of flood waters for the creek, the effects of which are most pronounced in the lower reaches of the watershed. Notably, a Spill Area has now been identified extending from the main Carruthers Creek channel upstream of Shoal Point Road bridge through a significant portion of the Pickering Beach neighbourhood south of Seabreeze Road to Lake Ontario. A flood spill area at Seabreeze Road is due to the low topography in the area relative to Carruthers Creek, and a change in the hydraulic characteristics of the valley (see Figure 3). Implications for Changes to the Floodline It should be emphasized that the changes to the Floodline reflect the low risk of severe flooding associated with a Regional (Hurricane Hazel) event directly over the watershed. As a result of the change to the Regional Floodline, work on private property will now be subject to detailed review by the Toronto and Region Conservation Authority which was not previously the case. For example, basement apartments, expansions to buildings, new garages and decks will now be subject to review within this area with the possibility that such work may not be permitted depending on the circumstances of the site. New dwellings on vacant land and land severances will not be permitted. Through the Official Plan Review, staff will be suggesting that a Special Study Area be established for the lower Caruthers Creek area to recognize the new floodline and the Town s commitment to arrive at solutions to mitigate flood risk in this area. Pickering Beach Land Severance The effects of this exercise became apparent through a recent land severance proposal in the Pickering Beach neighbourhood. Lynda and Gordon Everson recently applied to Durham Region Land Division Committee to sever their property at 2964 Seabreeze Road. Through its consideration of the application, the Toronto and Region Conservation Authority indicated that the entire property is within the Regional Storm Floodplain associated with Carruthers Creek. Given this situation, the TRCA evaluated the application against the applicable floodplain policies. The TRCA indicated that the flooding is caused by a combination of a back water effect from the Shoal Point Road bridge across the Carruthers Creek along with relatively flat and low topography in the area related to the creek. They noted that there was not any apparent safe ingress or egress from the area in the event of a Regional Storm, and that these conditions pose a risk to human safety and property pursuant to standards established by the Ontario Ministry of Natural Resources. As a result of these factors, the proposed severance was opposed by both the TRCA and the Town. The TRCA proceeded to further evaluate the spillway and established the new flood area as shown on Figure 3. The owners later appealed their applications to the Ontario Municipal Board, but subsequently withdrew prior to the scheduled Hearing.

8 Subject: Carruthers Creek Watershed Environmental Assessment P a g e 8 Carruthers Creek Watershed Environmental Assessment Date: April 22, 2010 Figure 4 Timeframe of Subdivision Approvals Lower Carruthers Watershed Planning and Development Services

9 Subject: Carruthers Creek Watershed Environmental Assessment P a g e 9 Previous Studies The control of stormwater runoff is usually defined through watershed or subwatershed studies and applies to all development proposals. Management criteria and performance targets are informed by comprehensive modeling studies. Factors affecting stormwater control criteria include land use designations, flood vulnerable areas, erosion sites and environmental factors (i.e. baseflow, groundwater resources, terrestrial and aquatic habitat). The Carruthers Creek Watershed was the subject of past technical studies which will be reviewed as part of this exercise, including the following: Carruthers Creek Master Drainage Plan, Final Report. Totten Sims Hubicki Associates, June, Revised September, Carruthers Creek Stormwater Management Study, Final Report. Totten Sims Hubicki Associates. June, Carruthers Creek Stormwater Management Study, Synopsis Report. Totten Sims Hubicki Associates. November, Carruthers Creek Stormwater Management Strategy, Addendum No. 1. Carruthers Creek Modeling Review. Totten Sims Hubicki Associates. August, Stormwater Management Study, A8 Secondary Plan, Cosburn Patterson Mather. May, Individual Studies and reports filed in support of development applications within the subwatershed. Impacts of Increased Urban Runoff The effects of urbanization on the drainage characteristics of watercourses are well documented, including the hydrologic, physical and ecological impacts that result from the process of urban development. As natural landscapes are modified and paved to accommodate residential, industrial or commercial development, the health of the local ecosystem tends to decline, although current stormwater management practices are designed to mitigate these impacts. The urbanization process increases the amount of urban impervious surfaces which prevent water from infiltrating into the soil. Impervious surfaces include roads, sidewalks, driveways, rooftops, and parking lots. Associated with an increase in impervious cover is an increase in runoff volume and velocity and a decline in infiltration potential. These changes, in turn, lead to increases in stream erosion and a reduction in groundwater recharge and annual baseflow within local water courses. Changes to the hydrologic regime ultimately impact the physical state of the watercourse. As the energy within the system increases, given the higher velocities and volumes of flow, the natural rates of erosion and sedimentation also increase, resulting in a loss of riparian vegetation and in stream habitat, an increase in water temperature and a change in channel characteristics.

10 Subject: Carruthers Creek Watershed Environmental Assessment P a g e 10 Carruthers Creek Watershed Environmental Assessment Figure 5 Northeast Pickering Urban Area in Proposed ROPA 128 in the context of the Carruthers Watershed Planning and Development Services Date: April 22, 2010

11 Subject: Carruthers Creek Watershed Environmental Assessment P a g e 11 This is one issue that the Town raised as an important component in its objection to the proposed urbanization of Northeast Pickering proposed within Durham Region Official Plan Amendment No. 128 (see Figure 5). Due to its small size, the Carruthers watershed does not have the same capacity to assimilate downstream impacts from land use change as larger watersheds such as the Rouge River, Duffins Creek or Lynde Creek. Although ROPA 128 includes policies to undertake the preparation of a watershed plan as a requirement of local planning approvals, such planning would by necessity need to accept the principle of urban development as a base case. In staff s view, the evaluation of the principle of new urban development beyond existing urban area boundaries should not have been undertaken without a watershed study being done in the first instance. The Ministry of Municipal Affairs and Housing, in its March 12, 2010 draft Decision to the Region of Durham on ROPA 128, advised that amongst other matters it proposes to delete the proposed Northeast Pickering Urban Area from ROPA 128. Staff s comments on this and other components of the Draft Decision will be reported on under separate cover. Although the Ministry s Decision has not been finalized, it remains prudent to understand the long term implications on the watershed related to the potential urbanization of this area, and its impacts on Ajax should be included as part of this exercise. Proposed Environmental Assessment This project is being proposed as an Environmental Assessment (EA) which would: review and update the hydrology for the watershed as required; identify potential risks to the hydrology for the watershed including approved urban areas and the long term potential for urbanization in the Carruthers Headwaters; identify options to mitigate the downstream flood risks based on existing, approved and potential urban developments within the watershed; identify solution(s) to mitigate/remediate the risk of flooding within the watershed, and in particular, the Flood Remediation Area. Staff suggest investigating a Flood Remediation Area bounded by Audley Road to the east, Bayly Street to the north, Pickering Beach Road to the west and Lake Ontario to the south. The proposed Environmental Assessment should recommend flood solutions that could include: Physical modifications and improvements to existing facilities, structures and stream channels, including those within or near the Flood Remediation Area; New facilities, structures and modifications for managing the Regional Storm event; and Recommendations regarding the downstream impacts of introducing the principle of new urban development within the Carruthers Headwaters; Operational or structural improvements. The EA will develop a hydrologic model for both existing Official Plan condition (based on the existing Region of Durham, City of Pickering and Official Plans) and the potential

12 Subject: Carruthers Creek Watershed Environmental Assessment P a g e 12 future watershed development as set out in Durham Region s adopted ROPA 128 land use scenarios for the watershed. The model will reflect future development, approved stormwater management plans including, as a minimum, additional stormwater management facilities. The proposed terms of reference are provided within Attachment 1. FINANCIAL IMPLICATIONS: The proposed Environmental Assessment would be an unbudgeted capital project. Should this report be endorsed, the financial implications of the project, including costs and funding sources will be presented when the contract award is presented at a future meeting of General Government Committee. At his point, the cost of the proposed Environmental Assessment is very difficult to estimate, however based on other EA s undertaken in the Town, the cost could be in the range of $300,000 to $400,000. Firm estimates will be provided upon receipt of proposals. The funding for this project will come from the General Levy. If required, funds will be transferred at year end from the Working Funds Reserve. COMMUNICATION ISSUES: A Public Open House has been scheduled for May 6, 2010 at 7:00 pm in the Ajax Council Chambers to present this issue and to outline the proposed process. The Public Notification letter for this Open House is provided within Attachment 2. Through the Environmental Assessment Process, Public Information Centres (PICs) will be offered to allow an opportunity to comment on Solutions. Other approaches including newsletters and the Town s website, will also be be used to inform the public as well as update presentations to Council and the Town s Environmental Advisory Committee. These details will be established should a contract be awarded for this project. CONCLUSION: Effective storm water management criteria is one of the important management initiatives currently being practiced in the watershed. The science of stormwater management is continually evolving and it is essential that watershed managers continue to demand the highest level of available technology and encourage the use of innovative design techniques. Staff are of the view that the initiation of an Environmental Assessment process is a prudent approach that will include mitigation approaches for flood risk in the lower Carruthers watershed. Gary Muller, MCIP, RPP Manager of Planning Kevin Tryon, CET Manager of Engineering Development Approvals Attachments: 1. Draft Terms of Reference for Environmental Assessment 2. Public Notification Letter for May 6, 2010 Open House Paul Allore, MCIP, RPP Director of Planning and Development Services