Bowmanville Marsh Habitat Restoration and Public Access Project

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1 Bowmanville Marsh Habitat Restoration and Public Access Project Terms of Reference for Detailed and Conceptual Design Works December 2015

2 1.0 Background and Purpose The Bowmanville Marsh Habitat Restoration Project focuses on improving the wetland conditions and habitat opportunities within the Bowmanville Marsh, a 33-hectare Provincially Significant Lake Ontario coastal wetland located in the Municipality of Clarington, and within the 66 ha Bowmanville/Westside Conservation Area that is owned and managed by CLOCA. 12 years of monitoring data collected through the Durham Region Coastal Wetland Monitoring Project (DRCWMP) has shown that Bowmanville Marsh is in a generally poor, declining condition. The ultimate goal of the Bowmanville Marsh Habitat Restoration Project is to significantly improve the wetland conditions in the marsh by isolating the marsh from the Bowmanville Creek and controlling water levels in the marsh in a way that better mimics natural pre-regulation Lake Ontario water level fluctuation. The installation of a berm and control structure along the mouth of the wetland will be required to achieve this goal. Water level control within the Marsh will allow for both periods of low water levels to stimulate wetland plant growth (for up to 1 year in length), and periods of high water level to limit plant growth (for up to 1 year in length). Bowmanville Marsh is partially separated from Bowmanville/Soper Creek along its eastern boundary by an earthen levee. Some of this levee has been naturally created by deposition from the adjacent creek over the last century, over the same period of time, dredged material from surrounding harbor activities has also been placed on the berm. At the north limit of the Marsh, flood water from the Bowmanville/Soper Creek periodically enters the Marsh during spring freshet or significant rain event floods. Beyond the occasional flow event into the north end of the Marsh, the wetland water level is controlled by the water level of the Bowmanville/Soper Creek at the Marsh outlet (southeast limit). The creek water level is directly linked to the water level of Lake Ontario. The goal of the public access component of this project is to incorporate low impact recreation features taking into consideration the Bowmanville Marsh Habitat Restoration Project staging and access requirements for construction equipment. 1

3 Several technical studies have been completed in support of this project and are listed below: Durham Region Coastal Wetland Monitoring Project: Wetland Conditions and Management Report (Module 16 is Bowmanville Marsh) prepared by CLOCA and Environment Canada dated December Bathymetry survey completed by Canadian Wildlife Services dated April Topographic Survey completed by CLOCA dated March Digital elevation model of topographic and bathymetry surveys prepared by CLOCA dated December Bowmanville Marsh Restoration Hydrological Study prepared by CLOCA dated March Bowmanville Marsh Restoration Water Level Monitoring Study prepared by CLOCA dated A Soil Investigation for Proposed Bowmanville Marsh Investigation prepared by Soil Engineers Ltd., Dated April The investigational geotechnical study outlines the borehole and soil sampling data collected along the existing levee and within proposed berm/control structure location. The purpose of this study is to generate a detailed design for the Bowmanville Marsh Restoration Project and a concept plan for the public access component. The detailed design will include a berm and water level control structure at the mouth of Bowmanville Marsh. The proposed berm and control structure should be designed to provide a range in marsh water levels. Another previous study investigated the potential range in water levels. The maximum proposed water level will be assumed to be no greater than 75.76, which is the maximum historical high water elevation of Lake Ontario (1952) and the minimum proposed water level will be below the normal creek water levels. Lowest possible water levels within the marsh are proposed approximately once every 10 years, for the equivalent of one full growing season. A secondary berm and control structure will be required at the north limit of the Marsh to control high flow inputs to the Marsh from the Bowmanville/Soper Creek. The proposed inlet structure at the north end of the Bowmanville Marsh should also be incorporated into the detailed design. The purpose of the public access conceptual plan is to connect the existing parking lot to the berm and control structure project with an accessible trail, naturalized planting, interpretive signage, fishing nodes, kayak and canoe access and an accessible portage feature. Figure 1 presents an aerial photo of the marsh and identifies key locations. 2

4 PUBLIC ACCESS

5 2.0 Study Approach The following outlines the two stage approach for the proposed restoration project: Stage 1: Detailed Design of Berm, Control Structure and Inlet Control Structure Detailed review of project background material. Site visit and project start-up meeting. Develop and present feasible design options to CLOCA and Municipality of Clarington Present design alternatives Complete detailed design of preferred design option. Finalize engineering drawings and report. Prepare construction cost estimate. Obtain approvals from applicable Municipal/Provincial/Federal Agencies. Stage 2: Conceptual Landscape Design Detailed review of project background material. Site visit and project start-up meeting. In consultation with CLOCA staff, prepare an analysis of the study area in its proposed form featuring existing infrastructure to guide the landscape design process. Develop the best options for public access based on hydrologic and hydraulic constraints; proposed berm location, bathymetry, terrestrial natural heritage data; fish data; and existing surrounding land use. Provide conceptual designs and mapping identifying public access opportunities for pedestrians, anglers, non-motorized recreational boating activities including launching and portaging, wildlife viewing and interpretation activities. Public safety design considerations. Signage and/or commemorative features to acknowledge project partners. Public Process CLOCA has included public consultation throughout the Management planning for the Bowmanville/Westside Marshes Conservation Area Master Plan, and Bowmanville Marsh Restoration Project. CLOCA will continue the commitment to public consultation through the design and development of this project. Public information sessions to showcase the design of restoration features will be arranged, financed, and managed by CLOCA. CLOCA will also work closely with staff from the Municipality of Clarington, to ensure the Restoration works compliment the municipal development of the Port Darlington waterfront parkland development. CLOCA reserves the right to administer this project in two (2) parts should they choose to do so. Please prepare the bid in two (2) parts to correspond to the above sections. 4

6 3.0 Deliverables Report submissions will be required through the study process as follows: Final Study Report with design drawings - 6 copies. The final report/drawings will also be made available to CLOCA in digital form (PDF). The consultant should also budget for a minimum of three (3) meetings with CLOCA to be held at project start-up, presentation of design alternatives, and completion of design. 4.0 Proposal Contents and Submission All proposals shall be evaluated based on the suggested methodology and work program, company experience, staffing experience, knowledge of the watershed, and cost. CLOCA reserves the right to reject any or all proposals should it be deemed in their best interest to do so. A complete proposal shall include the following information: I. A Work Plan including a brief description of the methodology should be provided. Any optional/additional work suggested in the interest of creating a better product should be identified and priced as a separate item. II. III. IV. Per Diem and Project Component Costs shall be provided as well as total costs (including GST) for all work required to complete the project Company Experience with soils analysis and borehole projects shall be identified. Please list recent similar projects and provide references. Similar information should be provided for any sub-consultants that are part of the study team. Key Staff Members that will lead the various components of the study shall be identified, and a summary of recent experience for each individual provided. Where subconsultants are proposed, list projects where the various study members worked together. The structure of the study team is to be clearly identified with one individual ultimately responsible for reporting to CLOCA. V. Any Potential Conflicts shall be listed including on-going work for development or personal interests within the area. Two copies of proposals are to be received by the Central Lake Ontario Conservation Authority by 2:00pm, January 18, Late submissions will not be accepted. 5