Pilot Treatment Wetland in Lower Duck Pond, High Park -

Progress Report and Award of Phase II (Ward 19 - High Park)

The Works and Utilities Committee recommends the adoption of the report dated January6, 1999, from the Commissioner of Works and Emergency Services.

The Works and Utilities Committee reports, for the information of Council, having referred the report to the Storm Water Group for information, and having requested the Committee Administrator to include this group on the mailing list for storm water issues.

The Works and Utilities Committee submits the following report (January 6, 1999) from the Commissioner of Works and Emergency Services:

Purpose:

To provide, for information purposes, a progress report on Phase I of the proposed Pilot Treatment Wetland in Lower Duck Pond, High Park.

Furthermore, to obtain authorization to award the implementation of the Pilot Treatment Wetland (Phase II) in accordance with the Terms of Reference and the scope of work described in the agreement, dated September26, 1997, between CH2M Gore & Storrie Limited and the City of Toronto, and including additional work as described in the body of this report.

Funding Sources, Financial Implications and Impact Statement:

Funding for this project has been included in the 1999 Capital Budget Submission and $500,000.00 of this is in the Interim Funding Request, which was approved by Council on December 16 and 17, 1998. The funding is available in Account No. WP953.

Recommendations:

It is recommended that:

(1)the progress report for Phase I of the Pilot Treatment Wetland project for the Lower Duck Pond in High Park be received for information;

(2)(a)approval be given to increase the contract price for Phase II of the Pilot Treatment Wetland by $75,100.00 from $282,011.34 to $357,111.34 including G.S.T. to cover additional construction costs related to unstable sediment deposits discovered at the bottom of the Lower Duck Pond in the course of the Phase I study work and additional cost related to site supervision and waterfowl control which were not included in the original scope of work; and

(b)approval be given to award Phase II of the Pilot Treatment Wetland in Lower Duck Pond (High Park), for a total price not to exceed $357,111.34 to CH2M Gore & Storrie Limited in accordance with the terms and conditions and the scope of work of the agreement dated September 26, 1997, between CH2M Gore & Storrie Limited and the City of Toronto and including the additional work described below; and

(3)the appropriate City officials be authorized and directed to take the necessary action to give effect thereto including preparation and execution of the necessary PhaseII agreement with CH2M Gore & Storrie Limited on terms and conditions satisfactory to the City Solicitor and the Commissioner of Works and Emergency Services.

Background/History:

The Lower Duck Pond is located in the south-east corner of High Park. The main source of storm water to the pond is from the Spring Creek watercourse, which runs along the east side of High Park and is fed from two large storm outlets in the north-east corner of High Park and draining a large drainage area north of Bloor Street.

The pond suffers from poor water quality due to the runoff pollutants from Spring Creek. Furthermore, the pond's water quality is adversely impacted by many geese and ducks which inhabit the pond and surrounding lands.

In 1997, Terms of Reference for a Request for Proposal were issued by the former City of Toronto for the design and implementation of a biological treatment facility to improve the quality of water in the Lower Duck Pond. The proponents were asked to submit proposals based on a two-phase design/build process, with PhaseI providing for the development of a conceptual design and consultation with the public and other stakeholders, and Phase II providing the detailed design, construction and installation of a biological treatment system. Five firms submitted proposals and after detailed evaluations, the proposal submitted by the team headed by CH2M Gore & Storrie Limited for a Natural Treatment Wetland was determined by the Review Committee as the overall best proposal meeting the pre-determined criteria.

The Board of Management of the former City of Toronto at its meeting no. 1997-38 starting on September25, 1997 (Minute No. 2.15), in considering the report from the City Engineer, entitled "Water Quality Improvement Project Utilizing Biological Processes ("Living Machines") for the Lower Duck Pond in High Park - Phase I", authorized the engagement of CH2M Gore & Storrie Limited for Phase I of the project for a cost of $69,754.37 including G.S.T.

Subsequently, the City entered into an agreement with CH2M Gore & Storrie Limited (dated September 26, 1997) for carrying out Phase I of the project. Under the terms of the agreement, the City has the option, upon completion of Phase I, to award Phase II to CH2M Gore & Storrie Limited at a contract price of $282,011.34 including G.S.T.

Comments and/or Discussion and/or Justification:

1.Phase I - Progress Report:

1.1Preferred Treatment Wetland Alternative:

Phase I consists of the development of the conceptual design for the design/build of a Pilot Treatment Wetland to be located in the Lower Duck Pond in High Park. The purpose of the Pilot Treatment Wetland is to improve the water quality in the Lower Duck Pond by utilizing biological treatment processes.

CH2M Gore & Storrie Limited commenced work on the development of a conceptual design in January 1998. The project followed the Class Environmental Assessment for Municipal Water and Wastewater (Schedule B) planning and design process.

There are different types of Engineered Wetlands, e.g.:

-Natural Wetlands;

-Surface Flow Constructed Wetlands;

-Sub-Surface Flow Constructed Wetlands; and

-Floating Aquatic Plant Systems.

Based on an evaluation of the advantages and disadvantages of the various types, it is recommended to construct a Surface Flow Wetland because it is best suited for the southern Ontario climate and will tolerate hydraulic loading fluctuations. The constructed wetland will be located at the inflow of Spring Creek into Lower Duck Pond and will take approximately 15 percent (0.25 ha) of the Lower Duck Pond area.

Various native plant species such as bulrush will be planted in the wetland, and the base flow from Spring Creek will be diverted permanently into the wetland. Increased flows from Spring Creek during rain events will be partly diverted into the wetland and partly bypass the wetland depending on the flow rate. The splitting of the inflow rate will be determined during initial operation of the wetland to ensure maximum efficiency.

Water sampling carried out over a two-year period has determined that the pond water and sediment contain high levels of suspended solids, various contaminants and E-coli bacteria. The proposed wetland will reduce sediment, contaminant and E-Coli levels. The wetland will also provide wild life habitat.

Furthermore, the wetland will determine the feasibility and effectiveness of a Surface Flow Constructed Wetland for the treatment of storm water. Its location, adjacent to park pathways, will also allow for public viewing and it is proposed to install viewing points and information panels for the public.

The wetland will also provide research potential for school and university students.

1.2Public Consultation:

A Notice of Intent was published in the Toronto Star on January 27, 1998, to inform the public of the start of this project. In March 1998, a newsletter on the project was sent out to various review agencies, local interest groups and interested individuals. This was followed by the first public open house at the Keele Recreational Centre on March 5, 1998, to describe to the public the water quality problem of the pond and to present alternative improvement solutions. Comments from the public were very supportive of the project. A public tour to view the site was held on April 18, 1998. A second newsletter was sent out in May 1998, followed by the second public open house, on May 27, 1998, to present a recommended wetland design. Again, comments from the public were supportive for the construction of a treatment wetland.

Subsequently, the consultant completed an assessment screening report detailing the process, the findings and the preferred treatment wetland alternative. This report was reviewed by City staff and filed for a 30-day public review period, as set out by a Notice of Completion published in the Toronto Star on July 7 and 8, 1998.

Only one government agency responded to the Notice - no further comments from the public were received.

1.3Bottom Sediment in Lower Duck Pond:

During the Phase I study work, it was discovered that there is layer of unstable sediment approximately 1.0 metre thick at the bottom of the Lower Duck Pond . It appears that the sediment primarily originates from erosion occurring in Spring Creek and from suspended solids carried by storm water runoff which has settled out in the pond over the years. This layer of sediment is substantially deeper than anticipated prior to the proposal call and increases the construction cost of the pilot treatment wetlands described under item 2 below.

With respect to the erosion problem along Spring Creek, it is noted that in recent years the Works and Emergency Services Department, in cooperation with the Parks Department, has carried out improvements to Spring Creek to alleviate the erosion problem. It is intended that inspections of the creek bed be carried out yearly to address further erosion problems as early as possible.

With respect to the sediment carried by storm water, it should be noted that there are two small sedimentation ponds upstream of Spring Creek at the north-east corner of High Park. The purpose of these ponds is to allow suspended solids carried by the storm water runoff from the two storm sewers discharging into Spring Creek at that location to settle out. Sediment deposits in these ponds are periodically removed by the Works and Emergency Services Department. However, these ponds are not very effective because they are too small and because of their geometric configuration. A Class Environmental Assessment Study (Schedule B) is being carried out concurrently with the study work for Lower Duck Pond to develop improvements to the two sedimentation ponds, and we expect to report on the results of the study and the preferred improvement solution in the spring of 1999. Once the effectiveness of the two sedimentation ponds has been improved, the amount of sediment from storm water runoff entering Spring Creek and Lower Duck Pond will be substantially reduced.

1.4Phase I - Conclusions:

Based on the results of the review process and the response received during the public consultation process, it can be concluded that the project has the support of the public.

Therefore, in consideration of the poor water quality condition of the existing pond and the improvements and benefits which can be achieved by implementing the preferred scheme, it is proposed that the proposed treatment wetland as described above be implemented.

2.Scope of Work and Phase II Award:

Phase II of the project consists of the detailed design, construction and installation of the natural treatment wetland proposed under Phase I for the improvement of water quality utilizing biological processes for the Lower Duck Pond in High Park. In accordance with the agreement for Phase I, the proponent, CH2M Gore & Storrie Limited, agreed to enter into an agreement for Phase II implementation of the work at a total project cost of $282,011.34 including G.S.T. As indicated above, it was discovered during Phase I that there is an unstable sediment deposit approximately 1.0 metre thick at the bottom of the existing pond. The proposal received was based on sediment deposits being on average approximately 0.40 metre thick. The deeper sediment layer increases the time required for design investigations and increases construction cost for temporary works, berm construction and the wetland preparation and installation. In total, the increased design and construction cost related to deeper sediment deposits amounts to $47,000.00 including G.S.T.

Furthermore, the original scope of work as stipulated in the RFP as well as in the proponent's proposal and the agreement between CH2M Gore & Storrie Limited and the City, did not include construction site supervision and waterfowl control which is required to protect newly planted bulrush shoots from being eaten or damaged before they are firmly established. The cost for site supervision amounts to $22,500.00 and waterfowl control to $5,600.00 including G.S.T.

The total increase in contract price for Phase II amounts to $75,100.00 and increases the total contract price to $357,111.34 including G.S.T. Funding for this project has been included in the 1999 Capital Budget Submission and $500,000.00 of this is in the Interim Funding Request, which was approved by Council on December 16 and 17, 1998. The funding is available in Account No. WP953.

Accordingly, it is recommended that the above described increase in contract price be approved and Phase II be awarded to CH2M Gore & Storrie Limited.

Construction of the Treatment Wetland facility should be carried out in the winter and planting should take place in early spring while the plants are dormant. Accordingly, it is proposed to commence construction in February 1999 and complete the work in May 1999. It should be noted that staff of the Parks Department have actively participated in the study work of this project and concur with the proposed improvement work to the pond.

Conclusions:

Various types of wetlands for Lower Duck Pond have been evaluated and a Surface Flow Constructed Wetland which is best suited for local climatic conditions and existing hydraulic conditions is recommended. The wetland will cover approximately 15 percent of the existing Lower Duck Pond. The facility will remove suspended solids, contaminants and E-coli bacteria which are present at high levels in the pond water and in the storm water entering the pond. The wetland will also create habitat for wild life and will determine the feasibility and effectiveness of such a facility for treating storm water. Finally, it will be available for public viewing and educational research for schools and universities.

The proposal has undergone extensive public consultation as part of the Class EA (Schedule B) process and has been well received by the public and government agencies. In consideration of the public support as well as the water quality improvements and other environmental benefits which will be derived from this project, it is proposed to proceed with the implementation of Phase II which provides for the detailed design and construction of the project.

As a result of deeper than anticipated bottom sediments in Lower Duck Pond and a required increase in the scope of work related to construction supervision as well as the control of waterfowl immediately following planting of the wetland, the total contract cost for Phase II (design and construction) has increased by $75,100.00 from $282,011.34 to $357,110.34 including G.S.T.

Funding for this project has been included in the 1999 Capital Budget Submission and $500,000.00 of this is in the Interim Funding Request, which was approved by Council on December 16 and 17, 1998. The funding is available in Account No. WP953.

Contact Name and Telephone Number:

David Crichton, P.Eng., Manager, Design and Construction District 1

Technical Services Division, Toronto Community Council Area

Phone: (416) 392-7674; Fax: (416) 392-7874

E-mail: "dcrichto@toronto.ca"