Highland Green Park or Pond #64 is a wet pond with both the forebay and main cell requiring clean out in 2020 to remove accumulated sediments and restore the functionality of providing water quality treatment of surface storm runoff originating from the surrounding developed lands.
This storm water management pond is within a regulated area of the Eramosa Karst Provincial Earth Science Area of Natural and Scientific Interest. Accordingly, the City of Hamilton has secured a permit from the Hamilton Conservation Authority for the work to proceed.
Contractors will gain access from Shadetree Crescent with a mud mat installed at the entrance. The laydown and storage area will be located in the space between the site entrance and the main cell, with light-duty fiber barrier surrounding this area.
The Karst features to the north will be protected from any unintentional sendiment flow by light-duty fiber barriers.
The work will involve the following steps:
- The construction site will be protected with construction fence to prevent access. The fence will be installed on the south side to prevent access along the path from Fairhaven Drive and the path into the facility on the northwest side along Richdale Drive.
- Sediment Sampling – will be done by a qualified professional to determine the chemical composition of the accumulated sediment, and to determine the best method for disposal or beneficial re-use. No dredging works will be allowed to proceed until the Engineer’s recommendations have been provided to the City.
- Fish & Wildlife Rescue – The Contractor will not be authorized to proceed with any work, including pumping activities, until the qualified Biologist has: (1) evaluated the site; (2) provided documentation to the City that no fish rescue is required; or (3) carried out a fish rescue. Once the City has confirmed the receipt of the Biologist’s documentation, the City Project Manager will provide the Contractor with written authorization to proceed.
- Pump By-Pass – The Contractor will set up a dam and pump to by-pass any incoming flows to the facility from the street and routed around the west side of the main cell into the outlet structure. The pump suction head intake will be protected with fine mesh screen.
- Sediment Removal – Prior to removing sediment, the Contractor is to de-water the work area. All de-watering activities are to discharge to sediment bags, for filtering purposes which will be located on the north-east side of the main cell, above the top of bank. Sediment within the facility will then be stockpiled within the sloped area of the facility and be allowed to de-water. Once the sediment has sufficiently de-watered, it will be put into dump trucks and transported off-site to a suitable disposal location.
- Erosion and Sediment Control – Silt sacks will be used within the street catch basins to capture any free sediment that may become mobilized during hauling of material off-site. The grating of the outlet structure of the facility is to be covered with filter cloth, to prevent sediment from leaving the work area. Heavy duty silt fence barrier (OPSD 219.130) will be installed on the north side top of bank of the main cell. Additional preventative measures, such as silt socks or coir rolls, maybe be required and will be stored on-site.
- All disturbed areas will be restored using the OSC Early Succession Wet Meadow mix for restoration areas within the facility, sourced from Ontario Seed Company.