Скачать или смотреть Randle Reef remediation Stage 3 animation

Located in the southwest corner of Hamilton Harbour on Lake Ontario, Randle Reef is the largest contaminated sediment site on the Canadian side of the Great Lakes. Stage 3 of the Randle Reef project is underway. The 3rd and final stage involves capping the ECF. The Randle Reef Remediation Project is a joint initiative involving the Government of Canada, the Province of Ontario, City of Hamilton, Halton Region, City of Burlington, Hamilton-Oshawa Port Authority and Stelco.

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Randle Reef, located in Hamilton Harbour in Lake Ontario, is the largest contaminated sediment site on the Canadian side of the Great Lakes. The Government of Canada and its partners are cleaning up the site.

The Randle Reef Sediment Remediation Project is divided into 3 stages. In Stage 1, we built an Engineered Containment Facility, known as the ECF, and in Stage 2 we dredged the contaminated sediments and placed them in the ECF, cleaning up the site.
In Stage 3, an environmental cap is installed over the ECF, to isolate and compress the contaminated sediment.

In this stage, we first place a geotextile liner on top of the dredged sediment. This is covered with a thin layer of secondary material, which is a by-product of steel making, providing a stable base to build on.

Next, we add drainage stone over the secondary material to help remove water from the sediment.

To monitor sediment compression during construction, we install settlement plates throughout the ECF. These plates help us measure changes in elevation overtime.

To further compress the sediment and remove water, we install vertical wick drains through the sediment

Removing the water from the sediment will strengthen the soil, preparing it to support the future Port facility that will be built here.

More than 13,000 wick drains will draw out residual water, channelling it to the ECF perimeter. From there, the water is pumped and treated in an on-site water treatment plant and then safely discharged back into Hamilton Harbour.

Another layer of secondary material is placed over the wick drains. Anchor blocks and tie rods are added to provide structural integrity for the inner wall of the ECF.

Next, we install an impermeable synthetic barrier across the entire surface. The barrier will prevent contaminated water from rising to the ECF surface and ensure surface water doesn’t flow down to the contained sediments.

Sand is placed above and below the impermeable barrier for protection, followed by layers of gravel and geotextile grid.

We temporarily add 150,000 tonnes of gravel to help compress the sediment and push remaining water through the wick drains for collection and treatment.

We leave the gravel in place for about six months before removing it.
Next, we install a drainage system around the perimeter to collect and treat any future stormwater before it flows back into the harbour.

Finally, the surface of the ECF is then paved, completing the transition of this contaminated area to a useful port space for the Hamilton-Oshawa Port Authority.