Environmental Stewardship
Chedoke Creek Remediation
Council Communication Updates
Chedoke Creek updates provided to Hamilton City Council and Standing Committees.
Chedoke Creek Remediation Workplan
The City of Hamilton was served a Ministry of the Environment, Conservation and Parks (MECP) Order on December 4, 2020, as a result of the Main/King Combined Sewer Overflow discharge that occurred between January 2014 and July 2018. The City of Hamilton has been working closely with the MECP and the Royal Botanical Gardens (RBG) to develop a remediation workplan for both Chedoke Creek and Cootes Paradise in response to the Order.
Chedoke Creek Targeted Dredging
The goal of the targeted dredge project is to improve the condition of the creek prior to the beginning of the discharge event. As indicated in the MECP approved Chedoke Creek Workplan, the City implemented short term offsetting remediation projects in areas around lower Chedoke Creek and Princess Point to further improve the condition of the water. The Cootes Paradise Workplan addresses the long term offsetting work required by the order. The goal of the Cootes Paradise Workplan is to improve the quality of water into both Chedoke Creek and the receiving bodies of water.
Project Update:
On December 20, 2022, the MECP Director approved the City’s requested deadline extension to December 31, 2023, with all other items in the Order remaining in effect, and unaltered. On March 3, 2023, the MECP Director issued a revised amendment which requires that the in-water targeted dredging work be completed by August 31, 2023, with the remaining activities in the approved Chedoke Creek Workplan completed by December 31, 2023.
Subsequently on March 14, 2023, after positive and collaborative discussions between the City and the MECP, the MECP Director issued a revised amendment, which supports the City’s concerns regarding the previous deadline and still expedites the remediation of Chedoke Creek. As such, the City is now required to complete the in-water targeted dredging work on or before October 31, 2023. On October 13, 2023, due to the unseasonably wet weather experienced through July and August, as well as equipment challenges caused by larger rocks and unexpected materials within the dredged footprint, the City of Hamilton requested a 1-month extension moving the in-water work deadline from October 31, 2023, to November 30, 2023. On October 30, 2023, the MECP granted the extension requiring the City of Hamilton to complete all dredging activities by November 30, 2023, and complete the remaining activities in the approved Chedoke Creek Workplan by December 31, 2023.
On November 17, 2023, the project team successfully completed the targeted dredging activities, concluding the four-month effort to remove sediment from the bottom of Chedoke Creek.
The transportation of the dried sediment off the Kay Drage Park site subsequently began on December 1, 2023. As required by the Order, all of the approximately 16,000 tonnes of sediment was disposed by December 31, 2023. Approximately 300 truckloads was needed to transport all the sediment to approved landfills
Offsetting projects, removal of sediment (targeted dredging) and potential impacts to the community
As part of the Chedoke Creek Workplan, offsetting remediation projects were completed to complement the targeted dredging work. Two initiatives including the installation of floating treatment wetlands and the installation of a small scale aeration system were undertaken to improve water quality conditions in the creek.
Floating vegetative mats, also known as floating treatment wetlands, are used to manage and remove excess nutrients from surface waters under a variety of conditions. These wetlands are artificial floating platforms that allow aquatic plants to grow in sites of varying water levels. Native wetland species are planted on the platforms allowing aquatic root growth below into the underlying water. The roots trap suspended sediment and discourage growth of algae by reducing phosphorus and nitrogen, thereby improving water quality. The City has installed one floating treatment wetland within Cootes Paradise, with support from the RBG, which can be seen from the Desjardins Trail. Expansion of the project to other areas within Cootes Paradise is currently under evaluation.
Diagram description
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As pollutants enter the waterway, algae feeds off the harmful nutrients. The algae then multiplies, causing disruption to the natural ecosystem.
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The floating wetlands allow plants to grow above the algae. The roots then trap suspended sediments and discourages the growth of algae by reducing phosphorus and nitrogen from the water.
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Reduction in phosphorus and nitrogen therefore improves water quality, stimulating greater natural plant growth and a healthier habitat for fish, birds, insects and other wildlife.
Together the plants and bacteria create a living, breathing filter system that helps reduce the amount of contaminants and harmful nutrients in the water.
The City of Hamilton installed a small scale aeration system in Chedoke Creek to help increase oxygen levels at the bottom of the creek while decreasing the amount of excess nutrients that contribute to algae blooms and cloudy water. Due to a decrease in temperature, the pumps were turned off in the winter months. The system was removed to allow targeted dredging activities to take place. A larger aeration system will be considered during the Lower Chedoke Creek Environmental Assessment Study.
How does it work?
- A compressor pumps air to the bottom of the creek through diffusers.
- In this process, the oxygen-poor water rises to the surface where it picks up oxygen from the diffusers and the surface.
- The oxygen-rich water then returns back down to the bottom where beneficial aerobic bacteria use the oxygen to digest organic matter, eliminating harmful excessive nutrients.
The dredge activity removed approximately 8,000 cubic metres of sediment from Chedoke Creek over a 4-5 month period.
Pre – Targeted Dredging
Work to complete the dredge design included a topographic survey, species at risk investigations, hydrologic & hydraulic modelling and sedimentation investigations. The sediment quality samples were collected at numerous locations within Chedoke Creek, the Princess Point Embayment and Cootes Paradise in the spring of 2021. Additional deeper samples were collected in August 2021 to better inform the dredge design.
Dredging
Targeted dredging occured within an identified area of Chedoke Creek to remove contaminated sediment from the creek bottom. Over a 4 to 5 month process the following activities were completed:
- Preparation - Work areas within the creek were isolated using a turbidity/silt curtain that had a weighted line to maintain contact with the bottom of the creek. The top float line isolated the work area at the surface. Fish and wildlife were removed from the work area prior to the dredging activities, reducing potential interaction with the dredging operation in accordance with governing protocols.
- Removal - Sediment was removed from the creek bottom using a hydraulic dredge which utilized a cutterhead and pump to vacuum and transport the sediments to the dredge material management area which was located within Kay Drage Park. The average combined dredge depth was approximately 1.0 m which removed approximately 8,000 m3 of sediment from the bottom of the creek.
- Dewatering - The intentional removal of water from solid material or soil. To remove and dispose of the sediment efficiently, dewatering occured at the dredge material management area. A trench was built within the material management area to facilitate the dewatering process. The sediment slurry (mix of solid material and water) was pumped into a geotextile container. An environmentally safe polymer was added to help bind the solids together and separate the water. The separated water was then drained from the geotextile container while the sediment remained inside. The separated water was pumped to a nearby sanitary sewer main (on dry days only) and was treated at the Woodward Wastewater Treatment Plant. Once the container
iswas full of sediment and the contents dried, it was hauled to a landfill. - Repeat - The dredge area was broken up into two zones, North and South. The total dredge area spans between 100m north of the Desjardins Trail pedestrian bridge and 100m south of the Kay Drage Park bridge. Each zone was broken-down into small sections so that only half the creek, as required by permitting, was blocked by dredging operations. Starting in the North Dredge Zone, after each section was completed, the contractor reset in the next section and continued to dredge until complete.
Post – Dredging
- Restoration works occured at the material management area, Kay Drage Park in the spring of 202
54. - Surface water quality testing has continued after the dredge work was completed. Results are compared to historic data to determine the impacts of the dredge activity.
- Various post dredging monitoring efforts will take place to support each agency’s permitting and approval requirements including any changes in water levels, sediment quality of the newly exposed creek bottom and the functionality of any added species at risk habitat.
| Agency | Required Permitting | Approved Permit |
|---|---|---|
| Ministry of Environment, Conservation and Parks | Permit to Take Water Overall Benefit Permit |
MECP PTTW No. P-300-9212648817 MECP SAR WC-C-001-22 |
| Hamilton Conservation Authority | Conservation Authority Work Permit | HCA – 2022 – 06 |
| Ministry of Transportation | Building and Land Use Permit | MTO – BL – 2022-20T-00000036 |
| Transport Canada | Canadian Navigable Waters Act Permit | TC – 2021-405815 |
| Fisheries and Oceans Canada | Species at Risk Act Permit | DFO- SARA- 21-HCAA-00211 |
| Royal Botanical Gardens | Research Permit | RBG – 2021-07 |
| City of Hamilton | Construction Dewatering Sewer Discharge Permit | #220701-G (22760) |
Chedoke Creek Remediation
Frequently Asked Questions
The Chedoke Creek Workplan outlines the steps associated with targeted dredging in Chedoke Creek. This work will remove nutrient laden sediment from the creek bottom and is scheduled to be completed before the end of 2023. The goal of the targeted dredge project is to improve the condition of the creek prior to the beginning of the discharge event.
The Cootes Paradise Workplan addresses the long-term offsetting work required by the order. The goal of the Cootes Paradise Workplan is to improve the quality of water into both Chedoke Creek and the receiving bodies of water.
On August 14, 2024 the City received MECP approval of the Chedoke Creek Workplan Post Work Report, summarizing targeted dredging project activities that addressed MECP Director’s Order 1-PE3L3.
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