Backgrounder - City of Hamilton managing contaminated soil at the Kenilworth Water Reservoir

Timeline of Events

• Early 1960s - Kenilworth Water Reservoir under construction.
• 1964 - Kenilworth Water Reservoir is commissioned and becomes operational.  
• January 2020: Hamilton Water began a planned $6.4M capital rehabilitation and upgrade project at the Kenilworth water reservoir
• June 15 - Contractor notices visual concerns with the soil and tests two small samples.
• June 26 - Results of initial soil testing shared with the City. Showing high levels of benzo(a)pyrene; a type of polycyclic aromatic hydrocarbon (PAH). City staff determine that more tests are needed to assess additional soils in the area.
• July 8: Contractor engages soil sub-consultant to complete more fulsome soil quality assessment.
• July 20 - 23: Testing of soil takes place – 10x10 grid with 195 samples.
• August 18: Soil sample results are received – they indicate approximately 50 per cent of reservoir soil contains various levels of Polycyclic aromatic hydrocarbons.
• August 20: City engages with MECP regarding contaminated soil.
• August 31 to September 14 - As a precautionary measure, the City completes three separate water quality tests to ensure no impact to drinking water. No concerns are detected at either Kenilworth reservoir or Woodward pumping station.
• September 17 - Jacobs Engineering is engaged to study whether the contaminated soil could be reused for the current project.
• October 6 - Jacob Engineering suggested that reusing the soil for the purpose of completing the current contract is acceptable from a legislative perspective.
• October 6 - Hamilton Water staff meet with the MECP to discuss the soil contamination issue.
• October 23: City provides MECP with Material Handling Plan for soil as part of current construction project.
• October 30 - Hamilton water staff engage with Public Health Services.

Soil Testing

• Soil testing was completed by dividing the area at the Kenilworth Water Reservoir into 10 ft. x 10 ft. boxes.
• 195 samples were taken
• Approximately 50 per cent of the soil samples were shown to contain various levels of Polycyclic aromatic hydrocarbons.
• The total volume of soil at the Kenilworth Reservoir is approximately 18,000m3. Therefore it is estimated that approximately 9,000m3 (or about nine tonnes) of soil may be contaminated.

IMAGE MISSING: https://staging.hamilton.ca/sites/default/files/media/browser/2020-11-04/kenilworth-water-reservoir-exceedance-map.jpg

Overview of Current Rehabilitation Project

• Repairs to the exterior roof of the reservoir
• Joint repairs, some requiring excavation
• Interior concrete restoration
• Demolition and removal of structural elements including concrete and steel
• Restoration, grading and landscaping

Polycyclic aromatic hydrocarbons (PAHs)

• Polycyclic aromatic hydrocarbons (PAHs) are a class of chemicals that occur as products of incomplete combustion of compounds like coal, crude oil, and gasoline.
• Most commonly the source of PAHs in surface water and soils is from vehicle emissions. PAHs generated from these sources can bind to or form small particles in the air.
• PAHs are found in coal tar, crude oil, creosote, and roofing tar, but a few are used in medicines or to make dyes, plastics, and pesticides.

Additional Documents

Kenilworth Access Soil Testing Report(PDF, 69.71 KB)
Kenilworth Letter of Opinion