A marine construction company based in Kingston, Ontario, has been fined $45,000 after being convicted of discharging sediment into the St. Lawrence River during shoreline work on Treasure Island, a provincially significant wetland area.
Inner Harbour Marine Services Limited was convicted on July 17, 2025, of one offence under Ontario’s Water Resources Act for “discharging, causing or permitting the discharge” of material that impaired water quality. The company was also ordered to pay a $11,250 victim fine surcharge and given nine months to pay.
According to a court bulletin from the Ministry of the Environment, Conservation and Parks (MECP), the offence occurred between April 10 and 11, 2023, while the company was carrying out shoreline stabilization work at a private residence.
Investigators said the firm had been excavating and placing large armour stones along the shore without installing sediment and erosion controls required by its permits from the Cataraqui Region Conservation Authority and the Ministry of Natural Resources.
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A hydrogeologist with the MECP observed excavator tracks in the water and a visible sediment plume spreading from the site into the river. Follow-up inspections confirmed that sediment-laden water had been discharging into the St. Lawrence for at least 20 hours.
Water sampling showed total suspended solids within the plume were more than 100 times higher than background levels. The ministry determined the discharge impaired water quality and likely caused moderate, sub-lethal effects on fish and aquatic invertebrates in the area.
Inner Harbour Marine Services complied with orders to stop work and install sediment controls, but an investigation by the ministry’s Environmental Investigations and Enforcement Branch led to charges and the subsequent conviction.
The company specializes in in-water construction projects such as dock building, break wall construction, and shoreline remediation for residential and commercial clients.
