Storm sewer system tied to Honda's suspended EV expansion moving forward, outfall to Spring Creek

 

Posted September 22, 2026

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New Tecumseth's Committee of Adjustment is expected Thursday night to grant a minor variance to permit Honda of Canada Manufacturing (HCM) to locate a stormwater outfall within 30 metres of an Environmental Protection zone on its site, infrastructure originally designed to serve the company's now-indefinitely suspended electric-vehicle expansion.

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The minor-variance application for 4700 Industrial Parkway seeks relief from the Town's zoning requirement for a 30-metre setback from an Environmental Protection zone.

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An Ontario environmental approval issued in 2025 covers a stormwater-management pond serving 105.3 hectares of the expansion area. Stormwater from the system would ultimately be discharged through a new outfall into Spring Creek.

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According to HCM's supporting materials, the proposed system is designed to control stormwater quality, quantity, erosion and water balance. It includes a wet pond, oil-and-grit separators, storm sewers and infiltration trenches. The system is intended to treat runoff before it reaches the creek.

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The monitoring requirements focus on the quality and quantity of stormwater, erosion, water balance and thermal effects associated with the outfall.

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The Subject Lands are part of the broader HCM lands and are generally bounded by Industrial Parkway to the south and east, and MacKenzie Pioneer Road to the north. The proposed outfall is located within the northwest portion of the Subject Lands and will discharge into Spring Creek.

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Spring Creek is a small, spring-fed creek within the Boyne River subwatershed that flows eastward along the southern boundary of urban Alliston. The creek supports a cool-coldwater thermal regime and is identified as permanent, direct fish habitat.

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Admittedly, the project will, however, result in localized disturbance within the floodplain, riparian corridor, and vegetated protection zone associated with installation of the outfall and energy-dissipation features.​

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According to the reports, the following environmental constraints and mitigation measures will be expected as part of the long term monitoring:

• 30 m vegetated buffer to Spring Creek;

• 30 m vegetated buffer from Significant Woodlands;

• Tree removals conducted outside of designated timing window to protect birds and bats: no tree removal between March 15th and November 30th;

• Buffers and SWM pond edges to be planted with seed mixes that include nectaring species to attract local insect populations, thereby increasing the availability of flowering plant species for foraging bats;

• The ESC Plan (Arcadis, 2026) will be implemented during construction to minimize the potential for erosion and sedimentation from the construction site;

• In order to mitigate the potential for adverse effects on downstream fish and fish habitat due to accidental spills, spill prevention and response measures will be implemented;

• In-water and near water works will be restricted to the period of July 16 through September 30;

• Detail Design of the proposed stormwater outfall to Spring Creek will minimize vegetation removal, avoid suitable trees for bats, and meet requirements under the Fisheries Act to avoid

  harm to fish and fish habitat;

• A salt management plan has been prepared in support of the proposed development to mitigate use of chloride-based ice/snow controls (roads and sidewalks) within the proposed expansion area specifically as it relates to snow storage areas. This will minimize the potential for discharge of chloride-laden water to any natural heritage features and their buffers;

• Where possible primary sources for “new light” will be directed away from adjacent retained ecological features; and

• In order to reduce opportunities for the colonization of invasive and non-native species, areas where disturbance has exposed bare soils should be seeded with a cover crop and native species seed mix.

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"The proposed outfall has been designed to minimize effects on Spring Creek, associated Fish Habitat, Significant Woodland, Significant Valleyland, and Significant Wildlife Habitat. Construction within the valley floodplain will involve direct disturbance limited to the outfall footprint. Potential impacts during construction are expected to be short-term and mainly related to erosion, sedimentation, or accidental spills, which will be managed through an ESC Plan, spill prevention measures, and construction timing restrictions."

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Click link for complete report https://shorturl.at/VjuY0