EGP South, Winterization

In late 2024, the EGP South Loop mainline construction in Coquitlam was temporarily paused to prepare for the Lower Mainland’s challenging winter and spring conditions. With heavy rain, snow, and significant meltwater anticipated, Evergreen implemented a robust and collaborative winterization plan. This plan was essential to ensure that the right-of-way (RoW) remained environmentally stable during the pause in activity.

One of the core strategies focused on water conveyance. The RoW was segmented using a quadrant-based drainage strategy, employing ditches to reduce both water speed and volume. Poly-lined ditches and berms were installed, along with rock check dams in areas prone to groundwater issues. Wattles and aggregate were added as additional protection to slow down water and trap heavy sediment. Where possible, the team worked to maximize natural drainages by redirecting water efficiently off the RoW to prevent erosion and pooling.

Another key focus was slope stabilization. All disturbed surfaces were compacted and smoothed through bucket packing, enabling water to quickly shed off the RoW, thereby minimizing infiltration that could destabilize soils. In more erosion-prone areas, rock buttressing was placed along cut slopes to reinforce them and maintain structural integrity. High side ditching was also implemented along the upper edge of the RoW to manage overland flow and prevent uncontrolled runoff from entering the construction footprint. Hydromulch with fall rye was used on exposed soils to protect against raindrop erosion, enhance surface stability, and foster root growth for added reinforcement.

Cover management was also essential to maintaining environmental security. Hydromulch with a fall rye cover crop strengthened surface resistance against erosion from overland flows and rainfall. Soil stockpiles across the RoW were given full coverage to prevent erosion due to rain, snow, and surface runoff. Adaptive measures, such as using poly sheeting, geotextiles, and erosion control blankets, were applied where hydromulch coverage had deteriorated or where additional protection was needed.

Minimizing ground disturbance played a vital role in the strategy. Site access was tightly controlled to reduce disruption to protective measures already in place. This cautious approach helped preserve surface cover and maintained the integrity of the implemented erosion and sediment control strategies throughout the winter period.

Collectively, these efforts—water conveyance, slope stabilization, cover management, and strategic disturbance minimization—formed a comprehensive and proactive environmental management plan. This multi-layered approach ensured the RoW remained stable and protected through the seasonal pause, setting a strong foundation for the safe resumption of construction in the spring.

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