Kirbys Road, Montville – Stormwater Renewal & Road Reconstruction

The Goal

The primary goal of this project is to replace an aging 600mm Reinforced Concrete Pipe (RCP) stormwater system with a high-performance 600mm HDPE pipe system at Kirbys Rd, Montville. The works aim to restore structural integrity, stabilize an eroded downstream embankment, install new precast headwalls with rip-rap scour protection, and execute full road pavement reconstruction to ensure safe, long-term asset performance for Sunshine Coast Council.

The Challenge

Key challenges include carrying out deep excavations—up to approximately 3.5 meters below the road surface—along a narrow, 5-meter-wide rural carriageway under live traffic conditions. The project also requires resolving an unstable, suspended downstream pipe outlet caused by slope erosion, carefully identifying and working around underground utilities, coordinating tree clearing directly with the Sunshine Coast Council Arborist, and minimizing disruption to local residents.

The Solution

To safely execute the renewal, a two-phase staged construction approach will be implemented alongside temporary localized road widening to maintain continuous access. Traffic will be controlled during work hours using single-lane Stop/Go management and heavy-duty protective barriers, transitioning to portable temporary traffic lights overnight. The redundant RCP sections will be removed and replaced with 600mm HDPE piping and precast end structures, while suitable site-cut material will be reused to backfill and stabilize the downstream embankment. Full road pavement reconstruction will follow, verified through independent Level 1 GITA field density and compaction testing across all backfill lifts.

The Result

The Montville community will benefit from upgraded, fully compliant stormwater infrastructure that effectively manages regional runoff, eliminates structural erosion risks, and restores the rural road corridor. The project delivers a smoothly reinstated pavement, protected drainage outlets, and a safer, more resilient road network for local residents and traffic.