In the face of ongoing erosion concerns at Horokiwi Stream, Pāuatahanui, with bad weather approaching in the upcoming week. Porirua City Council made a call to CCL and a swift and collaborative effort was undertaken to protect the embankment from further damage. The urgency of this project was clear—each significant rainfall event had been eroding 100–200mm of the embankment, threatening nearby infrastructure and properties.
A Precision Approach to Stream Stabilisation
The team tackled the challenge head-on, diverting streamflow to facilitate the placement of 10 linear metres of 1-metre concrete blocks, embedded deep into the streambed. This required meticulous excavation, ensuring the blocks were securely positioned at up to 75% depth below the streambed and two metres high to withstand future flood events. Innovative engineering techniques included strategic bunding for water diversion and angling the blocks between 5–10 degrees for optimal stability.
Collaboration & Rapid Execution
One of the standout achievements of the project was its remarkable speed. Despite the initial two-day timeframe, the entire team rallied together to complete the works in a single day—a testament to their efficiency and coordination. Key factors contributing to this success were our precise logistical planning, rapid mobilisation of materials, and effective streamflow management. A big thank you to the Downers maintenance team for providing the traffic management at short notice.
Overcoming Challenges in a Dynamic Environment
Working directly within a swiftly moving stream presented technical complexities. Excavation precision was essential to ensuring stability, while temporary concrete block placements helped dissipate water energy and control flow during construction. With short notice and an upcoming storm on the horizon, the ability to adapt and execute solutions in real-time was crucial.
Protecting Infrastructure & Community Assets
This stabilisation project was not just an engineering achievement—it provided critical protection for Grays Road and the surrounding properties. Local residents, tenants and landowners dropped by to have a look throughout the day and expressed their gratitude for the effort, relieved to see proactive measures taken before future weather events could exacerbate the erosion. Our team worked well into the evening to get the job done.
Stakeholder Recognition & Success
The Porirua City Council inspected the completed works and acknowledged the team’s effort, later reaching out to CCL management to commend the quality and efficiency of the project. Their appreciation underscored the importance of fast, responsive infrastructure interventions when faced with environmental risks and we’re proud of our team members who put their hand up for the job at such short notice.
