Kapuni Weir in New Zealand had been experiencing ongoing erosion at the weir base and surrounding banks. The issue had threatened the structural integrity of the weir. In order to address the problem, Bluemont Rock Bags™ were selected as the weir erosion control solution to protect this hydraulic structure.
Project Snapshot
Location: Kapuni Weir, New Zealand
Client: Downer NZ
Application: Weir erosion and scour protection
Rock Bags Installed: 2t Eco-Green Bluemont Rock Bags™
Project Overview
Kapuni Weir is a river control structure that sees constant water movement over and around it. That kind of ongoing flow naturally takes a toll on the base and surrounding banks over time. Without protection in place, that wear eventually becomes a structural problem.
The Challenge
The weir base and nearby banks had been gradually wearing away under the force of the water. Left unaddressed, this would eventually undermine the weir itself and destabilise the riverbank alongside it. The site needed a solution that could handle the water flow while working around the uneven shape of the weir and banks.
The Solution
Bluemont Rock Bags™, also known as Kyowa Filter Units, were selected for their ability to conform to irregular surfaces and resist displacement under sustained hydraulic forces. They provide a flexible, durable solution suited to the dynamic conditions present at weir structures.
Results
The installation stabilised the erosion-affected zones around Kapuni Weir, protecting the toe and flanks from further scour and reducing the risk of structural undermining. The rock bags conformed well to the natural surroundings. It provided a durable layer of protection without the need for major civil works. For the client, it was a practical solution that could be deployed quickly in a live river environment.
Related Applications
Bluemont Rock Bags™ handle a wide range of applications – from weir and dam toe protection to riverbank stabilisation, bridge scour protection, and erosion control in high-flow environments.
Contact us to learn more, we are here to help resolve all types of erosion issues. Alternatively, call +61 2 9091 0360 or email info@rockbags.com.au for Australian-based projects, or info@rockbags.nz if you are based in New Zealand.
