Bio Engineering
Innovative Edge protection for River Management
As the client-side Project Manager for Greater Wellington, Holmwoods is leading the charge on innovative, nature-based flood protection along Te Awa Kairangi / the Hutt River in Lower Hutt.
This forward-thinking approach - known as Bio-Engineering - repurposes mature willow trees into bundled tree groynes that are anchored into the river berms to provide natural erosion protection. These groynes not only deliver immediate resilience against strong river flows, but also regenerate, re-root and strengthen the riverbanks over time. To further stabilise the berms, we plant willow poles across the remaining areas, creating a living, self-reinforcing system.
As the willows mature and the berms stabilise, our long-term plan is to transition the river edge to a native canopy, progressively thinning the willows and replanting with indigenous species to restore the natural ecology of the river corridor.
The programme involves complex sequencing—balancing narrow planting windows with the ideal times for willow cutting and placement and optimal earthworks seasons to maximise regrowth and survival.
Holmwoods has led the end-to-end delivery of these works: from design development and planning through to contractor engagement and construction oversight. This project showcases our ability to deliver innovative, non-standard solutions with commercial rigour, environmental responsibility, and uncompromising safety standards—all while achieving outcomes that are on time, on budget, and built to last.
To hear more about this leading-edge work, check out Greater Wellington’s video below, where we discuss the bio-engineering techniques in action.