Innovation in erosion control
Bamboo retaining structures. A nature based solution to control erosion: a pilot test on the Richmond River.
Efficiency - LEP_23_033_LLC_08
The issue
The enormous scale of erosion across the broad landscape, following the 2022 flood event in the Richmond River catchment, overwhelmed many landholders. The task of remediation is beyond belief and beyond budgets. The conventional hard engineering approaches to erosion control, based on steel, rock and concrete are extremely costly and, considering the scale of the demand and the environmental context, not feasible in most cases. Yet the ongoing impacts of sediment input into the river system across the catchment continue to raise red flags and the cost of doing nothing has a dear and dire forecast.
The solution
A small team of creative thinkers mustered to explore alternatives to slope stabilization using cost effective and time efficient, nature-based approaches. As a collaboration, with an innovative geotechnical engineer, a researcher from University of Sydney, and Landcare as partners, we set off to expand the options of slope stabilization using retaining structures made from bamboo poles. We held a vision of light weight, easy to install structures that biodegrade over time as planted native vegetation takes hold.
With funding from Kyogle Council to put this to the test, we selected an advancing head cut, with a 60% to near vertical scarp greater than 5m, adjacent to the Richmond River at the Kyogle High School to test the theory. The horizontally stacked bamboo pole walls were installed as bound bundles, ensuring integrity if one pole failed, with vertical piles and anchors to secure in place.
The impact
Whilst time will tell, at a 10th of the cost of conventional approaches, the retaining walls are holding the site stable, planted trees are growing fast and the outcomes look promising. The durability of the bamboo underground remains a question with many variables at play, but you never know unless you try! This trial is worth watching. If you are interested in this pilot, stay tuned by emailing landcare.support@brrvln.org.au