Landslide remediation – 3 years on
Learnings from 3 years of working on landslide remediation in the Northern Rivers
Capacity building - LEP_23_033_LLC_BRRVLN-05
The issue
In February and March 2022, the Northern Rivers Region of NSW experienced a catastrophic rainfall event. As well as widespread and devastating flooding the region was impacted by major landslides. Whilst restoration focus was on flood damage or immediate damage to infrastructure there was a gap in addressing the scars left by landslides. Left untouched landslide scars continue to erode, washing sediment into already stressed river systems. Without support these scars are covered by weed species which do little to stabilise the sites and pose further risks to adjacent vegetation.
The solution
Very soon after the disaster Border Ranges Richmond Valley Landcare Network partnered with other landcare networks in the Northern Rivers to provide support for landholders via informational workshops as well as to advocate for funding support. North Coast Local Land Services (NCLLS) understood the impact of landslides in the region to the protection of threatened ecological species and threatened ecological communities including subtropical rainforest. They have provided funding for landslip remediation planning, implementation of works, and most recently for follow up maintainence of sites.
- Soil erosion treatments included hydromulching, bank revetment, drainage, cover crop planting (annual grass species) and installation of jute mesh and coir logs.
- Revegetation techniques included; drone seeding, hydro mulching, supporting native recruitment, hand planting and seeding.
- Weed works were undertaken on all sites.
The impact
More than 3 years on the results of landcare’s stabilisation efforts are showing. Sites where weed works have been undertaken have a bigger diversity and higher density of native species as they are not being outcompeted by weeds. By far the most successful revegetation method was to support and augment natural recruitment of native vegetation on sites. Self-sown seedlings outgrew hand planted stock. The second best solution was hand planting of selected, hardy, tube stock. More advanced seeedlings performed better as did those that were heavily mulched.Sadly, there was little success from hydromulching and drone seeding trials carried out on a range of slip types. As well as the ecological impact of addressing soil stabilisation and revegetation the works had a significant positive impact on landholders’ mental health.
How to Restore a Landslip video series
Landcare NSW worked with BRRVLN and RLI to create a 3-part video series called How to Restore a Landslip as part of the Landcare NSW People Led Prevention project.
Key facts
- 50 landholders supported in the landslip restoration ventures
- Over 15 hectares of landslide impacted land supported toward recovery
- Supporting ecological recovery of disaster impacted sites also supports the emotional recovery of landholders