Landslide assessment, Townsville, Queensland, Australia
In response to wet season heavy rainfall and tropical cyclone events, Townsville and the surrounding area was impacted by a range of slope instabilities including shallow slumping, rockfalls and debris flows.
PSM was engaged by Townsville City Council to assess the potential for and likely consequence of landslides on Townsville growth areas as well as roads providing emergency access and evacuation routes.
engineering and technical OPPORTUNITIES
Many previous landslide occurrences had not been well documented and were frequently only verbal accounts. There was a combination of active and relict instability features and geo-hazards often occurring on steeper slopes. Assessment and mapping of inaccessible areas also had to be completed remotely.
approach AND innovation
Following our rigorous assessment, PSM’s innovative and tailored approach included:
- Geomorphological and landslide mapping of elevated areas around Townsville
- Review of previous risk assessments as well as assessments for landslide, rock fall and debris flow hazards in previously unassessed areas
- Completion of a desk top study including aerial photograph interpretation, review of GIS data (including geological, lidar, land use)
- Review of historical data including informal meetings with road authorities
- Completion of an intensive field mapping program including geomorphological and geological mapping of steep terrain areas likely to be susceptible to slope instability
- Production of landslide overlay maps providing suburb-scale landslide risk zoning for planning land use
- Provision of recommendations to Townsville City Council to improve the planning scheme, landslide mitigation guidelines, and updating of council disaster management plans.
PSM successfully provided useable landslide hazard overlay maps, potential improvements to land use planning schemes and improved response and mitigation guidelines for dealing with future landslide events.