Geo-Hazard Mapping and Slope Risk Assessment

High resolution Drone-LiDAR survey for slope risk assessment of remote and densely vegetated slopes adjacent to rural road


A rural road travelling through remote and rugged terrain to the north-west of Sydney includes a large number of geotechnical risk sites. The steeply inclined slopes adjacent to the road alignment are prone to rockfall and landslide and require routine inspection, slope risk assessment and geo-hazard mapping as part of the geotechnical management plan. The rugged nature of the area, dense vegetation and various sandstone escarpments limits the ability of conventional inspections to assess only the slope areas which are immediately adjacent to the roadway, leaving the majority of the slope largely unassessed.

High Resolution LiDAR
High Resolution LiDAR
Geo-Hazard Mapping
Geo-Hazard Mapping
Digital Terrain Modelling
Digital Terrain Modelling

Diodrone utilised high-resolution drone-LiDAR to survey the slopes on both sides of the valley from creek to crest, which in some places exceeded 250m of vertical relief.

The LiDAR point cloud was classified for ground points using automated classification followed by extensive manual refinement to ensure that boulders, erosion gullies and other geotechnical features were retained in the ground classification and evident in the resulting digital terrain model (DTM). Additionally, all overhangs, commonly present throughout the area and a primary source of rockfall, were classified in the point cloud.

High-resolution LiDAR and detailed point cloud classification for use in Slope Risk Assessments and geo-hazard mapping.

The resulting deliverables provided geotechnical engineers with a high-fidelity DTM for use in rockfall modelling as well as identifying the location and extent of boulders, landslide debris, erosion gullies and overhanging rock formations – essentially providing a heatmap of potential rockfall sources throughout the assessment area.

lidar derived digital terrain model (dtm) used for rock-fall modelling and slope risk assessment
The LiDAR derived Digital Terrain Model was used for rock-fall modelling as well as identifying the location of potential rockfall sources.
Geotechnical risks identified and mapped for use in rockfall modelling and slope risk assessment
Geotechnical risks identified and mapped for use in rockfall modelling and slope risk assessment.