Attachment C - Soil Survey Report · MCU18/0013

Project No. 1-20119                                                                                                        Page | 3
March, 2018
Ref: 1-20119, 2018-03-02, BR VER 2
Sam Hopper – Slope Stability Assessment and Geotechnical Report - Proposed Residence, 24 Arakon Crescent, Sunshine Beach




2.0 ASSESSMENT METHODOLOGY

    2.1 Method
The assessment of the stability of slopes at the site has utilised a Hazard and Risk Assessment
approach. In this method, the potential stability hazards on the site are assessed using certain
features/properties of the site (i.e. slope angle, ground water conditions, etc.). This method
provides a ranking for each of the identified hazards.

Using this hazard ranking and based on assumed consequences, an assessment of risk can
then be made using a risk matrix.

    2.2 Hazard & Risk Analysis
The general processes in assessment and management of risks associated with landslides are
given in detail in the National Disaster Mitigation Program (NDMP), “Landslide Risk
Management (LRM) Guidelines”, Practice Notes and Geoguidelines as published in the
Australian Geomechanics Journal Volume 42 No. 1, March 2007. Figure D1 (Appendix D) is an
extract from the paper showing the typical processes in flow chart form.

As shown in Figure D1, hazard identification is an initial step in this process, and is the basis for
this study. Due to unknowns associated with development applications and their influence on
the surrounding environment, this study has been restricted to a qualitative evaluation of hazard
rating, with respect to natural slope instability. Landslide management areas were then derived
from these hazard/likelihood ratings and assessed consequences to evaluate the assessed risk.

The effects of earthquake on slope stability have not been included in this study.

The terminology adopted in this report has been designed to be consistent, as far as
practicable, with national standards including the Australian New Zealand Standard AS/NZS
ISO 31000:2009 “Risk Management – Principles and Guidelines” and the above NDMP LRM
Guidelines.

The methodology undertaken by Soil Surveys Engineering Pty Limited in assessing the Hazard
Management Areas was based on the following steps:-

          A review of published information and aerial photographs to identify areas that have
           potential to be affected by slope instability;
          A review of regional features including topography, geology and geomorphology;
          Identification of potential hazard zones based on topography, geology and
           geomorphology;
          Site inspection and review of field investigation data;
          Development of a Risk Assessment map that can be used to assess the proposed
           development.

This study has identified hazard ratings using a classification system consistent with the
procedures detailed in the paper entitled “A Method of Zoning Landslide Hazards”, prepared by
McGregor and Taylor. This method has been adopted on a wide range of projects and has
proven to be robust.