Slope Stability Report

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Table 1: Results of AGS Qualitative Risk Assessment
                Hazard                     Likelihood         Consequence                 Risk Level
             Global Failure              Barely Credible       Catastrophic               Low
    Shallow slumping of surface soils       Likely                Minor             Low to Moderate


Based on the results of the AGS assessment, the perceived risk based on the conditions
encountered and information available at the time of the assessment is “Low”.

7.0 Hillside Construction
The following works should be implemented in additional to other items highlighted within
this document. These points are considered to be typical good hillside construction practice
as explained in attached documentation:

•     Foundations for both lightly loaded and heavy structures should be supported on either
      piles or high level footins founded into medium dense sands and must extend 2.0 m below
      the surace level as a minimum.
•     Where slopes are not supported by an engineer designed support system, natural slopes
      within or near building envelope or movement sensitive areas should be no steeper than
      2H:1V.
•     Building platform fill should be limited to a maximum height of 1 m. The filling should be
      step keyed into the natural slope and battered no steeper than 3H:1V unless an engineer
      designed retention system is in place.
•     Unsupported cuts steeper than 2.5H:1V will require engineer designed retention systems.
•     All stormwater and surface water is to be discharged by an approved stormwater drainage
      system. The use of subsurface drainage systems are not suitable unless greater than 50
      m downslope from the envelope at this site.
•     Ongoing maintenance of the effluent wastewater area is also considered mandatory. The
      location of the application area should be located below the proposed building. Plumbing
      and services must also not be allowed to leak and regular maintenance and inspections
      should be undertaken.
•     Erosion protection of cut and fill batters will be required. Batters should incorporate crest
      and toe drainage. Batters should be vegetated appropriately to minimise erosion.

8.0 Geotechnical Recommendations
The following sections details specific geotechnical constraints or recommendations in
addition to general hillside construction notes.

8.1 Site Preparation and Earthworks
The following comments are provided in relation to site preparation for earthworks.



12 May 2021                                                        Propsoed Residential Extensions