Attachment C - Soil Survey Report · MCU18/0013

Project No. 1-20119                                                                                                        Page | 17
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




The proposed infiltration system is to utilise a buried Atlantis Flo-Tank system (refer Section
1.6) which we understand will allow for controlled infiltration of collected water into the
subsurface materials at a depth of approx. 1.6m below the existing surface. The location and
potential water infiltration of this device has been taken into account for the stability assessment
in Section 5.0.

Please refer to Section 8.0 for further details in relation to soil permeability recommendations.

Other usual treatment options associated with Good Hillside Practice, as outlined in Appendix J
should also be adopted. Some of these are implicit or assumed by the analysis. For example,
provision of surface water drainage measures (such as a lined drain across the slope uphill
from the dwelling) and properly engineered retaining walls. Such treatment options should be
clearly stated as part of the risk management requirements.

    6.3 Site Specific Recommendations

           6.3.1       General

The site risk assessment has assumed that several measures were in place including properly
designed and constructed retaining walls (where applicable), site drainage and scour protection.

           6.3.2       Scour

It is essential that any permanent batters/slopes that result from the development (e.g. adjacent
to existing dunes etc.) are suitably protected from erosion and scour by appropriate drainage
and the establishment of ground cover and shrubs, etc. Runoff should not be allowed to
discharge directly across the batters without suitable scour protection.

Top soiling and seeding or hydromulching on any cut areas steeper than 1:5 (11 degrees) is
suggested so that protection could be provided until such time as the grass cover is
established. The type of protection may also need to be discussed with the local council given
the adjacent dune environment.

           6.3.3       Retaining Structures

At this stage, we understand that retaining structures will be utilised for several parts of the
proposed development. It is assumed and expected that any walls (regardless of type) would be
designed and constructed to meet relevant retaining wall codes and good engineering practice
as well as the recommendations from this report for this site.

           6.3.4       Continued Maintenance

As with all developments, continued maintenance of the proposed site works is essential to
maintain the assessed risks outlined in this report.

Maintenance should include but not be limited to the following:-

          Maintaining clear drainage paths for surface water flows.
          Maintaining and promoting revegetation of exposed batter areas.
          Regular maintenance checks to ensure any damage is repaired in a timely manner.