Appendix4-SlopeStabilityAssessment · MCU18/0135

Structures Engineering Design                                                                 18197-001-Rev0
                                                                                                6 August 2018

4.5    Drainage
Adequate site drainage should be constructed to ensure that stormwater runoff is directed away from the
house walls and footings. All collected surface water, roof water, and any pool water overflow should be
directed by pipes or lined swales to the council stormwater system. Where adequate fall cannot be achieved
to drain water to the council stormwater system, collected water could be directed by pipes to the east,
outletting well down slope (min. 8 m from structures). Stacked rock flow dissipaters should be constructed at
the drainage outlets along with erosion matting and/or vegetation to the surrounds.
As a minimum surface drainage should include a surface swale drain along the southern side of the
residence to intercept surface runoff from the neighboring property. Surface drainage such as swale drains,
diversion bunds or grated channel drains along the western property boundary should also be constructed to
intercept any runoff from the road.

Subsurface disposal of stormwater must not be undertaken.



5.0     SUMMARY & CONCLUSIONS
Based on the findings of our assessment we consider, from a geotechnical viewpoint, that the site is suitable
for the proposed development and that there would be a Low Risk of slope instability subject to
implementation of the recommendations given in this report.



6.0     LIMITATIONS
Your attention is drawn to the document Limitations, which is attached to this letter report. Please contact
the undersigned should you wish to discuss any of the above matters.
Yours faithfully

TECTONIC GEOTECHNICAL PTY LTD




Scott Davis BEng CPEng RPEQ 16439                Ashley Davey BEng (Geological) MIEAust RPEQ 8159
Senior Geotechnical Engineer                     Director/Principal Geotechnical Engineer

Attachments: Ground Drill Soil Test Report (ref. 18/180 dated 7 June 2018)
             Qualitative Terminology for Use in Assessing Risk to Property
             Some Guidelines for Hillside Construction
             Limitations




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