Appendix G - Geotechnical Report

Total Concept Homes                                                                           20332-001-Rev0
                                                                                            15 December 2020

2.3    Groundwater
No signs of groundwater seepage (‘springs’) were observed during our walk-over, and neither was any
seepage encountered during borehole drilling. Groundwater conditions may vary seasonally, and could
rise to shallower depths, particularly following periods of prolonged or heavy rainfall.

2.4    Surface Drainage
Broadly, the natural surface drainage follows the ground surface contours, which over the proposed
development areas tended to fall to the north. Surface water flows affecting the proposed residence and
eastern part of the driveway alignment would be considered negligible, given the topographical position
towards the crest of a well developed spur. The natural ground does rise above the western part of the
driveway alignment, where a catchment over the area of an existing residence may proliferate.

No significant erosion was noted during our walkover inspection.
Surface water is expected to drain well from the site considering the moderate to steep natural gradients
and low permeability of the soils in the immediate subsurface, and relatively shallow depth to rockhead.

2.5    Vegetation
The immediate periphery of the proposed driveway consisted of periodically slashed grass, which was quite
long at the time of our inspection. Small to medium size mature trees were noted on the sloping ground to
the north of the proposed driveway, which were observed to be relatively ‘plumb’.

Around the area of the proposed residence, slashed grass was also present over most of the area, with
some large mature trees just to the west of the proposed building location. These were also noted to be
quite straight at the time of our inspection, with no tilting or distorted growth present, which can be an
indicator of slope instability.

2.6    Buildings and Other Structures
The existing residence comprised a one storey, low set, masonry walled structure, constructed over a cut
and fill earthworks pad. The residence was mostly on cut to the south, which ranged up to around 1.5 m
depth. Fill on the northern side of the residence was supported by a grouted rock wall and ranged up to 2 m
height. The grouted rock facing supporting the fill did not show any signs of global instability having affected
the structure; with the residence generally being in good structural condition, other than some minor cracking
to the concrete apron to the slab. It was noted that the cracking was coincident with the daylighting point for
underslab pipework (assumed to be for wastewater and water).

Although not within the subject site, a retaining wall was present along the south-western boundary, which
would be adjacent to the proposed driveway access. This was estimated to be in the order of about 4 m
height, and was constructed of large concrete blocks, spread over two tiers. This is shown below in Text
Figure 8.




Text Figure 8: Looking south-west over retaining wall on neighbouring allotment

It was presumed that this had been recently constructed, and it was not clear whether upslope surface water
flows were being captured by the structure, and if so, where discharge was being directed to.




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