Slope Stability Report 26-5-2019 OPW19-0193

TRUBUILT
SLOPE RISK ASSESSMENT REPORT



2.5        Topography

The topography of the site comprises:

      •   The site comprises a series of mainly east-west oriented hills that are up to 160m above the toe;
      •   Creeks through the site form a dendritic pattern;
      •   The base of the valleys comprises a flatter area comprising flood plain deposits;
      •   The creek meanders across the valley floor, based on historical aerial photographs it appears that the
          course of the creek has changed over the last 70 years with meanders becoming cut off;
      •   The gradient of the hill sides vary between 40% and 80% with isolated areas graded at >100%;
      •   The valley floors grade at between 0% and 25%;
      •   The area where the house is proposed generally grades at about 20% to 35% towards the south, with
          an area with a gradient of <10% near the road and grading at between 45% and 60% to the south-east
          and south-west with a ridge between.

Key details of the site topography are shown on the site plans in Appendix 1. Drawings DWG-01 and DWG-02
show the contours of the site in general and of the proposed house location, DWG-03 shows the gradients of
the slope in the vicinity of the proposed house.


2.6        Groundwater

No groundwater was encountered on the site during the investigation.

However, based on the geology and site conditions it is expected that an intermittent perched groundwater
table would develop in superficial soils following periods of extended rainfall.

A large clump of bracken ferns was noted on the site between HA1 and HA2, these are generally associated
with intermittent seepage. Drilling was located both above and below this featured but no groundwater way
observed, and the lower part of the soil profile was largely dry. It is possible that these ferns are present due
to shallow seepage of water from the roadside drainage into the slope.

Note that these groundwater observations are made on the condition of the site at the time of the
investigation. Groundwater conditions on the site may be affected by short and long-term weather cycles,
climate change and surrounding development. Where possible, tell-tale signs, geological conditions or
regional geology that may contribute to groundwater seepage will be identified during the investigation.
However, the specific performance of seepage or groundwater may not be able to be fully defined during the
duration of the investigation. Consequently, changes to groundwater conditions, including but not limited to
ceasing, new or increased groundwater seepage, may affect the property in the future.


2.7        Surface Drainage

The surface drainage of the site comprises:



LEONTAKIANAKOS-R-001                                 Page 5                                             26 May 2019