Geotechnical Report

   The southern portion of the front yard included flat grass covered terraces supported by gabion basket
    retaining walls; further description of the retaining walls is provided in Section 4.3.4 below.
   The vegetated median strip (17m width) separating the two lanes of Spoonbill Street sloped down to the
    north-east at approximately 20°.
   The surface levels in the neighbouring property to the south-east were generally similar to the site
    surface levels although the neighbouring front yard appeared to be supported by a low height timer
    sleeper retaining wall; further description of the retaining walls is provided in Section 4.3.4 below.
   The neighbouring house to the north-west appeared to have been constructed on a flat building platform
    created by localised cut to fill earthworks; the fill appeared to have been placed over the rear yard area.
    The front yard had been cut into the hillside and concrete block and timber sleeper retaining walls
    (maximum 0.8m height) supported the cut faces. The timber sleeper retaining wall returned north-east
    to form the central portion of the common boundary with the subject site. The north-eastern half of the
    common boundary with the subject site and the north-eastern site boundary of the neighbouring
    property were formed by a timber sleeper retaining wall (0.3m height) which supported the neighbouring
    yard area.



4.3.2 Groundwater and Surface Drainage
   As noted in Section 4.2, no groundwater seepage was noted in either the GeoCon2012 investigation or
    the JKG investigation. A wetland area is present to the north-east of the site which is likely to have shallow
    groundwater and we note that groundwater levels can rise, especially after heavy or prolonged rainfall
    events.
   Based on the topographic setting of the site, the majority of the surface run-off would be expected to
    flow downhill to the north-east.
   A concrete swale drain on the south-western side of Spoonbill Street is likely to capture run off from the
    moderately steep vegetated median strip and direct it to the road stormwater system.
   A stormwater outlet pipe is present in the northern corner of the neighbouring site to the north-west
    and some erosion was evident at the pipe outlet (see Plate 4).




                 Plate 4: Stormwater Outlet Pipe on Neighbouring Property With Erosion




36409UR                                             5