Development Application part 2 Application Forms REC11/0145

          Consequences to Property                      Insignificant

    With these factors considered we classify the allotment as:-

                             LOW RISK OF LANDSLIP

    Although we consider the allotment has a low risk of landslip, building work undertaken on the site should
    follow accepted methods which preserve slope stability.

    Such measures are discussed in the following section.


    HAZARD MITAGATION - CONSTRUCTION RECOMMENDATIONS

    We consider the primary risks for landslip occurring within this allotment is stormwater scour or
    vegetation removal.

    The vegetation beyond the eastern boundary must be maintained.

    We would also recommend limiting construction activities to at least 6.Om away from the eastern
    boundary to maintain stability of the embankment face beyond the boundary.

    All excavations both temporary and permanent away from this offset must be adequately retained to
    arevent rollapse Excavations for rataimm^, walls can have exoosed cut batters of 1 to 1.5 (vertical to
    horizontal) taken from the base of the excavation. These earthworks must incorporate shallow surface
    spoon drains at the base and along the high side of the cut. Drains must have an efficient outflow down-
    slope and clear of the construction area. Any exposed soil face should also be protected against the
    potential for stormwater erosion. Should these recommendations be un-achievable the builder should
    seek guidance from this office on temporary shoring, benching or other suitable techniques.

    All earthworks should be constructed in accordance with AS3798-1996 'Guidelines on earthworks for
    commercial and residential developments' and sound engineering theory.

    The builder must ensure the stability of neighbouring structures is maintained through not
    undermining their foundations. This is achieved via restricting any earthworks to above a line
    radiating downwards at an angle of I in 1.5 (vertical to horizontal) from the base of the
    foundation/structure to be protected.

P   Retaining walls for landscaping purposes would need to be constructed with consideration of maintaining
    stability of the surrounding ground during construction. Such measures would include limiting the slope of
    any excavations to a slope of 1 vertical to 1.5 horizontal and protecting the works against stormwater
    scour. The retaining wall designs must allow for the lateral soil pressures expected including additional
    surcharging from sloping backfills.

    Although we consider the allotment a low risk of landslip there will always be a risk of landslip under
    severe stormwater conditions.

    Measures that will reduce this risk include the following but are not limited to.

    The finished ground surface should be leveled and graded to ensure no concentration of stormwater
    runoff leading to ground scour can occur.

    Any collected stormwater from areas other that the roof should be disposed of downslope from the
    proposed dwelling and should also ensure no ground scour can occur.

    All stormwater runoff from hard landscaped areas should be directed around the perimeter of the house
    and contained within the site via diversion bunding, scour proof drains and field inlets.