response to information request 3 Allambi

 5. Provide an amended Stormwater Management Plan that is consistent with the
    recommendations of the site specific geotechnical assessment.
 6. Provide additional information to demonstrate how a low risk slope stability is
    achieved for the subject development and no adverse impacts are created on
    the neighbouring land (north, south and west).

Robert Gibb (RPEQ) from Tectonic provides the following commentary:

      ‘In Section 6.5 of our report, we intimated that the use of an engineer designed
      soakage/infiltration system would be acceptable from a stability perspective. This
      is what has been proposed by Westera.’

      ‘As part of our stability assessment for the site, we have provided a qualitative
      assessment in accordance with AGS 2007, which indicates a ‘Low Risk’ of
      instability could be achieved, subject to the implementation of the
      recommendations of our report. It should be noted that as part of the method used
      within AGS 2007 consideration for effects on adjacent properties is required.
      Stability for the proposed development was demonstrated further with numerical
      analysis, an extract of which was included in our report showing a factor of safety
      of 1.5 for long term conditions. To maintain this, a non-worsening condition should
      be achieved in terms of surface run-off and stormwater infiltration comparing
      existing conditions against those proposed at the site. Section 6 of the Westera
      Stormwater Management report indicates that the neighbouring properties or
      receiving environment would not be adversely affected, where the soakage trench
      is constructed in accordance with their design.’




Figure.6 Stormwater Management Plan Details




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