Revised Civil Engineering Response Cover Letter

ISSUE 19
The earthwork cross sections do not appear to extend into the adjoining properties to
the east and indicate the recently constructed access driveway and surface levels

Information Required:
Indicate on the adjoining driveway on the engineering cross section plans and also include
on the plans any measures necessary to protect the structural integrity of the driveway
and the adjoining property

RESPONSE
Please refer to the attached updated civil drawings which show the as constructed levels
of the adjacent driveway. It is confirmed from the subdivision works that the driveway is
typically 0.8m back from the cadastral boundary and whilst there is a sandstone boulder
wall (1 block high) along part of this boundary, the maximum step is 0.4m and not in the
locations of where the earthworks cross sections are cut. To address this, Top of wall and
bottom of wall RLs (TOW, BOW) are given on drawing 2123 - R04 (Rev C). None of the
proposed height changes are more than 600mm and, given the setback to edge of
driveway concrete, means the adjacent driveway pavement will not be undermined. Exact
construction methodology for footings in this area is to be managed as part of the
structural engineering works. It is proposed that a condition is included with any decision
notice to confirm that development works would not undermine or impose loads
unaccounted for to the adjacent lot driveway pavements.



ISSUE 20

Information Required:
Provide updated OPW drawings for the bioretention basin which address the following
issues:
20.1 Provide survey for the existing drainage system that the bioretention device will
connect into (i.e. existing pit IL and pipe diameter and outfall IL). Confirm that the basin
subsoil drains will drain effectively.
20.2. Show the proposed subsoil drain layout in plan view.
20.3. Inconsistent level information is shown in the boxed text and on the sections for the
bioretention on drawing R07 – resolve inconsistencies

RESPONSE
Item 20.1. The invert of the proposed stormwater pit was confirmed on site (measured by
engineer) to be 1.65m deep. This provides sufficient depth for the proposed detention
tank connection.
Item 20.2. Please refer to the attached drawing 2123/R07 for updated subsoil layouts
Item 20.3. Please refer to the attached drawing 2123/R07 for updated RLs.



ISSUES 21 & 22

Information Required:
21. It appears that a detention basin was provided within the downstream drainage
reserve as part of the original development of the industrial estate. Consider whether the
detention tank proposed is necessary given this downstream infrastructure.
22. If the detention tank is retained, address the following:

2123 – 3 Taylor Court, Cooroy                                                              3
CL/cl