24572-05 Response to Council information request - Engineering · MCU24/0125

FRONTAGE WORKS

Item 6 – Kerb and Channel and bike lane.

Response

Frontage works including kerb and channel and a 2.0m wide bike lane are detailed on the
revised drawings.



EARTHWORKS

Item 7 & 8 – spot levels, retaining walls and cross sections.

Response
Additional information for the earthworks has been added to the revised drawings, including
cross sections showing bulk earthworks levels and the interface with neighbouring properties.
Separate plans have been provided to show retaining wall levels and heights (TOW, BOW) and
standard details. Refer plans C020 – C024.



EXTERNAL DRAINAGE WORKS AND NON WORSENING

Item 9 – Provide updated SWMP and drainage design details.

Response

A revised SWMP accompanies this response and addresses the non-worsening issue. A
detention tank has been added to the design to mitigate peak flows. Stormwater long sections
including HGL information have been included in the revised drawings for both the 10% and 1%
AEP events. It should be noted that within the development site we have elected to pipe the 1%
AEP event to the detention tank, however there will be some minor surcharging at the pit
immediately downstream from the detention tank in the 1% AEP (2100) event as the
downstream pipe network is only designed for a 10% AEP (2015) event. Refer also to wording
in the SWMP that explains the rationale for the detention tank design and sizing. With respect to
item 9 d) we consider Council’s position that there shall be no surcharging of the existing
network in the 1% AEP (2100) to be unreasonable and not in consistent with standard
stormwater design principles where the major event is conveyed via the road network or other
overland flow paths.