Callaghan & Toth 24-4-14 Response to Information Request

extent of earthworks and western tributary plan, long section, and cross-sections in Figures
9, 10, and 11 of the flood study showing the minor reshaping of the channel.

Natural channel design principles will be incorporated in the reshaping of the tributary and
features will include:
e Arock lined invert approximately 1.5m wide
e Removal of vegetation acting as weeds and currently clogging the watercourse
e Plant out the banks that have been reshaped with groundcover and stabilising plants
e.g. Lomandra spp to a density of one plant per 2m”
e Retain existing trees in the riparian buffer areas
e Infill planting in riparian areas to achieve a density of 1 plant per 1.5m” focusing on
canopy and pioneer species to achieve shade cover of the watercourse.

17. Justification for any infrastructure / road within the riparian buffer area.

Response:

Even though there is some encroachment it is considered that the overall intent of the
Biodiversity Overlay and mapped Riparian Buffer Areas is achieved on site by:

e Maintaining a riparian corridor along both waterways, generally a minimum of 10m
wide. In some areas the riparian buffer is much wider.

e Existing native vegetation is to be protected.

e Revegetating the riparian buffer areas on both waterways to maintain wildlife
corridors.

e Minimising encroachment into the riparian buffer areas. In some locations a 10m wide
buffer is not achieved as shown in orange on plan 1225-33.

o Lot 15: The defined bank is heavily vegetated with shrubs and mature trees at
present, and Q100 flood level in contained in the bank. We have moved the
rear boundary back as far as practical to allow the minimum 5m vegetated
buffer from top of bank.

o Proposed pedestrian footbridge on Eastern Tributary has been removed from
riparian area.

o Lot 26: We have allowed for a 3m wide grassed area behind the lot so Park
maintenance access is provided.

o Road 1 Road Reserve: Some minor areas have been removed where
necessary for turfed sections beside the road. On plan 1225-45 the Typical
Bio-retention Swale Detail shows that base of swale and batter on western
tributary side are vegetated to form part of the riparian planting.

The area of riparian buffer that could not be achieved as noted above has been offset
by planting an area of the Eastern Tributary (see yellow areas on plan 1225-33). An
offset planting area of 580sqm area has been used to offset the 340sqm shortfall.

Road 1 centreline, Road Reserve and lots 17-20, 29 front boundaries have been
moved approximately four metres further back from the Western Tributary to allow
more riparian planting and move the road away from the banks. The road centreline
and swale have also been curved to minimize tree removal.

e Maintaining water quality by providing a stormwater treatment system that achieves
best practice pollutant load reductions.

X:JOBS\CT Projects in progress\1225 30 lots lake MacDonald Drive\Correspondencelstage 3 & 4\Response to Info_Request_Jan2014.doc