MCU14/0056 Ecology Addendum report Att G - Information response

As discussed in the previous responses to item 32, the project proposes to retain the existing waterway corridor
(approximately 1.325ha) in its current form with an additional 10m buffer from the existing vegetation boundary to
safeguard impacts to bank stability and water quality. Soft treatments including biorention basins, a stormwater
detention area and landscaping with native species is proposed adjacent the protected waterway corridor to
minimise edge effects from the development. Further, bulk earthworks are not proposed within close proximity to
the retained waterway area and minimal hard surfaces (i.e. car park and Tourist Park) are located adjacent to the
buffered area.

No impacts on bank stability, including erosion and slumping is anticipated by the development. No works are
proposed within the existing riparian corridor and stormwater will be managed to maintain existing hydraulic
conditions. Detailed Bulk Earthworks Plans and Erosion and Sediment Control Plans will be prepared at operational
works to be approved by Council. Further, the SWMP details that the detention basin will be designed to mitigate
the effects of additional runoff and to ensure no worsening of stormwater flows up to and including Q100 stormwater
events. To assist with the removal of gross pollutants from run-off, Enviropod baskets are proposed to be installed in
all stormwater gullies and inlets (refer to the SWMP by VT Consulting Engineers for further detail on erosion and
sediment controls).

    f)   How the proposal protects riparian zones by maintaining water quality by filtering sediments, nutrients and
         other pollutants

As discussed in previous responses to Item 32, the waterway corridor will be retained in its current form with an
additional 10m buffer proposed on the existing vegetation boundary. Further, adjacent land uses to the waterway
corridor will include soft treatments such as bioretenison basins, a stormwater detention basin and landscaping with
native species to minimise edge effects from the development and allow runoff to be captured and filtered prior to
entering the waterway corridor area.

A SWMP has been prepared for the site which provides details on the proposed detention basins and stormwater
management of the site. This will involve a number of individual bioretention basin which will flow into a larger single
detention basin located at the South of the site. It is proposed that this detention basin will then drain to the existing
overland flow path at the South of the site via a new concrete headwall, channeling the stormwater towards the two
existing box culverts and Myall Street. The bioretenion system is designed to treat the stormwater runoff by filtering
runoff through densely planted vegetation and percolating the runoff through the filter media. The proposed design
is in accordance with the Water Sensitive Urban Design Technical Guidelines by Water Design. Further, to assist with
the removal of gross pollutants, it is proposed that Enviropod baskets be installed in all stormwater gullies and inlets.

Stormwater management and water quality standards will comply with the State Planning Policy Guideline – State
Interest – Water Quality August 2014 and SEQ Water Development Guidelines: Development Guidelines for Water Quality
Management in Drinking Water Catchments in 2012. MUSIC modelling for proposed bioretenion basis areas shows an
overall reduction in gross pollutant loads is anticipated from existing conditions through storm water management
proposed by the development and meets required Water Quality Objectives. Refer to the extract from the SWMP
below and IR Response Items 14 & 15 by VT Consulting Engineers for further detail.