080624 2383-01 FINAL Engineering Report for DA.pdf [As Published] · 132008.1128

BLUE CARE SUNRISE BEACH
ENGINEERING REPORT FOR DEVELOPMENT APPLICATION



2.            STORMWATER MANAGEMENT PLAN

2.1 SITE CHARACTERISTICS
The site of the proposed development has an area of 5.535ha. The site is vegetated and
currently undeveloped. Both lots have slopes of approximately 5% and drain to the Noosa
National Park. Lot 6 drains to the north and, Lot 1, to the west. Surface runoff, from the
site to the national park, occurs as sheet flow.

Lots 1 and 6 are separated by the Grass Tree Court road reserve.               This road is
constructed and provides access to the Uniting Church site, adjacent to Lot 6.

2.2 CATCHMENT AREAS
The site has been divided into two sub-catchments, based on the natural topography. The
post-developed sub-catchment boundaries are shown on Drawing No.2383-01 SK02.

The internal catchment area was further divided into impervious “clean” roof area and non-
roof area, as outlined in Table 2.1. The total roof area was determined from the Area
Schedules, provided by Smith and Tracey Architects. The non-roof area was assigned a
fraction impervious in accordance with the Brisbane City Council MUSIC Guidelines (BCC
Guidelines), and modelled as a separate source.

Table 2.1, Site Catchment Areas

        Internal Urban Area,                   Impervious “Clean”               Internal Urban
    Excluding buffer area (ha)                   Roof Area (ha)               Non-roof Area (ha)

                    4.427                            1.954                          2.473


Stormwater runoff from the site will be treated as follows:

-    “Clean” roof runoff will be harvested by draining to central retention storage for re-use;
-    Paved pedestrian areas and excess runoff from roof areas will drain to a gross pollutant
     trap (GPT) for preliminary treatment;
-    All runoff will be directed to bio-retention / detention basins sized to offset the increase
     in impervious areas; and
-    Runoff from the bio-retention basins will be discharged through spreader trenches to
     provide additional infiltration and decentralisation of flow, prior to it entering the National
     Park.
2.3 RE-USE OF STORED NON-POTABLE WATER
The water re-use criteria for the site aim to comply with the Queensland Development
Code (QDC) requirements enabling the benefits from Sections 5.10, 5.11 and 5.13 of the
Queensland Water Recycling Strategy (QWRS) (EPA, 2001) to be achieved. Based on
this, the criteria used to determine water re-use included the following:

-    ‘Fit for purpose’ uses
-    Source substitution
-    Wastewater minimisation


Blue Care Property Development Unit                     Version 1.1                                24 June 2008
2008 06 24 2383-01 Engineering Report for DA       Commercial in Confidence                              Page 5