20517 App J.pdf [As Published] · 132007.1259

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Concept Stormwater Management Plan
Essence of Peregian

  

 

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2.5.1.2. The guidelines then refer the user to the default regional water quality guidelines for slightly to moderately So
disturbed waters (Table 2.5.1.1). =

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According to Figure 2.5.1b of the Queensland Water Quality Guidelines (2006), the site falls within the ‘lowland
stream’ water type. Table 2.5.1.1 outlines the indicator values suitable for MUSIC Modelling (Refer to Section 4.3)
and are reproduced in Table 4.1 below.

Table 4.1: South-East Queensland Regional Water Quality Guideline Objectives*

 

Pollutant | Total Suspended Solids (mg/L) | Total Phosphorous (mg/L) | Total Nitrogen (mg/L)

 

 

 

 

 

 

Objective 6 : 0.050 0.500:
*Concentrations given are median values.

 

The following load reduction targets which satisfy water quality objectives (WQOs) of Maroochy Shire Council are
listed in Table 4.2. The reason for inclusion of these targets is explained in Section 4.2.2.

Table 4.2: Maroochy Shire Council Pollutant Load Reduction Targets*

 

 

 

 

 

Pollutant Load Reduction Target (%)
Total Suspended Solids 80
Total Phosphorous 60
Total Nitrogen 45

 

 

 

*MSC Planning Scheme Policy No. 5 (Section 7.2.4).

The design objectives are reductions in mean annual load leaving developed areas, compared to traditional
urban design where stormwater is not treated (Australian Government, 2006).

42.2 Water Quality Objectives Suitable to Site

The site is currently in a partially developed state. Its use as a Caravan Park and camping ground comprises
grassed areas, gravel access roads, demountable cabins, concrete pads for caravan parking, site amenity
buildings, an office and a bitumen entrance road. The proportion of hard (impervious) surface fluctuates
throughout the year due to the variable presence of vehicles and caravans. The presence of these surfaces and
other equipment brought to the site by guests leads to the likelihood of higher pollutant loads in runoff than the
site alone. Also, due to the fact that the site is not in a natural ‘undeveloped’ condition, it is considered that
concentration targets as required by Queensland Water Quality Guidelines cannot appropriately be applied to
this development.

It is considered that load reduction targets are more appropriate to determine the impact of water quality
treatment trains proposed for the development. The load reduction targets of Maroochy Shire Council have been

adopted for the purposes of this Stormwater Quality Management Strategy.

4.3 MUSIC Modelling

Water quality modelling of the proposed development has been undertaken using the Model for Urban Stormwater
Improvement Conceptualisation (MUSIC) Version 3.01, developed by the Cooperative Research Centre for
Catchment Hydrology (CRCCH). MUSIC enables the user to model the transfer of pollutants through a catchment
and provides an aid in determining how effective the stormwater quality treatment train is at meeting WQOs. The
critical pollutants to be modelled are Total Suspended Solids (TSS), Total Phosphorous (TP) and Total Nitrogen
(TN).

 

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