Representations

It is noted that current legislation and the Noosa Plan all point to Load Based Reductions
being appropriate for urban development. Additionally, the SEQWater Development
Guideline effectively notes that Environmental Values for water are set under the
Environmental Protection (Water) Policy 2009, which stipulates the appropriate targets be
sourced from Mary River Environmental Values and Water Quality Objectives. The Mary
River Environmental Values and Water Quality Objectives calls up the limits for Lowland
Freshwaters (as shown in Table 2 of the Covey Report). It also critically says at Section
3.1.3 “Stormwater Design Objectives” that design objectives for urban development are
contained in Urban Stormwater Quality Planning Guidelines 2010. These guidelines, within
Table 2.2, Summary of Design Objectives for Management of Stormwater Quality, again list
the Load Based Reduction Targets (same as State Planning Policy).

Despite the above information, it is recognised that the Lake MacDonald catchment requires
protection from impacts associated with urban runoff, given its ecological value and use as a
drinking water catchment. In lieu of this, it was proposed to over-treat stormwater runoff on
site in Covey Associates Report 100415 Iss. B.

The MUSIC modelling results from the submitted model are provided in Figure 2. The
pollutant load reduction rates required to be demonstrated on urban and commercial
development in South-East Queensland are as follows:

      Total suspended solids (TSS) – 80% reduction in mean annual load (kg/yr)
      Total Phosphorus (TP) – 60% reduction in mean annual load (kg/yr)
      Total Nitrogen (TN) -45% reduction in mean annual load (kg/yr)




         Figure 2 - Pollutant load reduction results from MUSIC Model for Report 100415 Iss. B


The pollutant load reductions highlighted in Figure 2 are well above what is required by the
State Planning Policy (2016) in terms of annual pollutant load reduction objectives. While
concentration based outcomes are not generally utilised for stormwater treatment, the
concentrations associated with a flow based sub-sample are as follows: