2017-07-11 Planning & Environment Committee Agenda

PLANNING & ENVIRONMENT COMMITTEE MEETING AGENDA                                    11 JULY 2017


The applicant submits that the POD’s water quality targets are redundant and requests that
condition 27 e) be amended to reference the State Planning Policy and Covey’s Stormwater
Management Plan which achieves pollutant load reductions well above required rates.
Assessment
Officers engaged a Water Quality Expert from WBM BMT to seek advice on Condition 27 e) and
the associated impact on Condition 27 k).
The advice from WBM BMT outlined that it is not reasonable to apply the water quality
parameters being represented in 27 e) or as currently conditioned in 27 k) for the following
reasons:
1.    The objectives on Condition 27 e) and 27 k) are for dry weather targets for receiving
      waterways and are not pertinent to stormwater discharges. The input parameters for the
      MUSIC modelling actually show that a forested catchment would not be able to provide the
      conditioned water quality objectives in a stormflow event.
2.    The concentration based objectives required by the Environmental Protection Water Policy
      have been replaced by load based reduction targets in current best practice industry
      standards. The document titled WSUD: Development Design Objectives for Water
      Sensitive Development in SEQ Version 2 by Water by Design 2007 states the following
      reason for the replacement:
      2.1. The concentration based approach fails to recognise the substantial difference
           between urban diffuse sources during dry and wet weather flows as well as the
           impact on receiving waterways (i.e. ecological processing etc).
      2.2. ANZECC recommends that load based guidelines are more relevant than
           concentration based guidelines in recognition of the important impact of total mass
           (or load) of Total Nitrogen, Total Phosphorous and Total Suspended Solids on
           ecosystem health.
3.    The Water Quality Targets are unlikely to be achievable with regard to conventional best
      practice stormwater management practices. There are no water quality treatment methods
      that are demonstrated to output waters at the concentrations required by Conditions 27 e)
      and 27 k).
4.    SEQ Water Development Guidelines: Development Guidelines for Water Quality
      Management in Drinking Water Catchments (SEQ Water 2012) is the relevant guideline to
      refer to for development in Drinking Water Supply Catchments. Item M26.1 of that
      guidelines requires that Land Uses, development, activities and stormwater management
      ensure no adverse impacts on water quality outside the boundaries of the site.
      For the purpose of the assessment, no increase of stormwater pollutant loads was adopted
      as no adverse impact on water quality outside the boundaries of the site.
      WBM BMT in their assessment corrected the MUSIC model and also ran a MUSIC model
      for a vacant industrial lot. The results demonstrated that the proposed development will not
      increase stormwater pollutant loads compared to the existing vacant industrial land use.


The representation on the conditions is therefore acceptable and it is recommended to change
Condition 27 e) and delete 27 k) as follows:
27.   The site must be provided with a stormwater drainage system connecting to a lawful point
      of discharge. The works must be undertaken in accordance with an Operational Works
      approval and the Queensland Urban Drainage Manual, and must include in particular:




                                                                                   Page 25 of 78