2015-04-28 Planning and Organisation Committee Agenda

PLANNING & ORGANISATION COMMITTEE MEETING AGENDA                                                 28 APRIL 2015



Critical Design Parameter                               Most Common Impacts on the Critical Design
                                                        Parameter

Speed at which water can filter through the             Sedimentation or blocking of the underdrainage
engineered sand (called hydroconductivity)              pipes which affects the speed water can move
                                                        through the engineered sand

Plant selection (in particular related to the density   Weed intrusion or conversion to non-specified
of plant leaf to root ratio )                           native plants that are not efficient at removing the
                                                        nutrients

Volume of water able to be held within the              Installation of other structures within the footprint
bioretention basin                                      of the bioretention basin.


Development approvals issued under the Noosa Plan include conditions for the bioretention
basins to be maintained in accordance with their own proposed maintenance manual or the
maintenance strategies recommended by WSUD championing body - Healthy Waterways.

During, and on completion of construction of the bioretention basins, officers undertake
inspections to ensure the basins are constructed correctly. However, after completion of the
development, no further audit of the basins for compliance with the development approval
conditions is currently undertaken.

6.    The future of Water Sensitive Urban Design to protect the Noosa Shire
      Environmental Values and Water Quality Objectives (EVWQO)

Continual advances in technology means changes are being investigated for future best
practise methods to make sure EVWQO are met in all Queensland waters. A new computer
modelling program has been developed called eWater Source Catchment Modelling. The
intent of the eWater Source catchment model is to be able to input different land
management practices across the catchment, then the theoretical quality of creek and river
water at any point in the catchment can be predicted within the parameters of the eWater
Source catchment model. The intent of the eWater Source catchment model is to indicate
the resilience of the waterways to absorb more development while theoretically maintaining
EVWQO. This is not currently possible under the MUSIC modelling.

eWater Source Catchment Modelling generates theoretical results to inform catchment
decisions. At a broad scale, the model has capacity to incorporate the influence of existing
and future stormwater quality improvement scenarios – such as WSUD (i.e. bioretention
basins), riparian buffer areas and other land management practices etc. across the entire
catchment and theoretically predict the influence of these on downstream waterquality.

In the future, and with improved data input accuracy, it is hoped the eWater Source
catchment model will be able to theoretically identify whether parts of Noosa and Mary River
are, or are not likely meet their EVWQO over the long term, and whether any changes in
upstream land use practice scenarios, including for example retrofitting of WSUD or other
offset strategies will help.

The eWater Source catchment model will be heavily relied on by Healthy Waterways for
future annual River Health Report Cards.

In conjunction with Healthy Waterways, Noosa Council Officers have already begun
investigating development of eWater Source catchment modelling for the Noosa River as
part of Council’s Hydrodynamic Modelling Project. In the event the eWater Source


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