2016-02-02 Planning & Organisation Committee Agenda

PLANNING & ORGANISATION COMMITTEE MEETING AGENDA                           2 FEBRUARY 2016


Examples of these practices include:
   sediment runoff from building sites due to lack of erosion and sediment controls;
   car washes (runoff of hydrocarbons and cleaning substances);
   back washing of pools and spas (chemical releases);
   cleaning and painting roofs (runoff of paint and cleaning substances); and
   littering (including cigarette butts) particularly around commercial areas.

Without compliance monitoring of these types of business activities and practices it is
feasible to consider they may be releasing contaminants which are likely to impact on the
EVs of the Shire’s natural waters. These impacts may over time be cumulative and
significant.

Compliance monitoring of these activities can be achieved through prioritisation of existing
resources.

New residential developments

With regard to stormwater quality leaving new residential developments, over the past 5
years ‘bio retention basins’ have become the most common stormwater quality treatment
device installed in new residential developments.

These bio basins are considered best practice and are a hybrid engineered and vegetated
filtration device used to remove sediment, nutrients, and litter from urban stormwater runoff.

Bio basins do not remove all the additional pollutants generated by a development, but are
sized and selected to achieve the best cost to efficiency ratio.

This ratio is 80% reduction in total Suspended Solids, 45% reduction in Total Nitrogen, 60%
Reduction in Total Phosphorous and 100% reduction in Gross Pollutants (i.e. litter)
compared to if there were no bio basins incorporated into the development.

To perform effectively, bio basins must be maintained.

Earlier on in the year, Council agreed to a review of both Council-owned and privately-
owned bio basins with a focus on maintenance. This decision ensures there will be:
   ongoing compliance with development conditions that require bio basin maintenance;
   the quality of stormwater runoff from developments with bio basins is the best it can
     be; and
   the owners of bio basins are educated about their purpose and how to maintain them.

The bio basins review is now underway and approximately 25% of Council-owned bio basins
have been audited.

Existing urban areas

As opposed to new urban developments, within existing urban areas stormwater
infrastructures such as Gross Pollutant Traps (GPTs) were put in place long before bio
basins (or other Water Sensitive Urban Design (WSUD)) technologies existed.
These GPTs have been installed throughout the Shire in public and privately developed
areas.



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