Attachment 7- Site Based Stormwater Management Plan

Table B: Post construction phase — stormwater management design objectives
Application:

(a) A material change of use for an urban purpose that involves premises 2500 metres? or greater in size and:
(a) will result in six or more dwellings; or
(b) an impervious area greater than 25 per cent of the net developable area.

(2) Reconfiguring a lot for urban purposes that involves premises 2500 metres? or greater in size and will result in six or more lots.

fete teressatei) Design objectives
Reductions in mean annual load from unmitigated development (%)

Total Total Total foro) Waterway stability

STs eT (| phosphorus aces 4) POU CMU CLE lil’

solids (TSS) (TP) (TN) PT
South East Queensland 80 60 45 90 Limit the peak 1-year
ARI event discharge
within the receiving
Central Queensland (north) 75 60 4o%s 90 waterway to the

pre-development peak

 

Central Queensland (south) 85 60 45 90

Cape YANKS, wet tropics and 80 60% 40 90 1-year ARI discharge
dry tropics
Western Queensland’ 85 60 45 go

Notes:

* Mapping of climatic regions is available on the State Planning Policy Interactive Mapping System.

¢ In lieu of modelling, the default bio-retention treatment area to comply with load reduction targets for all Queensland regions
in 1.5 per cent of the contributing catchment area.

* Water stability objective applies if development drains to an unlined waterway within or downstream of the site where a risk of
increased erosion exists due to changes in hydrology. Local government may also require application of the waterway stability
objective where there are planned future rehabilitation works to return a lined channel to a natural channel design.

* The SPP Water quality guidance material provides advice on the measures that demonstrate compliance with table B.

™ Note: Applies to population centres greater than 25,000 persons.
Note: Mackay Regional Council has adopted a 35 per cent reduction for TN.

Note: Townsville City Council has adopted a 65 per cent reduction for TP.

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