2184Response_OM13_222

Mr David Milligan, W Donald Milligan Pty Ltd                                   29 November 2013
Re: Response to Sunshine Coast Regional Further Information Request of 19 November 2013 – Noise,
      Dust & Odour Issues - Proposed Poultry Growing Sheds, Ridgewood
                                                                               L26013/BH/12-002



f.   Why WSCALM was set at 0.2 m/s

WSCALM was set to a value of 0.2m/s to account for plume transport during the
approximate 100 hours of wind speeds predicted by the meteorological model to be
above 0 m/s but below 0.5m/s. This notwithstanding, the updated modelling has
been conducted with a WSCALM value of 0.5m/s as per request from PEL (per email
25 November 2013).


g.   What the influence of thermal buoyancy on emissions would have on predicted impacts
     at nearby receptors above the height of the sheds (i.e. the site should be modelled to
     evaluate this).

In accordance with PEL request, representation of emissions has been updated to be
as buoyant point sources in accordance with the method presented in the Best
Practice Guidance for the Poultry Industry – Plume Dispersion Modelling and
Meteorological Processing (PAE Holmes for DEEDI, May 2011).

This amended source representation considers thermal buoyancy by way of
representing emissions at the predicted release temperature of air from the sheds for
each hour of the batch cycles. Vertical mechanical momentum has been excluded
using a momentum flux factor of 0 (rain hat function).            The point source
characteristics have been set with varying emission velocity by hour as a function of
the ventilation rate divided by the cross sectional area of the effective 16.5m
diameter point source.

It is our understanding that this representation is in accordance with the
recommendations of PEL.


h.   What the impact would be of setting the initial vertical dispersion at 6 m for a building
     with a total height of 5 m (both odour and dust).

As above, the emissions representation has been updated to point sources in
accordance with the recommendations of PEL. This issue is therefore no longer
relevant.


i.   What the impact would be of setting the initial vertical dispersion as modelled for the
     litter sources rather than a more representative value for stockpile heights

MWA Environmental had previously modelled SIGZI 0.35 (1.5m stockpile height
divided by 4.3) as a conservative representation. This has been updated to SIGZI
0.70 (1.5m stockpile height divided by 2.15) for a ground level source as per
modelling guidance.




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