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


1.   Please provide a response and or revise the modelling you performed with regard to the
     following points:
a.   How the year 2008 was determined to be representative of long term weather patterns;

A brief analysis of the Year 2008 compared to long-term average conditions at the
nearest Bureau of Meteorology station (Tewantin) is provided in Attachment 3.

The analysis indicates that the Year 2008 is sufficiently representative of long-term
trends to be applied for the purpose of this assessment. There are variations in the
frequency of winds from various directions and speeds as compared to long-term
averages but these are evident for any year when compared to long-term averages.

The odour objective being assessed relates to the 44th ‘worst’ 1 hour periods of each
year for each receptor location. The ‘worst’ conditions for odour dispersion are
typically associated with lower (less than 3 metre per second) wind speed conditions.
The analysis indicates that wind speeds during 2008 were lower than long-term
averages and thus may be considered a conservative year in this regard.


b.   The effect of the radius of influence on Station 1 in TAPM being set at 15 km;

The radius of influence for the Nambour station is the TAPM observation nudging
dataset has been updated to 5km as per the request from PEL (per email 25
November 2013).


c.   Whether the vegetation resolution in the inner domains affects the model output.

MWA Environmental provided information regarding the land use dataset to PEL by
email on 21 November 2013. Subsequent advice from PEL (per email 25 November
2013) is that the land use data supplied appeared appropriate.


d.   Why the Teixeira algorithm was used in CALMET

The CALMET model has been updated to apply the ‘MM5toGrads algorithm’
(ICLOUD=4) as per request from PEL (per email 25 November 2013).


e.   Whether the THRESHL setting of 0 in CALMET has produced spurious mixing heights at
     dawn and dusk

The THRESHL value of 0 was applied by MWA Environmental in accordance with
the recommended setting from Generic Guidance and Optimum Model Settings for
the CALPUFF Modeling System for Inclusion into the ‘Approved Methods for the
Modeling and Assessments of Air Pollutants in NSW, Australia’ (TRC for NSW OEH,
2011). Box and whisker plots of the mixing heights by hour of day are presented in
Attachment 4 for review. The results appear reasonable to MWA Environmental.




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