Attachment 6 - Odour Impact Assessment - Katestone · 132005.638.06

Figure A9      2020 diurnal profile of mixing height predicted by TAPM/CALMET

A2 Dispersion modelling

CALPUFF simulates the dispersion of air pollutants to predict ground-level concentration and deposition rates
across a network of receptors spaced at regular intervals, and at identified discrete locations. CALPUFF is a non-
steady-state Lagrangian Gaussian puff model containing parameterisations for complex terrain effects, overwater
transport, coastal interaction effects, building downwash, wet and dry removal, and simple chemical transformation.
CALPUFF employs the 3D meteorological fields generated from the CALMET model by simulating the effects of
time and space varying meteorological conditions on pollutant transport, transformation, and removal.

CALPUFF takes into account the geophysical features of the study area that affect dispersion of pollutants and
ground-level concentrations of those pollutants in identified regions of interest. CALPUFF contains algorithms that
can resolve near-source effects such as building downwash, transitional plume rise, partial plume penetration, sub-
grid scale terrain interactions, as well as the long-range effects of removal, transformation, vertical wind shear,
overwater transport and coastal interactions. Emission sources can be characterised as arbitrarily varying point,
area, volume and lines or any combination of those sources within the modelling domain.

Key features of CALPUFF used to simulate dispersion:

    •    Domain area of 80 by 80 grids at 0.1 km spacing, a subset of the domain defined in CALMET

    •    365 days modelled (1 January 2020 to 31 December 2020)

    •    Gridded 3D hourly-varying meteorological conditions generated by CALMET

    •    Partial plume path adjustment for terrain modelled

    •    Dispersion coefficients calculated internally from sigmas v and w using micrometeorological variables

    •    Transitional plume rise and PDF used for dispersion under convective conditions

All other options set to default.

The following source parameters were used for dispersion modelling:

    •    For sources at the composting facility, an effective height of 3m and a sigma z of 0.75 was used for all
         sources

    •    For sources at the landfill, an effective height of 5m for the active tip face and 1m for day cover and final
         cover was used. A sigma z of 1.25 for the active tip face and 0.25 for day cover and final cover was used.
         All four landfill layout scenarios used the same values for effective height, sigma z and total source areas.


 Katestone Environmental Australia Pty Ltd                                                       17 September 2026
 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final                                       Page 34