Meeting papers

                                                                                      Burgess Creek
                                                 Receiving Environment Monitoring Program
                                                                                 Annual Review 2022
patterns. Further research is necessary to establish dependable approaches to assess water
flow within this region.

The last detailed assessment of the impacts of the Noosa STP on Burgess Creek remains
consistent with the previous year's Burgess Creek Receiving Environment Monitoring Program
Annual Assessment and Review (2021) and was conducted in 2004. This modelling used the
only known measured flow rate within Burgess Creek and used flow data collected at the
nearby Teewah Creek. The principal issues of existing and historical land use remain largely
unchanged, but the increasingly variable rainfall events and intensity of these events may
have different consequences than originally assessed. Coupled with the Noosa STP
approaching the designed capacity and design life of the asset, reassessment of the current
disposal strategy into Burgess is recommended. Particular attention is recommended around
natural and sewage treatment flows within the western branch of Burgess Creek with the
changing climatic patterns to ensure the strategy of minimisation and disposal remains
unchanged from the original decisions.

A review of spatial variability of average concentrations of water quality parameters within
Burgess Creek showed that the Noosa STP outfall was not the sole influence on water quality
parameters, most notably microbiological indicators (E.coli, faecal coliforms and enterococci).
Microbiological indicators at Site B3, immediately downstream of the treated wastewater
discharge pipe, remain below upstream values represented in B8 and B2. Conversely, the
highest concentrations are represented at B1 and SW3, furthest from the outfall. Typically,
with good quality treated wastewater and the creek having a high flow rate and good mixing,
the microbiological indicators should decrease with distance downstream due to dilution and
natural degradation processes. Burgess Creek data does not follow this trend as
microbiological indicators increase with distance from the outfall after microbiological
indicators released within treated wastewater from the Noosa STP being compliant with
release limits within the EA and primary recreational water guideline limits. . This suggests
other contributing factors dominate microbiological quality in the Catchment.

The analysis of long-term trends in Burgess Creek has revealed an increase in enterococci
upstream at B8, where low flow rates and poor mixing prevail. Meanwhile, thermotolerant
coliforms have displayed a decreasing long-term trend at monitoring site SW3, with slight
increases observed at monitoring sites B3, B8, B5, and B6, while no clear trend was evident
at monitoring sites B1 and B2 from 2015 to 2021. Concentrations of microbiological indicators
were generally higher downstream at B1 and SW3, which resulted in the catchment's highest
concentrations of enterococci and thermotolerant coliforms. Notably, the highest average

  This document may not, in whole or part, be copied, photocopied, reproduced,
  or translated without prior consent from the CEO, Unitywater.                     Page 49 of 64

                                                                                            Page 263 of 310