2022-11-08 Planning & Environment Meeting Agenda

PLANNING & ENVIRONMENT COMMITTEE MEETING AGENDA                                 8 NOVEMBER 2022


seagrass. A hand-held GPS was used to assess the extent of seagrass bed, with a detailed map
produced based on the field data. The change in seagrass distribution was mapped from historical
imagery and this information was used to provide an analysis of the changes in seagrass
distribution through time from September 1989 to May 2020.
The assessment identified a total of 56ha of seagrass throughout the estuary, with the greatest
extent of seagrass occurring in Lake Doonella and along Weyba Creek. When compared to
previous assessments, there was no seagrass recorded upstream of the ferry crossing in 2020. It
was found that there has been a large decline in the coverage of continuous and dense seagrass
beds in several areas of the Noosa Estuary since 1989, with an estimated loss of up to 83% of
seagrass in this time, and some areas such as Lake Weyba where seagrass has been completely
lost. Only a small amount of recovery has been identified in areas in Lake Donnella.
Several factors are likely to have contributed to the decline. Large-scale flooding in 1992 is likely
to have been the primary cause of seagrass decline in several areas, with the floods resulting in
deposition of fine sediment and smothering of existing seed banks. Other factors influencing
seagrass decline vary dependent on the location and include increases in boat anchoring causing
direct physical damage to seagrass; shifting sand bars smothering large areas of seagrass;
changes due to urbanisation altering water quality or sediment dynamics; and the growth of
epiphytic algae leading to competition for light.
The report recommends “an adaptive approach that examines and implements measures that
maximise the resilience of seagrass beds, including the ability to respond to future natural disasters
and human pressures that are predicted to increase in the future”.
Other recommended management actions include the following:
•     Further assessment of the potential resilience of seagrass meadows to resist environmental
      changes in the Noosa Estuary to understand where to invest in future management actions
      for maximum gains
•     Identification of key triggers for past change in seagrass extent
•     Identification and management of potential negative inputs
•     Go-slow areas to minimise boat wash along the main channel
•     Reducing sediment in run-off and understanding the current sediment dynamics in the
      estuary
•     Investigation of the possible triggers for high epiphytic algal loads on the existing seagrass
      and assessment of the current water quality
•     Assisted restoration of seagrass meadows in suitable locations.
Future management of seagrass and factors influencing seagrass decline will be included in the
integrated water quality monitoring program, given that many of these factors (such as sediment,
land-based run-off) will be focuses of the program. Environment Services will continue to liaise with
The Nature Conservancy to discuss management strategies.
Previous Council Consideration
The full report was presented to the P&E Committee at the 12 April 2022 meeting. The report was
presented for awareness of Council, with a separate report proposed to be presented to Council
following further evaluation and consideration of future actions.
Council Ordinary Meeting 21 April 2022
That Council note the report by the Environmental Services Manager (Acting) to the Planning and
Environment Committee Meeting concerning the Noosa River Reef Shellfish Restoration Project
dated 12 April 2022 and;
A.    Note the 6 monthly report for the project submitted in accordance with the Alliance & Funding
      Agreement between Noosa Council and The Nature Conservancy;

                                                                                      Page 72 of 89