Development Application - Part 2 of 2 - Report & Plans · OPW11/0116

4.   RECOMMENDED OPTION

As was concluded in the previous 2006 report and supported by EPA, the "do nothing" option is still not preferred long-term
strategy, primarily due to the scope of the impacts associated with breaching of the Noosa River Spit. The modelling and
conceptual analysis of likely long-term behavior indicates that Option E [Figure 35] is the most effective. It achieves both the
primary goal of alleviating erosion along the Noosa River Spit [and eliminating the potential for breaching] as well as creating
conditions in which a protected recreational beach and lagoon area will remain stable. It limits the extent that the southern
channel can migrate southward while minimizing the potential impact of the works on natural estuary processes.

A discussion with local stakeholders was undertaken and concerns were raised by VMR about the closure of the southern
channel despite the dominance of the middle channel. As a result, it appears that dredging of the secondary southern
channel will be necessary to provide adequate navigation. As such, the strategy has been amended to include these works
[Figure 39]. Material from works is to be used as beach nourishment.




                                                       Submersed Closure                       ►          . _:S




              Dredging




                                                      Nourishment                      "f   tr^.it^L1 .^'' '
                                        Groynes
     Training Wall




                                                                               it




Figure 39: Recommended Strategy

     4.1.    Risk Assessment

All the options investigated [including the "do nothing" option] have associated impacts and risks. These risks can be
accepted, mitigated or managed. The recommended option has been assessed and the risks are outlined below.

            4.1.1. Uncertainty

The Noosa River is highly variable with the added complexity of predicted climate change. There are inherent limitations
associated with all assessment techniques and while it provides a valuable insight into the effectiveness of the proposed
works, a level of uncertainty remains. As such, a comprehensive monitoring strategy [Appendix C] is to be implemented to
allow for ongoing assessment of the performance and impacts works.            The monitoring strategy may recommend
modifications to the works to improve performance.