Change to Existing Approval - OPW11/0116.01

    PROPOSED CHANGE 2: DESIGN AMENDMENT



The ICM Report (2010) reviewed the advantages and disadvantages of the two preferred construction materials for the
works [Table 1].


Table 1 Ad vanta       es & d.
                             Isadvanta   es 0f rock & sand fll
                                                          -
                                                            I ed   eotextl1e containers [Extract from ICM     ,
                                                                                                               2010)
               Sand-filled Geotextile Containers                                               Rock
Advantages                                                         Advantages
.    Stable with suitable container sizes                          .    Stable with adequate rock sizes
.    Can be designed to allow for scour                            .    Can be designed to allow for scour
.    Flexible to accommodate additional scour if necessary         .    Flexible to accommodate additional scour if
.
    Easily removed /modified /extended if necessary                     necessary. Easily topped up.
.   Uses local materials [noneed to import materials]              .
                                                                        Easily extended
.   Uses floating plant [noaccess issues]                          .    Robust [nopotential for damage]
.
    User-friendly                                                  .    Voids may create habitat
.   Substrate may provide
.    Cost
Disadvantages                                                      Disadvantages
.    Vulnerable to damage from vandalism /vessel impact            .
                                                                       Import of materials required
     even with robust RPgeotextile. Higher maintenance.            .   If importing by truck, need for clearing and traffic
.
     Replacement cost [25yearlifetime]                                 issues along Hastings St
                                                                   .   Less user-friendly
                                                                   .    Cost
                                                                   .    More difficult to remove




Wtth regards to the preliminary design of the wall component at the end of Noosa River Spit, ICM (2010)concluded that:


         "It was originally preferred to construct [the wall at the end of Noosa River Spit] using rock due to
            concerns   regarding the potential for damage. During stakeholder consultation, it becoame evident that
            there were concerns regarding the use of rock, the difficulty of removal and the visual impact. At this
            stage, the preferred option is the sand-filled mega-container wall, although if maintenance becomes an
            ongoing issues, consideration may be given to rock armouring."

As such, the detailed design and approvals obtained for the works were for a sand-filled mega-container structure [Figure 4
& Figure 5].