2019-01-14 General Committee Agenda - Attachment 1 to Item 2 - Noosa River Partnership Proposal

The Nature Conservancy


       6.3.     Assessment of Options

A mix of qualitative and quantitative assessments of different construction options are
provided in the table below:

 Option                  Benefit             Cost              Risk                   Response
 Construct               Reef                Requires          Unlikely to            Undertake
 reefs in staged         construction        multiple barge    result in              staged
 approach over           method can be       or other plant    complete reef          approach to
 two phases              improved over       equipment         failure but may        restoration.
                         time (adaptive      mobilization/     result in need to      Incorporate
                         management).        demobilization    deploy oysters         pilot project
                         Possible            costs.            over several           lessons into
                         improved oyster     Depending on      time periods.          reef design.
                         survival/           size of barge     This is still likely   Work with local
                         enhanced            required this     to be cheaper          coastal
                         biodiversity for    could be up to    ($20-50k) than         engineers to
                         reefs               an additional     multiple barge         optimize final
                         established in      $100k per         mobilization           reef design for
                         later years         deployment.       costs.                 location to
                                                                                      minimize
                                                                                      threats.
 Use recycled            Lower cost          Requires          May result in          Work with local
 shell as reef           compared to         sufficient        slumping/              coastal
 base                    using rock as       recycled shell    spreading/             engineers and
                         reef base.          material to be    smothering of          ecologists to
                         Likely results in   available,        reef base due          optimize final
                         greater reef        biosecurity       to lightweight         reef design and
                         extent and cost     protocols and     nature of              materials for
                         effectiveness       permits in        materials and          locations.
                                             place.            lower reef
                                                               profile.
 Use only                Lower cost          Requires          Recruitment is         Assess the
 natural                 compared to         sufficient        less than              need for
 recruitment as          hatchery            natural spat      required to form       hatchery
 means of                produced            recruitment and   oyster                 produced
 populating              oysters. Does       minimal           reef/sustain           oysters in
 oysters                 not require         biofouling        population             Phase II and
                         translocation       during time of                           monitor natural
                         permit or           recruitment                              recruitment
                         broodstock                                                   over time with
                         harvest.                                                     view to move
                                                                                      away from
                                                                                      hatchery
                                                                                      produced
                                                                                      oysters if
                                                                                      natural
                                                                                      recruitment
                                                                                      sufficient




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