Annex 10 - Code 8 - Coastal Development & Tidal Works

  Performance outcomes                                            Acceptable outcomes   Response
  Residual Impact Guideline, Department of State                                        intertidal zone adjacent to the proposed restoration
  Development, Infrastructure and Planning, 2014. Where the                             footprint. Mangrove roots are excluded from the restoration
  significant residual impact is considered an acceptable                               footprint at a minimum distance of 2m. Seagrass is found
  impact on the matter of state environmental significance                              upstream and outside of the restoration footprint and is
  and an offset is considered appropriate, the offset should be                         excluded from the footprint at a minimum distance of 10m
  delivered in accordance with the Environmental Offsets Act                            from the footprint.
  2004.                                                                                 According to project consultants, ESP, macroalgae growing
                                                                                        on rocks, dominated by Padina sp. is sparse (less than 15%
                                                                                        of the surface area), with a footprint of less than 479m2.
                                                                                        The macroalgal assemblages are in relatively poor condition
                                                                                        due to high sediment loads observed on and around the
                                                                                        existing rocky reef and rubble areas, with some sections of
                                                                                        reef having a high coverage of fine sediment.
                                                                                        ESP also confirmed that given the speed at which Padina
                                                                                        can colonise hard surfaces (dead oyster shell) elsewhere in
                                                                                        the estuary (ESP 2021), it is anticipated that supplementary
                                                                                        habitat provided as part of the proposed restoration project
                                                                                        would be colonised rapidly within 1 year of deployment, and
                                                                                        that coverage would be similar to the current condition
                                                                                        within 2 to 3 years post deployment, particularly in sections
                                                                                        that particularly in sections that remain subtidal and not
                                                                                        covered by fine silt.
                                                                                        The proposed oyster reef patches are designed and
                                                                                        certified by engineers. The oyster reef patches are spaced
                                                                                        (1-4m apart) so as not to not impede fish passage, cause
                                                                                        significant erosion (due to wave refraction) or impact
                                                                                        negatively on natural hydrological processes of the
                                                                                        waterway including laminar river flow. The oyster reef
                                                                                        patches are set away from the shoreline and will not
                                                                                        interfere with overland flow and runoff as a result of floods.
                                                                                        Water quality will be maintained at the restoration sites
                                                                                        during the construction phase in accordance with the
                                                                                        sediment management protocol outlined in this Restoration
                                                                                        Plan (see Project Restoration Plan. Section 6.4: Sediment
                                                                                        management). The restored oyster ecosystems will
                                                                                        enhance water quality by filtering estuarine water, removing
                                                                                        algae and particulate matter from the water column and
                                                                                        converting nutrients, such as nitrogen and phosphorus, into
                                                                                        biogenic oyster growth as well as binding these into the
                                                                                        surrounding sediments.
State Development Assessment Provisions – version 2.6
State code 8: Coastal development and tidal works                                                                          Page 12 of 20