Enclosure 4 - Schedule 4a

 12.3 Prescribed tidal work is designed and      The design and construction of the prescribed tidal work is         No bank survey is available, however available aerial
 constructed in a way to ensure it does not      consistent with the following standards—                            imagery (2008 – 2016) indicates that adjacent
 adversely affect the stability of the bed and   (a) subject to paragraph (b), prescribed tidal work does not        foreshores are not experiencing significant long-term
 banks of any tidal water.                       cause, by changing the flow of water, the removal of, or            change and this is consistent with the lack of erosion
                                                 disturbance to, the sediment on the bed and banks of any tidal      scarps evident.
                                                 water;
                                                 (b) if a relevant planning scheme standard is more stringent than
                                                                                                                     Similar units have historically been utilised to provide
                                                 the standard mentioned in paragraph
                                                 a)—the relevant planning scheme standard, to the extent it is       protection to areas subject to wave erosion. As such,
                                                 more stringent than the standard mentioned in paragraph (a).        these units may result in accretion of the adjacent
                                                                                                                     foreshore although it is expected that tidal and flood
                                                                                                                     flows are dominant in most locations.

                                                                                                                     No modelling has been undertaken, however it is
                                                                                                                     expected that impacts would be relatively low given
                                                                                                                     the location close to the bank and the relatively small
                                                                                                                     footprint of the works. The units are angled to the
                                                                                                                     peak flood velocity to reduce impacts and oriented to
                                                                                                                     deflect ebb tide and peak flood flows toward the
                                                                                                                     channel (rather than toward the bank) to avoid
                                                                                                                     concentrating flows which might result in erosion of the
                                                                                                                     riverbank.

                                                                                                                     Localised build-up & scour is expected however the
                                                                                                                     proposed works are flexible and able to accommodate
                                                                                                                     minor changes. The majority of the sites appear
                                                                                                                     relatively stable with no sand ripples although aerial
                                                                                                                     photography indicates that they can be subject to
                                                                                                                     change. Significant sedimentation to the point of
                                                                                                                     burial is not expected. Sites 9 & 10 could potentially
                                                                                                                     experience the greatest changes, particularly in the
                                                                                                                     event of re-opening of the channel along the western
                                                                                                                     bank.

                                                                                                                     The works incorporate quarterly monitoring for the first
                                                                                                                     3 years and if any erosion or excessive accretion are
                                                                                                                     observed these can be evaluated and the reef units
                                                                                                                     can be modified, relocated or removed if necessary.




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Coastal Protection and Management Regulation 2003 – Schedule 4A – IDAS code for the development of prescribed tidal work