2019-12-16 GC Agenda - Item 5 - Attachment 1 - Noosa Spit Shoreline Erosion Management Plan-Part 1

Noosa Spit SEMP Final Report                                                                                                                                                                                                                                                                            8
Noosa Spit Shoreline Erosion


 Imagery                                                                         Observed Changes                                         Wind Climate               Notable           Orientation        Northern Spit      Southern Spit      Dominant Flow       High Tide            High Tide
   Date                                                                        (since previous image)                                  Compared to Average           Rainfall         and Condition        Length and         Length and          Channel          Recreational         Recreational
                                                                                                                                          (since previous             (since             of Mouth           Condition          Condition                              Beach               Beach
                                                                                                                                               image)               previous                                                                                      Availability at      Availability at
                                                                                                                                                                     image)                                                                                       central Doggie         eastern
                                                                                                                                                                                                                                                                       Beach           Doggie Beach


May 1994                                           Paraphrased from Tomlinson and Chamberlain (2006):                                  No wind data available    Data           not   N-S                 Average, wide,     Minimal   above    Central,    but   Limited to none      Wide      (infilled
                                                                                                                                       for 1992 to 1995          available                                submerged          HWM,       long    multiple                               shoals)
                                                   The southern channel was the dominant flow path and continued to cut back
                                                                                                                                                                                                          shoals to south    submerged          channels
                                                   into Noosa Woods until a new central channel was cut as a result of increased       Double Island Point:      Known events:
                                                                                                                                                                                                          and west           shoals to north-   through shoals
                                                   river flows due to cyclones Betsy, and Fran in January and March 1992,              SE dominates, less S in   TC Betsy
                                                                                                                                                                                                                             west               shallow
                                                   respectively, and ex-TC Daman in February 1992. This new channel removed            1991 than average         Ex-TC Daman
                                                                                                                                                                                                                                                adjacent     to
                                                   the southern spit. The three channels continued to operate, with the southern                                 TC Fran
                                                                                                                                       Tewantin:                                                                                                Doggie Beach
                                                   and central channels progressively infilling, although the central channel
                                                                                                                                       1991 typical year
                                                   retained dominance over the northern channel. An apparent lack of longshore
                                                   transport supply stagnated spit growth for a time. Continued growth of the
                                                   northern and southern spits forced the middle channel to realign to the north.




May 1996                                           Not reviewed by Tomlinson and Chamberlain (2006).                                   No wind data available    Higher   than        Shore-parallel      Average, wide,     Short   above      Multiple          Limited              Average
                                                                                                                                       for 1992 to 1995          average:             west           of   submerged          HWM, average       channels
                                                   Consolidation of the northern Spit to the flood tide delta continued, with the
                                                                                                                                                                 May 1996             coastline, then     shoals to south    submerged          through shoals,
                                                   gradual infilling and southward migration of the central and southern channels      Double Island Point:
                                                                                                                                                                                      NE-SW                                  shoals to north-   shallow
                                                   towards Noosa Spit. The southern channel continued dominate and to cut back         Autumn 1996 more N
                                                                                                                                                                                                                             west               adjacent     to
                                                   into Noosa Woods.                                                                   than average
                                                                                                                                                                                                                                                Doggie Beach
                                                   Growth of the southern spit continued, forcing the channel to adopt a shore-        Tewantin:
                                                   parallel alignment before exiting to the north-east.                                Less E in 1996 than
                                                                                                                                       average




June 2004                                          Paraphrased from Tomlinson and Chamberlain (2006) to 2002, updated to 2004:         Double Island Point:      Significantly        Shore-parallel      Short,   wide,     Minimal above      Central,          Varies, limited to   Wide
                                                                                                                                       Spring 1998 and 1999      higher       than    west           of   submerged          HWM, average       backwater         wide
                                                   The river entrance maintained its characteristic location, exiting in a north-
                                                                                                                                       less N to NE than         average   (and       coastline,   then   shoals to south-   submerged          adjacent    to
                                                   easterly direction midway between the training wall and the north shore. The
                                                                                                                                       average                   highest monthly      NE-SW               west               shoals to north-   eastern Doggie
                                                   central channel progressively merged with the southern channel, and the
                                                                                                                                                                 totals      on                                              west               Beach
                                                   northern channel reopened, progressively increasing in size over time. The          Tewantin:
                                                                                                                                                                 record):
                                                   southern channel continued to cut into Noosa Woods.                                 More S in 1997 and SE
                                                                                                                                                                 February, May
                                                                                                                                       in 1998 than average
                                                   High rainfall in the first half of 1999 contributed to formation of a new central                             to July 1999
                                                   channel. This led to progressive closure of the northern channel as the northern
                                                   spit grew and merged with the flood tide delta, and the central channel migrated
                                                   southwards to become the new southern channel.

                                                   The southern spit continued to grow, holding the southern channel close to
                                                   Noosa Woods, where the upstream end of the training wall quickly generated
                                                   additional scour. This contributed to dominance of the southern channel.

                                                   In 2003 an unknown quantity of nourishment was placed at either end of a
                                                   section of the southern channel (refer Figure 3-18) to reduce erosion on Doggie




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