PA3660-Coastal Hazard Assessment - 4 arakoon

                                                  Project related




6.3             Comparison to past assessment
BMT (2018) under took the ‘Noosa Shire Council Coastal Hazards Risk, Vulnerability and Adaptation
Assessment’ on behalf of Noosa Shire Council as part of the Coastal Hazard Adaptation Strategy. The
BMT (2018) erosion prone area reassessment covered all beach compartments within the Noosa Shire
local government area.

BMT (2018) calculated the erosion prone area components at each ETA line and averaged the values
across multiple lines to calculate the erosion prone area for each beach compartment. For comparison to
the assessment herein the BMT (2018) assessment for the Sunshine Beach compartment and ETA 602 is
most applicable.

Table 6-6 compares key parameters used in calculating the components of the erosion prone area
adopted by BMT (2018) and this assessment. Table 6-7 compares the components and width of the
erosion prone area.


Table 6-6 Comparison of erosion prone area calculation parameters
 Parameters                       RHDHV Assessment                       BMT (2018)                   BMT (2018)

 Location                         4-6 Arakoon Crescent                    ETA 596                          ETA 602

 Storm tide (m AHD)                        1.74                             2.20                            2.20

 Wave Height (m)                           6.2                               6.2                             6.2

 Dune Height (m AHD)                        12                               4.9                             4.9

 Depth of closure (m
                                           -12                              -11.5                           -11.5
 AHD)

 Active profile Height (m)                  24                              16.9                            16.9

 Active beach width (m)                    550                               525                            595

 Median sand size D50
                                           0.22                             0.22                            0.22
 (mm)



Table 6-7 Comparison of erosion prone area components and width
                   Long-term                          Recession due
                                   Short-term                               Dune        Factor of      Erosion Prone
                   Recession                         to Sea level rise
                                   Erosion (m)                           Slumping (m)   safety (m)        Area (m)
                      (m)                                  (m)

                       NxR         C1       C2              S                 D             F                 2100

    ETA 596             10         21        0              26               19             23                 99

    ETA 602             10         52        0              26               13             35                 136

   Sunshine
     Beach              10         37        0              26               16             29                 118
   (Average)

  4-6 Arakoon
                        10         19        0              18               14             19                 80
    Crescent


The following sections provide a detailed comparison of the parameters adopted for this study and BMT
(2018) and justification for any differences in the calculated components of the erosion prone area.




11 April 2024          4-6 ARAKOON CRESCENT, SUNSHINE BEACH                   PA3660-RHD-XX-ZZ-RP-Z-0001            34