Development Application - Part 2 of 2 - Report & Plans · OPW11/0116

Compared to Option D1 [see section 0], it is clear that the addition of the downstream closure resulted in a much greater
impact during the ebb tide.

Closure of the southern channel has been undertaken in the past and has proven effective at creating a sheltered lagoon
area with a stable beach foreshore that is suitable for recreational usage. Numerical modeling has confirmed that narrower
structures with lower crest levels can also be effective at reducing flow velocities along the Noosa River Spit foreshore. The
inclusion of a downstream submerged closure is a significant component in ensuring that this option is effective. This option
is particularly effective along the vulnerable sections adjacent to the existing rock wall, but tends to be less effective in
upstream areas on the flood tide.




                                                                                            1
                                                                                                urent cl eed Jm/sJ
                                                                                                     4"'e 1 50
                                                                                                       ',0-150
                                                                                                     3 0-100
                                                                                                       -Q-080
                                                                                            i___             070
                                                                                            - 850-060
                                                                                            II. 040-050
                                                                                            -835.040
                                                                                                     : 30 - 0 35
                                                                                            ® -030
                                                                                                             025
                                                                                            litititi     5.0 20
                                                                                                       1ir -015
                                                                                            II•            -010
                                                                                                       VJ-UU5
                                                                                            JJJJJJ^ _ -in.s 0 00
                                                                                                     _' i J-tied value




                                                                                                urr rt<,ledlm!si
                                                                                                     =1.:,:c 1 50
                                                                                                             1 50
                                                                                                         C-100
                                                                                                         C-080
                                                                                            I-# : . C - 0 70
                                                                                                       lu06U
                                                                                            (♦         a,' -0"0
                                                                                            II• :5-040
                                                                                            (♦           C-035
                                                                                            II• -           -030
                                                                                                            -025
                                                                                            II•             -020
                                                                                                            -015
                                                                                                            -010
                                                                                            li•             -005
                                                                                            JJJJJJJn 6 m 0 00

Figure 30: Results of MIKE21HD model [ebb & flood tide] for Option D2 [upstream & downstream closure]