MCU14/0056 Stormwater Quantity Management Plan Att D Information response

Table 5.6 – Q5 HECRAS Results Comparison
                                            Proposed Developed
        Existing Inundation Level                                         Increase
 XS                                          Inundation Level
                 m AHD                                                       m
                                                 m AHD

 70                107.01                          107.011                 0.001
 60               107.025                          107.026                 0.001
 50               106.927                          106.928                 0.001
 40               106.791                          106.793                 0.002
 30               106.438                          106.441                 0.003
 20               106.249                          106.249                 0.000
  5               106.089                          106.089                 0.000
  1               105.985                          105.986                 0.001
 -5               105.422                          105.422                 0.000
-10               105.378                          105.379                 0.001
-15               105.361                          105.361                 0.000

Table 5.7 – Q2 HECRAS Results Comparison
                                            Proposed Developed
        Existing Inundation Level                                         Increase
 XS                                          Inundation Level
                 m AHD                                                       m
                                                 m AHD

 70               106.774                          106.772                 -0.002
 60               106.767                          106.766                 -0.001
 50               106.664                          106.663                 -0.001
 40               106.537                          106.537                  0.000
 30               106.157                          106.159                  0.002
 20               105.911                          105.910                 -0.001
  5               105.819                          105.818                 -0.001
  1               105.695                          105.694                 -0.001
 -5               105.010                          105.009                 -0.001
-10               104.928                          104.927                 -0.001
-15               104.906                          104.905                 -0.001

The results presented above show marginal increases in in flood levels (1-3mm) during a Q1,
Q5 and Q10 storm event however decreases are seen during a Q20, Q50 and Q100 storm event.
These increases are not considered to cause an actionable nuisance. The development would
not adversely impact neighbouring properties and roads. Detailed HECRAS results are
presented in Appendix D.

An inundation plan for the developed site is presented in Figure 8, Appendix A.


                               J4279 Report 1.0.doc
                                 14 January 2015                                     Page 13