H - Revised Integrated Water Management Plan by Cardno (inc MUSIC file) (13.09.19)

                                                                                       Integrated Water Management Plan
                                                                               Noosa Marketplace : 2-20 HOFMANN DRIVE



4.2.2       Rainfall Parameters
Rainfall parameters input to RAFTS were sourced using ARR 2019 BOM IFD values.

4.2.3       RAFTS Parameters
Catchment characteristics are shown in Table 4-1. For the purposes of this hydrological model, land uses were
defined as per existing use. Catchment slopes were determined using drainage lines for each catchment.
Manning’s values were set to 0.045 for pervious areas and 0.015 for impervious areas as per Chapter 4.1 of
the Noosa Planning Scheme-Policy 5-Engineering Design Standards.
A critical aspect of hydrological models is the choice of loss rates (e.g. initial and continuing losses). QUDM
was used to source loss rates with Chapter 4 – Catchment Hydrology being used to investigate loss rates.
Section 4.2.3 recommends that the latest version of Australian Rainfall and Runoff should be used when
selecting loss rates.
Initial and continuing losses were set using the ARR 2019 data hub with values shown in Table 4-2.
              RAFTS Catchments

 Catchment          Total Area      Percentage Impervious         Vectored Slope       Catchment Manning’s 'n'
 ID                    (ha)                  (%)                       (%)                  Perv/Imperv

 1                     2.31                      95                    2.96                   0.045/0.015
 2                     0.77                      95                    5.10                   0.045/0.015
 3                     0.60                      95                    5.20                   0.045/0.015
 4                     0.69                      95                    3.36                   0.045/0.015
 5                     1.17                      50                    3.39                   0.045/0.015
 6                     0.34                      0                     1.81                   0.045/0.015
 7                     0.18                      0                     1.22                   0.045/0.015
 8                     1.15                      95                    1.34                   0.045/0.015
 9                     0.46                      95                    1.56                   0.045/0.015
 10                    0.88                      50                    1.41                   0.045/0.015
 11                    0.09                      50                    0.31                   0.045/0.015
 12                    0.06                      95                    0.84                   0.045/0.015
 13                    0.14                      5                     1.86                   0.045/0.015
 14                    0.53                      5                     2.07                   0.045/0.015
 15                    0.54                      0                     0.78                   0.045/0.015
 16                    0.16                      5                     0.09                   0.045/0.015
 17                    0.45                      0                     2.48                   0.045/0.015
 18                    0.17                      35                    3.58                   0.045/0.015
 19                    0.14                      0                     1.52                   0.045/0.015
 20                    0.42                      5                     1.28                   0.045/0.015
 21                    1.53                      95                    0.92                   0.045/0.015

Table 4-2     Initial and Continuing Losses for RAFTS Modelling
 Land Use                              Initial and Continuing Losses
 Rural Areas (Parks/Road verge)        27mm IL/ 2.6mm/h CL
 Urban Areas (Carparks/buildings)      2mm IL/0mm/h CL

A range of design storms were modelled with 10 differing temporal patterns and multiple durations as per ARR
2019. The maximum median storm was then used as the peak design flow.




V190428 | 10 September 2019 | Commercial in Confidence                                                              11