BBNE01676-0001-REP-001-0-Noosa Calile Overland Flow_Optimized

2.2.1.1 Topography
Model topography has been based upon 2015 Light Detection and Ranging (LiDAR) along with the detailed site survey. Design DEM has been
incorporated into the model to represent the proposed development.

The catchment has been modelled using a 0.5m hydraulic model grid size.

2.2.1.2 Boundaries
The inflow boundaries for the catchment have been read into the model using inflow polygons (2d_sa and 2d_bc) to represent inflow from
the WBNM hydrology model.

The outflow boundary for the model has been applied 70m downstream of the site, which is approximately 5m lower than the site outlet
and is considered suitable for this assessment. A normal depth rating curve has been adopted for the downstream with a water surface slope
of 0.02 m/m.

2.2.1.3 Roughness
The model roughness is represented by the Manning’s roughness coefficient, n, in the TUFLOW materials file. Manning’s coefficients have
been applied to reflect the land use within the catchment, assuming development conditions based on NSC zoning and aerial imagery.
Roughness coefficients are outlined in Table 2.4, while the spatial distribution of material types in the TUFLOW model extent is included in
FIGURE 2.3.

TABLE 2.4: ADOPTED MANNING’S ‘N’ ROUGHNESS

 Land Use                                                              Manning’s ‘n’

 Road                                                                  0.025

 Buildings                                                             0.3

 Vegetated Channel                                                     0.035

 Vegetation                                                            0.06

 Gravel/Grass                                                          0.065

 Dense Vegetation                                                      0.15

 Residential                                                           0.12


2.2.1.4 Structures
The stormwater network represented in the hydraulic model aligns with the stormwater plan and long-section developed by Alta Projects
and are presented in Appendix B.




NOOSA CALILE I BBNE01676-0001-REP-001-0                                                                                                   7