1909-13367 SRA referral response approved docs

A number of 1D and 2D items have been used to model the existing catchment. The below sections list
the 2D parameters that have been adopted.


1D Nodes

1D nodes have been used to model each of the individual sub catchments. Each node is defined by its
hydrologic and hydraulic parameters. Catchment nodes did not have hydraulic parameters as their
runoff hydrographs were linked to rainfall/flow areas which distributed the runoff hydrographs evenly
over a flow area. The exception to this was the 1D nodes connecting to the 1D channels. These nodes
had invert levels equal to the channel bed.



1D nodes were also used to connect 1d elements such as headwalls to the 2D mesh.



2D Grid

The 2D grid extents were extended both upstream and downstream of the development site. A 2m grid
cell size has been adopted. A 2D time step of 0.5 seconds was adopted for all models. The following
figure depicts the extent of the 2D grid extents.




                                             Flood Study                                          15
S19-007                               122 & 144 Myall St, Cooroy