The SOBEK model used a grid size of 20 m; this was considered sufficient for the level of detail required (Figure 6-2). Key development features such as roads, levees and shore protection structures were checked to ensure they were picked up as topographic features, and were refined where necessary. No formal protection structures exist in this area; therefore the low retaining walls that line the eastern bank of the creek were checked within the underlying topography for elevation. Culverts were incorporated beneath the road in two locations:

In addition to these, four culverts were identified along the boundary between Thompson Creek and the local properties and incorporated them into the model. The tidal boundary was applied at the mouth of the Thompsons Creek. The model was run for the 1% AEP storm-tide case in combination with a number of sea-level rise scenarios to determine the extent of inundation that would arise. The adopted storm-tide levels are shown in Table 6-1.

Figure 6-2     Extent of Breamlea model, showing river and tidal inflows and culvert locations (pink circles)

Table 6-1      Adopted storm-tide levels for Breamlea area