2018-05-14 GC Agenda Attachment 1 to Item 6 Lake MacDonald Dr Community Reference Group Investigations Report

Option 2B – Extended high level earth bund


As per Option 2A; however, the high level earth bund is extended along the rear (western) property
boundaries of those properties where flood waters currently pass from the main channel of Six Mile
Creek to the overland flow path which leads to Hamilton Road.

Based upon the results obtained from modelling Option 2A the option to extend the bund and
further exacerbate the impact was deemed unfeasible. Localised increases in upstream flood
levels of up to and beyond 1m would be expected with additional increases above 250mm also
expected in the main branch of Six Mile Creek.

Option 3 - Channel works (a)
The main water channel of Six Mile Creek adjacent to the western end of Liane Drive includes a
sharp right angle bend with high downstream embankment. This suggested mitigation option was
to excavate a channel to link the bends of the main channel to effectively straighten the main
channel and improve the efficiency of flood flows.

The flood model results for this option show no reduction in flood levels in the vicinity of Highland
Drive and only small localised reductions for either the moderate or major flood events.

Refer to Figure 15 and Figure 16.


Option 4 - Channel Works (a + b)
As per Option 3; however, the proposed works are extended to include and straighten the next
significant upstream bend of the main channel.

The flood model results for this option also showed no reduction in flood levels in the vicinity of
Highland Drive and only relatively small localised reductions for either the moderate or major flood
events.

Refer to Figure 17 and Figure 18.




Lake McDonald Flooding Community Reference Group Report                                        Page 26