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

Table of Figures
Figure 1: Contributing catchment to Highland Drive ........................................................................ 6
Figure 2: Historical Rainfall Records – Eumundi ............................................................................. 8
Figure 3: Percentage imperviousness of the Cooroy sub-catchments ........................................... 12
Figure 4: Hydrograph reference locations ..................................................................................... 14
Figure 5: Model Result Hydrographs - Location 2 ......................................................................... 15
Figure 6: Model Result Hydrograph - Location 3 ........................................................................... 15
Figure 7: Model Result Hydrograph - Location 5 ........................................................................... 16
Figure 8: Model Results Hydrograph - Location 7 ......................................................................... 16
Figure 9: Unmitigated Change in Flood Levels due to Ultimate Urbanisation - 5%AEP Event ....... 17
Figure 10: Unmitigated Change in Flood Levels due to Ultimate Urbanisation - 1%AEP Event ..... 18
Figure 11: Low level earth bund flood mitigation option - Moderate Flood Event .......................... 22
Figure 12: Low level earth bund flood mitigation option - Major Flood Event ................................ 23
Figure 13: High level earth bund flood mitigation option - Moderate Flood Event .......................... 24
Figure 14: High level earth bund flood mitigation option – Major Flood Event ............................... 25
Figure 15: Channel works (A) – Moderate Flood Event ................................................................. 27
Figure 16: Channel works (A) – Major Flood Event ....................................................................... 28
Figure 17: Channel works (A+B) – Moderate Flood Event ............................................................ 29
Figure 18: Channel works (A+B) – Major Flood Event................................................................... 30
Figure 20: Flood model results for moderate flood event............................................................... 34
Figure 21: Flood model results for major flood event ..................................................................... 35
Figure 22: No Dam outflow - moderate flood event ....................................................................... 36

Table 1: Mitigation Option Assessment ......................................................................................... 31
Table 2: Hydraulic Blockage Factors ............................................................................................. 32




Lake McDonald Flooding Community Reference Group Report                                                                    Page 2