LT Creek Floodplain Risk Management Study & Plan Community Consultation Meeting No 1 30th November 2016 Presented by: Richard Dewar, WMAwater Pty Ltd

Overview – NSW Floodplain Management Process We are here

LT Creek Catchment 7km2

Floodplain Risk Management Study Identify the magnitude of the flood problem House floor levels v flood levels How often are house floors inundated and what damages occur? Measures to reduce the flood problem? Flood Modification Property Modification Response Modification Evaluate the Value of each Measure Reduction in flood level Cost Environmental impact Social impact Levee Raising Warning Raised floors

Community survey Mail-out and online version (Survey Monkey) 200 letters sent to residents and 20 to key stakeholders Responses via post /Survey Monkey

Survey response summary

Survey response summary

Survey response summary

Survey outcomes 1 flood photo 1 person has flood debris marks No above floor inundation Concerns Silt Bluewater Avenue overflow & Croft Oval overflow Suggestions Dredging Bluewater Avenue Decrease insurance – individual inspections Wetland containment area to limit sedimentation

Building Floors Inundated Catchment Flood = rain over LT Creek catchment 1% AEP (100 year) nil PMF 52 Lake Flooding = rain over Lake Macquarie catchment raising lake levels 1% AEP (100 year) 7 PMF 108 CONCLUSIONS Very small tangible($) damages to buildings Minor intangible damages – inconvenience, worry, risk to life Hard to justify expenditure on flood mitigation measures

Flood Mitigation Measures Flood Modification Vegetation clearing – environmental impact Levees – visual impact, cost Dams, retarding basins – cost, no available space Dredging – next page Property Modification House raising – little interest, cost Flood proofing – only for commercial New buildings – Development Controls Response Modification Flood warning – too quick response Evacuation planning – infrequently used

Issues considered in the study report Water Quality Outside our Scope Will be mentioned but cannot recommend measures Dams in Newstan Colliery Many there already Will reduce peak flows and levels downstream Risk of failure – subject to Dams Safety regulations Will address in report Mining Activities in Newstan Colliery Unable to advise if affect flooding Water quality outside our scope

Sea Level Rise & Lake Macquarie Flooding Dredging Suggested for water quality purposes Nil benefit for flooding as no floors inundated Environmental impact on flora and fauna Not sustainable – must dredge forever High cost – where to place spoil? Dredging not permitted for flood mitigation in NSW Sea Level Rise & Lake Macquarie Flooding Addressed in separate FRMS Council has initiated sea level rise adaptation plans Flood warning for lake flooding being updated