12/07/2017. Developing a Practical Shelter In Place Policy A Case Study in Fairfield. Overview. Pressures

Transcription

1 Overview Developing a Practical Shelter In Place Policy A Case Study in Fairfield Steven Molino Leonie Gray Fairfield City Council Pressures Policies Problems Project Practicalities Politics 2 Pressures Rapid Growth after World War II Little consideration for flooding Major flooding in 1986 and 1988 Detention basins House raising schemes Planning controls Community education Urban renewal and consolidation Opportunity to reduce flood risks Practical Shelter-in-Place (SIP) policy 3 4 1

2 Mainstream flooding 1% AEP - 5,314 properties PMF - 15,655 properties Overland flooding 1% AEP - 9,753 properties PMF18,937 properties 2

3 Policies Emergency Management Australia SIP favoured only when evacuation is too dangerous NSW Government No residential development controls above 1% AEP plus 0.5m NSW State Emergency Service SIP only for existing development if evacuation is too dangerous Do not rely upon SIP for new development Local Government - SIP for new developments Tweed Shire Northern Beaches Newcastle Problems Residual Risk to Life Inadequate refuge level, size, stability Traversing floodwaters leaving or returning Medical emergencies access to hospital grade care Fire emergencies improvised lighting and cooking fire escape fire fighting access Loss of services (e.g. electricity, gas and telecommunications) Lack of basic supplies (e.g. water, food, medication) 9 10 Shelter-in-Place (SIP) Project Where is SIP appropriate? Where is SIP not appropriate? How to manage residual risk to life if SIP permitted? Risk Thresholds Flood Probability -5% AEP, 1% AEP and PMF Flood Hazard Duration of Isolation 2 hours 8 hours

4 Relationship to Building Residential attract, non- residential repel Residential buildings more likely to house vulnerable people (e.g. children, elderly, people with disabilities) Non-residential unoccupied at least 2/3 of time Occupants of non-residential buildings likely to be awake during flooding Suggested SIP Policy and Controls Four Risk to Life Zones for PMF event in Fairfield LGA:- Green Zone(Negligible risk to life) PMF Hazard H2 Yellow Zone (Low risk to life) PMF Hazard >H2, < 2 hours Orange Zone (Medium risk to life) PMF Hazard >H2, 2-8 hours Red Zone (High risk to life) PMFHazard >H2, > 8 hours Development Types Residential Replacement Residential Intensification Commercial or Industrial Critical or Sensitive

5 Controls Recommended risk to life controls for development type and risk to life category GREEN ZONE PMF, Hazard H2 YELLOW ZONE PMF, Hazard >H2, Duration < 2h ORANGE ZONE PMF, Hazard >H2, 2h< Duration <8h RED ZONE PMF, Hazard >H2, Duration >8h Residential Replacement 1, 2 1, 2 1, 3 1, 4 Residential Intensification 1, 2 1, 4, 5 1, 4, 5, 6, 7, 8 Not suitable Commercial/Industrial 1, 2 1, 5, 6, 7 9 Not suitable Critical and Sensitive Not suitable Not suitable Not suitable Not suitable For developments located across two or more risk to life classes, Molino the Stewart correct class is assigned based on the location of the 17 development s pedestrian access/egress point. Controls 1. Building stands in PMF -all 2. 10% floor above PMF -Green 3. 20% floor above PMF Yellowand Orange % floor above PMF -Red 5. 1% AEP pedestrian access Yellowand Orange 6. Flood emergency response plan residential Orange, non-residential Yellow 7. Risk reduction features residential Orange, nonresidential Yellow Emergency power Fire suppression 8. Medivac residential Orange 9. Orangenon-residential below FPL access to PMF refuge 18 Evacuation Practicalities Where to evacuate to? Existing risks Incentives to rebuild Secondary risks not confined to flood liable land Leave and enter Medical emergency Fire emergency Who is sheltering?

6 Politics State PMF control within extent of FPL? Controls beyond FPL Local controls above FPL? Conclusions Evacuation not practical response for most locations Secondary risks not confined to flooded land SIP more suitable alternative in certain instances Redevelopment with SIP can reduce existing individual risk to life but may increase number of individuals at risk Quantified risk analyses to determine acceptable, tolerable and unacceptable risks to life Controls to manage residual secondary risks to life

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