Wollongong City Local Flood Planwollongong.ses.nsw.gov.au/Wollongong_Flood_Plan_-_Oct_2003.pdf · Wollongong City Local Flood Plan – October 2003, Sub-Plan of Wollongong Local Disaster

WOLLONGONG CITY LOCAL FLOOD PLAN

A SUB-PLAN OF THE WOLLONGONG LOCAL DISASTER PLAN

(DISPLAN)

Chair, Local Emergency Management Committee

Wollongong City SES Local Controller

OCTOBER 2003 EDITION

TO BE REVIEWED NO LATER THAN OCTOBER 2008

ii

DISTRIBUTION LIST ......................................................................................................................... iv

LIST OF ABBREVIATIONS...............................................................................................................vi

GLOSSARY..........................................................................................................................................vii

PART 1 - INTRODUCTION.................................................................................................................1

1.1 Purpose .....................................................................................................................................1 1.2 Authority...................................................................................................................................1 1.3 Area Covered By The Plan .......................................................................................................1 1.4 Description Of Flooding And Its Effects ..................................................................................1 1.5 Responsibilities.........................................................................................................................1 1.6 Cross-Border Assistance Arrangements ...................................................................................8

PART 2 - PREPAREDNESS .................................................................................................................9

2.1 Maintenance of this Plan ..........................................................................................................9 2.2 Floodplain Management ...........................................................................................................9 2.3 Development of Flood Intelligence ........................................................................................10 2.4 Development Of Warning Systems ........................................................................................10 2.5 Public Education.....................................................................................................................11 2.6 Training ..................................................................................................................................11 2.7 Resources................................................................................................................................11

PART 3 - RESPONSE..........................................................................................................................12

3.1 Control....................................................................................................................................12 3.2 Operations Centres .................................................................................................................12 3.3 Operational Management........................................................................................................12 3.4 Liaison ....................................................................................................................................12 3.5 Communications.....................................................................................................................12 3.6 Activation ...............................................................................................................................13 3.7 Flood Intelligence ...................................................................................................................13 3.8 Preliminary Deployments .......................................................................................................14 3.9 Warnings.................................................................................................................................14 3.10 Information .............................................................................................................................15 3.11 Road Control ..........................................................................................................................16 3.12 Traffic Control. .......................................................................................................................16 3.13 Flood Rescue ..........................................................................................................................17 3.14 Evacuations.............................................................................................................................17 3.15 Registration.............................................................................................................................18 3.16 Essential Services ...................................................................................................................18 3.17 Logistics .................................................................................................................................19 3.18 Management Of Evacuees’ Pets .............................................................................................19 3.19 Assistance for Animals ...........................................................................................................19 3.20 Stranded Travelers..................................................................................................................19 3.21 All Clear .................................................................................................................................19

PART 4 - RECOVERY ........................................................................................................................20

4.1 Welfare ...................................................................................................................................20 4.2 Recovery Coordination...........................................................................................................20 4.3 Debriefing Arrangements .......................................................................................................20

ANNEX A - THE FLOOD THREAT ...............................................................................................A-1

General .............................................................................................................................................A-1 Weather Systems and Flooding ........................................................................................................A-2 Floods on the Creeks ........................................................................................................................A-3 Storm Surges ....................................................................................................................................A-4 Extreme Flooding .............................................................................................................................A-5

Wollongong City Local Flood Plan – October 2003, Sub-Plan of Wollongong Local Disaster Plan

iii

ANNEX B - EFFECTS OF FLOODING ON THE COMMUNITY ..............................................B-1

General .............................................................................................................................................B-1 Property Inundation ..........................................................................................................................B-1 Transport Disruption ........................................................................................................................B-2

ANNEX C - GAUGES MONITORED BY THE WOLLONGONG CITY SES LOCAL HEADQUARTERS ............................................................................................................................C-1

ANNEX D - DISSEMINATION OF SES FLOOD BULLETINS...................................................D-1

ANNEX E - TEMPLATE EVACUATION WARNING MESSAGE.............................................E-1

ANNEX F - ARRANGEMENTS FOR THE EVACUATION OF CARAVAN PARKS AND THE RELOCATION OF CARAVANS..................................................................................................... F-1

General ............................................................................................................................................. F-1 Advising Procedures......................................................................................................................... F-1 Evacuation of Occupants and Relocation of Vans............................................................................ F-2 Return of Occupants and Vans ......................................................................................................... F-3

MAP 1 - COUNCIL AREA.................................................................................................................... I

MAP 2 - FLOOD PLAIN MANAGEMENT AREAS.........................................................................II


iv

DISTRIBUTION LIST Wollongong City SES Local Controller ....................................................................1 Wollongong City SES Unit........................................................................................1 Illawarra/South Coast SES Division Headquarters....................................................1 NSW SES State Headquarters ...................................................................................1 Wollongong City Council Local Emergency Operations Controller.........................1 NSW Police Service, Illawarra Local Area Command..............................................1 NSW Police Service, Wollongong Police Rescue Squad ..........................................1 Wollongong City Council Local Emergency Management Committee Members ....4 Wollongong City Council Local Emergency Management Officer ..........................1 Wollongong City Council Local Emergency Operations Centre ..............................1 Wollongong City Council Mayor ..............................................................................1 Wollongong City Council General Manager .............................................................1 Wollongong City Council Technical Services Department.......................................1 NSW Fire Brigades, Helensburgh, Scarborough, Coledale, Thirroul, Bulli, Corrimal, Balgownie, Wollongong, Port Kembla, Unanderra and Dapto .................................1 Rural Fire Service, Wollongong City Rural Fire Control..........................................1 Ambulance Service of NSW, Bulli, Dapto, Warilla, Warrawong and Wollongong .1 Volunteer Rescue Association, South Coast Rescue Squad ......................................1 Caravan Parks, Oaklands, Lake Illawarra and Oasis Village ....................................1 Illawarra Electricity, Coniston Electricity .................................................................1 Telstra, Telecom Australia, Wollongong...................................................................1 NSW Agriculture, Agroffice......................................................................................1 Department of Community Services, Wollongong....................................................1 Roads and Traffic Authority, Wollongong ................................................................1 National Parks and Wildlife Service, Illawarra Area.................................................1 Evacuation Centres ....................................................................................................1 Hospitals ....................................................................................................................1 Schools.......................................................................................................................1 Council Libraries .......................................................................................................1


v

AMENDMENT LIST Suggestions for amendments to this plan should be forwarded to:

The Local Controller Wollongong City State Emergency Service PO Box 322 Fairy Meadow 2519

Amendments promulgated in the amendment list below have been entered in this plan.

Amendment List Number

Date Amendment Entered By

Date


vi

LIST OF ABBREVIATIONS

The following abbreviations have been used in this plan: AEP Annual Exceedance Probability AHD Australian Height Datum ARI Average Recurrence Interval (Years) ALERT Automated Local Evaluation in Real Time AWRC Australian Water Resources Council CBD Central Business District CBM Commonwealth Bureau of Meteorology DSC Dams Safety Committee DISPLAN Disaster Plan DLWC Department of Land and Water Conservation DoCS Department of Community Services DSEP Dam Safety Emergency Plan DVR Disaster Victim Registration EFE Extreme Flood Event GIS Geographic Information System GRN Government Radio Network LGA Local Government Area LEMO Local Emergency Management Officer LEOCON Local Emergency Operations Controller MR Main Road NPWS National Parks and Wildlife Service NRMA National Roads and Motorists’ Association PMF Probable Maximum Flood PMR Private Mobile Radio PSTN Public Switched Telephone Network RTA Roads and Traffic Authority SES State Emergency Service SEWS Standard Emergency Warning Signal SH State Highway TR Trunk Road UHF Ultra High Frequency VRA Volunteer Rescue Association


vii

GLOSSARY Annual Exceedance Probability (AEP). The chance of a flood of a given or larger size occurring in any one year, usually expressed as a percentage. For example, if a peak flood level (height) has an AEP of 5%, there is a 5% chance (that is, a one-in-20 chance) of such a level or higher occurring in any one year (see also Average Recurrence Interval). Australian Height Datum (AHD). A common national surface level datum approximately corresponding to mean sea level. Average Recurrence Interval (ARI). The long-term average number of years between the occurrence of a flood as big as, or larger than, the selected event. For example, floods reaching a height as great as, or greater than, the 20 year ARI flood event will occur on average once every 20 years. Catchment (river basin). The land area draining through the main stream, as well as tributary streams, to a particular site. It always relates to an area above a specific location. Design flood (or flood standard). A flood of specified magnitude that is adopted for planning purposes. Selections should be based on an understanding of flood behaviour and the associated flood risk, and take account of social, economic and environmental considerations. There may be several design floods for an individual area. Essential services. Those services, often provided by local government authorities, that are considered essential to the life of organized communities. Such services include power, lighting, water, gas, sewerage and sanitation clearance. Flash flooding. Flooding which is sudden and often unexpected because it is caused by sudden local or nearby heavy rainfall. It is sometimes defined as flooding which occurs within six hours of the rain that causes it. Flood. Relatively high water level which overtops the natural or artificial banks in any part of a stream, river, estuary, lake or dam, and/or local overland flooding associated with drainage before entering a watercourse, and/or coastal inundation resulting from super-elevated sea levels and/or waves overtopping coastline defenses. Flood classifications. Locally-defined flood levels used in flood warnings to give an indication of the severity of flooding (minor, moderate or major) expected. These levels are used by the State Emergency Service and the Commonwealth Bureau of Meteorology in flood bulletins and flood warnings. Flood intelligence. The product of collecting, collating, analyzing and interpreting flood-related data to produce meaningful information (intelligence) to allow for the timely preparation, planning and warning for and response to a flood.


viii

Flood liable land. Land susceptible to flooding by the Probable Maximum Flood. (PMF) event. This term also describes the maximum extent of a floodplain which is an area of a river valley, adjacent to the river channel, which is subject to inundation in floods up to this event. Flood of record. Maximum observed historical flood. Flood Plan. A plan that deals specifically with flooding and is a sub-plan of a Disaster Plan. Flood plans describe agreed roles, responsibilities, functions, actions and management arrangements for the conduct of flood operations and for preparing for them. Floodplain Management Plan. A plan developed in accordance with the principles and guidelines in the New South Wales Floodplain Management Manual. Such a plan usually includes both written and diagrammatic information describing how particular areas of flood prone land can be used and managed to achieve defined objectives. Floodway. An area where a significant volume of water flows during floods. Such areas are often aligned with obvious naturally-defined channels and are areas that, if partially blocked, would cause a significant redistribution of flood flow which may in turn adversely affect other areas. They are often, but not necessarily, the areas of deeper flow or the areas where higher velocities occur. Geographic Information System (GIS). A computerised database for the capture, storage, analysis and display of locationally defined information. Commonly, a GIS portrays a portion of the earth’s surface in the form of a map on which this information is overlaid. Local overland flooding: inundation by local runoff rather than overbank discharge from a stream, river, estuary, lake or dam. Major flooding. Flooding which causes inundation of extensive rural areas, with properties, villages and towns isolated and/or appreciable urban areas flooded. Minor flooding. Flooding which inconvenience such as closing of minor roads and the submergence of low-level bridges. The lower limit of this class of flooding, on the reference gauge, is the initial flood level at which landholders and/or townspeople begin to be affected in a significant manner that necessitates the issuing of a public flood warning by the Commonwealth Bureau of Meteorology. Moderate flooding. Flooding which inundates low-lying areas, requiring removal of stock and/or evacuation of some houses. Main traffic routes may be covered. Peak height. The highest level reached, at a nominated gauging station, during a particular flood event. Probable Maximum Flood (PMF). The largest flood that could conceivably be expected to occur at a particular location, usually estimated from probable maximum precipitation. The PMF defines the maximum extent of flood prone land, that is, the floodplain. It is difficult to define a meaningful Annual Exceedance Probability for


ix

the PMF, but it is commonly assumed to be of the order of 104 to 107 (once in 10,000 to 10,000,000 years). Runoff. The amount of rainfall which ends up as streamflow, also known as ‘rainfall excess’ since it is the amount remaining after accounting for other processes such as evaporation and infiltration. Stage height. A level reached, at a nominated gauging station, during the development of a particular flood event. Stream gauging station. A place on a river or stream at which the stage height is routinely measured, either daily or continuously, and where the discharge is measured from time to time so as to develop a relationship between stage and discharge or rating curve.


1

PART 1 - INTRODUCTION

1.1 Purpose

1.1.1 This plan covers preparedness measures, the conduct of response operations and the coordination of immediate recovery measures from flooding within the Wollongong City Local Government Area (LGA). It covers operations for all levels of flooding within the Council area.

1.1.2 The plan also covers arrangements for the management of coastal erosion / inundation in the Council area.

1.2 Authority

1.2.1 This plan is issued under the authority of the State Emergency and Rescue Management Act 1989 and the State Emergency Service Act 1989. It has been accepted by the Illawarra/South Coast SES Division Controller and the Wollongong City Local Emergency Management Committee.

1.3 Area Covered By The Plan

1.3.1 The area covered by the plan is the Wollongong City LGA which includes a number of urban and suburban areas from Helensburgh to Yallah and Windang. The Council area with suburbs is shown in Map 1. The Floodplain management areas are shown in Map 2.

1.3.2 The Council area is in the Illawarra/South Coast SES Division and for emergency management purposes is part of the Illawarra Emergency Management District.

1.4 Description Of Flooding And Its Effects

1.4.1 The nature of flooding in the Wollongong City LGA is described in Annex A.

1.4.2 The effects of flooding on the community are detailed in Annex B.

1.5 Responsibilities

1.5.1 The general responsibilities of emergency service organisations and supporting services (functional areas) are listed in the Local Disaster Plan (DISPLAN). Some specific responsibilities are expanded upon in the following paragraphs. The extent of their implementation will depend on the severity of the flooding.

1.5.2 Wollongong City SES Local Controller. The Wollongong City SES Local Controller is responsible for dealing with floods as detailed in the State Flood Plan, and will:


2

a. Control flood and coastal erosion/inundation operations. This includes:

• Directing the activities of the SES Units operating within the Council area.

• Coordinating the activities of supporting agencies and organisations and ensuring that liaison is established with them.

b. Maintain a Local Headquarters at Montague Street, NORTH WOLLONGONG in accordance with the SES Controllers’ Handbook and the SES Operations Manual.

c. Ensure that SES members are trained to undertake flood operations in accordance with current policy as laid down in the SES Controller’s Handbook and the SES Operations Manual.

d. Develop and operate a flood intelligence system.

e. Coordinate the development and operation of a flood warning service for the community.

f. Participate in floodplain management initiatives organised by the Wollongong City Council.

g. Coordinate a public education program so that residents of flood prone areas can be made aware of the flood threat.

h. Ensure that the currency of this plan is maintained.

i. Activate this flood plan and begin operations.

j. Identify and monitor people and/or communities at risk of flooding.

k. Direct the conduct of flood rescue operations.

l. Direct the evacuation of people and/or communities.

m. Ensure immediate welfare support is provided for evacuated people.

n. Coordinate the provision of emergency food and medical supplies to flood bound people and/or communities.

o. Provide an information service in relation to:

• Flood heights and flood behavior.

• Road conditions and closures.

• Advice on methods of limiting property damage.

• Confirmation of evacuation warnings.


3

p. Coordinate operations to protect property, for example by:

• Arranging resources for sandbagging operations.

• Lifting or moving household furniture.

• Lifting or moving commercial stock and equipment.

• Moving farm animals.

q. Arrange for support (for example, accommodation and meals) for emergency service organisation members and volunteers assisting them.

r. If SES resources are available, assist the Police Service and Council with road closure and traffic control operations.

s. Exercise financial delegations relating to the use of emergency orders as laid down in the SES Controllers’ Handbook.

t. Submit Situation Reports to the Illawarra/South Coast SES Division Headquarters and agencies assisting within the Council area. These will contain information on:

• Road conditions and closures.

• Current flood behavior.

• Current operational activities.

• Likely future flood behavior.

• Likely future operational activities.

• Probable resource needs.

u. Keep the Local Emergency Operations Controller advised of the flood situation and the operational response.

v. Issue the ‘All Clear’ when flood operations have been completed.

w. Ensure that appropriate debriefings are held after floods.

x. Assist in the establishment and deliberations of the Recovery Coordinating Committee after floods.

1.5.3 Wollongong City SES Unit Members.

a. Carry out flood response tasks. These may include:

• The management of the Wollongong City SES Local Headquarters Operations Centre.


4

• Gathering flood intelligence.

• Flood rescue.

• Evacuation.

• Providing immediate welfare for evacuated people.

• Delivery of warnings and information.

• Sandbagging.

• Lifting and/or moving household furniture and commercial stock.

• Moving farm animals.

• Assisting with road closure and traffic control operations.

• Assisting with emergency fodder supply operations.

b. Assist with flood preparedness activities.

c. Undertake training in flood operations.

1.5.4 Wollongong City Local Emergency Operations Controller (LEOCON).

a. Monitor flood operations.

b. Coordinate support to the Wollongong City SES Local Controller if requested to do so.

c. As required by the Wollongong City SES Local Controller, evacuate people at risk.

1.5.5 NSW Police Service, Illawarra Local Area Command.

a. Assist with the delivery of evacuation warnings.

b. Assist with the conduct of evacuation operations.

c. Conduct road and traffic control operations in conjunction with Council and/or RTA.

d. Ensure all evacuees are registered.

e. Secure evacuated areas.

1.5.6 Wollongong City Local Emergency Management Officer (LEMO).

a. Provide executive support to the LEOCON in accordance with the Wollongong City Local Disaster Plan.


5

b. At the request of the Wollongong City SES Local Controller, advise appropriate agencies and officers of the activation of this plan.

1.5.7 Wollongong City Council.

a. Maintain a plant and equipment resource list for the Council area.

b. Contribute to the development and implementation of a public education program on flooding within the Council area.

c. At the request of the Local SES Controller, deploy personnel and resources for flood related activities.

d. Close and reopen Council roads (and other roads nominated by agreement with the RTA) and advise the Wollongong City SES Local Controller, the Police and people who telephone the Council for road information.

e. Provide filled sandbags to urban and village areas in which flooding is expected.

f. In the event of evacuations, set up and operate animal shelter compound facilities for the domestic pets and companion animals of evacuees.

g. Provide for the management of health hazards associated with flooding. This includes maintaining water supply and sewerage systems and removing debris and waste.

h. Ensure premises are fit and safe for reoccupation and assess any need for demolition.

i. Provide geotechnical advice as required.

1.5.8 Commonwealth Bureau of Meteorology (CBM).

a. Provide Flood Watches and Severe Weather Warnings for the Wollongong City LGA.

1.5.9 NSW Fire Brigades; Helensburgh, Scarborough, Coledale, Thirroul, Bulli, Corrimal, Balgownie, Wollongong, Port Kembla, Unanderra, and Dapto.

a. Assist with the delivery of evacuation warnings.

b. Assist with the conduct of evacuations.

c. Provide facilities for pumping floodwater out of buildings and from low-lying areas.

d. Assist with the cleanup operations, in particular the hosing out of flood affected properties.


6

1.5.10 Rural Fire Service (RFS); Wollongong City Brigades.

a. Provide personnel in rural areas and villages to:

• Inform the Wollongong City SES Local Controller about flood conditions and response needs in their own communities, and

• Disseminate flood information.

b. Provide personnel and high-clearance vehicles for flood related activities.

c. Assist with the delivery of evacuation warnings.

d. Assist with the conduct of evacuations.

e. Provide facilities for pumping floodwater out of buildings and from low-lying areas.

f. Assist with the cleanup operations, in particular the hosing out of flood affected properties.

g. Provide back-up radio communications.

1.5.11 Volunteer Rescue Association (VRA); South Coast.

a. Assist the Wollongong City SES Local Controller with flood operations as requested.

1.5.12 Integral Energy, Wollongong.

a. Provide advice to the Wollongong City SES Local Controller of any need to disconnect power supplies or of any timetable for reconnection.

b. Clear or make safe any hazard caused by power lines or electrical reticulation equipment.

c. Assess the necessity for and implement the disconnection of customers’ electrical installations where these may present a hazard.

d. Advise the public with regard to electrical hazards during flooding and to the availability or otherwise of the electricity supply.

e. Inspect, test and reconnect customers’ electrical installations as conditions allow.

1.5.13 Telstra, Wollongong.

a. Maintain telephone services.

b. Repair and restore telephone facilities damaged by flooding.


7

c. Provide additional telecommunications support for the Wollongong City SES Local Headquarters as required.

1.5.14 NSW Agriculture, Agroffice.

a. Coordinate the supply and delivery of emergency fodder.

b. Provide advice on dealing with dead and injured farm animals.

c. Provide financial, welfare and damage assessment assistance to flood affected farm people.

1.5.15 Department of Community Services (DOCS), Wollongong.

a. Manage any evacuation centers established as per the Wollongong City DISPLAN.

b. Provide clothing, accommodation, food and welfare services for flood affected people, including stranded travelers.

1.5.16 Ambulance Service of NSW, Helensburgh, Bulli, Dapto, Warilla, Warrawong and Wollongong.

a. Assist with the evacuation of elderly and/or infirm people.

1.5.17 Roads and Traffic Authority (RTA), Wollongong.

a. Close and reopen roads that the RTA is responsible for that affected by flood waters and advise the Wollongong City SES Local Controller.

1.5.18 State Rail Authority (SRA), Rail Infrastructure Corporation (RIC).

a. Close and re-open railway lines as necessary and advise the Wollongong City SES Local Controller.

1.5.19 Department of Education, Catholic Education Office.

a. A list of contacts for schools located in the area covered by this plan is contained in the Wollongong City DISPLAN under the Vulnerable Communities section.

b. The people holding these appointments will:

• Liaise with the Wollongong City SES Local Controller and arrange for the early release of students whose travel arrangements are likely to be disrupted by flooding and/or road closures.

• Pass information to school bus drivers/companies and/or other school principals on expected or actual impacts of flooding.


8

1.5.20 Residential Caravan Park Proprietors, Oasis Caravan Park, Lake Illawarra Village and Oaklands Village.

a. Prepare a Flood Management Plan for the Caravan Park.

b. Ensure that owners and occupiers of caravans are aware that the park is flood liable and what they must do to facilitate evacuation and van relocation when flooding occurs.

c. Ensure that occupiers are informed when floods are rising.

d. Coordinate the evacuation of people and the relocation of moveable vans when floods are rising and their return when floodwaters have subsided.

e. Inform the SES of the progress of evacuation and/or van relocation operations and of any need for assistance in the conduct of these tasks.

1.5.21 Citizens’ Radio Emergency Service Teams (CREST) / Wireless Institute Civil Emergency Network (WICEN). Provide communications assistance.

1.5.22 Department of Land and Water Conservation (DLWC). Provide advice on flood related matters and coastal erosion/inundation.

1.5.23 National Parks and Wildlife Service. Illawarra Area. Monitor the effects of prolonged or intense rainfall in the Illawarra Escarpment State Conservation Area with a view to closing public access to management trails and evacuating the Scout and Guide camps at Mt Keira.

1.6 Cross-Border Assistance Arrangements

1.6.1 A local cross-border mutual assistance arrangement exists in which the SES and the NSWFB will deploy resources to support each other.

1.6.2 Large-scale operations involving the Illawarra / South Coast area will be coordinated by the Illawarra / South Coast Division SES headquarters.


9

PART 2 - PREPAREDNESS

2.1 Maintenance of this Plan

2.1.1 The Wollongong City SES Local Controller will maintain the currency of this plan by:

a. Ensuring that all agencies, organisations and officers mentioned in it are aware of their roles and responsibilities.

b. Conducting exercises to test arrangements.

c. Reviewing the contents of the plan:

• After each flood operation.

• When significant changes in land-use or community characteristics occur.

• When new information from flood studies becomes available.

• When flood control or mitigation works are implemented or altered.

• When there are changes that alter agreed plan arrangements.

2.1.2 In any event, the plan is to be reviewed no less frequently than every five years.

2.2 Floodplain Management

2.2.1 Participation in floodplain management activities organised by the Wollongong City Council produces the following emergency management benefits:

a. Sources of information for flood intelligence.

b. Development of warning services.

c. Development of strategies for flood mitigation.

d. Development of strategies to reduce damage through better design and location of present and future residential, commercial and community land uses.

2.2.2 The Wollongong City SES Local Controller will ensure that the SES:

a. Participates in floodplain management committee activities when those committees are formed.


10

b. Consults with the flood prone community about the nature of the flood problem and its management.

c. Informs the Illawarra/South Coast SES Division Headquarters of involvement in floodplain management activities.

2.3 Development of Flood Intelligence

2.3.1 Flood intelligence describes flood behavior and its effects on the community. The effects include:

a. Inundation (leading to a need for evacuation and/or property protection).

b. Isolation (creating a need for re-supply and/or rescue).

c. Disruption to community activities (for example, disruptions bought about by the loss of transport routes).

2.3.2 Flood intelligence is obtained by the process of gathering and assessing information for the purpose of estimating the likely impacts of pending and future floods. It is used to facilitate operational decision making and the provision of warnings and information to agencies and the public.

2.3.3 The SES will develop and maintain a flood intelligence system incorporating the following elements:

a. Records of gauges monitored. These gauges are listed in Annex C along with flood classifications, ownership details, reading arrangements and other information.

b. Flood intelligence records. These include records of the effects of flooding at different heights, the peak heights reached by past floods. This intelligence is collected from agencies and the public.

2.4 Development Of Warning Systems

2.4.1 The SES will establish and/or maintain a flood warning system for areas affected by flooding. This requires:

a. An identification of the potential clients of flood warning information at different levels of flooding (ie. who would be affected in floods of differing severities).

b. Available information about the estimated impacts of flooding at different heights.

c. Identification of required actions and the amounts of time needed to carry them out.


11

d. Appropriate means of disseminating warnings to different clients and at different flood levels.

2.5 Public Education

2.5.1 The Wollongong City SES Local Controller, with the assistance of the Wollongong City Council, the Illawarra/South Coast SES Division Headquarters and SES State Headquarters, is responsible for ensuring that the residents of the Council area are aware of the flood threat in their vicinity and how to protect themselves from it. This includes people knowing:

a. At what stage their property might be inundated (if applicable).

b. The evacuation routes that would apply to them.

c. The location of evacuation centres.

d. The importance of registering their evacuation at an evacuation centre.

e. The general contents of this plan.

2.5.2 Specific strategies to be employed include:

a. Dissemination of flood-related brochures and booklets in flood liable areas.

b. Talks and displays orientated to community organisations and schools.

c. Publicity given to this plan and to flood-orientated SES activities through local media outlets, including articles in local newspapers about the flood threat and appropriate responses.

d. Publication of flood-related community information on the Unit’s web site – http://wollongong.ses.nsw.gov.au/

2.6 Training

2.6.1 Throughout this document there are references to functions that must be carried out by the members of the Wollongong City SES. The Wollongong City SES Local Controller is responsible for ensuring that the members are:

a. Familiar with the contents of this plan.

b. Trained in the skills necessary to carry out the tasks allocated to the SES.

2.7 Resources

2.7.1 The Wollongong City SES Local Controller is responsible for maintaining the condition and state of readiness of SES equipment and the Wollongong City SES Local Headquarters.


12

PART 3 - RESPONSE

3.1 Control

3.1.1 The SES is the legislated combat agency for floods and is responsible for the control of flood operations. This includes the coordination of other agencies and organisations for flood management tasks.

3.1.2 The SES is also responsible for the control of coastal erosion/inundation and inundation operations when severe weather is forecast or occurring.

3.2 Operations Centres

3.2.1 The Wollongong City SES maintains an Operations Centre at Montague Street, NORTH WOLLONGONG.

3.2.2 The Wollongong City Council Emergency Operations Centre is located at Level 10, Wollongong City Council Administration Building, 41 Burelli Street, WOLLONGONG NSW 2500.

3.2.3 The SES will operate an after hours duty officer system whenever flood operations are not being conducted.

3.3 Operational Management

3.3.1 The unpredictable nature of flash flooding in the Wollongong area makes the pre-allocation of operational sectors impractical. Where possible sectorisation will follow the existing flood plain management areas as shown in Map 2.

3.4 Liaison

3.4.1 At the request of the Wollongong City SES Local Controller, each agency with responsibilities identified in this plan will provide liaison (including a liaison officer where necessary) to the Wollongong City SES Operations Centre.

3.4.2 Liaison officers are to:

a. have the authority to deploy the resources of their parent organisations at the request of the Wollongong City SES Local Controller,

b. advise the Wollongong City SES Local Controller on resource availability for their service, and

c. be able to provide communications to their own organisations.

3.5 Communications

3.5.1 The primary means of office-to-office communications is by telephone and facsimile.


13

3.5.2 The primary means of communication to and between deployed SES resources is by the SES GRN radio system.

3.5.3 All other organisations will provide communications as necessary to their deployed field teams.

3.5.4 Back-up communications are provided as follows:

a. GSM/CDMA Mobile telephones.

b. Satellite telephones.

3.6 Activation

3.6.1 This plan will be activated by the Wollongong City SES Local Controller when evidence leads to an expectation of flooding within the Council area. This could include:

a. On receipt of a Severe Weather Warning predicting flash flooding.

b. When other evidence leads to an expectation of flooding within the Council area.

3.6.2 On activation, contact with the Bureau of Meteorology to discuss the meteorological situation will normally be through the Illawarra/South Coast SES Division Headquarters.

3.6.3 The following persons and organisations will be advised of the activation of the plan regardless of the location and severity of the flooding anticipated:

a. Wollongong City LEOCON (for transmission to the NSW Police Local Area Command Headquarters).

b. Wollongong City SES Unit.

c. Illawarra/South Coast SES Division Headquarters.

d. Wollongong City LEMO (for transmission to appropriate Council officers and departments).

3.6.4 Other agencies listed in this plan will be advised by the LEMO on the request of the Wollongong City SES Local Controller and as appropriate to the location and nature of the threat.

3.7 Flood Intelligence

3.7.1 Sources of flood intelligence during times of flooding are:

a. Bureau of Meteorology. The Bureau provides:


14

• Flood Watches, which give an early appreciation of developing meteorological situations that could lead to flooding. These are normally provided on a regional basis.

• Large Wave Warnings, which provide notice of waves greater than 5 metres in height.

b. Illawarra/South Coast SES Division Headquarters. The Division Headquarters provides information on flooding and its consequences, including those in nearby Council areas.

c. Wollongong City Council. Information on road closures.

d. Public Works and Services Computerized River Watch (Flood-to-Fax) System. This system provides water levels and rainfall readings for a number of gauges as indicated in Annex C.

e. Active Reconnaissance. The SES monitors known problem areas including Lake Illawarra and coastal creeks.

3.8 Preliminary Deployments

3.8.1 When flooding is expected to be severe enough to cut road access to towns, within towns and/or rural communities, the Wollongong City SES Local Controller will ensure that resources are in place for the distribution of foodstuffs and medical supplies to the areas that could become isolated.

3.9 Warnings

3.9.1 Warning services operate according to the following arrangements:

a. The Wollongong City SES Local Headquarters:

• Provides advice to the Illawarra/South Coast SES Division Headquarters on current and expected impacts of flooding.

• Coordinates the delivery of warnings to the community by door-knocking, telephone, mobile public address systems, local radio stations and two-way radio.

b. The Illawarra/South Coast SES Division Headquarters issues warning information in the form of SES Division Flood Bulletins to:

• Media organisations and agencies listed in Annex D.

3.9.2 Warnings are provided as follows:

a. Bureau of Meteorology Flood Watches. Flood Watches are issued on a regional basis. On receipt of such warnings, the Wollongong City SES Local Controller will:


15

• Advise the Wollongong City Council and the Wollongong City Council Local Emergency Operations Controller.

• Provide the Illawarra/South Coast SES Division Headquarters with information for inclusion in SES Flood Bulletins on the estimated impacts of flooding at the predicted heights.

b. SES Local Flood Advices. The SES may issue Local Flood Advices. These are issued direct from the Wollongong City SES Local Controller.

c. Evacuation Warnings.

• A template guide to the content of evacuation warning messages is at Annex E. These are disseminated as follows:

Using public address systems from Police and other emergency service vehicles.

♦

♦

♦

♦

♦

♦

By door-knocks by Police and other emergency service personnel.

By telephone.

By two-way radio.

By direct access to community radio.

In Illawarra/South Coast SES Flood Bulletins.

d. Standard Emergency Warning Signal (SEWS). This signal may be played over radio and television stations to alert communities to Evacuation Warnings, Special Warnings or Dam-Failure Warnings. Approval to use the signal will be obtained by the Wollongong City SES Local Headquarters from the Illawarra/South Coast SES Division Headquarters.

3.10 Information

3.10.1 The Illawarra/South Coast SES Division Headquarters issues SES Flood Bulletins to media outlets and agencies on behalf of all SES units in the Division. SES Flood Bulletins contain the following information relating to all Council areas in which flooding is occurring:

a. Current warnings, together with indications of the likely impact of flooding at any predicted heights.

b. Current flood behavior.

c. Details of conditions and closures of main roads.


16

d. Advice on safety matters and means of protecting property.

3.10.2 SES Flood Bulletins are normally issued every 3 hours during periods of flooding.

3.10.3 The Wollongong City SES Local Headquarters provides a “phone-in” information service for the community in relation to current warnings, flood behaviour, road conditions and closures of local and main roads and advice on safety matters and means of protecting property.

3.10.4 Collation and dissemination of road information is actioned as follows:

a. The Wollongong City SES Local Controller provides road status reports for main roads in the Council area to the Illawarra/South Coast SES Division Headquarters and to the Illawarra Police Local Area Command Headquarters. The Division Headquarters obtains information from the Police, Council, RTA and NRMA.

b. The Illawarra/South Coast SES Division Headquarters distributes information on main roads to SES units, media outlets and agencies as part of SES Flood Bulletins.

c. The RTA’s Traffic Management Centre also provides road closure information via it’s website at http://www.rta.nsw.gov.au/trafficreports/ or phone 131 700.

3.10.5 The Wollongong City SES Local Controller is to ensure that the Illawarra/South Coast SES Division Controller is regularly briefed on the progress of operations and on future resource needs.

3.11 Road Control

3.11.1 A number of roads within the Council area are affected by flooding. The Wollongong City SES Unit maintains a record of which roads are commonly affected and some of these are described in Annex B

3.11.2 The Council closes and re-opens its own roads. It may also close and re-open any road managed by the RTA in it’s capacity as an agent of the RTA.

3.11.3 The NSW Police Service has the authority to close and re-open roads but will normally only do so (if the Council or the RTA have not already acted) if public safety requires such action.

3.11.4 The NPWS is responsible for the management trails within the Illawarra Escarpment State Conservation Area and will close public access to these during times of prolonged or intense rainfall.

3.12 Traffic Control.

3.12.1 In the event of major flooding, the Wollongong City SES Local Controller may direct the imposition of traffic control measures. The entry into flood affected areas will be controlled in accordance with the provisions of the State


17

Emergency Service Act, 1989 (Part 5, Sections 19, 20, 21 and 22) and the State Emergency Rescue Management Act, 1989 (Part 4, Sections 60KA, 60L and 61).

3.13 Flood Rescue

3.13.1 The Wollongong City SES Local Controller controls flood rescues, which are carried out using high clearance vehicles, flood rescue boats and (under some circumstances) helicopters.

3.13.2 Additional flood rescue boats and crews can be requested through the Illawarra/South Coast SES Division Headquarters.

3.14 Evacuations

3.14.1 The nature of flooding experienced in the Wollongong area is that of flash flooding so evacuations will typically be small in number and isolated but be required at very short notice. While not as a direct result of flooding, evacuations may also be required in the event of landslides triggered by prolonged or intense rainfall.

3.14.2 Where possible residents requiring evacuation should do so using their own transport. Should it be required the Wollongong City SES Unit can carry out evacuations using 4WD vehicles or Flood Rescue Boats.

3.14.3 Evacuations will be controlled by the Wollongong City SES Local Controller (or, at the Local Controller’s request, the LEOCON).

3.14.4 When evacuations are possible, the Wollongong City SES Local Controller will advise relevant DoCS personnel so that evacuation centres and welfare support can be set up in timely fashion.

3.14.5 Some residents may make their own decision to evacuate and move to alternative accommodation using their own transport. Such evacuees must be advised via the media to inform the Police or the SES of their evacuation and their temporary address.

3.14.6 Field teams conducting doorknocks will record and report back to the Operations Centre:

a. Addresses and locations of houses doorknocked and/or evacuated.

b. Number of occupants.

c. Details of support required (such as transport, medical evacuation, assistance to secure house and/or property and raise or move belongings).

3.14.7 The field teams will then carry out evacuations as required. Details of these premises will be passed to the Wollongong, Corrimal, Dapto, Warilla Police Station.


18

3.14.8 The NSW Police will provide security for evacuated premises.

3.14.9 Evacuees will be taken to or advised to go to the nearest accessible evacuation centre, which may initially be established at the direction of the Wollongong City SES Local Controller but which will be managed as soon as possible by DOCS. A list of evacuation centers can be found in the Wollongong City DISPLAN.

3.14.10On arrival, evacuees will be registered, medically checked if necessary and

provided with their immediate welfare needs.

3.14.11The expected duration of evacuations will dictate the welfare staff requirement and need for facilities at evacuation centres. If evacuations are expected to be of a short duration, evacuees may be provided with short-term accommodation at the centres. However, if they are expected to last for longer than 24 hours evacuees will be encouraged to leave the evacuation centres if they have alternative accommodation to go to. Alternatively, accommodation will be arranged for them in motels, hotels or by billeting.

3.14.12The caravan parks known to be flood liable are listed in Annex F, along with arrangements relating to the evacuation of residents and the removal of caravans.

3.14.13The Scout and Guide camps at Mt Keira may require evacuation during periods of intense or prolonged rainfall if the NPWS formally close the Illawarra Escarpment State Conservation Area.

3.14.14Transport and storage of furniture from flood-threatened properties will be arranged as time and resources permit.

3.15 Registration

3.15.1 NSW Police will ensure that all evacuees are registered on arrival at evacuation centres and details of registrations are sent to the Police District Headquarters by the quickest means available.

3.15.2 Assistance with registration will be provided by:

a. Red Cross

b. Other agencies as appropriate.

3.16 Essential Services

3.16.1 The Wollongong City SES Local Controller will ensure that the providers of essential services (electricity, water, sewerage, medical and public health) are kept advised of the flood situation. Essential service providers must keep the Wollongong City SES Local Controller abreast of their status and ongoing ability to provide those services.


19

3.17 Logistics

3.17.1 The Wollongong City SES Local Headquarters maintains a small stock of sandbags and has a motorized sandbag filling machine, and back-up supplies available through the Illawarra/South Coast SES Division Headquarters. Alternatively, local concrete trucks may be used.

3.17.2 The Wollongong City SES Local Controller may task aircraft for flood operations within the Council area if other transport means are not available or not suitable. During floods affecting more than one Council area, aircraft will normally be tasked centrally by the Illawarra/South Coast SES Division Controller. The Wollongong City SES Local Controller will establish a vetting committee to ensure that only essential items are moved whenever aircraft are used for supply operations.

3.18 Management Of Evacuees’ Pets

3.18.1 In the event of a large-scale evacuation, animal shelter compound facilities will be set up for domestic animals and companion animals. These facilities will be operated by NSW Agriculture with assistance from Wollongong City Council.

3.19 Assistance for Animals

3.19.1 Matters relating to the welfare of livestock, companion animals and wildlife (including feeding and rescue) are to be referred to NSW Agriculture.

3.19.2 Requests for emergency supply and/or delivery of fodder to stranded livestock, or for livestock rescue, are to be passed to NSW Agriculture.

3.20 Stranded Travelers

3.20.1 Flood waters and rock falls can strand travellers in the Wollongong LGA. Travellers seeking assistance will be referred to DoCS for the arrangement of temporary accommodation.

3.21 All Clear

3.21.1 When the danger to life and property has passed, the Wollongong City SES Local Controller will issue an ‘All Clear’ message signifying that response operations have been completed. This message will also advise details of arrangements for evacuation residents to return to their homes or indicate what longer-term accommodation arrangements have been made for those unable to do so.


20

PART 4 - RECOVERY

4.1 Welfare

4.1.1 The Department of Community Services will provide for the long-term welfare of people who have been evacuated.

4.2 Recovery Coordination

4.2.1 The Wollongong City SES Local Controller will ensure that planning for long-term recovery operations begins at the earliest opportunity. This is to be done by briefing the chairman of the Wollongong City Council Local Emergency Management Committee on the details of the flooding and assisting in the establishment of a Recovery Coordinating Committee.

4.2.2 The Recovery Coordinating Committee is to prepare an outline plan for recovery operations and be prepared to recommend how such operations would best be controlled and Coordinated.

4.3 Debriefing Arrangements

4.3.1 As soon as possible after flooding has abated, the Wollongong City SES Local Controller will advise participating organisations of details of response operation debriefing arrangements.

4.3.2 The Wollongong City SES Local Controller will ensure that adequate arrangements are in place to record details of the debrief and each item requiring further action is delegated to an organisation or individual to implement.

4.3.3 Follow-up to ensure the satisfactory completion of these actions will be undertaken by the Wollongong City Council Local Emergency Management Committee.


A-1

ANNEX A - THE FLOOD THREAT

General Flooding is common on the many short, steep streams that flow eastward from the Illawarra Escarpment across the urbanized coastal plain. The escarpment begins as a coastal cliff rising to 250 m elevation in Wollongong's northern suburbs and rises to a height of 670 m to the west of Dapto at which point it is about 20 km from the sea. East of the escarpment is a series of low ridges divides the small, steep stream catchments. The coast proper is lined with sand dunes, which impound small lagoons and swampy areas into which these creeks discharge. To the south of the city is the 35 square kilometer Lake Illawarra, a shallow tidal lake that occupies the area between plain and coastal dunes. The council area has been divided into eight areas of study used by Flood Management Committee (see Map 2). These areas are:

• Area 1 - North from Flanigans Creek, Thirroul to Clifton with Monash St, Wombarra a problem area.

• Area 2 – Includes Hewitts, Woodlands and Slacky Creek systems. Known trouble spots exist in George and Lachlan Streets and Hewitts Ave, Thirroul. The Princes Hwy and Lawrence Hargrave Dve at the bottom of Bulli Pass and the highway near Bulli Trotting Track in this area have suffered damage in previous events.

• Area 3 - Extends from Bulli to Corrimal and includes Whartons, Collins, Fanahars and Bellambi Gully Creeks systems. Area 4 – Encompasses the Towradgi Creek system in the Corrimal area. Nicholson Rd, Woonona, Lismore and Ellen St, Bellambi problem streets in this area as well as the area about and including the Northern Bowl in Bellambi Lane. The area between the Illawarra Railway line and Bellambi beach also a common flood zone.

• Area 5 – Centres on the central Wollongong area and includes Cabbage Tree Creek and Fairy Creek catchments. Chalmers St, culvert a regular flood area. Major damage has occurred in Anama St, Fairy Meadow, Montague St, Nth Wollongong with Campus East and Brandon Park also subject to flooding. Porter St, North Wollongong west of the railway line has suffered flooding and then downstream water inundation occurs in Ajax and Exeter St’s.

• Area 6 – Covers the Mount Keira to Farmborough Heights areas of Byarong Creek, American Creek and Allens Creeks. Major flooding in this area is in Wallawa St and Arrow Ave then crossing through Figtree Shopping Centre. O’Brien’s Rd, Unanderra flooding regularly with traffic disruptions to Springhill Rd at times.

• Area 7 – This area covers the Mullet Creek catchment from Farmborough Heights to Avondale and is the major tributary for Lake Illawarra. Extensive flooding in this area covers Kembla Grange and vast areas of the West Dapto and isolates Horsley communities.

• Area 8 – Is devoted to a small region in the Lake Heights area.


A-2

There are also several minor creeks that flow westward from the escarpment through unpopulated country to a series of water storage reservoirs. The more important of these, and the storage's to which they feed, are:

Avon River and Gallahers Creek: to Lake Avon. Cordeaux River and Kembla Creek: to Lake Cordeaux. Rocky, Cataract, Bellambi and Allen Creeks: to Lake Cataract. Waratah Rivulet: to Lake Woronora.

O'Hares Creek, a tributary of the Georges River, also flows west from the escarpment.

Weather Systems and Flooding Flooding can occur at any time of the year, but in different seasons it is triggered by different rain-producing mechanisms. There is a slight bias towards the January-June period as far as flood occurrence is concerned, and within this period the concentration is in the late summer and early autumn months. Floods may result from any of the five weather patterns summarized below: 1) Ex Tropical Cyclones: Rainfall and flooding that results from a cyclone moving

south and downgraded to a rain depression. Such weather systems can produce prolonged heavily rainfall. Heavy rainfall originating from these cyclones in the Illawarra can occur anytime between January and May and have historically resulted in widespread and localised flooding affecting dwellings.

2) Zonal Synoptic Patterns: This pattern occurs when the centre of a high or low-pressure system is located south of New South Wales directing a moist onshore flow onto the coast. These pressure systems often combine with a low-pressure trough and/or upper air disturbances to create a state of prolonged instability. In February 1984, moist air behind a front and a high-pressure system centred southeast of Tasmania, along with small surface low-pressure systems, resulting in extreme instability and intense rainfall. Zonal synoptic patterns together with easterly lows account for 50% of the flooding in the Illawarra.

3) Inland Depressions: These inland depressions or low-pressure systems originating from continental northern Australia that can dip down into New South Wales and intensify over coastal areas. These often occur in autumn, just after the northern monsoon season.

4) Easterly Lows: Defined as low-pressure troughs moving south from Queensland, generally just off the NSW coastline, before heading in a south-easterly direction. They occur predominately in the winter months.

5) Continental Lows: Low-pressure systems, which move across the continent towards the central NSW coastline. There is two types; a) Lows originating from central and southern Queensland moving south towards

Sydney, intensifying as they near or cross the coastline. Unlike inland depressions no trough structure is evident.

b) Where a low-pressure system moves eastwards across the southern continental areas, before intensifying near the coastline, thereby producing intense rainfall. East coast cyclones or lows as identified by Bryant(1991) would also fit into this category (these are easterly moving pressure systems, which


A-3

develop into intense cyclonic depressions when they pass over mountainous coastal terrain and a warm poleward flowing current. Predominately occur in winter and autumn.

6) Thunderstorms: Localised thunderstorms have caused localised flooding in various areas, usually to only sections of a suburb at any one occasion.

Average annual rainfall in the council area varies from less than 1,100 mm in the Dapto, Windang and Kemblawarra area to more than 1,600 mm along the escarpment southwards from Mt Keira. About 60-70 per cent of this falls in the summer and autumn quarters most of it in February, March and April. Rainfall of more than 50 mm in a day is recorded, on average, about eight times a year somewhere in the council area. Such rainfall frequently produces flooding, particularly when catchments are already wet. Very high daily falls (200 mm or more) almost always produce flooding, much of it severe. In recent decades, flooding has tended to occur frequently in some periods and then to become less common. Floods were common in the 1950-52, 1958-61, 1973-78, 1983-84, 1991-92 and 1998-99 with periods but much less so in the intervening periods. Severe floods are more common in the February-April period and in November than in other months.

Floods on the Creeks The dominant feature of creek flooding in the council area is that it is usually 'flash' flooding. The streams respond quickly to high-intensity rainfall and flooding can begin very soon after the beginning of heavy rains. This is especially true in the northern suburbs, where response times can be as low as 30-40 minutes. On the larger streams to the south (eg Allans or Mullet Creeks), response times are typically in the order of 4-6 hours.

Except for their headwaters, most of the catchments are heavily urbanised; a feature which increases the speed of rises in creek levels. Floodplain areas are of relatively limited size, and during periods of flooding only small proportions of total flow are carried within creek channels. The result is substantial floodplain inundation, often to considerable depths. Velocities of flow are usually high (often more than 2 metres per second) and flooding is characterised by very rapid rises and falls in water level. As it is common in urban catchments, flood peaks usually occur at night time. Overbank flows occur frequently, even in the less severe events of approximately 20-50% AEP (that is, floods that occur on average every 2 to 5 years).

Most of the creeks have been significantly modified by human intervention, and the construction of buildings near the watercourse can sometimes divert flows over areas some distance from the creeks themselves. Filling of land in the lower reaches of some of the catchments, particularly north of central Wollongong, has significantly reduced the pre-existing storage capacity of the floodplains. This causes water that would otherwise have remained within the banks of the streams to break out and in severe events upstream flood levels can be significantly higher than would previously have been the case.


A-4

The north-south orientation of the road and rail links means that all the creeks are interrupted by culverts and bridges which have limited flow capacity that are prone to blockage by debris, worsening these effects. Few road culverts are capable of passing events more severe than those of about 10 % AEP without overtopping. Inadequate waterway capacity or blockages are a frequent cause of flooding. Most of the creeks discharge into small coastal lakes, lagoons or swamps before reaching the sea. The mouths are prone to closure through build-up of sand at their outlets. This causes flood levels in the lakes and in the lower stream reaches to rise in the early stage of a flood before the flood waters scour the outlet. High velocities are often experienced at the outlets as the sand bars collapse. Previously observed flooding behaviour in watercourses in the area have generally been characterised by:

Peak flood discharges significantly greater than the capacity of the watercourses.

Rapid rise and fall of flood levels. High flood velocities resulting in extensive damage to creek bank vegetation

and erosion of creek beds and crossings. Large quantities of flood debris. At a number of locations the quantity of flood

debris appeared to exacerbate upstream flooding by blocking culvert and bridge waterways.

The design capacity of the urban stormwater drainage system in the area of interest is understood to be based on a 10 year or smaller Average Recurrence Interval (ARI) storm event. Hence, some properties have been flooded by surcharging of the stormwater drainage system and/or the inability of local runoff to enter the stormwater drainage system independent of, or in combination with mainstream flooding. Because of the short catchment response times, it is extremely difficult to accurately determine the timing and contribution of local flooding to overall flooding at a given built-up location in the study area. Thus, the determination of the likelihood and contribution of stormwater flooding requires some subjective assessment.

Storm Surges

Storm surge is an increase in the sea water level at the coast. The principal factors in the generation of a storm surge are:

• The wind stress on the sea surface, piling up water. • The atmospheric pressure reduction in the storm area raising sea water level. • The net water transport shoreward due to waves and swell breaking in the

shallows. • The local surge modification due to bottom topography, abnormally heavy

rainfall and the presence of currents, tides and natural oscillations.


A-5

In addition to wind and barometric set-up there is an additional rise in water level on the beach due to wave set-up. The wave set-up occurs between the zone of breaking waves and the beach, and can be as much as 10 to 20 per cent of the incident wave height.

The maximum water levels from a combination of high tides, wave set-up and storm surge could be greater than 2.0 metres AHD. Of this, high tide levels and wave set-up would account for much more than storm surge, which is estimated to be able to contribute only about 0.4 metres.

Extreme Flooding In extreme flood events water levels rise much quicker with faster velocities and cover areas with no previous experience of flooding.


B-1

ANNEX B - EFFECTS OF FLOODING ON THE COMMUNITY

General Flooding in the Wollongong City area (Population – 183,000 census 2001) occurs on average, about twice per year at least to nuisance level. Floods of 5-10 % AEP have the following range of effects:

• Severe disruption to transport on major arterial roads and the cutting of railway lines with the isolation of substantial populations for periods of several hours.

• The inundation of farmlands. • Flooding of residential properties and local roads. • The evacuation and rescue of residents from houses and caravans. • On a few occasions people have been drowned. • Damage to property and infrastructure is occasionally severe. • Flooding has destroyed houses and cars and fences have been washed

away. In more severe events, the depth and velocity of the floodwaters make them extremely dangerous.

Property Inundation All areas of the council region can be damaged by flooding or water inundation of some form. Several formal studies have investigated the numbers of properties liable to over-floor inundation in floods of 1% AEP Wollongong City Council estimates that approximately 2,500 homes would be liable to flooding in more severe events. Flooding occurs in those properties located on low-lying land on the lower reaches of the many creeks crossing the coastal plain. They include houses, commercial and industrial dwellings, and caravans. Most of the vans are in four caravan parks (Oasis, Lake Illawarra Village and Oaklands) at Windang, which are periodically flooded from Lake Illawarra. Scores of streets to the east of the Princes Highway and the Illawarra railway line have some flood prone land. Parts of the West Dapto, Dapto and Brownsville areas are also liable to flooding. Serious flooding events include the 1998 storm when 1,600 people were evacuated, 1,500 dwellings suffered structural and/or contents damage, with a portion so badly affected they were later condemned. Over 50 people were injured and one life was lost. In the 1991 flood, more than 300 residents had to be evacuated from caravans. In1984 more than 100 properties were inundated in the Dapto and Brownsville areas and in


B-2

1975, 1984 and 1991 large numbers of people were evacuated from the Windang caravan parks. Even in non-severe events, many properties may experience short periods of flooding of out buildings and yards. Channel erosion during floods has threatened houses and other premises. The Illawarra Retirement Village (Murranar Rd, Towradgi) and the Wollongong Nursing Home (Suttor Pl, Figtree) may be flood liable and precautionary evacuations have occurred in the past. Industrial, commercial and recreational areas have been flooded in various parts of the city. Examples include Woonona, parts of Corrimal, North Wollongong, Figtree and Unanderra shopping centres, the North Wollongong industrial area (Montague St), Kembla Grange industrial area, the Dapto industrial area (Bong Bong, Burringbar and Hamilton Sts) and parts of the steelworks. The Kembla Grange and Port Kembla golf courses have been severely damaged by floodwaters. Windang Public School has been flooded when the level of Lake Illawarra has been very high. Little farmland remains in the council area, but that in the valley of Mullet Creek was inundated to considerable depth in 1984. Water inundation or storm water passing into houses is possible in many areas, including properties high up on the escarpment due to rapid water run off in severe rainfall events. The majority of flooding occurs on the lower reaches of the creek systems.

Transport Disruption Transport disruption can also be severe. The main railway line has been blocked by washaways in the northern suburbs and by water over the line at Dapto, and flooding at Cringila, Port Kembla and west of Unanderra has cut spur lines. The Princes Highway has been cut on several occasions, mostly at Bulli, Woonona, Fairy Meadow, North Wollongong, Figtree, Unanderra, Kembla Grange and Tallawarra. The F6 Freeway and the Northern Distributor however are believed to be essentially flood free. Landslips and washaways on the Lawrence Hargrave Drive, Bulli Pass, Mt Ousley and Macquarie Pass, and the inundation of roads in neighboring Shellharbour City Council area, can mean that the city is completely cut off by land from the outside world. The localised nature of the 1998 storm caused a number of mudslides and also the liquefaction of a coal stockpile and coal wash dumps that inundated many properties causing extreme damage. The 1984 rain event over the escarpment caused 47 landslips, many of them blocking roads. The slopes of the escarpment, particularly but not exclusively in the northern suburbs, are unstable.


B-3

Residential and other roads within the city can also be cut, with the following significant roads having been cut previously: Road

Suburb Location

Otford Road Otford Hacking River Lady Carrington Drive Otford Hacking River Liddle Street Woonona Thompson Street Woonona Collins Creek Brompton Road Bellambi Squires Way Fairy Meadow Overflowing sewer O’Briens Road Figtree East of Church of Christ Montague Street Fairy Meadow Outside SES HQ Springhill Road Cringilla Intersection of Masters Rd Carters Lane Towradgi Pioneer Rd junction Northcliff Drive Berkeley Near Walker & Yacht club West Dapto Road Kembla Grange Bong Bong Road Dapto Near Hamilton & Burringbar Sts Darkes Road Dapto Rail line and creek crossings Windang Road Primbee Near golf range Bondary Road Windang Near Windang Rd Princes Highway Kembla Grange Near racecourse entrance Five Islands Road Cringilla Various Old Port Road Port Kembla Near the rail overbridge Scores of residential streets have experienced flooding, and whole neighborhoods can be cut off from outside tough usually for only short periods. Flood depths on Springhill Rd have been estimated at between 1.5 and 2.0 metres in some floods. Many small bridges and culverts can be submerged, and on some occasions roads have collapsed. Blockages of bridges and culverts occur commonly during episodes of flooding. The severe storm event of August 1998 bears evidence of this as many roads were cut or blocked by debris and erosion.


C-1

ANNEX C - GAUGES MONITORED BY THE WOLLONGONG CITY SES LOCAL

HEADQUARTERS During Flood and heavy rainfall events the Wollongong City Unit monitors a number of water level and rainfall stations as part of its intelligence and reconnaissance process. The Unit has access to real-time data from most of these gauges via the Manly Hydraulics Laboratory web site.

Gauge Name Type Stream

Huntley Colliery Combination Mullet Creek Cleveland Road Combination Mullet Creek Wongawilli Colliery Combination Mullet Creek, Robins Creek Bombarton Loop Combination Mullet Creek, Robins Creek, Forest CreekDarkes Road Combination Mullet Creek, Robins Creek Koonawarra Bay Continuous Stage Height Recorder Lake Illawarra Cudgeree Bay Continuous Stage Height Recorder Lake Illawarra The Entrance Continuous Stage Height Recorder Lake Illawarra Whytes Gulley Continuous Stage Height Recorder Lake Illawarra Budgong Creek Continuous Stage Height Recorder Budgong Creek Fairy Creek Continuous Stage Height Recorder Fairy Creek Byarong Creek Continuous Stage Height Recorder Byarong Creek Cabbage Tree Creek Continuous Stage Height Recorder Cabbage Tree Creek Towradgi Creek Continuous Stage Height Recorder Towradgi Creek Rixons Pass Automatic Rainfall Recording Station Russell Vale Automatic Rainfall Recording Station Mount Pleasant Automatic Rainfall Recording Station Some of these, e.g. Cudgeree Bay, are configured to generate proactive warnings when pre-determined levels are reached. In addition to these gauges active reconnaissance of known trouble spots is also carried out by Wollongong City SES members during operations involving flooding and heavy rainfall.


D-1

ANNEX D - DISSEMINATION OF SES FLOOD BULLETINS

The Illawarra/South Coast SES Division Headquarters distributes SES Flood Bulletins and other flood related information (including Flood Warnings) to the following regional media outlets: Television Stations:

Station Location WIN TV (Channel 9) Wollongong ABC TV Sydney Prime Sydney Capital Sydney SBS Sydney Radio Stations:

Station Location i98 Wollongong Wave FM Wollongong ABC Illawarra Wollongong Mac FM Shellharbour Power FM Nowra 94.1 Wollongong Newspapers:

Name Location Illawarra Mercury Wollongong Kiama Independent Kiama Other Agencies: • All Illawarra/South Coast SES Unit Headquarters • SES State Headquarters • Southern Highlands, Sydney Southern, Sydney Western, Sydney Northern SES

Division Headquarters • NSW Police, Wollongong and VKG Warilla • NSW Ambulance Service • NSW Rural Fire Service, Wollongong • NSW Fire Brigades, Wollongong • District Emergency Management Officer (DEMO) • Wollongong City Council


E-1

ANNEX E - TEMPLATE EVACUATION WARNING MESSAGE FOR [ENTER NAME OF AREA]

Evacuation Warning for [ ] Date/Time of Issue: [ ] Authorised By: [ ] The Bureau of Meteorology has predicted a flood level of [ ] metres at [ ] (place) at [ ] (time). This means that the following area(s) may be inundated [ ]. It is recommended that you prepare to evacuate/for evacuation within the next [ ] hours. If you leave it later, the roads may be congested or closed. To prepare for evacuation, you should: • Raise belongings by placing them on tables, beds and benches. Put electrical

items on top. Some items may be able to be placed in ceilings. • Gather medicines, personal and financial documents and momentos together to

take with you. • Listen to radio stations [ ] for further information and to

confirm this warning. • If possible, check to see whether your neighbours need help. • Make arrangements for care of pets or companion animals. If evacuation is necessary: • Turn off the electricity, gas and water. • Take three days’ supply of clothes with you. • If you have a car, drive to the evacuation centre at [ ] (specify

route if appropriate). • If you don’t have a car, buses will operate on normal routes. Special transport can

also be provided on request if necessary, telephone [ ]. • So that you can be accounted for, it is important that you register at the evacuation

centre. • After registering, you may go to the house of a friend or relative. Alternatively,

accommodation will be arranged for you. • The Police will provide security for your property while you are away.


F-1

ANNEX F - ARRANGEMENTS FOR THE EVACUATION OF CARAVAN PARKS AND THE

RELOCATION OF CARAVANS

General

1. The following caravan parks are flood liable:

a. Oasis Caravan Park

b. Lake Illawarra Village

c. Oaklands Village

Advising Procedures

2. Caravan Park proprietors will ensure that the owners and occupiers of caravans are:

a. Made aware that the caravan park is flood liable by:

• Handing a printed notice to occupiers taking up residence. The notice will indicate that the Caravan Park is liable to flooding and outline the evacuation and van relocation arrangements as detailed in this Annex.

• Displaying this notice prominently in each van.

b. Made aware that if they are expecting to be absent from their vans for extended periods, they must:

• Provide the manager with a key; in a sealed envelope; to the van.

• Provide a contact address and telephone number.

• Inform the manager if a vehicle will be required to relocate the van during flood time.

• Leave any mobile van in a condition allowing it to be towed in an emergency (ie: tyres inflated, jacks wound up, personal effects secured and annexes and lines for water, sewer, electricity and gas readily detachable).

c. Informed when a flood is rising. At this time, occupiers will be advised to:

• Ensure that they have spare batteries for their radios.


F-2

• Listen to a local radio station for updated flood information.

• Prepare for evacuation and van relocation.

3. The Wollongong City SES Local Controller will ensure that the managers of caravan parks are advised of flood warnings and the details of any evacuation order.

Evacuation of Occupants and Relocation of Vans

4. Caravan park proprietors will install flood depth indicators and road alignment markers within their caravan parks.

5. When an evacuation order is given:

a. Occupiers of non-movable vans should:

• Secure their vans by tying them down to prevent flotation.

• Isolate power to their vans.

• Collect personal papers, medicines, a change of clothing, toiletries and bedclothes.

• Lift the other contents of their vans as high as possible within the van.

• Move to a designated evacuation centre if they have their own transport, or move to the caravan office to await transport.

• Where possible, vans that can be moved will be relocated by their owners. Park managers will arrange for the relocation of mobile vans whose owners do not have a vehicle. Council and SES personnel will assist if required and may be able to provide additional vehicles.

6. Occupants of vans that are being relocated should go to a designated evacuation centre if they have their own transport. Those without their own transport are to report to the caravan park office.

7. Caravan park managers will:

a. Ensure that their caravan park is capable of being evacuated within a short period of time.

b. Advise the Wollongong City SES Local Controller of:

• The number of people requiring transport.

• Details of any medical evacuations required.


F-3

• Whether additional assistance is required to effect the evacuation.

c. Check that no people remain in non-removable vans that are likely to be inundated.

d. Inform the Wollongong City SES Local Controller when the evacuation of the caravan park has been completed.

e. Provide the Wollongong City SES Local Controller with a register of people that have been evacuated.

Return of Occupants and Vans

8. The Wollongong City SES Local Controller, using Council resources as necessary, will advise when it is safe for the caravan parks to be re-occupied.

9. Vans will be towed back to the caravan park(s) by van owners or by vehicles and drivers arranged by the park managers. Again, Council and SES personnel will assist if available.


I

MAP 1 - COUNCIL AREA


II

MAP 2 - FLOOD PLAIN MANAGEMENT AREAS


Documents

Wollongong City Local Flood Planwollongong.ses.nsw.gov.au/Wollongong_Flood_Plan_-_Oct_2003.pdf · Wollongong City Local Flood Plan – October 2003, Sub-Plan of Wollongong Local Disaster