Flooding

A large proportion of land in Wyong Shire is located within close proximity of our vast river, creek and lake networks. As a result, much of this land is flood prone during periods of prolonged rainfall.

The below map shows the areas of Wyong Shire that are considered prone to flooding (highlighted in purple)

floodplain-map.jpg

 


Types of flooding

Flooding in Wyong Shire occurs for a number of reasons-

  • River or creek banks are overtopped.
  • Lake levels rise and cover foreshore areas.
  • Stormwater drainage is unable to cope cope leading to "overland flows" running down a street or through backyards.

You may experience little warning of flooding.

Severe thunderstorms can cause localised flooding of stormwater and some creek areas within less than an hour.

Prolonged periods of intense rain may cause flooding of large rivers and creeks throughout the Shire while  flooding of the lakes often occurs after two or three consecutive days of heavy rain.
 


History of flooding

In June 2007, Wyong Shire suffered through one of the most significant flood events on record.

A severe East Coast low caused sustained heavy rainfall, king tides, huge storm swells and battering winds. Most famously, the weather event caused a container ship (The Pasha Bulker) to run aground on Nobby's Beach in Newcastle (an hour horth of Wyong Shire)

The 2007 flood reached a peak level of 1.65m in Tuggerah Lakes - which was still 0.45m below the highest recorded flood level of 2.1m in June 1949.

Interestingly, the record flood events for Ourimbah Creek and Wyong River have occured at different times.
The table below shows the top 5 floods and their respective years.

Rank Ourimbah Creek Wyong River
1 February 1992 June 1949
2 February 1990 June 1964
3 June 2007 June 1930
4 April 1946 April 1927
5 March 1942 March 1977

 


What is Council doing about flooding?

The NSW Government's "Floodplain Development Manual- 2005" makes Councils responsible for managing all flood prone land.

The Manual also provides a step by step management process which has been adopted by Wyong Shire Council.

  1. Data Collection
  2. Flood studies
  3. Management plans
  4. Implementation and monitoring

 

Flood Studies

In a Flood Study actual rainfall and flood height data is collected over a period of time.
This data is then used to run computer simulations of past floods. The simulation is then compared with the real results of the chosen flood event.

Once we are confident that the computer modelling is correct, it can be applied to a range of situations to accurately predict the effects of larger floods- producing flood maps.

The image below shows a simulation of the June 2007 flood near the University at Ourimbah.

ourimbah-floodsimulate.jpg


In 2013 we completed Flood Studies for Wyong River and Ourimbah Creek as well as the suburbs of Killarney Vale, Long Jetty and The Entrance.

In 2014 we worked on a flood study at the northern end of Tuggerah Lakes and in 2015 we plan to carry out flood studies in Northern areas of the shire such as Wallarah, Doyalson and the lower portion of Lake Macquarie.
 

Floodplain Risk Management Plans

Based off the data collected and modelled in Flood Studies, Council then produced Floodplain risk management plans.

In 2014 Council completed Floodplain Risk Management Plans for Tuggerah Lakes, Porters Creek and Tumbi Umbi Creek.

In 2015 Council aims to revise Floodplain Risk Management Plans for Wyong River and Ourimbah Creek, based on the updated flood mapping from recent studies.
 
See all Floodplain risk management plans below-

Implementing Plans

Once plans are finalised, the final step in the process is implementation.

This includes revision of land use zoning and development control plans, revision of emergency response procedures as well as capital works to better control flooding.

Capital works may include levees, raising roads, larger bridges, raising buildings and installation of flood depth indicator signs.

Council uses our flood mapping to determine where to install flood depth indicator signs.

The signs show the maximum depth of floodwaters across the road, but they do not show how fast the water is moving or if the road surface is still intact. The zero mark is set at the lowest road level further along the road.

In 2013 and 2014 Council upgraded many flood prone roads, reducing the risk for motorists and pedestrians during times of heavy rainfall and flooding - $8m was spent in Hamlyn Terrace alone.
 
Minnesota Road was one such project and reopened in September 2013.

minesota-road.jpg

Warnervale Road is another example, reopening in April 2014

warnervale-road.jpg

 


What you can do?

Preparing for flood events-
 

  • Know your risk.
  • Know where to go, know who to call, know your plan.
  • Prepare now to act early.
  • Check your insurance.

What to do in a flood-

  • Listen to local radio. Check Bureau of Meteorology updates.
  • Be prepared to evacuate.
  • Act early before roads are closed by floodwater.
  • Never drive or walk through floodwaters.

 

Who can help in a flood?

The State Emergency Service (SES) is responsible for responding to floods in NSW.
 
The local SES personnel will provide flood information, safety advice and arrange for the delivery of essential supplies to people isolated by floodwater. Where appropriate, the SES will conduct evacuations and undertake flood rescue.
 
As many homes, farms and businesses across NSW are susceptible to flooding, the SES has developed FloodSafe guides. These explain how to prepare for flooding and what to do when waters rise.
 
For help in a flood or storm call the NSW State Emergency Service on 132 500, or in life-threatening emergencies call 000.
 


Additional Floodplain Management information

 More information about Floodplain Management is available from:
 


Factsheet


Advice on a particular property

To get advice about flooding on a particular property, you need submit an enquiry form to Council:  doc format Coastal Hazards and Flood enquiry form (52.00 KB) 
 
This information includes:
  • Flood levels
  • Minimum habitable floor height required
  • Any other enquiry relating to flooding in any way.