Flood management

1. © Gosford City Council 2013
Brisbane Water Foreshore
Draft Floodplain Risk Management Study

2. © Gosford City Council 2014
Characteristics and value of the
Brisbane Water floodplain
The Brisbane Water estuary has only a small catchment of 165km2 with
the main water body being 28km2.
The catchment has undergone extensive rural, residential and industrial
development, however natural forest still covers about 50% of the total
catchment area.

3. © Gosford City Council 2014
Characteristics and value of the
Brisbane Water floodplain
The catchment is partly urbanised with major concentrations of
development centred in Gosford in the north and the region of Umina
beach, Ettalong beach and Woy Woy in the southwest.
Other smaller residential areas including Green Point, Kincumber,
Saratoga, Davistown, St Hubert’s Island, Killcare and Pretty Beach are
scattered along the eastern parts of the catchment.

4. © Gosford City Council 2014
Characteristics and value of the
Brisbane Water floodplain
The Brisbane Water foreshore represents the interface
between aquatic and terrestrial habitats.
Environmental values
These include bushland, wetlands, salt marshes, Casuarina
forests, mangroves, mudflats to seagrass beds, submerged
rock platforms and sandy or muddy estuarine beds.

5. © Gosford City Council 2014
Characteristics and value of the
Brisbane Water floodplain
The recreational uses of Brisbane Water estuary and
foreshore include a range of activities such as swimming,
bushwalking, boating, picnicking, recreational fishing,
foreshore parks and playgrounds, cycling and bird watching.
Recreational values

6. © Gosford City Council 2014
Characteristics and value of the
Brisbane Water floodplain
The economic value of Brisbane Water includes the
value of private dwellings, public infrastructure and
the income provided through tourism and recreation.
Economic values Over 250,000 dozen
Sydney Rock Oysters
were produced in
Brisbane Water in
2007/08, with a total
value of $1.3million.

7. © Gosford City Council 2014
As has occurred with many coastal cities and towns around Australia, many suburbs
of Gosford have been built successively within the local floodplains.
Flooding and the risk
management process
This has been evidenced in the recent flood events in Gosford during the mid to late
1980’s, early 1990’s and June 2007 when many properties were flooded.

8. © Gosford City Council 2014
As has occurred with many coastal cities and towns around Australia, many suburbs
of Gosford have been built successively within the local floodplains.
Flooding and the risk
management process
This has been evidenced in the recent flood events in Gosford during the mid to late
1980’s, early 1990’s and June 2007 when many properties were flooded.
What is a floodplain?
A floodplain is an area of land that has been formed by flooding
over time and is still subject to periodic inundation. Floodplains
are also referred to as flood prone land. Floodplains or flood
prone land is all land affected by flooding up to and including the
Probable Maximum Flood (PMF) event (or the highest
conceivable flood that nature can produce).

9. © Gosford City Council 2014
What is a floodplain?
A floodplain is an area of land that has been formed by flooding
over time and is still subject to periodic inundation. Floodplains
are also referred to as flood prone land. Floodplains or flood
prone land is all land affected by flooding up to and including the
Probable Maximum Flood (PMF) event (or the highest
conceivable flood that nature can produce).
What causes floods?
Flooding is defined as a relatively high water flow that overtops natural or artificial
banks in any part of a stream, river, estuary, lake or dam resulting from:
• heavy or prolonged rainfall and/or
• super-elevated sea levels and/or
• waves overtopping coastline defence.

10. © Gosford City Council 2014
What is a floodplain?
A floodplain is an area of land that has been formed by flooding
over time and is still subject to periodic inundation. Floodplains
are also referred to as flood prone land. Floodplains or flood
prone land is all land affected by flooding up to and including the
Probable Maximum Flood (PMF) event (or the highest
conceivable flood that nature can produce).
What causes floods?
Tidal action, such as King Tide and storm surge which is generated by
storms off the east coast of Australia, are also very common causes of
flooding in the Gosford Region which cause flooding within the Brisbane
Water estuary and along the coastal foreshore areas.

11. © Gosford City Council 2014
How are floodplains managed?
Local government is primarily responsible for control of
development on flood prone land. However, the NSW State
government, the State Emergency Service and the Bureau
of Meteorology also have a major role to play in managing
the flood risk.
The State government provides specialist advice and
financial support to assist councils to develop Floodplain
Risk Management Plans which consist of the following
stages:
Form a
Floodplain Risk
Management
Committee
Collect data Flood Study
preparation
Floodplain Risk
Management
Study
preparation
Floodplain Risk
Management
Plan
preparation
Implementation of
the Plan
Review the
Management
Plan

12. © Gosford City Council 2014
How are floodplains managed?
Local government is primarily responsible for control of
development on flood prone land. However, the NSW State
government, the State Emergency Service and the Bureau
of Meteorology also have a major role to play in managing
the flood risk.
The State government provides specialist advice and
financial support to assist councils to develop Floodplain
Risk Management Plans which consist of the following
stages:
Form a
Floodplain Risk
Management
Committee
Collect data Flood Study
preparation
Floodplain Risk
Management
Study
preparation
Floodplain Risk
Management
Plan
preparation
Implementation of
the Plan
Review the
Management
Plan

13. CCC.013 Administration/Procedural Matters
© Gosford City Council 2013
Proposed Recommendation
THE COMMITTEE requests that the Outlook Calendar function be used to
assist in the scheduling of Committee meetings.