Building and Development

Flooding on Private Property

Flooding on Prrivate Porperty

Is my house affected by floods?

Gosford LGA is surrounded by many waterways which in the past or sometime in the future will exceed the capacity of their channels or basins and flood adjoining land.

Council is undertaking a program of flood related studies to determine to what extent these waterways will flood and what hazards exist for each floodplain.

Following this, a Floodplain Risk Management Plan is developed for each waterway to protect existing and manage future development in identified problem areas.

From these studies, council produces flood maps to assist in identifying the extent and characteristics of each individual floodplain.

When a study is completed, the 1% AEP map, which defines a major flood event and which is the map used across NSW as the basis for determining development control is placed on council’s website for community information.

How do I obtain flood information for my property?

Council has flood maps available for its main waterways which give an indication of areas that will most likely be affected by various flood events. However, these maps are not detailed enough to provide flood levels for individual properties.

If you require more detailed information from that supplied on the maps and in relation to a Development Application, you can complete a Flood Level Enquiry Form.

Note: It is not council's general practice to provide flood information about a property over the phone.

Is my house protected by flood mitigation measures?

Many areas in Gosford City have flood mitigation measures in place. These measures may include a levee bank, channel that has been widened, a floodgate, a detention basin or larger drains which aim to reduce the frequency of flooding and the length of time the stormwater remains on flood liable properties. 

However these measures can fail in severe and prolonged storm events, therefore it is important to be prepared for a major flood if your house is located on identified flood liable land or within close proximity to a creek, water course, water body, depression, etc.

To find out whether your property is within an area identified as being affected by flooding up to a 1% AEP flood event, please refer to the Flood Mapping section.

If your property is affected by flooding, please see our Preparing for Flood Emergencies Fact Sheet.

Am I liable for any work I do in a drainage easement, flood area or watercourse?

In short, yes. A solution to solving your problem may adversely affect your neighbour. You should not construct any works that divert stormwater flows onto your neighbour’s property as you could be held liable by your neighbour for any damage as a result of such action.

A common problem in built up residential areas is the construction of boundary fences and gates which impede natural overland flow paths.

You should be careful, when making these types of improvements to your property, that you choose construction materials which will not dam or divert overland flood waters. These types of improvement works may require development approval if located within a floodplain or overland flow path.

Likewise, placing fill on flood liable land may cause an increase in floodwaters upstream and downstream.  Placing fill around your house and blocking or diverting pipes may also lead to serious flooding problems either to yourself or your neighbours. Many properties which were once flood free can be made flood liable because of these types of works.

You should always check with council before placing any fill material on or near an existing pipeline, overland flow path or watercourse.

Similarly, do not attempt to change the location of a natural watercourse. There is a good reason why nature has placed the watercourse in that location and by relocating it you could cause damage to both your own and other people’s properties and cause detrimental impacts on local flora and fauna.

Before undertaking any type of work near or within a drainage easement, on flood prone land or within a watercourse, please check with council to seek advice on whether the work is permissible and whether a development application will be required.

Flood insurance issues

Any property which is identified as being flood prone and that attracts development controls will have a message placed on the property’s planning certificate.

Council is aware that some insurance companies are also identifying flood prone land as a result of undertaking their own flood studies, analysis and flood mapping exercises, or using data from studies conducted by NSW councils’.

This information is being used by individual insurance companies to assess the hazard and risk and to then set premiums for flood insurance.

The insurance industry also uses its own estimates for flood risk assessment and its own definitions for flooding. These may differ when compared with council’s information. To assist the insurance industry in using the best flood information to determine flood premiums, Council has shared its flood information with the insurance industry.

From enquiries made of a number of insurance companies by council, it would appear that the method of setting policies and premiums is done on an individual company basis. This leads to some difference with premiums and flood liability across many properties under different insurance companies.

You should therefore make your own enquiries about how your insurance company classifies flooding (and stormwater), and how this relates to your insurance provisions and premiums. 

For general information about flooding see the Flooding in Gosford page. 

The Flood Mapping page provides more detailed information and a link to maps in the Gosford LGA

To assist in flood preparedness, council worked together with Wyong Shire Council and the SES to produce a Flood Safety Brochure  for residents of the Central Coast.

For further information please see our Flood, Insurance and Your Property Fact Sheet

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