A set of maps were produced to provide an initial indication of the areas that may be potentially impacted by increases in sea levels of up to 90cm by the year 2100. These maps were based on static calm water conditions using topographical information currently held by Gosford City Council.

The information produced in these maps was in response to the Council resolutions dated 27 January 2009 & 1 December 2009 and the NSW Government's "NSW Sea Level Rise Policy Statement" (released in October 2009). Council acted in a transparent manner by producing these maps to share information held by Council with the community.

The NSW Government released the "Sea Level Rise Policy" to support adaptation to projected sea level rise impacts. The Policy Statement provides the following Sea Level Rise Planning Benchmarks for use in assessing the potential impacts of sea level rise in NSW for an increase of 0.9m by 2100 (relative to 1990 mean sea level).

The actual extent of impacts may be greater or lesser than that shown but the maps represent the best information the Council held at the time. If you require further information on sea level rise please refer to Council's Sea Level Rise Planning in Gosford web page.

With regards to sea level rise mapping, at its meeting of 4 September 2012, Council resolved that:

1. Council revise the way flooding and sea level rise information is presented on its website be separating current flood mapping and information from information on sea level rise.
2. Sea level rise mapping on Council’s website be presented in a single series of maps across vulnerable areas based on King Tide levels and 20cm, 50cm and 90cm increments.

King Tide Inundation Map

King Tides are especially high tides which occur at the time of the new moon or full moon during the summer and winter months. At these times the moon and the sun are in line and the gravitational pull is at its strongest.

On the Central Coast, the highest tides occur during the winter months of June, July and August, and the summer months of December, January and February. The highest of each of these periods are known as the King Tide. The winter king tide usually occurs at night and therefore goes unnoticed. Consequently the summer king tide usually catches the most attention. King tides are particularly problematic for developed low-lying riverine and estuary lands throughout Gosford Local Government Area.

During such events, stormwater is unable to discharge into the river or estuary as the lower reaches of the stormwater drains fill with tidal waters. For example, intense rainfall and storm surge from east coast low pressure systems during a king tide may increase the flood height.

There is also the potential for issues to arise for both private and public infrastructure surrounding Gosford’s estuaries and coastline with regards to flooding and permanent tidal inundation as sea levels rise.
Note: These maps are a communication tool only and are not suitable for decision-making.

How to Use the Map Information

There are two methods available for viewing Sea Level Rise mapping by using:

• Online Mapping, or
• Locality Map Index

Online Mapping

Customers with high-speed Internet access can view Council's sea level mapping data online by selecting the mapping category listed below.

Access the King Tide information using the online mapping service here.

Once you have opened the online mapping tool, select from the top menu bar a search method to locate a property of interest (i.e. Locate Property).
Various mapping layers (Flood Extents, Acid Soils, RFS Bushfire Prone) can be selected from the Map Contents - Constraints menu panel located left of the displayed map.

Locality Map Index

Refer to the Map Index Grid to help you obtain the map number of the area that interests you, then select the corresponding map from the Sea Level Mapping for Gosford City Localities table shown below.

Maps are numbered from lowest to highest. The entire grid is not represented in all maps as data is not held for all areas.

All maps referenced in the table below are presented in Adobe Portable Document Format (PDF).