Council actively monitors the condition of Tuggerah Lakes and other coastal lagoons including The Entrance channel and uses the Manly Hydraulics Laboratory Flood Intelligence Tool (MHLFIT), which helps guide when Council intervention is required in order to mitigate the risk of flooding.  Council also uses a gauge at The Entrance Bridge to provide a quantifiable measure of the influence of ocean tides on the estuary, and subsequently how constricted the channel is.  So channel constriction is not just measured through visual observation.

Our coastal lagoons, are opened when water levels reach a trigger level, and when the lagoons are closed.  This is a similar approach to that taken in other coastal local government areas. See our coastal lagoon web page for more information and current lagoon water levels.

For Tuggerah Lakes, our procedure is more unique and complex. Unlike the other coastal lagoons, Council may intervene in its management of the channel before it is closed and when water levels are predicted rather than reached.

MHLFIT uses Bureau of Meteorology predicted rainfall data to forecast potential lake levels up to four days before they occur, so Council intervenes at an earlier point in the process. This management approach is documented in the Tuggerah Lakes Interim Entrance Management Procedure – which prescribes actions to be undertaken that are tailored to different entrance conditions.  Works may include berm scraping (reducing the height of the sand), pilot channels (creating a narrow channel with heavy machinery to create a second opening that will naturally widen) and emergency openings (in the unlikely situation of a completely closed channel).

Council is currently working towards the development of an Entrance Management Strategy through the Tuggerah Lakes Coastal Management Program. Interested community members can register their interest in staying up to date with news and opportunities to be involved.

Council’s procedure for managing The Entrance Channel can be found within the Tuggerah Lakes Entrance Management Study.

At the request of community members and the Catchments to Coast Advisory Committee, an additional intervention trigger was endorsed as part of the Interim Entrance Management Procedure and Resolved by Council at the 14 December 2022 Ordinary Council meeting. In addition to the relevant response being triggered if Council’s Flood Intelligence Tools predict a flood level of 1.3m AHD or greater in Tuggerah Lakes (up to four days before they occur using conservative rainfall forecasts), it may also now be triggered if a measured water level of 7mAHD at the Yarramalong Water NSW gauge (211014) and 6mAHD at the Ourimbah Creek Water NSW (211013) gauge is recorded concurrently.

No. The foreshore of Tuggerah Lakes is and always will be flood prone. 

View the Tuggerah Lakes online flood mapping tool which  converts current and predicted flood levels directly from the Bureau of Meteorology into a visual display. 

The minor flood level for Tuggerah Lakes is just 0.9m AHD, which is the level at which some roads start to be flooded.

Statistically there is about a 50% chance of at least this level of flooding each year. Over the past 100 years there has been flooding in the lake up to 2.1m AHD (in June 1949); there have been six floods higher than 1.7m AHD, including the July 2022 flood, which was the sixth highest at 1.72m AHD.

Council estimates that the largest flood that could conceivably occur – called the Probable Maximum Flood – could reach 2.7m AHD. This also happens to be the minimum floor level that Council has been setting for habitable areas of residential buildings around the lake over the past 40 years. (If there is a part of your house that is used for habitable purposes, and it is located below this level then it is unlikely to have been approved for habitable purposes; in this case it may have been approved as non-habitable (such as a storage area or carport) but repurposed – possibly by a previous owner - without approval as a habitable area. If this is the case for your property, then please restore the area to the use for which it was approved.)

Tuggerah Lakes is generally just above average sea level (which is approximately 0m AHD); it is normally in the range of about 0.2m AHD to 0.4m AHD. Generally, if there is about 200mm of rain then the lake level can slowly rise about 0.6m over about three or four days to a minor flood level of 1.3m AHD. With about 350mm of rain, lake water level can rise even further over this timeframe and can result in major flooding of 1.6m AHD. Note that these levels are still not very much higher than mean sea level; which is because the lakes are very large, so the flood waters can spread over a large area.

Let’s put this into perspective: in comparison to Tuggerah Lakes the high tide level at other locations on the Central Coast, such as Woy Woy in Brisbane Water or Spencer on the Hawkesbury River can be up to 1.2m AHD, even on a sunny day with no rain, as the tidal range is larger, more like the open ocean at these locations. These sunny day levels are 0.2m higher than a minor flood level in Tuggerah Lake. The Central Coast also has some other coastal lagoons, which are much smaller versions of Tuggerah Lakes. These are all perched up above normal mean sea level. Terrigal Lagoon is the lowest of these. and Council attempts to open Terrigal Lagoon when it reaches 1.23m AHD. Sometimes Council may have to wait longer to successfully open Terrigal lagoon depending on the ocean conditions: wave runup, especially at high tide, can keep filling the channel back up with sand. The other coastal lagoons have higher let-out levels: Avoca at 2.09m AHD, Wamberal at 2.40m AHD, and Cockrone at 2.53m AHD. These lagoons are much easier to successfully open because of the increased energy of water running out of the lagoon from a higher level, which can quickly cause the pilot channel to widen, overcome the wave action, and allow the lagoon level to recede.

Unlike these coastal lagoons, which are predominately closed, Tuggerah Lakes is predominately open (the last time it completely closed was in 1987). If there is likely to be a flood in Tuggerah Lakes, then Council has an adopted procedure to help sand at The Entrance Channel to be better able to scour away so that the channel can gradually widen to let out more floodwater. But like Terrigal Lagoon, it can be very difficult to get the entrance to start naturally widening further until the lake level gets to at least 1.3m AHD. At lower levels there is simply not enough energy in the flowing water for sand to scour away to allow the channel to naturally widen.

Yes. 

There’s a natural movement in the height of the water within Tuggerah Lakes, which supports the health of the estuary.

Estuaries such as Tuggerah Lakes with intermittent entrances are extremely dynamic and changes to channel conditions are a natural process. The recent constriction of the channel can be attributed to mild wave conditions and lower rainfall in the catchment.

When The Entrance channel is in a more constricted state, water levels in Tuggerah Lakes tend to be slightly higher on average.

This natural variation in water levels is an important process that can improve water quality and amenity. The higher water levels immerse the lake’s fringing wetland habitats, assist with the distribution of wrack and improve mixing of the water between shallow nearshore areas and deeper parts of the lakes. The fluctuations in lake levels also help to free and lift wrack that can get trapped near the shoreline, and place it in areas where it can aerobically break down (such as saltmarshes, fringing wetlands, and foreshore reserve areas), reducing odour.

View the timelapse video that shows the dynamic movement of The Entrance channel

Central Coast Council engaged NSW Government’s professional specialist advisor, Manly Hydraulics Laboratory, in July 2020 to undertake the Tuggerah Lakes Entrance Management Study. The project aims to develop an evidence-based Interim Entrance Management Procedure for Tuggerah Lakes to reduce the risk to life, public and private infrastructure and public health.

Following the release of Angus Gordon’s independent report, Review of Central Coast Council’s Lagoon and Lake Entrance Management, Policies and Practices, Council has released the Tuggerah Lakes Entrancement Study: Stage 1 Review of Previous Studies report as recommended.

The Stage 1 report includes a summary of over 20 studies from 1987 to present relevant to entrance management at Tuggerah Lakes. The report provides key background information and conceptual models to assist in understanding the complex nature of entrance processes and management at Tuggerah Lakes. Findings from the review will inform subsequent stages of the project and these will involve detailed modelling and consideration of the environmental, economic and social impacts.

View the Tuggerah Lakes Entrance Management Study: Stage 1 Review of Previous Studies for more information.

In August 2022 the Tuggerah Lakes Entrance Management Study was completed which included development of the Interim Entrance Management Procedure to assist Council in reducing flood risk and impacts on the community. 

The Interim Entrance Management Procedure is supported by flood intelligence tools that provide real-time predictive lake level modelling and data to ensure a proactive, informed and consistent response by Council when flood events are predicted. 

The Interim Entrance Management Procedure is intended to guide Council’s channel management until the Entrance Management Strategy is completed through the Tuggerah Lakes Coastal Management Program. This process will provide opportunities for the community to get involved and have their say, as well as allowing all the social, economic and environmental factors to also be considered in deciding how we manage one of our greatest natural and recreational assets into the future.

View the complete Tuggerah Lakes Entrance Management Study for more information.

View the Interim Entrance Management Procedure for more information. 

The Tuggerah Lakes Estuary Management Plan (TLEMP) was adopted by the former Wyong Shire Council in 2006. The TLEMP was developed over a nine-year period and provides strategic direction for the management of the Tuggerah Lakes estuary and its catchment.

The TLEMP was developed to identify priorities, costs and likely timeframes for taking further action. It incorporates the social, economic and environmental values of the Tuggerah Lakes and was subject to community consultation before it was finalised and implementation began. The EMP provides guidance on the types of actions that should be undertaken to protect the estuary, the order in which they should be completed and the estimated cost.

The TLEMP is considered the platform by which Council will manage the estuary into the future. Its primary objective is to provide direction for the management of Tuggerah Lakes and its catchment in order to ensure the sustainability of its ecological systems. Council continues to refer to the Tuggerah Lakes Estuary Management Plan in developing our annual business plans and budgets.

The overarching aims of the TLEMP are to ensure that:

• the quality and quantity of water meet the needs of the community and lakes and rivers
• the plants along the banks of rivers, lakes and in wetlands are protected because these are essential to a healthy ecosystem
• biodiversity and ecological integrity of the lakes ecosystem are maintained or enhanced
• human activities can take place while protecting cultural heritage and enhancing soil, water and ecosystem health
• the social and economic needs of the community are met while protecting the environment of the coastal zone
• we continue to improve our understanding of how the estuary works and incorporate this knowledge into management.

Snapshot of the Tuggerah Lakes Estuary Management Plan – Part 1

Snapshot of the Tuggerah Lakes Estuary Management – Part 2

Tuggerah Lakes Estuary Management Plan Part 1

Tuggerah Lakes Estuary Management Plan Part 2

Tuggerah Lakes Estuary Management Plan Part 3

Tuggerah Lakes Estuary Management Study 2001-2004

The Tuggerah Lakes Estuary Management Study builds on the knowledge of the Tuggerah Lakes detailed in the Estuary Processes Study and details key issues and management options for improving the health of the Tuggerah Lakes estuary and its catchment. The study looks at options for areas such as stormwater management, saltmarsh rehabilitation, water quality, the channel, dredging and many others. The study contains input from a Community Reference Panel (including boating, fishing, environment, Aboriginal peoples, Dunecare and other representatives), as well as technical experts and local business organisations.

Estuary Management Study

Tuggerah Lakes Estuary Management Study Summary

Tuggerah Lakes Estuary Management Study full document inside cover

Tuggerah Lakes Estuary Management Study Part 1

Tuggerah Lakes Estuary Management Study Part 2

Tuggerah Lakes Estuary Management Study Part 3

Tuggerah Lakes Estuary Management Study Part 4

Tuggerah Lakes Estuary Management Study Part 5

Tuggerah Lakes Estuary Processes Study 1998-2000

Prior to developing management actions for the Tuggerah Lakes estuary, an Estuary Process Study was developed to outline the current environmental condition of the system and establish a ‘baseline’ from which to work. This involved looking at all the existing scientific studies and the completion of further studies covering many of the ecological processes of the lakes. Research looked at characteristics such as water quality, saltmarsh and seagrass habitats, sediments and their movement and stormwater. Written by Council staff and State Government agencies, the Process Study was hailed “the best in the state” by scientists who reviewed it.

The Tuggerah Lakes Estuary Management Plan (TLEMP) is the current certified Coastal Zone Management Plan which aims to rehabilitate the Tuggerah Lakes estuary and its catchment to support ongoing health and vitality and protect against future impacts. 

Since 2008, the Australian Government has provided $30.95 million in grant funding to assist with implementation of various aspects of the plan: 

2008-2013: $20 million Australian Government Caring for our Country grant

2004-17: $3.25 million Australian Government National Landcare Programmes grant

2017-20: $3 million Australian Government Improving Your Local Parks and Environment grant

2020-23: $4.7 million Australian Government Environment Restoration Fund grant. 

Council has produced a video which outlines the science behind the estuary including estuary processes, water quality, human impacts, funding and future management of Tuggerah Lakes – take a look

What has been done?

The Tuggerah Lakes Estuary Management Plan included four action plans relating to water quality, ecology, socio-economic values and knowledge and management. These action plans included 100 individual actions, of which 86% have been completed or are ongoing.  
By working with our project partners and the local community, the following key achievements have been completed (as of June 2020): 

• 40km rural stream rehabilitation
• 13km urban stream rehabilitation
• 2.5ha saltmarsh reconstruction
• 29ha saltmarsh rehabilitation
• 374ha wetland conservation and restoration
• 277 gross pollutant traps
• 37 constructed wetlands
• 29km of shared pathway
• 32 boat ramps & jetties
• 4 foreshore beaches
• 33 regional and local playspaces
• Ongoing financial support for Environmental Groups (formerly Landcare)
• Award winning community education program
• Long term water quality improvement at multiple locations
• Extensive research & innovation to improve future management

View the Tuggerah Lakes Estuary Management Plan: Summary of Implementation Report 2008-20 for more information

Map of Projects

We are always working to improve the estuary and catchment in high priority locations. You may not always see where we are working, so instead why not explore the many on-ground works completed during the implementation of the TLEMP. The map contains locations and information on projects completed by Council and its partners through various grant programs as well as Council funded projects. 

View the Tuggerah Lake Estuary Management project map

Tracking progress

Central Coast Council monitors the ecological health of our lakes, estuaries, rivers, creeks and lagoons to evaluate condition, measure change through time and target investment and on-ground works to improve ecosystem health. A healthy waterway is one that supports natural processes, is resilient to change, can recover from human impacts, and is relatively stable and sustainable through time. 

Sampling is undertaken for all estuaries on the Central Coast, including Tuggerah Lakes. The annual results are published in our Central Coast Waterways Report Card. By reporting the monitoring results to the community each year, Council aims to raise awareness about the state of our waterways, and the pressures that affect ecological health

What's next?

Management of estuaries and coastal environments is complicated and our plans need to evolve over time. There are many values and risks to be considered when preparing a management plan, and this is done in consultation with technical experts and the local community. 

All coastal areas in NSW are managed in accordance with the Marine Estate Management Act, the NSW Coastal Management Act and through the development and implementation of Coastal Zone Management Plans. 

Recent changes to the legislation has meant that the current plans are being transitioned across to new Coastal Management Programs.

Over the next 2-3 years, Council will work with the NSW Government, the Tuggerah Lakes Expert Panel, technical experts and the local community to develop a new Coastal Management Program for Tuggerah Lakes. This will replace the existing Estuary Management Plan and will provide the framework to manage the estuary into the future.

The sandspit which naturally forms across The Entrance Channel is actually a great masterpiece of nature, strong enough to hold water inside the perched estuary during periods of low rainfall yet soft enough to blow out during a flood event. Council management of the channel aims to find a balance between allowing the sand spit to naturally do its job during periods of low rainfall, and giving it a bit of a helping hand when heavy rains are forecast.  

Tuggerah Lakes is a naturally shallow estuary, with an average depth of approximately 1.7m (Lake Macquarie averages 8m depth for comparison!) and the estuary is perched approximatly 0.3m above sea level so allowing sand to naturally build up across the channel during periods of low rainfall prevents the net loss of water from the estuary that would occur if the channel was wide open during these times.  

Allowing the lake levels to fluctuate and occasionally rise higher than normal also immerses the lake’s fringing wetland habitats and improves mixing of the water between shallow nearshore areas and deeper parts of the lakes. It also helps to lift wrack (floating seagrass that has detached from the lake bed) that can get trapped along the shoreline and facilitate for it to wash ashore onto higher ground where it can aerobically dry and break down in the sun, reducing odour.

When the channel is in a heavily constricted state (as it is now) we can pro-actively help to get it into a more ‘flood-ready’ state by doing some pre-flood berm preperation works. These include scraping back sand to widen the throat of the primary channel and constructing a secondary pilot channel with the end plugs kept in place. It is important to note that we can’t dig the secondary channel too far north as that would risk causing severe erosion issues on the northern shore in the event of a major flood.

There are many benefits to keeping the end plugs on the secondary channel until triggers are met. For effective sand scouring to take place upon opening, there needs to be enough water depth in the lake to create adequate pressure to maintain the secondary channel in an open state. Concurrently, ocean tide and wave conditions need to be carefully considered as large swell or high tide conditions may result in infilling of both water and sand into the system.  

These pre-flood berm preparation works mean that if flood forecast thresholds are reached, and conditions are right to achieve maximum flow to burst open the secondary channel, the process of digging the end plugs off the secondary channel is quick and efficient. Modelling and experience have shown that these actions can help marginally reduce the peak water levels during a large flood, however no amount of intervention will ever eliminate the flood problem.  

Why is the lake level taking so long to recede?  

• Heavily constricted channel state: The Entrance Channel is currently classified as being in a heavily constricted state, as ocean tides have been gradually pushing more and more sand across the entrance channel due to prolonged periods of low catchment rainfall. This is actually a very important natural phenomenon for shallow, perched estuaries; preventing the net loss of water that would occur from the lake system if the channel was wide open during prolonged periods of low rainfall.  
• Unusual southerly location of primary channel: The primary channel has also been following an unusual path in recent years, much further south than normal.  This is likely the result of the groyne at The Entrance Beach, which was built by the NSW State Government in 2017 to maintain sand on the South Entrance beach. Unfortunately, an unintended consequence of the construction has been erosion on the northern side of the rock groyne which has encouraged water to flow to the extreme south of the channel, where there is a rock shelf limiting the depth and reducing its capacity to operate effectively. Council has recently made representation to the NSW Government asking for further consideration to be given to the impact of the groyne on the effective operation of The Entrance Channel.
• Lake level not high enough to maintain a secondary channel: Recent efforts to establish a secondary pilot channel were done pre-emptively and pro-actively, whilst lake levels were only at 0.8m, despite our Interim Entrance Management Procedure advising a lake level of 1.3m is needed to create enough water pressure to successfully maintain the pilot channel in an open state and allow the entrance to widen. During April, despite our efforts to re-dig the secondary channel open on multiple occasions, it continued to close over at each high tide due because the lake level was not high enough to overcome the ocean energy pushing sand in.