Wamberal Beach Terminal Protection and Sand Nourishment - Investigation and Concept Design

Introduction

Introduction

The Gosford Beaches Coastal Zone Management Plan (CZMP) contains an action to progress a long-term solution for Wamberal Beach erosion. The CZMP outlines a preferred protection solution (terminal protection structure) and the technical studies needed to inform further decision making, but it does not provide for the delivery of a seawall and sand nourishment. 

On 29 January 2019, Central Coast Council resolved to work with the NSW Government to progress designs for a terminal protection structure (seawall) at Wamberal. Manly Hydraulics Laboratory (MHL) were engaged to complete coastal assessments and develop concept plans for a long-term solution for Wamberal Beach in May 2020.

Following the July 2020 storm event which saw the emergency response place 2,400 tonnes of large rocks, over 2,000 tonnes of rock bags and 4,000 tonnes of sand along Wamberal Beach, the NSW Government Wamberal Seawall Advisory Taskforce was set up to provide technical advice and assistance to Council in progressing a long-term solution for Wamberal.

There are many technical, financial, social and environmental complexities that need to be worked through to develop the long-term solution. Council understands that the best coastal erosion management solutions are developed when state and local governments, residents and the broader community work together.

Council will be engaging with the Wamberal and broader Central Coast community throughout this project.

View the phase 1 consultation information here! 
View the phase 2 consultation information here! 

Frequently asked questions

Why is Council investigating options for a terminal protection structure (seawall) and sand nourishment Wamberal Beach?

Wamberal Beach has a long history of coastal erosion, with beachside infrastructure exposed to impacts from coastal storms.

The Gosford Beaches Coastal Zone Management Plan (CZMP) outlines a terminal protection structure (seawall) and sand nourishment as the preferred course of action for managing identified coastal hazard threats at Wamberal Beach. 

A technical study is being progressed to provide options to more sustainably manage the erosion threat over the longer-term. Council are looking at options to improve the community access and beach amenity condition, as part of the long term solution.

This coastal engineering and economics study will ensure Council progresses the Wamberal Beach based actions in the CZMP.

Who recommended a terminal protection structure (seawall) and sand nourishment for Wamberal Beach?

The terminal protection structure (seawall) and sand nourishment have been recommended by experts as a preferred erosion strategy at Wamberal Beach for several decades. 

In the mid-1990s a Coastal Processes Study (PWD, 1994) and Coastline Management Plan (WBM, 1995) detailed the nature of the erosion issue and recommended either ongoing sand nourishment or a terminal protection in the form of a seawall. “a terminal protection structure in the nature of a buried rock revetment is to be designed and constructed to the satisfaction of Council and NSW Public Works, such construction to occur as soon as practicable and in an orderly, co-ordinated manner”

In the late 1990’s a range of coastal protection options were proposed by WRL (1998) for Council. A ‘Seabee’ seawall, spanning lagoon to lagoon, was designed and modelled in detail.

An Environmental Impact Statement (EIS) for the coastal protection solution was finalised in 2003 by MHL, which found that a seawall with periodic small-scale sand nourishment was acceptable. Council adopted the EIS for the seawall and sand nourishment solution in 2004. Funding however could not be secured and the approved protection works did not progress further.

Most recently, Council investigated the erosion issue and what to do about it, through a Coastal Hazard Definition Study (CHDS, 2015), a Coastal Zone Management Study (CZMS, 2017) and the preparation of a Coastal Zone Management Plan (CZMP, 2017). The Gosford Beaches CZMP outlines actions to address the erosion risks at Wamberal Beach. Sand nourishment and a terminal protection structure (seawall) was again determined to be the best solution to the long standing issue.

What is the Gosford Beaches Coastal Zone Management Plan?

The NSW Government has laws in place that guide how the NSW coastline is managed.

Coastal Zone Management Plans (CZMPs) identify coastal management issues and the actions required to address these issues.

The Gosford Beaches CZMP was prepared in line the state government legislation, and in consultation with the Central Coast community. The plan was certified by the Minister for the Environment in May 2017 and identifies several key management actions for Wamberal Beach, including:

  • TW11:  Terminal protection- Council to action review, design and funding of terminal protection structure for Wamberal 
  • TW14:  Investigation of sources of sand and determination of the feasibility of beach nourishment for Wamberal Beach
  • TW15:  Beach nourishment coupled with a terminal revetment to increase the buffer against storm erosion.

Were the community consulted through the CZMP?

The community were consulted as part of the Gosford Beaches Coastal Zone Management Plan (CZMP; 2017), and preceding Coastal Zone Management Study (CZMS; 2015). A CZMP Community Engagement Strategy was developed and endorsed by Council in November 2013, this document guided consultation throughout the CZMS – CZMP processes.

Community consultation included:

  • public exhibition of draft documents (CZMS, CZMP)
  • CZMS - targeted community presentations to discuss potential management options for each study area, including Terrigal/Wamberal (2015)
  • community drop-in sessions (include at Terrigal SLSC; 2015)
  • public notices
  • promotion via local newspaper.

In addition, workshops were held with the Council’s Catchments and Coast (advisory) coastal sub-committee established at that time.
 

What is the role of the Wamberal Seawall Advisory Taskforce?

The NSW Government established the Wamberal Seawall Advisory Taskforce on 31 July 2020 to provide Council with support to implement a sustainable long term solution to coastal erosion issues at Wamberal Beach. Dr Phil Watson has been appointed as the Chair of the Taskforce with Council’s CEO, Member for Terrigal Adam Crouch MP, representatives from the Department of Planning, Industry and Environment, and Council’s appointed project manager. 

The scope of the Taskforce is ‘advisory’ in nature. The Taskforce meets on monthly basis.  More information on the Wamberal Seawall Advisory Taskforce is available on our website.
 

What is the MHL coastal engineering and economics study?

In May 2020, Council engaged Manly Hydraulics Laboratory to prepare concept plans for a terminal protection structure (seawall) and sand nourishment solutions for Wamberal Beach. The study will include: 

  • literature review, to take stock of what is known and identify any information gaps 
  • coastal protection assessment, to determine sand movement, beach behaviour and impacts/opportunities around public access and amenity 
  • concept design options for a terminal protection structure (seawall) and sand nourishment, and potential seawall alignment 
  • sand nourishment investigation to help maintain public beach amenity
  • cost benefit analysis to guide development of possible funding models. 

This study will allow Council and the community to make an informed decision on the best combination of protection and sand nourishment options for Wamberal Beach.
 

Who decides if the proposed terminal protection structure (seawall) and sand nourishment works program is delivered?

There are many stakeholders involved in this decision-making process including: Council, NSW Government, beachside property owners, interest groups and the broader community members.

It is important to understand that while sand nourishment coupled with a terminal protection structure (seawall) has been identified as the preferred long-term solution for Wamberal Beach, the Gosford Beaches CZMP does not provide for the construction of a seawall. Indeed, the solution is complex - requiring input and agreement from a number of parties.

There are many steps to work through before a long-term solution can be implemented at Wamberal Beach. Finding a solution that strikes the right balance is not straight forward. Technical, financial, environmental, social, legislative and land ownership challenges must be addressed. 

There is no guarantee that all the factors required to facilitate the seawall and sand nourishment solution will be satisfied. However, in the absence of a long-term solution the risk of further erosion impacts will remain. 

What are the next steps for the Wamberal Beach terminal protection structure (seawall) and sand nourishment project?

The next steps for Wamberal Beach are as follows:

  • continue with the coastal engineering and economics study looking at concept option and feasibility for implementing the Gosford Beaches CZMP actions
  • continue to consult with the community on erosion solutions for Wamberal Beach at all stages of the study 
  • continue to participate in the NSW Government Wamberal Seawall Advisory Taskforce
  • develop a methodology for implementing a long-term solution, that is legally permissible, environmentally and socially acceptable and financially viable.

Who will pay for the delivery of the long term (seawall and nourishment) solution?

There are several financial questions that need to be worked through prior to the delivery of a long-term solution for Wamberal Beach. These questions include: 

  • How much will the proposed program of works cost?
  • How will the works be funded?
  • Who will pay what?

A funding model is yet to be determined. However, the key beneficiaries (i.e. those who will benefit most) from the proposed program of works will need to contribute to the delivery and maintenance of the sustainable long-term solution.

A targeted coastal economics (cost benefit) assessment is underway as part of the MHL coastal engineering project. This assessment will incorporate up-to-date cost estimates specific to the concept design being proposed. At this stage, concept designs for a terminal protection structure (seawall) and sand nourishment solution are being worked through. Broader community benefits in addition to protection are being looked at through this study. 

The coastal economics assessment will be help guide the development of possible funding models.
 

Is retreat (buy back) being considered?

Council has no planned retreat policy. The resolution of Council is to proceed with MHL coastal engineering and economics assessment, consistent with the Gosford Beaches Coastal Zone Management Plan:

38/19 - That Council request the Chief Executive Officer to commence the Wamberal Terminal Protection and Sand Nourishment preliminary investigations and concept design.

Council is looking into the costs of potential erosion solutions and potential funding models. 

Any long-term solution must be technically feasible, legally permissible, environmentally and socially acceptable and financially viable. 

The coastal engineering and economics assessment currently underway will update the Wamberal Beach cost benefit assessment (CBA) completed by Marsden Jacobs for the State Government in 2017. This earlier study assessed the economic merits of the generic coastal management scenarios for Wamberal Beach. Unlike the MHL assessment, detailed costings were not available for the preliminary CBA completed in 2017, as the options considered in that study were not progressed to a fully developed concept design stage.
 

How long will any proposed (seawall and nourishment) solution last?

The life of any structure would be determined through a detailed design process, the current MHL studies are concept designs. Seawalls on open coast environments, like Wamberal Beach, typically have an initial design life of 50 years. However, many seawalls on the Australian open coast are over 100 years old.

Sand nourishment is central to the long-term solution being investigated. Wamberal Beach is relatively stable. Therefore, any sand added to the beach system through nourishment will remain within the natural system for some time (although it may move back and forth between the dunes, beach and surfzone). 

The life span of the proposed program of works will be designed to consider future climate change (i.e. sea level rise). The program of works would be delivered to appropriate coastal engineering standards.
 

How will the terminal protection structure (seawall) component of the long-term solution impact the beach?

There is no simple answer to this question. 

There are many different factors that determine if a seawall structure will interact with waves and the beach. 

  • Seawall location and alignment: The location of a seawall relative to the beach profile that moves back and forth over time is important. Did you know that seawalls located behind the active beach do not interact with waves under most circumstances? There are many seawalls that co-exist with healthy, high quality beaches. Manly, Bondi and Newcastle (main beach, not Stockton) are good examples of this situation.
  • Type of seawall and its geographical footprint: In locations like Wamberal Beach sloping rock revetments typically interact with waves and beach more than vertical seawalls, which can be placed further landward on the beach. This is because the sloping structures take up more space on the beach. A range of seawall types are being investigated for Wamberal.
  • Applying sand nourishment to the works program to replenish the beach and improve beach amenity. Adding sand to Wamberal Beach would reduce the interaction of waves with the potential seawall, by moving the natural beach profile towards the ocean and burying the structure.

The coastal engineering study currently underway is looking at behaviour at Wamberal Beach and assessing coastal and environmental impacts from the proposed program of works, including the impact on public access and beach amenity both now and into the future.  Climate change impacts are also being considered. 

Did you know that ad hoc protection works have been placed at Wamberal Beach for many decades? 

From Terrigal Lagoon to the Wamberal Surf Life Saving Club, the beach is backed by rocks, building rubble and other works. These materials have been placed in front of the erosion scarp by various entities since the 1970’s. 

When Wamberal is in an eroded state, the ad hoc protection materials interact with the waves. When the beach system naturally recovers (builds out) over time, the rock and rubble become buried. A properly designed and constructed seawall would interact with the beach in a similar way, but in a more effective and less hazardous manner.

Replacing the ad hoc coastal protection works, with a properly designed and constructed seawall that improves beach access and amenity is one of several broader community benefits being looked at. 
 

What is sand nourishment?

Sand nourishment involves placement of sand on a beach to combat against erosion and improve beach amenity. 

Sand nourishment can involve placing small or large quantities of sand into a beach system. Sand can be delivered to the dry beach face or placed underwater in the surf zone. 

The placement method is somewhat dependant on the method of how the sand is extracted elsewhere and transported to the beach. 

Guidelines for Sand Nourishment Science and Synthesis for NSW have been developed by the NSW Government. 
 

Is sand nourishment being considered?

The preferred long-term solution for Wamberal Beach includes a sand nourishment program to ensure long-term outcomes for Wamberal Beach.

Sand nourishment requirements, resources and cost estimates are being looked at through the MHL study. 

There are emerging opportunities for sourcing sand for nourishment purposes at Wamberal Beach, which were not available previously.

Where will the terminal protection structure (seawall) be located? On public land or private land? Will land be purchased if a terminal seawall is built on private property?

The Stage 3 coastal engineering assessment proposes terminal protection structure (seawall) alignments for various concept options. Proposed footprints of each concept option can be shown in the report (available online). All concept designs have a proportion of their footprint in private land with large footprint designs extending further seaward into public land.

It is important to note that these alignments are concept designs. True alignment would be determined during a detailed design phase and would involve seeking consensus between private and public landholders.

Developing a methodology that can support the coordinated delivery of an embayment-wide solution across a mix of private and public land is one of the key challenges that needs to be worked through.

There are no plans in place to purchase private property.

Has Council applied for funding from the $83.6 million available from the State Government’s Coastal Management Grants Program?

In August 2018 Council successfully lodged a grant application to the NSW Government to receive funding for the investigation and design phase of a preferred long-term (seawall and sand nourishment) solution. The application did not include construction of a seawall.

The coastal engineering and economics study underway is being co-funded (50:50) through the NSW Coastal and Estuaries Grants Program.

Phase 1 community consultation

Phase 1 community consultation
The consultation on community values and uses for Wamberal Beach has now concluded.

Between 9 November and 7 December, Central Coast Council conducted community consultation which included a values and uses survey for Wamberal Beach, drop-in formation sessions at Erina Fair and Wamberal Surf Life Saving Club as well as virtual drop-in sessions. We also hosted an online question and answer tool. 

Council undertook the values and uses survey to better understand the value of Wamberal Beach to the community, how it was being used prior to the emergency works and how it is being used now (post emergency works). 

The community can: 

Your attention is drawn to the provisions of the Government Information (Public Access) Act 2009 which allows for possible access to certain public and personal documentation. View our privacy statement.

Faqs View

How could the broader community get involved during the phase 1 consultation? 

Council knows that good coastal management outcomes can only be achieved through active involvement and support from coastal communities. Council has been working with the community on a long-term management solution to the Wamberal Beach erosion issue for some time.

During the phase 1 consultation, the community were invited to: 

  • complete the online values and uses survey (now closed)
  • speak with project staff and coastal experts at community information sessions (there were in person and virtual sessions available) 
  • submit a question online and have the project team get back to them

We will continue to seek the communities experience and input throughout the current MHL coastal engineering and economics study that is underway. 

Phase 2 consultation is now open, click here to find out more

Phase 2 community consultation

Phase 2 community consultation
Consultation on supporting studies and concept plans now open.

Stage reports 1-4 along with supporting concept design renders were made available for public review as part of phase 2 consultation. 
The available reports include:

  • Stage 1 Literature Review - to take stock of what is known and identify any information gaps.
  • Stage 2 Coastal Protection Assessment - to determine sand movement, beach behaviour and impacts/opportunities around public access and amenity. 
  • Stage 3 Concept Design Options - for a terminal protection structure (seawall) and sand nourishment, and potential seawall alignment.
  • Stage 4 Sand Nourishment Investigation - to help maintain public beach amenity.

The concept render designs were developed to assist in visualising the concept seawall design options. Seawall alignment, access points and terminal ends will be determined during a detailed design phase.

The Stage 5 (Coastal Monitoring Studies, to monitor beach conditions) and Stage 6 (Cost Benefit Analysis to guide development of possible funding models) are currently under review and will be available here soon for you to view.

Council will continue to engage with the Wamberal and broader Central Coast community throughout the project to ensure that community opinion, sentiment and understanding are reflected in the decision-making process for a long-term solution to this complex problem. 

How can I get involved? 

You are invited to: 

Between 29 July and 10 September the community were invited to: 

Feedback for phase 2 consultation was accepted until 10 September 2021.  

Faqs View

What was involved in Stage 1 Literature Review?

Stage 1 was to take stock of what is known and identify any information gaps. The objective for this study was to review previous studies related to coastal hazards and coastal management and previous design of terminal protection for Wamberal Beach.

The report contains a compiled review and summary of over 30 studies relevant to the context of the Wamberal Terminal Coastal Protection Assessment.

What was involved in Stage 2 Coastal Protection Assessment?

Stage 2 determined sand movement, beach behaviour and impacts/opportunities around public access and amenity. Objectives for this study included:

  • existing profile data assembly
  • geotechnical data review
  • preliminary crest alignment
  • beach width analysis
  • impact assessment to beach users and beach amenity.

What was involved in the Stage 3 Concept Design Options?

Stage 3 entails concept design options for a terminal protection structure (seawall), sand nourishment requirements and potential seawall alignment. Objectives for this study included:

  • crest alignment
  • seawall options – rock, vertical, stepped and hybrid
  • cost estimates
  • minimum engineering standards.

A total of five seawall concept designs have been developed with cross-section drawings and footprint mapping. The designs range from revetment to vertical and promenade style structures. This study also includes a review of the relevant engineering standards.

What was involved in the Stage 4 Sand Nourishment Investigation?

Stage 4 outlines sand nourishment requirements for Wamberal Beach and investigation of potential sand sources including indicative unit cost estimates. Objectives for the study include:

  • sand requirements
  • sand sources
  • sand nourishment cost estimates.

The key objective of Stage 4 is to provide an acceptable level of public beach amenity for the Wamberal/Terrigal embayment over the life of a terminal protection structure. 

What is involved in the Stage 5 Coastal Monitoring Studies?

Stage 5 consists of additional coastal monitoring studies to observe past and present-day beach conditions to better understand the natural fluctuation of the beach. Monitoring includes:

  • installation of a Coastsnap monitoring site on Terrigal Drive
  • installation of Trailcam, Lidar wave runup monitoring station 
  • live Coastal Monitoring Public Webpage to display monitoring data.

Stage 5 is ongoing, with all monitoring stations established and operating. A testing version of the public webpage has been developed and is currently undergoing testing and quality assurance. 
 

What is involved in the Stage 6 Cost Benefit Analysis? 

Stage 6 will include a Cost Benefit Analysis (CBA) to assess the full range of costs and benefits associated with the project and a Distributional Analysis (DA) to demonstrate how costs and benefits are distributed. Principles of the study aim to:

  • assess the costs and benefits of options for managing the identified threat posed by coastal erosion to Wamberal
  • understand the social and economic impacts of each option in terms of housing, local tourism, environmental benefits, beach amenity, supporting industries and the long-term viability of Wamberal.

The CBA and DA will guide the development of possible funding models.

What can I expect from the Concept Render Designs?

The concept designs were developed to help visualise each of the seawall options and show the extent of the proposed footprints. True alignment of the wall, terminal ends and beach access pathways would be determined during a detailed design phase, which will encompass further community consultation.
 

Have environmental studies been undertaken in accordance with the current study?

No. The environmental studies would be undertaken as part of a detailed design phase. 
Environmental studies/approvals are a legislative requirement for the construction of a terminal protection structure and sand nourishment operations

What is Councils plan for the “68 dwellings identified as potentially impacted by coastal hazards by 2050”? will development applications be assessed? 

Any Development Application (DA) submitted will be considered on its merits under the relevant planning controls and certified CZMP.

What information is being used to inform the updated Cost Benefit Analysis (CBA)? How will this information differ to the previous CBAs developed? 

The new CBA will include updated economic data such as current land value and rate information. Council has provided Balmoral economists with beach use data from the Surf Live Saving Club to assist in determining beach value. 

The costs of associated emergency/ongoing maintenance works will put a cost on the “do normal” (or do nothing) approach; which was not considered in the previous CBA. 

The Stage 1 report is a review of all of the previous studies, how will this review and the learnings from the previous studies be used to inform decision-making around a preferred solution for Wamberal Beach this time?

Stage 1 outlines information relevant to the context of the Wamberal Terminal Coastal Protection Assessment, demonstrating a long history of coastal erosion. Our understanding of coastal processes and engineering have advanced since the development of those studies, which have influenced new design options being presented in the current studies. 

Information gaps in the previous CBA were identified and have been used to inform the new CBA undertaken, particularly by including a distributional analysis.

Previous studies demonstrated funding as a downfall to progression of any long-term solution for Wamberal Beach. Lessons learnt have shown the need for a funding model to be developed which will be a key deliverable to progress into a detailed design phase.

What are the beach amenity impacts of the proposed seawall options for Wamberal Beach? 

Table 5.4 Summary of amenity impacts of proposed options for Wamberal Beach (extracted from Stage 2 – Coastal Protection Amenity Assessment) lists impacts for each option.

Table 5.4
Table 5.4 Summary of amenity impacts of proposed options for Wamberal Beach.

Does the existing Environment and Planning legislation allow for sand nourishment from alternate sources?

It is possible to use sand from alternate sources but a particular type of sand is required. Where sand is sourced alternatively (i.e. not from the same beach embayment) it must be first deemed a viable source by demonstrating similar characteristics such as grain size/colour and be free of contaminants. The Guidelines for Sand Nourishment Science and Synthesis for NSW is the guiding document for sand nourishment in NSW.

Any operations involving sand nourishment would require environmental assessment and possible environmental protection licences dependent on how sand is applied (i.e. offshore vs on land). The Environment Protection Authority (EPA) issues environment protection licences under the Protection of the Environment Operations Act 1997 (POEO Act).

Sand nourishment operations at Wamberal Beach must be consistent with the Coastal Management Act 2016 and State Environmental Planning Policy (Coastal Management) 2018.

Where's it happening?

Wamberal Beach, New South Wales 2260, Australia

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