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

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

Wamberal Beach Terminal Protection and Sand Nourishment - Investigation and Concept Design
This project is currently open for consultation.

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. The initial stage of engagement will help us understand the value of Wamberal beach to the community, with further engagement next year around the options available for the long term.

How can I get involved? 

You are invited to: 

Got a question? 

Feedback for phase one community consultation will be accepted until 7 December 2020

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.

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Phase one community consultation on values and uses for Wamberal Beach
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Paul Donaldson
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Casey Johnston

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. 

How can the broader community have their say?

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.

We will be seeking the communities experience and input again through the current MHL coastal engineering and economics study that is underway. You can get involved now by:

Early next year we will be: 

  • seeking your feedback on the draft concept designs developed
  • hosting community workshops to refine the process and the draft concept designs.

The concept designs will then be placed on public exhibition providing an additional opportunity for the community to provide feedback.
 

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 the detailed design process, which is the next step. 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 coastal engineering assessment is looking at proposed terminal protection structure (seawall) alignments for various concept options. We do not yet know what the planned footprint of each concept option is and what the land implications will be.

The seawall footprint from the previously approved Wamberal terminal protection structure was located across a mix of private and public land.

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?

Council successfully lodged a grant application in August 2018 to the NSW Government for funding the investigation and design phase of a preferred long term (seawall and sand nourishment) solution.  

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

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