Coastal Erosion Action Plan - Mercury Bay

Coastal erosion and its impact has been an issue that has exercised the Mercury Bay Community over many years This page sets out the Coastal Erosion Programme for the entire Mercury Bay.

There have been many storm events that have seriously impacted the Coastal Environment, particularly property owners and public land and infrastructure. The most significant of these events in living memory is the 1988 cyclone Bola, which caused significant damage to both public and private property and resulted in a number of protective measures being implemented to mitigate any likely recurrence.  Also, the natural changing, moving nature of the coastal environment has meant many changes in terms of both coastal erosion and accretion, which have generated varying responses. Since that time other measures varying in nature have been undertaken, usually in response to changes in the coastal environment some of which have occurred over long periods of time and others over short time spans.

In 2013, a Whitianga Coastal Action Plan was developed which set out actions to deal with the future of the coastal environment in the Whitianga area of the Mercury Bay Community Board Area.

Actions in other parts of the Mercury Bay Community Board Area have varied and been dependent on a number of factors including the scale of erosion, the response of residents most affected or at risk, likely impact on public infrastructure and the nature of the change in the costal environment.

There have been a significant number of reports undertaken of the coastal environment in Mercury Bay dating from 1972 through to 2012.

In May 2016 the Mercury Bay Community Board endorsed a Coastal Erosion Programme for  the entire Mercury Bay, which will help guide the community on how they can respond to the on-going influences of the sea in the Mercury Bay area. The Programme is accompanied by a Plan of Action, which sets out the nature of the works programmed for each individual area. 


Implementation

Implementation of the programme for each beach area will be accessed on a priority basis, dependent on the degree of risk and urgency. A detailed and fully costed programme of works will be developed for consideration and approval by the Community Board.

Funding will be from existing budgets for various coastal erosion works. This will require a full review of all Mercury Bay Coastal Erosion projects and reallocation of funds to align with this programme.

Input will be needed from coastal experts in both coastal science and coastal planting to develop the most appropriate detailed plans and methodologies for the dune restoration and planting at each beach area.

Contact and liaison will be required with the communities in each area to generate support for the programme and the establishment of Beach Care Groups with the objective of them taking ownership for the establishment and on-going care of dunes and plants.


Interested parties

There is a wide range of interested parties which include:

  • Thames-Coromandel District Council
  • Waikato Regional Council
  • Mercury Bay Community Board
  • Community Ratepayer & Resident Groups
  • Owners / Residents of Coastal Properties Users of the Coastal Environment
  • Local Support / Volunteer Groups
  • Department of Conservation
  • Coastal Environment Groups e.g. Forest and Bird Protection Society
  • Wider Mercury Bay Property Owners and Residents

These interest groups will play a key part in implementing the Programme and Action Plan and influencing its direction and priorities as it is delivered. In particular a partnership needs to continue with the Waikato Regional Council to progress an agreed works programme with required resource consents.

The following shall be the Programme for the management of the coastal environment in Mercury Bay.

a) That the primary focus be to protect, reinstate, rebuild, enhance and grow the sand dunes and beaches of the Mercury Bay coastal areas.

b) That the solution of choice be reinstatement of sand dunes and planting with native coastal environment plants.

c) That the application of this Programme be applied on a beach by beach basis with the methodology to be used for each determined by the individual circumstances prevailing at each beach.

d) That in all situations the reinstatement and planting programme take account of the whole coastal environment and ecosystem and ensure its protection and integration into the programme.

e) That the sand dune reinstatement and planting programme be promoted as a community beach care programme with volunteers to prepare, plant and maintain the planting to the greatest extent possible.

f) That in the event sand dunes and / or plants are washed away in adverse weather events they be replaced until consolidated and to the stage that they survive and fulfil their role to enhance and rebuild the dune and beach system.

g) That structures (hard structures) other than sand dunes and planting be used only in circumstances where there is a threat to life, public infrastructure, a private dwelling or significant commercial business premises.

h) That where hard structures are used they be built in a way that they are covered with sand dunes and planting in the shortest possible time following their construction so that their purpose becomes a backstop structure in the event of the sand dune and planting being washed away.

i) Where a storm event creates and unplanned situation that there is an immediate threat to life, public infrastructure, a private dwelling or significant business premises then emergency works be undertaken in the form of a hard structure which, once the immediate threat has subsided, be either removed or made permanent following required practices for the construction of hard structures. If the structure is made permanent it is to be covered with sand dunes and planting in the shortest possible time following construction so that the purpose becomes a backstop structure in the event of the sand dune and planting being washed away.

j) That where hard structures already exist a programme be implemented where they are covered with sand dunes and planting in the shortest possible time so that their purpose becomes a backstop structure in the event of the sand dune and planting being subsequently washed away.


Implementation Principles

The following Principles shall be the basis for the implementation and management of the Mercury Bay Coastal Erosion Programme.

a) Sand dunes be reinstated.

b) The dunes be planted with the native species spinafex, pingao and knobby clubrush.

c) The plants be sourced from quality suppliers.

d) The gradient of the dunes be at the rate of 20° or less.

e) The planting be carried out under supervision with best practice planting and fertilising.

f) The plants be protected by post and rope (or similar) barriers until established.

g) Points of public access to the beaches be established and clearly delineated to encourage people to use them rather than walk through the dune plants.

h) Signage be placed to inform beach users of the sensitivity of the beach environment and the beach care programme in place to protect and enhance the beach area and seeking cooperation, support and engagement in the programme.

i) Best practice plant maintenance be implemented with regular weeding, spraying and replacement of dead or dying plant