Dunedin's Ocean Beach Domain is the frontline in an ongoing battle between sea and land that has serious implications for the low-lying suburbs behind the dunes. The forces at work, not least the hand of man, have shaped a significantly modified environment.

Change has been brought about by the pressure for raw resources in a developing city, the introduction of marram grass and ultimately the need to tame the coast for the physical protection of the city.

There are lessons here for those who are prepared to look at the mistakes of the past, say Paul Pope, of the Dunedin Amenities Society, and the late John Perry.

• Kaituna
Ocean Beach is a highly modified environment. The normal activity and movement of sand has been altered in favour of a more stable landscape. The former back-dune areas have been extensively mined and become recreation areas.

The coastline still stretches from the St Clair cliffs in the west to Lawyers Head in the east, but the sand dunes have become much thinner and steeper.

In 1848 in the west around St Clair, the sand hills were much smaller and lower, and the mouth of a lagoon ran through these dunes. They accumulated and grew as you moved east towards Lawyers Head.

High ground was in the west at the St Clair hills and in the east at the beginning of Otago Peninsula and beyond them, Otago Harbour and its extended tidal areas.

Between these features was a low-lying wetland named Kaituna. It was covered with silver tussock, rushes and flax and was an area of traditional food-gathering for Maori who sought tuna (eel), pukeko and weka.

There is also evidence that the Kaituna area was once thick with trees, probably kahikatea. They lay buried under the surface of the wetland and were often dug up and used as firewood by early settlers.

A significant feature was a track along the landward edge of the sand hills, which provided easy access to Kaituna.

By 1876 the urban growth of Dunedin had pushed housing to the edge of the sand hills at Ocean Beach. Sand was being removed constantly by householders to raise the level of their sections. Occasional floods are reported in the 1870s, but mostly from the harbour, into South Dunedin.

On one occasion a Mrs Rae and her two daughters were rescued by a gasworks boat crew from Rankeilor St. Their dog was reportedly left behind.

Dunedin's battle of dunes

Otago Daily Times
Sat, 1 May 2010

Dunedin's Ocean Beach Domain is the frontline in an ongoing battle between sea and land that has serious implications for the low-lying suburbs behind the dunes. The forces at work, not least the hand of man, have shaped a significantly modified environment.

Change has been brought about by the pressure for raw resources in a developing city, the introduction of marram grass and ultimately the need to tame the coast for the physical protection of the city.

There are lessons here for those who are prepared to look at the mistakes of the past, say Paul Pope, of the Dunedin Amenities Society, and the late John Perry.

• Kaituna
Ocean Beach is a highly modified environment. The normal activity and movement of sand has been altered in favour of a more stable landscape. The former back-dune areas have been extensively mined and become recreation areas.

The coastline still stretches from the St Clair cliffs in the west to Lawyers Head in the east, but the sand dunes have become much thinner and steeper.

In 1848 in the west around St Clair, the sand hills were much smaller and lower, and the mouth of a lagoon ran through these dunes. They accumulated and grew as you moved east towards Lawyers Head.

High ground was in the west at the St Clair hills and in the east at the beginning of Otago Peninsula and beyond them, Otago Harbour and its extended tidal areas.

Between these features was a low-lying wetland named Kaituna. It was covered with silver tussock, rushes and flax and was an area of traditional food-gathering for Maori who sought tuna (eel), pukeko and weka.

There is also evidence that the Kaituna area was once thick with trees, probably kahikatea. They lay buried under the surface of the wetland and were often dug up and used as firewood by early settlers.

A significant feature was a track along the landward edge of the sand hills, which provided easy access to Kaituna.

By 1876 the urban growth of Dunedin had pushed housing to the edge of the sand hills at Ocean Beach. Sand was being removed constantly by householders to raise the level of their sections. Occasional floods are reported in the 1870s, but mostly from the harbour, into South Dunedin.

On one occasion a Mrs Rae and her two daughters were rescued by a gasworks boat crew from Rankeilor St. Their dog was reportedly left behind.

ODT Sat, 1 May 2010 by

Dunedin's Ocean Beach Domain is the frontline in an ongoing battle between sea and land that has serious implications for the low-lying suburbs behind the dunes. The forces at work, not least the hand of man, have shaped a significantly modified environment.

Change has been brought about by the pressure for raw resources in a developing city, the introduction of marram grass and ultimately the need to tame the coast for the physical protection of the city.

There are lessons here for those who are prepared to look at the mistakes of the past, say Paul Pope, of the Dunedin Amenities Society, and the late John Perry.

• Kaituna
Ocean Beach is a highly modified environment. The normal activity and movement of sand has been altered in favour of a more stable landscape. The former back-dune areas have been extensively mined and become recreation areas.

The coastline still stretches from the St Clair cliffs in the west to Lawyers Head in the east, but the sand dunes have become much thinner and steeper.

In 1848 in the west around St Clair, the sand hills were much smaller and lower, and the mouth of a lagoon ran through these dunes. They accumulated and grew as you moved east towards Lawyers Head.

High ground was in the west at the St Clair hills and in the east at the beginning of Otago Peninsula and beyond them, Otago Harbour and its extended tidal areas.

Between these features was a low-lying wetland named Kaituna. It was covered with silver tussock, rushes and flax and was an area of traditional food-gathering for Maori who sought tuna (eel), pukeko and weka.

There is also evidence that the Kaituna area was once thick with trees, probably kahikatea. They lay buried under the surface of the wetland and were often dug up and used as firewood by early settlers.

A significant feature was a track along the landward edge of the sand hills, which provided easy access to Kaituna.

By 1876 the urban growth of Dunedin had pushed housing to the edge of the sand hills at Ocean Beach. Sand was being removed constantly by householders to raise the level of their sections. Occasional floods are reported in the 1870s, but mostly from the harbour, into South Dunedin.

On one occasion a Mrs Rae and her two daughters were rescued by a gasworks boat crew from Rankeilor St. Their dog was reportedly left behind.

Update: April 2010

Data collection and information covering research into the different aspects of the Ocean Beach is continuing to come to hand, although completing some research is taking a little more time than the Council would ideally prefer. The Project Team's report to the Council on the best options for Ocean Beach can only follow the receipt of all relevant information, and that report will now almost certainly be in the second half of 2010.

On the beach itself, a combination of wind, rain, and very high tides have lowered sand levels significantly. As significant 'steps' have also formed in a number of areas, extreme care should be taken when accessing the beach at any time.

from the Otago Daily Times
By David Loughrey on Fri, 16 Apr 2010

The future management of Dunedin's "first line of defence" against the ocean, the city's coastal dune reserves, will soon be decided after hearings held this week.

The coastal dunes reserves management plan hearings attracted 52 submissions from groups including Save the Otago Peninsula and the Yellow-eyed Penguin Trust. Ten people attended Wednesday's hearings to speak.

Under the Reserves Act 1977, local authorities are required to develop reserve management plans.

Dunedin City Council staff identified 10 coastal reserves, including at Brighton, Karitane, Long Beach, Ocean View, Waikouaiti and Warrington, to be included.

The idea was to protect and preserve the natural processes of the dunes, and manage natural, biodiversity, scenic and cultural values, while providing for recreation that did not damage those values.

Hearings committee chairwoman Cr Fliss Butcher said a major issue that emerged at the hearing was horses and dogs on Warrington beach.

There was "definitely" a problem with uncontrolled dogs, and their effect on nesting birds.

The issue of horses may be dealt with in a separate process, but the reserve was a recreational area, and horse-riding was a recreational activity.

Other issues included concerns about erosion, something the committee would bear in mind, Cr Butcher said.

She hoped community groups similar to the Tomahawk/Smaills Beachcare Trust could be set up to look after the reserves, with help from the council.

"It's really important," she said of the plan.

"These dunes are our first line of defence."

The committee would deliberate next week, and the plan would go before the community development committee, before being signed by the council.

- david.loughrey@odt.co.nz

ODT By David Loughrey on Wed, 14 Apr 2010

Differing views have emerged on the possibility of saving low-lying areas in southern Dunedin from sea-level rise.

Consulting engineer Dave Tucker yesterday said engineering solutions were available to deal with the issue, while Sustainable Dunedin co-chairman Phillip Cole, also an engineer, said a retreat from the area was inevitable.

A report released on Monday identified South Dunedin, St Kilda and St Clair as "hot spots" vulnerable to what could be a 1.6m rise in sea levels by 2090.

The report on the effects of climate change in Dunedin was commissioned by the Dunedin City Council, written by University of Otago Emeritus Professor of Geography Blair Fitzharris and released on Monday.

It said the city would eventually have to protect, retreat or evacuate areas including South Dunedin, St Kilda and St Clair.

Other problem areas were the harbourside, the lower Taieri Plain, including the Dunedin airport, populated estuaries along the coast, and the ecosystems of upland conservation regions.

In his report, Prof Fitzharris said the city needed to focus on "adaptation" to deal with the problem, and that was not a one-off event but a process that involved awareness-raising, the development of knowledge and data, and risk assessment.

Some adaptation was occurring on a limited basis, he said.

"However, there remain significant challenges to achieving concrete actions that reduce risks."

Implementing measures such as planned retreat and dune management, building design, prohibition of new structures and siting requirements that accounted for sea-level rise was difficult.

Mr Tucker has previously told the council it needed to form long-term mitigation strategies to deal with the effects of climate change.

Yesterday, he said two areas of Dunedin were not protected by hills: the St Clair and St Kilda beaches area, and the lower harbour near Port Chalmers.

The areas of risk if the sea came through were not just South Dunedin, but all the reclaimed land in the city, including land up to the Dunedin railway station, and up to parts of the University of Otago.

He suggested a "barrage" across the harbour that would take advantage of a natural bottleneck between Port Chalmers and Portobello.

The barrage would link Goat and Quarantine Islands, trapping water in the upper harbour during high tide and releasing it at low tide. That would deal with sea-level rise at the harbour end of the city, and could include turbines to produce electricity.

The beach end of the city "could be saved in some engineering manner".

"You only need to go to Holland," he said, where technology had been developed to keep the North Sea out of the country.

"I'm quite sure if you got consultants from Holland they would come up with ideas to stop sea ingress."

Update: March 2010

There have been some fluctuations in sand levels at the western end of Ocean Beach, with a small 'step' created by wave action near the Salt water Pool.

The regular access routes to the beach are all accessible at the present time, with sand levels at the St Kilda end actually starting to form additional dunes. With the more settled nor' easterly weather we have been enjoying recently, it is likely that sand will continue to build up while the settled weather continues.

There has been a steady accretion of sand over the length of Ocean Beach since late December, although there has been a small 'step' created by wave action at the eastern end of the beach. The regular access routes to the beach are all accessible at the present time, although there is so much sand at St Kilda it is actually impeding access a little. This additional windblown sand will be shifted in the next week or two. With the more settled weather we have been enjoying recently, it is likely that sand will continue to build up over the next month or two.

Research continues into the best options for the future management of the Ocean Beach, and the Project Team tasked with carrying out this research will be reporting back to the Council later in the year.

Sand levels have remained constant and high throughout December. During the last two weeks of December, regular south-westerly winds resulted in a slight reduction in the sand levels at the salt water pool end of the seawall, re-exposing some rocks, but the same winds have also resulted in an increase in the sand deposits at Lawyers Head. At the time of writing of this report, the sand bar, usually just off shore, had moved landward creating a very wide, flat beach at low tide.

Access to the beach remains available at all points, however access via the accessibility ramp might be difficult due to a slight drop at the bottom. Sand levels on the beach continue to be monitored regularly.

Ocean Beach has continued to remain popular with New Zealand Sea Lions and even Leopard Seals. Please keep an eye out for advisory signs (with an outline of recommended behaviour around these animals) that are now in place.

From the ODT By Chris Morris on Mon, 7 Dec 2009

Members of the public have until mid-January to have their say on a new management plan for coastal reserves around Dunedin.

Dunedin City Council staff have identified 11 coastal reserves across the city - including at Brighton, Karitane, Long Beach, Ocean View, Waikouaiti and Warrington - to be reclassified under the council's draft coastal dune reserve management plan.

The change would result in the reserves' status being changed from recreational areas to local purpose (coastal protection) zones, providing new powers to protect the sensitive areas at the expense of some recreational rights.

Councillors at a recent meeting of the community development committee voted to approve the draft management plan, containing the reclass-ifications, for a two-month period of public consultation.

Depending on the number of submissions received, a public hearing could follow.

A report to the meeting by council reserves policy and planning officer Dolina Lee said the change aimed to protect and preserve the dunes while providing for recreation where possible.

Under the Reserves Act 1977, local authorities were required to classify the primary use of the reserves they owned.

Speaking to the Otago Daily Times earlier this year, council community and recreation services manager Mick Reece said changes in the reserves' status recognised the importance of protecting the coastal environment from flooding, erosion and other threats.

"You can't recreate if the dunes disappear and you are inundated, so the primary driver for managing the reserves should be coastal protection," he said.

Consultation was the latest step in the development of the draft plan, stretching back to 2002.

Approval of the reclass-ifications was needed by the Department of Conservation, and a final approval of the changes would be made at a subsequent council meeting.

Sand levels have recovered well, and at the time of writing this update, access to the beach is available at all points. Sand levels on the beach are being monitored regularly, and will be augmented on an "as required" basis over the summer.

Ocean Beach is also proving popular with New Zealand Sea Lions, and a number of these animals are frequenting the beach from time to time. Advisory signs (with an outline of recommended behaviour around sea lions) are now in place.

The generally high beach profile (the level of sand) on Ocean Beach continues. The track from the Esplanade end has been re-opened, and the steps to the beach have been reinstated. While there has been some sand loss, a good deal of the very healthy reserves of sand remained until recently.

The Project Team is reviewing the information that is being gathered as background for the Long Term Management Plan, and the program for completing the studies and preparing the Plan remains on track. The maintenance regime will continue as the information gathering process draws to a close.

The sand loss on Ocean Beach over winter months (July especially) has now been largely recovered. In the interim, the damage to the Reno mattresses (that provides protection to the toe of the dune at Middle Beach) was repaired, as was damage to that section of the rubble wall that had been uncovered. The repaired Reno mattresses and the reinstated rubble wall have been re-covered by sand, and the remaining machinery has now been removed from the beach.

Monitoring of sand levels will go on, and the maintenance regime will also continue on an 'as required' basis as the information gathering process concludes. The Project Team appointed to draft the Long Term Management Plan is now meeting on a regular basis, while the program for completing the studies of the beach, adjacent off shore environment, as well as the eventual preparation of the Plan itself, remains on track.

St Clair surfers would have noticed an incredible increase in the volume of sand being deposited at the base of the sea wall, and out into the break its self. I have heard it described at the beginning of the week as pipeline-like. below: a view the new Hotel on the Esplanade with sand build up. And the 6 dogs on the beach where Dogs are prohibited on St Clair Beach.
Pic at Bottom: Harbour dredging's have been deposited on the wharf the last few weeks and trucked to Moana Rua Rd where massive amounts have been dumped off the end to build up the toe of the dunes. This spoil has then immediately been washed into St Clair with the east swells. You can see the scarp at the base of fill.

Nature's way may be Middle Beach answer

ODT Thu, 27 Aug 2009

The initial response to coastal erosion is often the construction of a sea wall, but Phillip Cole argues that will not do the job at Middle Beach. He advocates a policy of "managed retreat" instead.

Pictures and stories last month serve as a timely reminder to those who will decide the fate of Middle Beach when the project team discusses the initial results from the year-long gathering of data in September.

In an Otago Daily Times front-page report six months ago, the Dunedin City Council reiterated that it would be looking at a range of "hard" and "soft" options for Middle Beach and that it would not be ruling anything in or out in coming to a solution.

The different types of solutions will have their own sets of unique problems and financial costs, a fact acknowledged by the council. The time scale of several years before any construction can take place, however, is the most telling feature of all.

So where does that leave the Middle Beach problem? The stadium costs and other major project spends will leave the council with very little money for this project.

The council has stated that $400,000 over the next three years has been set aside to deal with the problems (already depleted by at least $60,000 due to the recent events) but, rather alarmingly, no money has been set aside for a long-term management plan, or indeed for the four years until "any construction can take place".

By default, then, the council may have to consider the option that wasn't mentioned in either story but was raised at the submissions hearing - that of a "managed retreat".

• Often, the initial response to shoreline erosion is to build a sea wall.
• A sea wall will not solve the problem at Middle Beach.
• Sea walls force waves back to the ocean.
• These waves take the sand in front of the sea wall and deposit it far away from land.
• The water in front of the sea wall gets deeper and makes for bigger waves next to the shoreline, so you always have to build larger sea walls.
• The sea will always win this battle, because the force of water will always be stronger than any sea wall.
• Adopting a managed retreat policy at Middle Beach will be successful if it begins at a grassroots level.

An open and honest approach will have a successful outcome, as it will involve all major players in the planning process and address their concerns.

Although the process will take time, a consensus can be reached that will enable a managed retreat to be the best alternative to solving the long-term problems of Middle Beach.

Indeed, this could take place in the "several years" before any construction takes place, as quoted in the newspaper report.

One could argue that consultation at a local level could have already begun since the submission hearings in April 2008 to hear and consider the views of the people that will ultimately be affected by whatever action the council decides upon.

A golden opportunity presents itself to the council here.

An integrated planning strategy can be developed where people affected by the erosion can be relocated into new sustainable housing developments where they would no longer be affected by the current sewage, drainage and flooding problems that will continually arise whenever there is a downpour in South Dunedin.

Property owners who would be affected could have compensation paid at market rates for their properties, or "swap" their current homes for new ones built to replace them.

Managed retreat, in the case of Middle Beach, is an important soft engineering coastal defence technique which aims to achieve sustainable flood defence by creating new defences further inland and allowing the land behind the existing sand dunes to be flooded by the incoming tide.

The existing coastal defence, in this case the sand dunes, would be breached, allowing the land to be tidally inundated and colonised over time by salt marsh vegetation. When established, the vegetation disperses wave energy during storms, reduces erosion rates and provides an important habitat for coastal flora and fauna. A new embankment is usually constructed beforehand on the landward side of the site to reduce the risk of flooding.

It is widely recognised that managed retreat of a shoreline can reduce the costs of coastal defence while offering numerous environmental benefits. Managed or "planned" retreat allows the shoreline to advance inward unimpeded. As the shore erodes, buildings and other infrastructure are either demolished or relocated inland. In many situations attempting to stop erosion through structural or non-structural solutions is a losing battle.

Shoreline protection efforts and/or their repeated maintenance would be too costly and ultimately ineffective at preventing further erosion. A managed retreat approach typically involves establishing thresholds to trigger demolition or relocation of structures threatened by erosion. The advantage of a managed retreat system is that it is usually less expensive than costly structural stabilisation projects that may only be a temporary solution, especially in highly erosive areas such as Middle Beach. It also maintains natural shoreline dynamics and enables shoreline habitats to migrate inland.

There are no direct costs, aside from the removal of any defences already in place, and maintenance costs are very low. The inter-tidal region is able to dissipate wave energy and protect property and land, while supporting a wide variety of plants, invertebrates, molluscs, birds and fish. Sediment flow is also restored to its natural state; beaches can be naturally replenished due to erosion of the coast, providing protection and the balance of the coastline returns.

Yes, this method can be politically difficult to implement, particularly where significant development has already occurred. It may cause shorefront property values to fall. With an in-built political and institutional preference for "hard" engineering schemes this solution will face a lot of opposition.

But what came first - the shoreline or the buildings? The future, as we all know, is unknown. Scientists forecast sea level rises, but there are unknowns that could rapidly change their forecasts. Therefore, the traditional approach to design cannot be applied to Middle Beach, simply because historical data is less applicable.

A change in outlook is required by how people plan for such challenges, how the community accepts the change, and crucially, how our council involves the communities to adapt to change. Rising sea levels do not come into the equation, as most of South Dunedin is currently below the present sea level.

The council has an opportunity here to be both forward-looking and bold in its search for a solution to the problem. History has shown that man cannot control nature, especially where sea action is concerned and the council should take this on board when looking for a solution.

As the council parks and reserves team leader Martin Thompson said (ODT, 16.01.2009): "We are at the mercy of the sea, basically, in terms of what sort of storm events we get . . ."

A sobering thought indeed.

The high beach profile (the level of sand) on Ocean Beach for the first half of the year has proved invaluable in recent weeks. While there was some sand loss in the early part of winter, a good deal of the very healthy reserves of sand remained until recently. Much of it was stripped away by the strong winds and high tides experienced during July. With the removal of that sand buffer, a section of the rubble wall has been uncovered and there has also been damage to the Reno mattresses that provided protection to the toe of the dune at Middle Beach. The Reno mattresses are being repaired, the rubble wall reinstated, and sand levels at Middle Beach are being topped up on an 'as required' basis.

That maintenance regime will be continued while the information gathering process draws to a close. A Project Team has been appointed to study the information that is being collated for the Long Term Management Plan, and the program for completing the studies and preparing the Plan remains on track.

Encroachment by heavy seas checked
ODT By Allison Rudd on Mon, 27 Jul 2009

It was estimates $50,000-$60,000 had been spent at Middle beach in the past few days trying to protect rock mattresses laid at the base of the dunes, which had been exposed by last week's heavy seas, and trucking in sand dredged from Otago Harbour and tipping it down the face of the dunes.He estimated the width of the dunes had decreased by 2m-3m in the past two years.The end of Moana Rua Rd fell away last Thursday, and the face of the dunes was now close to a large fence erected in 2007 to stop people from using a dune-top track which has also since succumbed to the sea.

It was difficult to believe the Moana Rua surf club building had once sat between the end of the road and the beach, he said.

"When we demolished that [in 2001] there was a lot of criticism. People said it would have made a good restaurant. But the area it was sitting on does not exist any more."

From a POLL at the Otago Daily Times Sat, 25 Jul 2009
Below are two comments related to the POLL