I’ve been writing, researching and working on coastal ecology and restoration in Dunedin for nearly 35 years now. If you’d like learn more about the history of the area and some of its physical processes visit my Facebook page “The Beginners Guide to Coastal Conservation.” Ocean Beach is an interesting an vibrant area with a great deal of history. Sadly, it’s a history that has seen the area maligned and mismanaged. Since 2008 the City Council has been in a “holding pattern.”  This has seen little in the way of research, consultation and planning for the future. That in my view has been a terrible mistake and the council and the community must begin urgently working on this issue.

The documentation of historical and physical change at Ocean Beach Domain provides a compelling overview of coastal zone management issues in New Zealand and indeed for coastal areas throughout the globe. However, the lessons of historical change to the physical attributes of coastal management have proven to be hard ones to learn.

Ocean Beach is in a worse predicament now as a major coastal buffer for the city than it was more than a 150 years ago. Moreover, the expanded development of Dunedin as an urban centre has now placed greater pressure on the site as a key physical and ecological barrier to the effects of storm surge and erosion events. Greater strategic thinking and planning must now be implemented that changes the historical course of Ocean Beach Domain. We can no longer sustain short-term construction and ad hoc reaction to events and physical change. We must abandon short-term planning in favour of long-term planning for physical, social and environmental change.

With that long-term planning there must be long-term funding and development of policies that adjust to the needs of positive coastal zone management. The cyclical nature of physical events that impact on the coastal zone, have often been managed too late to create any strategic improvements for the coastal environment of Ocean Beach Domain. The recommendations below are a synopsis of a comprehensive submission I made to the City Council in 2008, and the entire submission can be read here. Its worth noting that some of these changes may take 5, 10 even 20 years. However, it is my view that the following actions should be implemented;

• Changes in the use and occupation of the Domain reserve may be required to improve the coastal width.
• The closure, removal and habitat restoration of Moana Rua Road from the formerly active dune area.
• A moratorium on the renewal of all occupations on the Domain held under the provisions of the Reserves Act 1977.
• A review of the placement of all infrastructural assets on the reserve and their effects on the broader coastal environment, including the sewerage treatment plant.
• The development and implementation of a distinct coastal hazards programme in conjunction with the Otago Regional Council for Ocean Beach Domain that creates a meaningful and positive relationship between the two organisations.
• The creation of a new Ocean Beach Domain Board to implement a strategic operational plan and deliver policy as required for the management of the Ocean Beach Domain.
•  Development and funding of a public dune care organisation that represents the public in dune protection activities and education that is overseen by the Ocean Beach Domain Board.
• The development of a new Ocean Beach Domain Management Plan under the auspices of the Reserves Act 1977.
• The long-term re-establishment of vegetated fore and rear dune plant assemblages that use the width of the formerly active dune between the MHWS and Victoria and Tahuna Roads.
• Remove all fill material from the end of the St Clair sea wall to Middle Beach.
• The re-profiling and replanting of all fore dune areas between the St Clair sea-wall and Lawyers Head to assist in the creation of new incipient dune formations.
• The closure and redevelopment of access points to the coast that are sustainable for long-term use and meet the recreational requirements of the changes in use of the reserve.

The St Clair Sea Wall – History Repeating Itself

Damage of the sea wall at St Clair Esplanade is a pertinent reminder of the power and ferocity of the ocean and the continuation of an issue that has been prominent in Dunedin since the beginnings of colonial settlement. The first sea wall built at St Clair was in the early 1870′s and appears to have been privately built, and was eventually transferred to the ownership of the Caversham Borough Council. In 1885 the wall was badly damaged during a period of high seas and the Caversham Borough Council began rebuilding the wall in 1888. However the wall did not last and by 1890 it was reported that the 630 feet wall built for £800 “has all but been demolished by the sea, with the exception of 80 feet at its west, and even this portion is considerably disturbed and undermined.”

Several design flaws were reported by marine engineer CY O’Connor, notably that it had been placed too far out to sea and that its foundations were “too low.” Worse was to come, when in 1891 a significant storm did considerable damage to the whole Ocean Beach area. Further storms occurred in May 1898 when the dunes were breached and there was 3 feet of water in Larkworthy Street. By May 11th 1898 much of St Kilda between Ocean Beach and Cargill’s Road was inundated, and in July 1898 the sea breached the dunes again and St Kilda was saturated with the Pacific Ocean.

By 1910-1911 both the Ocean Beach Domain Board and the City Council had received advice on options for the reconstruction of the esplanade. The rebuilt esplanade was officially opened in 1913, but by 1914 almost all of the sand immediately in front of the wall at St Clair beach disappeared and this was repeated to a greater extent in 1919, 1939 into the high erosional period of the 1990′s. Erosion of the beach and the dunes has become a regular historical and present day feature of both the beach and dunes immediately east of the wall. This has largely been due to the “end wall effects” where once waves reach the wall it “bounces” off them with the returning wave washing back off a normal sand beach.  More sand is carried off shore, promoting beach loss. Seawalls harden the coast and reduce its ability to adjust naturally exacerbating erosional problems by reflecting and concentrating wave energy and erosion.

Dunedin’s various local authorities have struggled for the last 150 years to manage the coastal issues at St Clair and St Kilda. Sadly, it is a historical record of failure to understand the natural processes of the dune and coastal environment that affects the coastline that we perilously live beside. The problems with the wall and the wider erosion issues of Ocean Beach Domain cannot be dealt with in isolation, but must be integrated into a programme that deals with the coastal environment as a living entity rather than just as an engineered solution. In my view the following will need to be looked at;

• Re-positioning of the wall further landward to widen the beach.
• Re-design and softening of the access points for recreational use.
• Investigation into the redesign of the wall toe to decrease wave energy.
• Investigation and experimentation with soft engineering to reduce the end wall erosion.