Dunedin Surf Break Controversy
Earlier this week I had the pleasure to visit Dunedin and two great New Zealand surf spots, Aramoana and Whareakeake. The purpose of my trip was to present evidence at a Resource Consent hearing opposing the Port of Otago’s request to continue dumping dredge spoils from the harbour channels in the water immediately offshore of these two surf breaks.
The evidence statement was actually prepared by my colleague Dr. Shaw Mead, but he was unable to attend the hearing so I went in his place. This evidence was prepared in support of the New Zealand Surfbreak Protection Society’s request to have the dumping stopped at these inshore sites and done exclusively at a site that exists in deeper water and further offshore (known as the ‘A0’ site).
There are many complicated and conflicting issues at the heart of this problem. First off, there are two surfbreaks, ‘The Spit’ at Aramoana and Whareakeake (also known as ‘Murderers’). Aramoana is a beachbreak that is known for heavy, hollow, A-frame peaks. The break exists along a stretch of beach that is heavily influenced by human intervention, i.e. somewhat artificial. That beach is there partly because of ‘The Mole’; the 1.3 km long jetty that sits in the middle of what was a natural sand spit extending in to the mouth of Otago Harbour. Construction on The Mole started way back in 1884 and from information I have found on the internet, was fully completed in the 1950’s.
Thursday, 9 May 2013
The second surf break that is part of this controversy is the right hand point break at Wareakeake, also known and ‘Murderers’ (pic below). This break is a natural surf break, i.e. its existence is not dependent on an earlier human activity as is the case with The Spit. It is just a point break that pulls in NE swell and causes the wave crests to break along the depth contours of the bay.
THE PROBLEM - The problem is that the Port of Otago is seeking permission to dump up to a maximum of 450,000 cubic meters of material at three separate inshore dump sites, 50,000 at Shelly Beach (the beach to the east of The Mole), 50,000 offshore Aramoana and The Spit surf break and the rest at the site offshore of Hayward Point (the latter two sites are indicated in the first map figure). I should note that The Port has been using these sites for dumping maintenance dredging spoils since at least the mid 1980’s.
Surfers in the area are objecting for two reasons, first, many believe that the inshore Aramoana site is ‘full’ and that further dumping of material will cause what some feel is a continuing trent of deterioration of the surf break quality and consistency over the past two decades. The other objection is that the Hayward Point dump site is in the swell window for Whareakeake and by putting a mound of stuff in the way you could be detrimentally affecting the incoming swells to the right hand point break.
The way I see it, the opponents have some very strong arguments supporting their position, which, besides seeking to stop the dumping, also calls for a detailed assessment of the mechanics of the surf breaks.
Firstly, the amount of material to be dumped at these sites is likely to be two to six times as much as has been dumped in recent years. Although The Port currently has the permits to dump up to 200,000 cubic meters of material at Aramoana; in reality, the 26-year average for dumping has been just ~27.000 cubic meters and only 20,000 over each of the past five years. This is less than half of what The Port seeks permission for in this current permit request. The local surfers believe, and justifiably so, that because The Port is beginning an already approved expansion project, that they will use the full amount of dumping capacity in their permit. If this happens, it would represent a 2-fold increase in dumping (relative to recent years and the long term average) at Aramoana. Furthermore, the bulk of the dumping would occur at the Heyward Point site. If the maximum material were dumped, 350,000 cubic meters per year, this would represent a 6-fold increase in dumping volumes at that site relative to recent an long term averages.
It should be noted here that The Port already has approval for another dumping ground, that no one objects to the use of, that sits well offshore of the area in deep water. The problem is that The Port does not currently own or operate a dredge that has the ability to reach the offshore site on a consistent basis (due to the relatively severe wind and wave climate of the area). From what I understand, there are plans to get a dredge of this sort at some point in the future. However, it seems that The Port hopes to use its existing equipment and get a jump on the channel expansion work and increasing the amount of dumping at the near shore sites accessible by the current dredge.
Secondly, both of these surf spots have been designated, under New Zealand Law, as Surf Breaks of National Significance in the recently enacted New Zealand Coastal Policy Statement. There are only 17 breaks with such a designation and two of them are right where The Port wants to dump their stuff. The law states that these breaks should be protected and that a ‘precautionary approach’ should be taken whenever activities are planned that may adversely affect the break. I just don’t see how dumping 50,000 and 350,000 cubic meters of stuff (2 and 6 times the long term average) constitutes a ‘precautionary’ approach.
And finally, this is a test for New Zealand environmental law and for the recognition of surf breaks in general. It is just a matter of circumstance that the Port of Otago unwittingly helped to create a world class surfing wave at Aramoana through the construction of The Mole and the modification and stabilization of the ebb tidal bar. But they did. And the break became part of the accepted human landscape to such an extent that it was protected under law. I say they have to live with it and find a way to preserve and protect what is there and what has become a major national and international surfing destination.
When I was down there, I happened to catch ‘The Spit’ when it was working. It is a great wave. Lets try and keep it that way.
The presence of The Mole has had two primary effects on the surfing waves along the sand spit at the entrance to Otago Harbour. First it has fixed the location of the ebb-tidal bar that sits off the harbour entrance. The dredged channel keeps the tidal currents higher and contained within the channel. This causes some sediment to be deposited at the offshore end of the channel ensuring that the bar stays pretty much in one place. Before human intervention, it is likely that the location of the bar and channel meandered according to the incident wind and swell conditions. Dredging has been going on in Otago Harbour since the late 1800‘s. The second effect is the stabilization and growth of the beach to the west of the mole and the erosion of the sand to the east. Otago Harbour in its natural state was ‘flood dominated’ meaning that the incoming (flood) tide currents were stronger than the outgoing (ebb) tide current. This results in a net inflow of sediment to the harbour and is the reason why the sand spit east of The Mole curves into the harbour mouth. You can see these effects quite clearly in the images above and below.
The magic of the waves at The Spit is that the place has the tendency to produce well defined A-frame peaks with hollow tubes. These peaks are formed primarily by the interaction of incoming swell waves with the sand bar that sits east of the entrance channel and offshore of the harbour entrance. The best swell direction is northeast, and under these conditions, the swells bend and refract over the outer bar concentrating energy along the wave great so that wave height is locally elevated and the wave breaks earlier where the energy is concentrated, making the unique A-frame shape. The tell-tale ‘V’ in the whitewater in the picture below is the result a wave breaking with a nice A-frame shape,
There are many breaks in the world that work this way, one of the more famous is Matakana Island in Tauranga, New Zealand and others include ocean Beach in San Francisco, CA, South Stradbroke Island and Duranbah in Gold Coast, NSW, Australia.
