Guest Post by John Dickson. Surfing Ōpōtiki, the story from above and beneath the waves.

Ōpōtiki and East Coast, long considered the "Sunshine Triangle of New Zealand" as 
celebrated on the cover of this 1981 Holiday guide.The guide was started in the early
 1960's by Margaret and John Ruskin. It continues to be issued every year, celebrating and 
promoting the attractions of the Eastern Bay. Source: Barbara Collett (2019).

Ōpōtiki, the Eastern Bay of Plenty, and the Raukumara Peninsula has long been a popular holiday destination for tourists, this area sometimes called the "Sunshine Triangle". While long sandy beaches with sparkling clear ocean waters have always been popular for holidaymakers at the height of summer, swells rolling in from the Pacific Ocean have made this a desirable destination for surfers in particular. For a unique perspective on our Eastern Bay surf, from Ōpōtiki surfer John Dickson read on....  

Our beautifully sculpted playground. The Ōpōtiki coastland
looking eastwards from the Onekawa Pā. Flat sandy beaches are 
embraced by and watered from the rugged mountainsides of the 
Raukumara Ranges. Source: John Dickson (2020).

Tragedy in the surf.

In early March 2004 two experienced Ōhope surfers were drowned whilst surfing at the normally peaceful Omaio Bay, east of Ōpōtiki. Moe mai ra kōrua, moe mai ra!   

99 days out of 100 there is not even a hint of a surfable wave at Omaio, which is a secluded deep water, west facing bay. Some local surfers described the waves that peaked (or pulsed, as surfers would commonly describe the dramatic rise in a swell size) that afternoon as a “1 in 100 years swell”.  The modest but challenging 2 to 3 metre waves the two surfers reportedly paddled into were generated by Cyclone Percy, a Category 5, 900 hecto-pascal, severe tropical cyclone with winds exceeding 230 km/h (145 mph). It was an active tropical storm from February 24 – March 5, battering Tokelau, Samoa and the Cook Islands over that period. Remarkably, no lives were lost to the storm in those islands. But at that secluded bay, 56km northeast of Ōpōtiki, and over 3,000 kilometres from the Cooks, the huge sets of waves which suddenly pulsed that afternoon reportedly surpassed 9 metres, or 27 foot best described as heaving walls of water rather than waves.  Unsuited to the break, waves powered by the ocean-borne swells turned the steep, stony shore into a cauldron; raking huge driftwood logs off the beach, and making safe exit from the water next to impossible.

That the men entered the water at the ‘novelty break’ that is Omaio, is instructive: the most commonly surfed breaks further east - which I will sketch out below - were presumably overwhelmed by the sheer scale of that swell. Either too dangerous to surf, or the points faced waves beyond their capacity to arrange into sortable sections.

This MODIS image taken by a NASA satellit,
shows a clearly defined eye in the storm. 
Source: Jacques Descloitres, MODIS Rapid Response
Team, NASA/GSFC. Retrieved from: 
 https://commons.wikimedia.org/w/index.php?curid=1130453)

Ocean transmitted energy.

This sad event provides a window into a unique, local, oceanic power event, illustrating the forces that have shaped the distinctive bays, coves and beaches forming the varied coastal topography of the Eastern Bay of Plenty.  

The rocky greywacke headlands of Whakatāne Heads divide the Whakatāne River mouth from Otarawairere Bay, and further rocky outcrops form a barrier between Otarawairere and Ōhope. From Ōhope a shallow 30 kilometre expanse is interurrupted by Ōhiwa Harbour and the Waitohe River mouth, the Ōpōtiki Harbour formed by the Waioeka River mouth with Hikuwai on the other side of the estuary, and finally the window facing towards Whakaari (White Island) at Tirohanga Beach. 

Coastal topoography around Whakatāne Heads interacting with the ocean-generated swell creates ideal
surfing conditions. In this aerial view of Kohi Point and the heads, incoming swell is visible just off the coast.
Source: Modified from Google Earth (2020).

The rocky cove formations, each fed by at least one gushing, clear stream rising in the steep inland hills just beyond, resume beyond Tirohanga at Opape. From there the rather benign, mostly shallow, sandy beaches which characterise much of the Bay of Plenty conclude. Jagged points formed by erosion-resistant greywacke shelter shorter sandy bays, more typical of the Coromandel Peninsula. 

Countless small bays, inlets and boulder strewn coves punctuate the magnificent rohe of mana whenua such as Nga Tai and Te Whānau-ā-Apanui iwi, and their constituent hapu. For centuries these provided excellent sheltered places for Māori to launch and beach waka. (canoe). Still they teem with in-shore marine life, whilst off-shore various species of whale, tuna, swordfish, marlin, orca and shark feed in these nutrient rich waters, including the peak predator of the Pacific, the Great White.

This is a constantly sculpted coastline. A shoreline, which due to it’s complete protection from Aotearoa’s more powerful and predominant easterly and southerly swell, is relatively calm and tranquil most of the time. Although the degree of scouring, erosion and rock splintering varies annually, the sculpting does occur predictably. Natural forces, particularly oceanic ones, are cyclical. Primarily it is scouring by simple tidal action - two high and 2 low tides every ‘day’. But when a certain water temperature, and humidity, and wind direction in the upper-South Pacific Ocean coincide favourably, phenomenally powerful cyclones are generated. Most are initially generated in the Coral Sea, and either meander or race south-east, with occasional unpredictable reversals towards Queensland.

Swell generated by these far-off storms - which sometimes pass close to or even traverse East Cape - bring consistent, powerful, challenging and sometimes world-class waves to local shores: or ngaru toa, in the Māori language. In discussing our present-day  surfing culture, here I would like to acknowledge the Polynesian tipuna particularly Hawaiian and Tahitian, who long long ago originated the practice of riding waves both prone and standing. Modern-day surfers acknowledge them with aroha, high regard and deep gratitude. 

Generally speaking, January to May (Summer into Autumn) is the ‘window’ which swell-starved Eastern Bay of Plenty surfers patiently wait to open. Cyclones, with sometimes curious names bestowed by meteorologists who diligently track their traverse and provide warnings to navigators and landlubbers alike. While we may ponder the seeming randomness behind names given to cyclones, naming actually follows a well developed system that allows identification of events and communication between forecasters, agencies, and the public. The weather map below from 1982 shows several named systems off the coast of North Island.

Tropical Cyclone Abigail approaches Norfolk Island in February 1982.
Cyclone Hettie has now degraged to a Low Pressure System off the
Chatham Islands. Note the strong south-east wind-flow  across East
Cape, favourable for the points and bays of the Eastern Bay of Plenty.
Excellent surf could be found across the entire East Coast.
Source: John Dickson Surf Diary 1982, map ex. New Zealand Herald (1982).

 

Cyclic climate events such as La nina and El nino oscillations (Opposite phases of the El Nino Southern Oscillation, or ENSO) are also important factor impacting wind directions and hence swell in the Eastern Bay of Plenty.

Modern Satellite imaging and powerful computers are able to analyse 
large amounts of data for weather forecasting and climate modelling. Analysis
of cloud temperatures collected by satellite are used to track developments of tropical
cyclones as seen in this image as used by the 
New Zealand Metservice. Source: Japan Meteorological Agency. Retrieved from
https://www.metservice.com/warnings/tropical-cyclone-activity (2020).

How big is that wave? The parameters.

For surfers our two important parameters are face height and swell period. A little local colloquialism for Ōpōtiki, for more than one foot we use the term foot, ie "3-4 foot". The most commonly surfing days around Opotiki would be riding waves of 2 to 3 foot, or simply ‘a metre’.

Those influenced by Californian measures speak of wave face dimensions such as “waist high; head high; overhead; double overhead…” etc.  As you can see this is a relatively qualitative and subjective measure, which has led to countless debates and arguments and many exaggerations. It is also a reasonably reliable indicator of size. But this means  those 2 - 3 feet waves could legitimately described as ‘head high’ such as: “yeah Morries was great today…head high and uncrowded”

Measurement and description can be complicated  by the ‘other’ legitimate size measure: unsurprisingly, the Hawaiian measure. So, for example, a  generous 6 foot / 2 metre, overhead curl in New Zealand would commonly rate as - let’s be really generous here - “4 foot Hawaiian”, using the international scale. The same wave would likely be deemed “8 to 10 foot” double-overhead in Mother England!  Wave size measures vary depending on where you surf. Human nature, and popular culture trump science every time! 

The second, less controversial, parameter is swell period. Surfline define this as follows: “swell period/ or interval is the time required for one complete wave length to pass a fixed point, and it is given in seconds.”  In simpler terms, how fast or slow the wind generated kinetic energy moves as it transfers, in a certain direction, through the colliding water molecules, in wave formation. The people at the highly prestigious Magic-Seaweed website put it this way: “In deep water, long-period waves travel faster than short-period ones. So when they hit shallow water they slow down more abruptly and break with more punch. The combination of those two factors makes longer-period waves more powerful than shorter-period ones.” (my emphasis)

Matakaoa near East Cape showing the kind of wave conditions typical
of a summers day. Source: John Dickson (2020).

While we often talk of waves "travelling" it is important to note the actual ‘waves’ - the aqualine object of our desire -  do not go anywhere. It is simply the energy being transmitted through the water molecules which causes the rise and fall and creates the illusion of travelling waves.

One other simple and key aspect of surf, is the often misunderstood concept of sets. As disorganised energy arranges and orders itself (temporarily, before becoming dispersed whenever a wave breaks), the wave energy forms groups - or as surfers and watermen call them: sets. There are various myths about this, one of the most common that every set has 7 waves and the 7th is the largest. Maybe in Hollywood!  Personally I’ve seen 1 wave sets, 7 wave sets, and once whilst surfing at Opape with 3 others (on the morning of a reasonable eruption at Whakaari in January 1981) continuous waves, each the same size, and none of any real power. This lasted about 45 mins before the sea went back to flat. The desire to see some sort of organisation in waves may be more due to our human desire to find patterns in otherwise random events. 

Surfing Ōpōtiki.

What does all this actually look like for Ōpōtiki surfers? In effect, a couple of on-shore (Northerly) windy days may produce a jumbled swell of 0.5 to 1 metre wave faces, with a swell period of 6 or 7 seconds. Depending on continuing wind conditions these waves may be surfable for a day, only. Off-shore winds (such as our beloved but intermittent South Easter) whilst ‘cleaning’ and ‘air brushing’ the wave faces favourably, both aesthetically and for the quality of surfing, quickly ‘kill’ the swell - leading to the familiar flat Eastern Bay ocean. It’s not called Pacific for nothing!

In contrast, a cyclone tracking towards New Zealand, and set to pass off the East Cape (such as those pictured in the meteorological chart above), may be expected to produce surfable waves of at least 2 to 3 metres in shore height, and a period of 12 seconds plus. Waves from this wind action may be surfable for 2, 3 or even more days. It’s worth noting that on New Zealand’s west coast (the famed breaks of Raglan and Piha for example) multi-day swells with a period of 12 - 14 seconds are somewhat routine.  That coast is subject to swell generated in the southern oceans - ‘the Roaring 40s’ as they are called.
 

Nobody moves to Ōpōtiki specifically for the surfing! That’s a Gisborne thing. 

Currents.

All this seashore carving wave action as we've been discussing, turns rocks to sand. The predominant longshore current in the the Bay of Plenty moves east to west, so one can say  that the prized fine sand beaches of Mount Maunganui owe some debt to the East Cape, in addition to large amounts of material deposited from the Taupō Volcanic Zone and further east. The types of sand we find on a particular beach gives clues to source rocks and region of origin of these materials. Light coloured sparkling sands of the Bay of Plenty contain large amounts of eroded pumice and volcanic glass, while east of Torere and around the Whakatāne Heads dark pebbly beaches are formed by eroded greywackes and other sedimentary and metamorphic rocks of the Raukumara Peninsula.

Powerful currents become apparent to anyone who enters the water to swim or surf or fish when ‘the swell is running’ (parlance for - big waves are breaking): invariably there will be a strong westwards undertow, meaning that to stay fixed in one spot requires ongoing swimming or paddling against the flow.

The small bays where strerams enter the sea are typical of 
the numerous, small, sandy coves of the East Cape. This image shows
a small but still rideable wave. Source: John Dickson (2020).

This bay is unique on the East Caost for its concentration of dense,
black iron-rich sands more typical of the West Coast of the North Island.
This black sand contrasts strongly with the pale deposits of rhyolitic 
volcanic ash visible in the cliffs. Source: Ilmars Gravis (2020).

Sand provides clues to the origins of sediments and clues to the
currents depositing sediments. The sparkling pale sand above from Pikowai
 is comprised mostly of eroded pumice and eroded volcanic silicic
volcanic glass carried to the sea by rivers passing through the Taupō Volcanic Zone.
Sediments are then reworked and deposited by longshore currents running west 
to east. Source: Ilmars Gravis (2020).

While some quartz and other silicic minerals are visible amongst these
coarse grains from the Whakatāne River mouth, a large proportion of eroded 
greywacke and other sedimentary rocks are clearly visible. Coarse and angular 
grains show that these sediments are deposited relatively close to their source.
Source: Ilmars Gravis (2020).

Surf breaks.

Ocean swell in and of itself is not the only necessary ingredient for great surf (and I’ve dealt with the ever changing, ever fickle Bay of Plenty wind situation earlier!). Wave energy needs to meet and collide with a suitable break - a point, a reef, a river mouth, or a sandbank. This is where Ōpōtiki surfers are both fortunate and unfortunate. The largest expanse of our coastline is the unbroken, shallow sand beaches from Ōhiwa to Tirohanga. This type of sea-floor topography is generally unfavourable for surfable waves. The swells simply approach shore and collapse in one huge section on the many sandbanks running parallel to shore. These waves are ‘close outs’, as surfers term it. On occasion, with the right wind and gaps appearing in those sandbanks, they can be surfed.  At times they produce excellent surfable waves, but that’s a rarity.

Fortunately though, we do have  three  river-mouths providing regular favourable surfing conditions. The Whakatāne Heads, which is by far the superior and possibly the best river mouth break in New Zealand on a good day; next the more gentle and temperamental Waoitahe rivermouth (pictured - top of page); and finally the Ōpōtiki Bar (the confluence of the Waioeka and Otara rivers). This dual river-mouth bar is reasonably consistent, and local surfers await with interest the impacts of the harbour bar groyne proposal (see image below), a subject of intense debate for over 20 years. You can read more about the proposed harbour development on the Ōpōtiki District Council webpage here.

Ōpōtiki Harbour Development concept. Source: Ōpōtiki District Council
Retrieved from: https://www.odc.govt.nz/our-council/current-projects/harbour-development/Pages/default.aspx (2020)

  

By far far the best local surfing breaks are the easterly points. If treated with respect Omaio can occasionally provide suitable conditions. Hawai (similar sounding but not to be confused with Hawai'i) a shingle strewn point/rivermouth combination which holds surfable waves up to a solid 3 metres is by far the most commonly surfed. Finally Maraenui, less symmetrical than Hawai, less accessible and less crowded, is surfable on even bigger days. 4 metres, 5 metres… A lot depends on the swell angle.

Hawai point/rivermouth with small wave size indicative of the quality it holds even at 3 metres.
Source: Mike Yukich (2020).

These points, when fed by long-period Cyclone-generated swell, and burnished by south-east breezes, do satisfy any competent surfer. The fact that they are surrounded by bushland, have pristine water, and host ample sea and birdlife only add to the sense that these break are taonga tuku iho (loosely translated as treasures for all people).

It bears mention that one other, superb river-mouth break exists in close proximity to these points - the Motu. Currently local iwi are asserting a form of ‘local governance’ on the waves there, and actively prohibit surfers entering the water, preventing enjoyment of a sometimes machine-like right hand breaking wave. Since Gondwanaland split, resources have been contested and in time this too will pass.


Tides. 

Finally meriting mention, the moon induced action which has implications for both coastal sculpting by natural forces, and surfing: tidal action. The highest to lowest tide marks in Ōhiwa Harbour vary by up to a modest 2 metres. By contrast, the Severn River in England has a 15 metre range; such a massive influx of water causing a surfable wave (known as a tidal bore) on occasion. Tidal action is integral to the health of the rocky shore, and also a catalyst to the ongoing, incremental breakdown of rock. 

Tides influence the shape and quality of waves for surfing. For example, a low tide may expose the wave energy to a more abrupt demise as it hits the shore on a shallow reef.  This can lead to the more desirable, challenging pitching waves so sought by proficient surfers. By contrast a high tide on a sandbar beach break may yield higher (larger) wave faces, ridable for a longer duration as the amount of water available to the moving energy has more potential to endure before dissipating into the universe. I suspect Ilmars, administrator and author on this blog, ccould talk more intelligently about the Law of Conservation of Energy than I can - 5th Form Physics is a long distant memory, and I may have been reading Surfer magazine under the desk that lesson anyway! If only teachers had used surfing as a representative context for knowledge, then I may well have stayed the course. 

Each break has its peculiar characteristics - some breaks may only ‘work’ on a particular tide, others will work all day on a solid swell. There are many reasons why surfers have developed a reputation for - shall we just say - ‘unpredictable work habits’. As sketched out here, the parameters of swell, wind, and tide provide a multi-dimensional ever changing playing field. Responding to that, and catching a wave that, to quote The Beachboys, places you “on top of the world” requires careful attention to the elements, and tons of luck. When it’s time to drop everything and go, one must!

Greg Sleep, Summer of 2018 at Whakatāne Heads showing 2-3 metre cyclone-generated waves.
Source: David Marven (2020).

John Dickson first stood on a board and surfed waves at Ōhope, in the summer of 1969. He went on to surf in Hawai’i, California, Spain, Portugal, Morocco, Mozambique, South Africa and the East and West coasts of Australia. He now, very happily, surfs mainly around Ōpōtiki or Gisborne. More on the author at his blog:
http://adventuresinbelieving.blogspot.com/2012/05/pacific.html

John Dickson, in his element, up and riding. Source: John Dickson (2020).