Supernatural Swells

Designing shorelines and surfing the consequences

Tim Maly
Tim Maly
Feb 4, 2015 · 16 min read

By Tim Maly

A version of this article ran in ACID, a magazine about more than just surfing.

Let’s start with the Wedge. The Wedge is a notoriously deadly spot at the end of the Balboa Peninsula near Newport Beach, California. It’s popular with bodysurfers, bodyboarders, and a few surfers who like their take-offs scary. The Wedge is known for epic and unpredictable waves, a freak of physics that creates peaks twice as high as those in neighbouring beaches when conditions are right.

The best days at the Wedge originate in the Southern Hemisphere as swells created by tropical storms and typhoons. Those swells cross the Pacific in a journey that can take a week or more. Once they reach Newport, they slam into the steep underwater slope of sand, peaking suddenly and — here’s the important bit — bouncing off the rock jetty that extends into the sea. The reflection combines with the next wave, doubling its power and creating massive opportunities, up to 30 feet, for experienced surfers to enjoy a memorable ride — one that generally ends up with a closeout.

When the US Army Corps of Engineers built the Wedge’s jetty in the 1930s, they weren’t trying to create a dramatic surf spot. They were just trying to protect the entrance to Newport Harbor. The Wedge is a side effect.

Surfing has always been an opportunistic sport. Great surf spots are accidents of geography, created by the complex geometry of the shore interacting with the consequences of distant storms. The character of a break is determined by a mixture of tides, wind, prevailing swells, and the shape and slope of the terrain on the seafloor. Exactly how all these conditions interact is chaotic and difficult to predict. Mess with any of them and a spot will be changed. Sometimes it’s an improvement, but more often it gets ruined. Waves are fragile.

The thing is, people and nature are messing with the coast all the time. This is a story about the forces that shape shorelines.

The Wedge, Newport Beach, California

Coasts aren’t stable. They are highly energetic ecosystems in constant flux. Every beautiful mile of beach that you encounter (assuming people didn’t create it) got that way gradually, thanks to the combined action of wind, tides, rivers, rainfall, currents, wildlife, and waves. In some places, the shore is disappearing under the erosive pounding. In some places, it’s growing with deposited silt, sand, and soil. The process never stops, so the coasts never stop changing. For the most part, it’s a relatively slow, continual process, punctuated by dramatic transformations wrought by storms. These dynamics are complicated by human activity.

Coasts are valuable. For as long as there have been people, we have settled in coastal areas. On shore, coasts are a popular place to build homes and industry. At sea, waterways are the lifeblood of coastal communities for both transportation and food.

People are builders. When we settle in an environment, the tendency is to start making and remaking structures and the landscape to our benefit. But these modifications are in conflict with a shifting terrain. We’d like our investments to last. No one who lives or works in any of these places looks kindly on the possibility that their architecture might wash away.

Intentionally and unintentionally, we routinely move sediments. It runs deep in our relationship with the landscape. Pretty much everything we do interacts with erosive processes.

Here’s an incomplete list: Urbanization, agriculture, and forest-clearing alter erosion patterns on land and deposit silt in water bodies. We carve out hills and cliffs to install housing, roadways, and fortifications. We fill in or dig out marshlands to create harbours and landing areas. We trample pathways to popular spots, or we build boardwalks to contain the damage. In some places, we create artificial reefs. In others, we blow reefs up. We remove sediment from waterways, creating destabilized channels that refill faster. We use walls and artificial beach replenishment to hold the waves at bay, trying to keep our real estate in stasis.

Even in the places where humanity doesn’t intervene directly, our influence is felt. Overfishing transforms migratory ecosystems; trash and waste makes its way into the food chain; and a changing climate means changing weather patterns, with a side of rising sea levels to match.

From a surfer’s point of view, the bottom line is this: Any change to the character of a shoreline means a change in the character of its waves, and there are a lot of very good reasons why someone might want to change the character of a shoreline. There are even more ways to do it. This galaxy of techniques is rarely talked about as landscape architecture, but that’s exactly what it is.

The modification you are most likely to encounter on a day-to-day basis is coastal armouring. The goal is to fix the border between land and sea so that landowners can rest easy, knowing that their investment will continue to exist. A line is drawn in the sand, beyond which waves must not pass. Normally, this line is made of concrete or stone. Over the centuries, coastal engineers have developed an incredibly diverse set of techniques to manage an incredibly diverse set of needs.

Large waves, produced by storm force winds, break against the harbour wall in Dover, England

Seawalls and revetments run along the coast. Their role is to endure the pounding of the waves directly. The most basic and oldest kind of wall is a vertical one. It’s the easiest to design but also one of the most fragile. Because it reflects a wave’s energy directly, interactions can cause dangerous standing waves to form. When it fails, it tends to fail catastrophically. Curved and sloped walls are harder to design but do a better job of dispersing a wave’s energy, reducing the turbulence as waves land and retreat.

The problem faced by all of this landscaping is that it’s being done under extreme conditions. Ocean waves carry a great deal of energy and that energy can’t be destroyed, it can only be redirected. A lot of coastal erosion management plays out as two steps forward over here, two steps back somewhere else.

If you’ve ever stuck your foot in the sand and noticed the patterns of micro-channels that are etched as the retreating surf flows around your ankles, you have some sense of of how preventing erosion in one place can make it worse in others. Hard walls don’t absorb the wave’s power. Instead, they redirect it, increasing the effect on unprotected areas.

At the immediate level, that means the bases of sea walls are prone to scouring. Energy that would have travelled further inland without a wall is reflected back to pull more sand away on the beach side. Over time, the beach disappears, and when the ocean runs out of beach, it starts digging out the land underneath the wall until it collapses.

Even before the wall fails, its presence can mean a serious change to the dynamics of the area. In 2001, a right point break near Madeira’s Lugar de Baixo in Portugal was threatened by a proposed marina, pitting one kind of water recreation against another. Working with local and international groups, the Save the Waves coalition was formed to pressure the government to move the marina to a nearby bay. It was a partial success. While construction was relocated, a seawall was constructed to protect an onshore shopping complex. Today, the wave remains, but the new coastal geometry means increased backwash. It’s been damaged. There remains some hope that when the seawall needs replacing, it could be redesigned to reduce its impact on surfing conditions.

Mounds made of stone or concrete blocks can help alleviate some of these problems. Because they are irregularly shaped, they break up the regular rebounds of the waves. The problem is that these irregular structures give water something to grab on to; they are prone to being shifted by the tides. They may fail more gracefully, but their life spans aren’t as good as the more solid walls; they require more regular maintenance. They are especially unsuitable for the most energetic shorelines. Places prone to massive storms risk seeing them washed away completely, loose stones scattered on the seafloor.

Beyond the structures that run along the shore, groynes and jetties extend out into the water, often perpendicular to the coast. Their function is to reduce the movement of sediments along the shore, breaking up currents and keeping beaches in place. Alongside beach replenishment efforts where sand is pumped or trucked into place, groynes can help protect a shoreline by maintaining a buffer beach between the waves and the land where stuff has been built. But much as with the sea walls, the unprotected areas on the other side of groyne suffer. They end up starved of the sand that would have been washed down by the currents, and so those areas disappear much more quickly.

To combat these issues, and with a growing understanding of the hydrodynamics involved in these complex situations, there has been a growing movement towards softer infrastructure. New and strange species of architecture have been added to the repertoire.

High waves hit tetrapods in Makurazaki, Kagoshima, Japan.

Tetrapods, designed by Laboratoire Dauphinois d’Hydraulique in 1950, combine the flexibility of mounds with the strength of concrete. Tetrapods look like Gulliver-sized children’s toys, made up of four limbs connected to a core. They are scattered along the shoreline in interlocking piles, sometimes on top of soil, sometimes in front of a more traditional wall. Like the rocks they replace, they break up and disperse more wave energy. However, because of their extending limbs, they get tangled up with one another, making it harder for the waves to shift them around, and resulting in a more lasting configuration. Every time a wave hits, they shift around a little bit, but not too much.

The tetrapods are no longer protected by patents, and so in the intervening years many companies have created variations on the basic design, with names like the Stabit, the Akmon, the Dolos, and the Xbloc — each with its own special advantages in terms of manufacturing, durability, or behaviour under the pounding surf.

Softer still are the geotextiles. These high-tech fabrics can take the form of netting or blankets to envelope the landscape, or hulking tubes that look like enormous sand bags. Sometimes they are out in the open, but for the most part geotextiles operate covertly. They are the hidden cores of many slopes, mounds, levees, and even artificial sandbanks and islands.

But this is just what happens on land. Underwater, there is a different kind of landscaping. It is almost completely invisible, even if you know where to look. In order to ensure the safe passage of ships, waterways which might naturally fill up with silt must be kept clear by dredging.

The Queen of the Netherlands, a Dutch dredging ship.

Dredging is the mechanized uplift of silt and sediment from ocean and river beds. Some kind of machine, probably on a barge, is towed out to the target area. Guided by charts and, these days, GPS, the machine pulls muck off the bottom and dumps it into another barge, which carts it away. Dredgers can be huge backhoes, wide-mouthed suction systems, Archimedes screws, giant cutters, buckets on a conveyor belt, or complex pneumatic systems.

The stuff that’s dredged up, if it’s clean enough, can be reused to make artificial islands, revitalize topsoil, fill geotextiles, or nourish beaches, but most of it is thrown away, dumped into landfills or out to sea.

Dredging is a Sisyphean process. Cutting a channel creates a space with steeper walls where more water flows more quickly. The increased flow, in turn, speeds up erosion, which accelerates the rate that the channel refills. The more you dredge, the more you need to dredge.

Aerial view of beachfront houses showing erosion on the Gold Coast, Australia.

So far, we’ve talked about all of these techniques in isolation, but they are more likely to be applied in combination. The Superbank, in Queensland, Australia — one of the best surf spots in the world — offers an illustrative example. Running two kilometres between Snapper Rocks and Kirra, it is known for its long rides in big, beautiful hollow waves.

Much like the Wedge, the Superbank is a side effect. But where the Wedge is the result of a hard infrastructure jetty, the Superbank is a result of a network of infrastructures, both hard and soft.

The Tweed River reaches the ocean here and its shipping channels must be kept clear; left alone, a sand bar tends to form, running ships aground. First, engineers built a pair of groynes on each side of the river mouth, extending it further into the ocean and keeping sand from neighbouring beaches at bay. Over time, the beach on the southern side grew, as currents washed new sand into place, and the groyne held it there. In response, the government built a long thin jetty lined with suction tubes that drop into the water. These pull sand off the ocean floor on the southern side, run it through town via an underground network of pipes, and dump it out on the northern side.

Snapper Rocks, part of the Superbank in Gold Coast, Australia

The beaches on the northern side have long acted as both a tourist attraction and a buffer against the massive waves of tropical cyclones. In the late 60s and 70s, a string of cyclones stripped the beaches almost completely, washing away all the sand. Because of the groynes protecting the Tweed entrance, the sand that would have naturally flowed over was kept in place on the southern beaches, starving the beaches to the north. The new system corrects for that.

To supplement the permanent system of suction and pipes, temporary pipes can be used to redirect the replenishment where it’s needed on the northern beaches, while a floating dredge barge can be pulled in to clear the river mouth from time to time. Together, the jetty, the pipes, and the dredge make up the Tweed River Entrance Sand Bypassing Project.

When major surf competitions come to town, it’s not unusual to see the pumps fired up, making sure that the sand bank has formed just right. This is landscape as process, a continual maintenance of a shifting terrain. It costs nine million AUD a year.

The economics play a huge role in any decision about how to reshape the coast, and surfing advocates have begun to play up the touristic and commercial benefits that the sport brings to communities.

To encourage that notion, and to begin to put a dollar value on it, surf-sympathetic economists are looking at things in a variety of ways. First, there are the direct economic benefits: in 2010, about $6 billion was spent on surfing gear, worldwide. Second, there are the indirect benefits: surfing tourism attracts people to communities where they’d otherwise not go, and to spend money in local shops, restaurants, and hotels while they visit. Those local benefits have to be measured on a case-by-case basis, but often come up in the tens of millions of dollars. When it comes to an argument about a marina versus a surf spot, this information can help make the case for one kind of recreation over another (or for both).

The problem these groups face is that, economically, they are often in conflict with a juggernaut. The global shipping industry shows up over and over in the stories of waves put at risk, damaged, or destroyed. Shipping demands that channels be dug, harbours expanded, and shores stabilized. When it’s a fight between fun and commerce, commerce generally wins. Surfing’s $6 billion seems like a lot, but there were $80 billion worth of cargo containers on the sea in 2008. Not the contents, not the ships, or the ports that service the ships — just the cheap metal boxes. All told, in 2008, the shipping industry was estimated to be responsible for $436.6 billion in economic benefits, reaped while moving $4 trillion-worth of cargo around the world.

It’s not even close.

To get a sense of the scale, consider the landscaping shockwave that is spreading up and down the Atlantic coasts of the Americas. The origin of the shockwave is the Panama Canal.

Over the past 50 years, more and more of the world’s manufacturing has been happening in Asia — China in particular. But all that stuff that gets made eventually has to make it to market to be sold, and it’s getting sold in the rich parts of the world, which is to say Europe and North America. Air travel is too expensive, so almost all of that stuff moves by boat. If you are moving from China to the Eastern Seaboard and you can either go west, past Africa and across the Atlantic or across the Pacific and then into the Atlantic. Since you are a massive shipping conclomerate run by serious people, you don’t dream of sailing around the the Cape of Good Hope or Cape Horn. If you head west you’ll take the Suez Canal into the Mediterranean. If you go east you’ll cut through the Panama Canal. The Panama route is ~5% shorter so most US-bound traffic chooses it.

Freighter sailing in the Panama canal seen from Contractor’s Hill

The Panama Canal was completed in 1914, after 33 years of digging. At the time, it was pretty roomy. But times changed, the economy globalized, shipping became crucial to world trade, and ship engineering got more advanced. Ships grew right to the limit. There is a term of art in shipping circles: Panamax. Panamax is the dimensions of the largest ship that can squeeze through the Panama Canal, and, consequently, the largest ship that will leave Asia bound for New York. That is to say 295 m long, 32 m wide, 12 m below water level, and 58 m above it. We can build them bigger. Indeed, there are plenty of post-Panamax ships at sea, the largest able to carry nearly four times as much cargo as their Panamax siblings. But no one running a harbour in the Atlantic side of the Americas has needed to worry about that, because those ships couldn’t economically come calling.

Now, the Panama Canal is being expanded. There will be a new Panamax, and harbours that can’t accommodate these new larger ships will be left idle. All up and down the Atlantic coasts, harbours are desperately digging out deeper and wider channels to accommodate the new ships. New York alone has dug up 42 million cubic yards of dirt over a decade. It’s a race against the construction timeline, and not everyone can win. Some of those harbours will get bypassed. Either way, thousands of years from now, archaeologists will be able to find the channels cut through our waterways, just as today’s archaeologists can trace ancient riverbeds.

Some geologists argue that we are living in the Anthropocene — a new geological era where human impact has grown to such a level that we should be thought of as a geological force. We have an impact that rivals continental drift and rogue asteroids. You know the infamous hockey stick graph that shows an exponential uptick in carbon output?

On top of all that, we have to consider the unregulated, highly experimental and completely out of control terraforming project humanity has collectively undertaken by dumping unbelievable amounts of carbon into the atmosphere. The long-term effects of climate change are difficult to predict, though we have already committed to whatever they will be. We do know that more extreme weather (which means more storms, which is sort of good news for surfers) is pretty likely. We also think that sea levels will rise, which will change the character of every wave, everywhere on earth.

Villingili Island, in Male, Maldives.

In the face of higher seas being whipped up by more intense storms, coastal communities the world over are having to rethink how they will relate to the ocean. No one is thinking harder than the Maldives, located just off the south coast of India. A series of 26 atolls with 1,190 islands, it has plenty of great surf spots. For now. The highest point in the country is about 2.4 m above sea level. The country faces the very real possibility that it could be completely submerged.

Slowly, the world is coming to grips with the understanding that we failed. Climate change is happening and it’s not going to stop. Most of the world doesn’t face quite so extreme an existential threat as the Maldives, but even small changes in water level mean big changes to the demands on coastal infrastructure.

When Hurricane Sandy made landfall, the damage to New York City was horrendous. This was partially due to bad timing — Sandy hit at high tide. Had the storm hit six hours earlier or later, the flooding would have been much less extreme.

But it was also largely due to coastal landscaping. Much of the worst flooding happened in low-lying areas made of new infill. Three hundred years ago they were water, not land. Underwater, the shipping channels cut into the normally shallow estuary, and the consequent accelerated erosion that’s seen whole marshy islands wash away, gave the storm a high volume of water to work with. Had the estuary been landscaped differently, things might have been much easier.

As our understanding of the dynamics of coastal systems improves, new and more radical approaches are being proposed. In the wake of Sandy, everything from a mega-wall across the Verrazano Narrows to a “managed retreat” abandonment of low-lying areas have been floated. Perhaps most intriguing was a network of proposals that relied on soft infrastructure. Archipelagos of small islands to absorb and deflect waves, marshlands and shallow reefs of oysters to dampen them. Perhaps this will create rideable breaks. Who knows?

Let’s go back to the Wedge for a second. It’s not really a freak of physics. It’s better understood as a freak hybrid of nature and engineering, like every coastal area touched by human hands. Considering the pace and the scale at which we modify our environment, there will be a lot more freak hybrids. The surfing community, like every coastal community, needs to reassess its relationship with the ocean. Every wave is going to change.


A field guide to the designed world

Thanks to Indhira Rojas

Tim Maly

Written by

Tim Maly

big into cyborgs & architecture



A field guide to the designed world

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