The key point here is that its not a permanent construct, its using natural mechanisms to slow down wave energy and encourage regrowth of the dunes and littoral zone.
In Australia we've had a lot of permanent fix approaches which were massively counter-productive. If you want to stop sand being mobile then be prepared to lose it entirely. Really? about 200m-500m back from the waters edge is probably the limit of where routine construction should take place. it doesn't make for million dollar views but its safer for that property owner, the commons (assuming you live in an economy where the intertidal zone is public access) and the dunes.
The Gold Coast is a huge sweep of beach which depends on sand from the river Tweed, which was walled off to make a clear run for boats, and now they have to pump sand to replenish. Noosa depends on sand pumping. Rocks might help, they might even make some fantastic surf breaks but they wind up altering the nature of the beach. If you want a beach like surfers paradise or main beach or noosa, you really don't want rocks.
The berm he's made suits his local hydrology. It won't be exactly the same everywhere.
I kind-of hate being the typical HN naysayer. I'm not a tidal engineer or an ecologist or civil engineer. This is stuff which is discussed quite a lot in Australia, since we cling to the coast and an image of ourselves as "in love with the sea" it becomes increasingly necessary to look at how to hold on to what we've got. The run of sand up the eastern seaboard of Australia is amazing. (its like barchan dunes, permanently on the move, in our case south-to-north)
I've visited some of the beachfronts of Washington state and Oregon and they're glorious. Huge trees litter the tide line, amazing to see. We've nothing like that in Australia really, our rivers aren't full of giant redwood logs like that. We have different problems with disappearing Kelp forests, as does the Californian coastline, Oregon might have some of the problems Washington State does.
> The key point here is that its not a permanent construct, its using natural mechanisms to slow down wave energy and encourage regrowth of the dunes and littoral zone.
“A volume of 21.5 million m3 of sand, dredged from 5-10 km offshore, covered an area of 128 ha, spanning 2.4 km along the coastline and extending up to 1 km offshore. The sand was deposited in the form of a hook-shaped peninsula. Wind, wave and tide action were allowed to distribute the sand further.”
Another technique is used at Elmer Beach in the UK. Rock breakwaters are built with gaps between them. This means that the natural movements of sediment with the tides fills up the space behind them, ie between them and the shoreline. They also make for nice sheltered little bays.
It's an odd thing to quibble about, but 200km is quite a distance, and not what I'd say 'coastal'.
I'm 135km from the coast (I'm north west of Sydney, AU) but that's a 2h5m drive away. I'd not claim to be coastal.
200km means no one in the UK could be considered not coastal -- IIRC it's impossible to be more than ~115km from the coast.
I think a more telling statistic is that in Australia, more than 85 per cent of people live within 50 kilometres of the coast - mind, even 50km inland wouldn't fit what I would think of as coastal dwelling.
Nah, it's not an odd thing to quibble about. I did try to word it such that it wouldn't be misinterpreted as me saying "200km is the same as coastal."'
I appreciated the info in the GP comment and I realize Australia is likely more extreme than average, but one of the reasons humans are so concerned about rising seas and eroding beaches is because it impacts so many lives.
If 90 percent of people lived more than 200km from the coast and it was sort of "a handful of weirdos" that lived near the beach, I think humans wouldn't be so distressed by these things. It would be "Meh, nature out there can do what it wants. My house is safe and life goes on."
I still fondly recall my English teacher at high school (several decades ago) describing our population here as 'like the scum around the edge of an empty bathtub'. Despite that I do remember him as a cheery chap.
Anyway, I'm sure most of the population lives near water, mostly oceans, but sometimes (inland) along rivers. Proximity to the coast is very misleading, as obviously the risk is predominantly down to elevation.
As I noted, 100% of the UK live within 120km of the coast, and my weirdo assessment of their populationi aside, with an average elevation of 160 metres, most of the land will be fine. London's screwed, of course, with even only minor sea level rises. They're an exceptional case in all kinds of ways. Let's move on.
Best info I can find is an NPR article that suggests some research 15 years ago estimated about 600M people lived within 10 metres of sea level. So, if Greenland goes, they're all displaced.
Anyway, this doesn't really contest TFA's point, which seems to be 'large aggregate will slow down erosion'. Obviously holding your soil in place doesn't help much if it's held in place under 10 metres of saltwater.
Most people live near water and in flood plains. Water is essential to life and essential to growing food, plus waterways get used for transport.
I used to get all up in arms about "Why! Do people live There! When it keeps flooding???" Then I looked at the data etc.
We could stand to do a better job of working with the environment and building things more able to survive known issues for specific places. I'm always interested in clues to how we can do this better, but there is no place on Earth without some kind of natural disaster that routinely threatens the area.
> ...but 200km is quite a distance, and not what I'd say 'coastal'.
Yes - viewed from your location, 200km definitely isn't.
But in the "from orbit" view - 200km away still has huge effects on the geology, climate, economy, etc. of a place. Or - ask someone who grew up in western Kansas, then joined the Navy.
I used to love in inter city north Melbourne for the cool life style. I moved to northern rivers area after 30 years of living in the city. I moved to a house about 1.5km for the beach. Over three years that went from “the closest I’ll ever live to the beach!” To “I can’t be bothered going to the beach, it’s a bit cloudy, not worth it!”. I now live 400m to the beach and go everyday. I’ve grown up a bit an realised that I may never live like this again!
We definitely are a costal nation. I love hearing the ocean roar as I go to sleep.
Don't worry, I can walk to 2 different beaches in 10 mins, but they're both "crap" and "doggie beaches", so we instead drive 40 minutes to go to a "good beach"...
Note that all the projects mentioned are along the US Pacific coast. So I don't think you are being a naysayer, as much as pointing out that it is not useful everywhere.
I live on the east coast of Florida, and we have similar problems to Gold Coast with infrastructure blocking the longshore drift of sand. Sand is constantly in need of replenishment in locations say, south of Port Canaveral. I wonder if we will ever have a property right to the river of sand in the same way that water rights are enforced upon rivers. I seem to remember a method proposed of placing wave attenuators just past the break as a way of depositing sand, but unfortunately I cannot remember the name of it and could not find it through a quick search. I was hoping that we might try this method where I live.
I think that can happen naturally, unless they are dumping rocks on my hometown California beach. There is a layer of rocks below the summer sand level that are exposed in winter. I guess they could have dumped rocks years ago when erosion was problem.
My hometown beach was fixed by restoring connection to lagoon behind it and allowing the sand to be dumped in the ocean not the lagoon. Restoring the lagoon and digging a channel helped but what really helped was building new bridge that didn’t block the flow.
They used to dredge sand to have enough in summer. Now there is plenty in summer but can get rocky in winter after storm.
You’re absolutely correct that in this area, his dynamic berm fits the hydrology, and that these are not good solutions in other places.
Examples:
- If the coast is too steep, the rocks won’t reach an equilibrium, and you now just have erosion of rock before your erosion of sand.
- If egg-laying sea/coastal life needs sand like sea turtles or some birds
- Surfers and tourism (as you mentioned)
- If the sand erosion is acting as a source for something downstream; stopping the sand movement will cause erosion in that area (nourishing the beach with sand would probably be a better fit)
Slight aside with this question: how much awareness is there in Australia with the collapse of the Thwaites Ice Shelf? Considering Australia's national identify of beach culture, that collapse is going to change everything. I'm curious if there is discussion, and if so of what nature. In the 'States the situation is virtually unknown. https://www.scientificamerican.com/article/antarcticas-colla...
It's understood that we're going to be affected and that its a when not if in some peoples minds. The thing is that we have more direct and present climate change issues so sea level rise which is slow (to date) is not figured in planning compared to existing sources of higher mean tide such as land sinking, combined with big rain events. Brisbane where I live already has king tide events swamping some streets. 10cm is enough to be potentially problematic, never mind 1.5m.
"The river with a city problem" is a good read about the insanity of building greater Brisbane on a giant floodplain.
Kiribati is already under. We get quite a lot about Oceania problems, displacement.
I think thwaites is still treated as the next generations problem.
A stable beachy coastline is in dynamic equilibrium. Erosion is the result of more sediment being washed away from the system than is deposited. The root cause of the disturbance in the system is probably some damn in a river which is mentioned in the article.
A local measure that reduces wave energy creates a sediment trap, reducing or reversing local erosion.. However some where downstream from this site there is now less sediment coming in than is going out. So there it is going to erode now.
These type of measures usually end up pushing the problem downstream (a coastal system has a dominant sediment transport flow direction).
Actual solutions must look at an entire coastal system and usually involve continuous dredging, damn removal or lots of breakwaters, walls etc. This is all well known amd cam be modeled to a pretty good accuracy with software. However time amd time again a town solves their problem by pushing the erosion to their neighbours
This… isn’t experimental. While the US Army Corps of Engineers might not have updated their shore protection manual to include “dynamic breakwaters [and beaches]”, we have design formulae to say what size rocks and what thickness of fill you need for your desired steady state* profile. Bonus points because the smaller rocks are significantly cheaper than the large, immobile armor units, and they can even withstand ice floes better if your coast freezes up.
* there will still be seasonal variation based on summer/winter wave patterns and weather.
That was my first reaction, too. Forget "US Army Corps of Engineers" - I'm thinking this technique was probably old stuff back when the Roman Empire was a shiny new thing.
The Ritz-Carlton Hotel near Half Moon Bay, CA is famous for their unauthorized dumping of large rocks on a public beach to prevent erosion taking out their cliff-top hotel. They were forced to remove the rocks.[1]
Those pictures are a few years old. Compare Google Earth.[2] They're a few years from losing the golf cart path. The hotel might have another 20-30 years.
I don't understand why they would be fined/forced to remove erosion abatement measures. Sure that might reduce beach access, but without it the beach will go away? I guess there will always be a beach, it will just move inland over time. I wonder how the California Coastal Commission will deal with the universal access requirement when the beach literally eats its way into private property.
Well that clarifies that. It's interesting that this sort-of automatic eminent domain doesn't require some form of compensation to the (previous) owner of the land. It also just sits poorly with me that the public's interest in a small portion of beachfront is resulting/going to result in the destruction of such a nice place -- albeit that I know almost none of the particulars.
The key word there is "unauthorized". If they went through some official process with an erosion abatement/remediation plan and got the right review and approvals, they wouldn't then be forced to clear the rocks away.
I like seeing stuff from Hakai show up here regularly, I think they generally do a good job writing about interesting things around the water.
The Demon river article about the catastrophic floods in BC last year is well worth the (long) read. I've shared it with a number of friends: https://hakai.org/the-demon-river/
I’d probably want to protect my property too, but I can’t help but feel that the long-term solution here is some kind of plan for decommissioning coastal assets. Nothing is permanent, particularly where long-term shifts in weather patterns, sea levels, etc. may render residences and livelihoods unviable, and while this transformation of coastal geography is amplified by anthropogenic climate change, it’s not new and won’t ever go away.
I am reminded of the two interpretations of the story of King Cnut and the tide[0]: the misconception that he tried to control the sea, and the actual story in which he was subordinate to it.
Instead of using concrete jax or tetrapods (as Japan does) they're basically using what would amount to concrete demolition debris (and natural rocks of different sizes) to shore up the coastline which is receding due to the damming of the Columbia River (which prevents sedimentary deposits) as evidenced from photos from the early 1900s --but despite that the author goes on to attribute it to sea level rise but never providing how much it rose by the 1900s or even today which would be informative, but I have suspect it's just the author's conjecture.
I think here in the Netherlands this is also done for a couple of years now [1]. Apparently they also used a "waste" product of steel manufacturing for it instead of just rocks. No idea if it was because of this experiment.
Beach impermanence is a fact. Longshore current and erosion baffles are not new concepts. Encouraging people to just dump rubble on their beaches could have a lot of unforeseen consequences.
This sort of citizens science mirrors anti-vax journalism.
In melbourne australia, we have been preserving our beaches with rocks forever, at least since the 1930's. We were losing 20m every 10 years, not 10m per year.
I dont think this is a new concept.
Artificial reefs and breakwaters would be a good use of oligarch yachts. Nobody's going to buy those things because they don't want to reveal who actually owns them.
These people must have bought these properties sight-unseen by mail or something. Why would you build a house were the beach retreats tens of meters per year?
We have the same issue with a stretch of land in Denmark. There's part of the country where the North Sea erodes a tall sand cliff. The view is great, so people decided to build holiday home on top of it. People pay $200.000+ for these houses, then complains that nothing is done to secure the cliff when the sea inevitably eats another couple of meters the following winter.
I can maybe see it being reasonable if you purchased the house 50 years ago, when the sea was really fare away. What I don't get is why you by a house 5 meters from a cliff, when you know that the sea can eat 2 meters in a winter. Why should tax money go to secure your poor investment? These houses are essentially worthless, yet priced like it's a 30 year investment. Hilariously some of the owners have been forced to pay property tax on lots that a half way down the cliff or out in the sea.
You're looking at a microcosm of the phenomenon, but effectively you're just seeing the tragedy of democracy. Once a group realizes it is more cost-effective to just lobby the government to do something than doing it themselves, they'll just do that.
It's possible the houses are old, and built before people realized what was happening. Others in this conversation have blamed the damming of the Columbia river, which occurred in the 1930s, so maybe the effect wasn't present before that.
Here's ChatGPT's summary with the query "Please summarize this article in 3-4 paragraphs: <pasted article>"
========
A group of residents in North Cove, Washington State, has developed a solution to the erosion of their coastline using piles of loose cobble. After dropping a load of rocks from the end of a road in 2016 to see what would happen, local farmer and drainage commissioner David Cottrell expanded the project to create a two-kilometer-long berm of rocks and stumps that shifts with the waves and collects sand, rebuilding the beach. The community's solution looks less like conventional structures such as sea walls and more like the dunes and berms that centuries of storms and tides build on their own, resembling the techniques many Indigenous communities use to cultivate shellfish.
As climate change progresses, coastal communities worldwide are searching for solutions to combat rising sea levels. Hard barriers like sea walls and riprap often cause further erosion and are expensive to build. By contrast, building beaches back could be enough to prevent some of the catastrophic land loss that many states in the US are forecasting due to climate change, according to coastal resilience experts.
North Cove's solution is influencing projects nearby and in California, Europe, and Guam, and is transforming the tools that agencies and communities can apply elsewhere. Engineers have long depended on rigid sea walls, and North Cove's berm is showing the benefits of a softer approach. The project has been successful in rebuilding the beach, and some species, including clam beds and shorebirds, have returned to the area.
> I wish there was software that reads an article and spits out a tl;Dr. I don't have patience to read a narrative, give me the info
It's really not that long and if you're genuinely interested you make an effort to read it. Not everything can be boiled simply down to a handful of sentences without losing key detail.
In Australia we've had a lot of permanent fix approaches which were massively counter-productive. If you want to stop sand being mobile then be prepared to lose it entirely. Really? about 200m-500m back from the waters edge is probably the limit of where routine construction should take place. it doesn't make for million dollar views but its safer for that property owner, the commons (assuming you live in an economy where the intertidal zone is public access) and the dunes.
The Gold Coast is a huge sweep of beach which depends on sand from the river Tweed, which was walled off to make a clear run for boats, and now they have to pump sand to replenish. Noosa depends on sand pumping. Rocks might help, they might even make some fantastic surf breaks but they wind up altering the nature of the beach. If you want a beach like surfers paradise or main beach or noosa, you really don't want rocks.
The berm he's made suits his local hydrology. It won't be exactly the same everywhere.
I kind-of hate being the typical HN naysayer. I'm not a tidal engineer or an ecologist or civil engineer. This is stuff which is discussed quite a lot in Australia, since we cling to the coast and an image of ourselves as "in love with the sea" it becomes increasingly necessary to look at how to hold on to what we've got. The run of sand up the eastern seaboard of Australia is amazing. (its like barchan dunes, permanently on the move, in our case south-to-north)
I've visited some of the beachfronts of Washington state and Oregon and they're glorious. Huge trees litter the tide line, amazing to see. We've nothing like that in Australia really, our rivers aren't full of giant redwood logs like that. We have different problems with disappearing Kelp forests, as does the Californian coastline, Oregon might have some of the problems Washington State does.