And That, Kids, Is Why You Shouldn't Build on a Bluff

One of my geotweeps, CGKings317, once tweeted this rather remarkable video showing coastal erosion over the course of a year:

It gives you a sense of just how delicate coastlines can be. There’s the ocean, and storms; wind, water and gravity, all working to lay the land low. 17 meters (almost 56 feet) of prime seaside real estate now sleeps with the fishes.

And we build seawalls and groynes, pile riprap, terrace and wire and drain, do our damnedest to make these temporary landforms permanent, but good Mother Earth just sticks her tongue out at us, goes “Nyah-nyah!” and takes another few bites out of what we thought we could preserve.

I live in the Seattle area, where coastal erosion is a daily fact. The bluffs I see today aren’t the same ones I’ll see next year. They may look similar, but they’ve changed, and one day, they’ll be gone.

One of my favorite places in the whole of the Pacific Northwest is Discovery Park. I first saw it in 2007. It was, in fact, the first place I got a sunburn up here. And that bluff – my Arizona eyes had never laid eyes upon anything like it!

Discovery Park South Bluff, 2007

It feels rock-hard, but it’s just hard-packed glacial sediments, and the Sound wears away at it year by year.

Discovery Park, South Bluff, 2010

See the chunks of it being carved out? Every year, a little bit more gone; every year, it’s changed.

Discovery Park, South Bluff, 2009
Discovery Park, South Bluff, 2010

Geology feels rock-solid, at first. There’s nothing that gives the sensation of being forever quite like a rock does. And some changes happen so gradually we barely notice them. But the world changes all the time. Little changes, building up over time. There’s a bluff there now; someday, there will be only the water. Water will in its turn be replaced by land again, elements dancing, continents fussing with their appearance, gone traveling. Look at the world through a geologic timescale, and it’s a busy place, always different, always fascinating, frequently eroding.

Remember that when you’re considering that beachfront house.

And That, Kids, Is Why You Shouldn't Build on a Bluff

12 thoughts on “And That, Kids, Is Why You Shouldn't Build on a Bluff

  1. HS

    Excellent post, thanks! I grew up in San Diego, and you wouldn’t believe the silly things developers do there. Not only building houses right on the bluff (then they want city money to shore up their disappearing foundations), but also building in flood plains and in the middle of flammable chaparral (not leaving an ugly fire break, of course). Then they sue for city resources when they are flooded, or cause the deaths of firefighters when fire season rolls around again. But heaven forbid we rein in the developers and their contributions to “economic growth.” They’ve bought all the right people.

    As for people that buy those houses- well, a lot of folks don’t think of themselves as part of natural systems. Nature is something you visit, not something you participate in. The most interaction they have with their environment is the high cost of their fire and flood insurance. And they’re often the ones that suffer most because of the developers’ poor decisions and excellent marketing. Southern California is so depressing.

  2. 3

    I live in the south San Francisco Bay, and I’ve walked many of the ocean beaches between San Francisco and Monterey Bay. The number of people who build at the top of eroding bluffs never ceases to amaze me. I like to think that they’re doing it to keep the kids from arguing over who gets the house when they’re gone — because the house is going to be gone, too.

  3. 5

    What a great example of how the earth is constantly changing! I hope you don’t mind me sharing this post with intro geology students. I’m always excited to find new ways of grabbing their attention and showing them why they should care about geology. This would fit the bill!

  4. 10

    @N. Nescio

    What is sad about nature reminding people how silly it is to think that possessing a deed means they ‘own’ land?

    We just live here.

    Excuse me? Are you telling me that you have no empathy for the people who lose their land as it erodes away? I’ve seen it firsthand. It’s terrible! And it’s not like you can just move to wherever or push back the property boundaries; that isn’t how it works. You say we just live here, but when one’s land is eroding away, the land they live on what is eroding away, so here won’t be there much longer! Think a little bit before spouting off nonsense like that.

  5. 11

    I have some sympathy for those who moved in without knowing that the building site is geologically fragile; that’s partly due to the horrible lack of science education in our country, and communities that allow development helter-skelter without requiring an actual geologist to review the building plans and say things like, “that bluff is eroding” or “that’s an old landslide that can easily be reactivated” or “that barrier island is only going to last until the next hurricane”.

    I have no sympathy for anyone who knew the risks and moved in anyway, because “it can’t happen to me” or “it can’t happen again”.

    But I suspect people in the former category are more numerous than those in the latter.

  6. 12

    I have no sympathy for anyone who knew the risks and moved in anyway, because “it can’t happen to me” or “it can’t happen again”.

    So, how far back from the bluffs should people buy and build? Would you please draw me a clear line some distance from the bluffs where your empathy kicks in? Don’t forget to provide the date from when your line is valid.

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