Where I grew up, lakes were important. We would spend considerable time driving to them, and once there, camp next to them for a couple of weeks. Every now and then we'd go and camp next to the really really big lake. The one with England on the other side, or so my brother would tell me. All the lakes had these big chairs along the swimming areas that lifeguards sat in. The really really big lake had extra tall chairs. I remember thinking that they could probably see England from up there!

But despite the importance of lakes in our recreational regime, lakes were actually fairly uncommon in Upstate New York and New England. A surprising number of lakes in the US Northeast are actually rivers or streams that have been dammed. Much of the landscape was glaciated and much of that was blanketed with glacial drift, in which ponds and lakes often form, but since the landscape is hilly (often mountainous), rivers and streams have joined low spots together into a dendritic network of flowing water. Many of the lakes that may have been there right after the glaciers retreated had been swallowed up by this network.

For example, this is the region of upstate New York where I spent much of my childhood and teenage years:


There are lakes, but most of the terrain is uplifted and drained by streams and rivers. Indeed, many of the lakes you see on this map are formed by dams and are not natural. One of the main walleye fishing lakes in New York State is the Great Sacandaga, a reservoir.

Where I now live,in Minnesota, there is not that much change in elevation, so there are lots and lots of lakes, to the extend that this is called "The Land of Lakes." If you've ever seen "Land o' Lakes" butter or other dairy products ... well, that's from here. Land o' Lakes is one of our local businesses.

For example, this is where I spend much of my time during the summer here in Minnesota:


The same glacier covered this area and upstate New York, but here there are more lakes, owing mainly to the flatter terrain. Also, very few of these lakes are regulated by dams (though more were in the past during logging days, the dams now in disuse) and I'm 99 percent certain that not one of the lakes shown on this map are human-made. (This map and the one above of New York show roughly the same land area.)

It is worth noting that people who live in Upstate New York can typically tell you where various rivers and streams are, and can tell you what river or stream feeds into what other rivers and streams. In contrast, I've found that Minnesotans often have no idea what the nearest stream or river is, or where it goes . In the region depicted here, if you ask someone which way the Mississippi River is (all the water you see here drains into it) people will simply not know or will point in a random direction.

A lake is the landscape thumbing its nose at time. All elevated regions ... all places on Earth where you can stand in one place all day and NOT have the briny sea lapping at your ankles (or knees) at least a couple of times a day ... are subject to being eroded down to sea level, someday. Wind, rain, phytochemical activity, and running water will eventually flatten any and every continent to the level of the ocean's tides.

Or at least, that is what the forces of erosion would do were it not for forces of uplift and deposition happening at the same time. And as mountains or uplands rise above the theoretical tide line, rivers cut down into the emerging hills, and seas grind away at the edges, every here and there forms a low spot that does not drain gravity-ward, and that can hold water for a time. Sometimes that time is days, after a rain. Other times, it is tens of thousands of years, until the low spot is breached by erosion and let out to the sea. Eventually, every lake may give up its basin to a stream, and thus its water to the ocean directly, by surface flow (it had already been feeding the sea indirectly via groundwater movement and evaporation).

(There is another way to think of lakes that views them as windows into an underground system of rivers and reservoirs. That perspective works better in a different kind of discussion, so we'll set it aside for now.)

There is no reason to believe, by the way, that the forces of uplift and deposition on continents is in balance with the forces of erosion. There is no reason to expect that there have not been times in the past when most of the continental regions of the Earth was inundated by shallow seas, with few rises and almost no mountains above them. Conversely, there may be times where much of the world's water is trapped in ice, so the ocean rests much lower than the continental margins, and much of the land is high and dry. I sometimes wonder how one would characterize the present day in this regard, relative to other time periods. There are major "inland seas" (the Caribbean, for instance) but it seems some major seas and low areas have been elevated in recent millions of years (the Tethys Sea, which once ran from Gibraltar to the Black and Caspian seas, cutting off Africa from Eurasia; The Miocene seas and lowlands of South Asia now known as Pakistan and Afghanistan; the sea that was an arm of the Pacific, where the Amazon now stands; etc.)

For many lakes, their death precedes their capture by the growing network of rivers and streams, as they are filled in with sediment, converted to bog and eventually become a flat marshy spot. The cost you pay for being amenable to settling water is muck and other sediments filling you in. Lakes with outlets don't have this problem to the same degree, but those outlets are essentially topographical hemorrhages, cutting down even if there are ephemeral human dams in the way, stranding the shorelines and making the lake into an ever growing valley or canyon.

So when you see a lake, take a good look. It might not be there tomorrow.

Well, OK, it probably will be there tomorrow, but at the medium to large temporal scale, all lakes are temporary features of the landscape, thumbing their metaphorical noses at the tide line, to which, eventually, they are bound to sink. Unless something else, much more severe, happens to them, like being ground up by a glacier or subducted into the fiery mantle of the earth. Or the sun exploding. Or it turning out that the Universe is only a simulation game being played in some other universe that does exixt.

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Thanks for the lake essay. I read it while sitting at the front window of my northern Minnesota lake home, gazing out at the waters as they flow north to Hudson Bay, and hoping that the Canadian metals company that wants to build a copper mine 5 miles from my lake will fail in their efforts...

Lakes are uncommon in upstate New York? This is news to me. My perception may be colored by growing up in the middle of a desert, but New York seems to be slam full of lakes to me.

By CherryBomb (not verified) on 18 Jul 2010 #permalink

CherryBomb: Great, I'm glad you have learned this new information about the geography of New York!

New York has many lakes, and impressive lakes. The finger lakes are pretty cool, for instance. But the comparison I make here is accurate, and it is not just a comparison of NY and Minnesota, but rather, a comparison of different terrains and how they erode, and how they respond to being wet. though I did not discuss arid regions, that is a big interest of mine.

(There are actually several lakes in Phoenix, but the only hold water every few centuries!)

I've adjusted the post to include graphic illustrations of my point so it is clearer.

The larger and medium-sized lakes are reborn after each ice age, as the glaciers sweep away the soft sediments as they travel across.
Sweden and Finland are especially rich of lakes -the many Scandinavian settlers in Minnesota would have felt right at home (see Vilhelm Moberg's epic about Swedish immigrants in Minnesota), although the continental climate makes the summers warmer and the winters colder.
On some very few places, you can find buried peat bogs from the Eemian that evaded the "big sweep" of the latest glaciation. These are quite valuable for science, since they provide a snapshot of organic materials.

Ocean basins do not have time to fill up with sediments, so in an anoxic site like the bottom of the Black Sea, it should be possible to find intact driftwood, and even locate the site of origin using isotope abundances. Get some automated submersibles going, with sophisticated sonar/radar to locate logs under the silt. and you would eventually be able to do dendrochronology sequences into the ice age, and beyond :-)

By Birger Johansson (not verified) on 18 Jul 2010 #permalink

That's the best essay I've read about lakes!

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Great! Now that the strike is over, I am going to read this post again, I liked it so much the first time.