I had some fun with artificially created geographic features lately, first with the largest artificial islands and then with islands joined artificially to the mainland. Now, I thought, I’d flip the concept to its opposite extreme. Instead of land on water, how about water on land? What might be the largest area of terrain intentionally flooded to make an artificial lake or reservoir?
My continuously growing bag of possible topics might come in handy, I though. This was my big spreadsheet that I use to tally new bits of geo-trivia as I come across them, most of which will never see the light of day on Twelve Mile Circle. Yes, I did seem to recall something. Ah, here it was: according to the CIA’s World Factbook, "Lake Volta is the world’s largest artificial lake by surface area (8,482 sq km; 3,275 sq mi)."
That introduced a quandary. Did "largest" mean a measurement of area or volume? Would it mean the list might change with fluctuations in rainfall or during times of drought? Those were not issues with islands. Islands weren’t measured by volume. Their surface area might changed slightly due to tides or erosion although probably not significantly assuming proper maintenance. Reservoirs, however, could change drastically by size or volume repeatedly during their lifetimes. Suddenly, something so simple in my mind became much more complex as it unraveled.
I did learn a couple of new terms in the process, though. "Conservation Pool" is an optimal level that meets the needs for which the reservoir was created. "Flood Pool" is the absolute maximum a reservoir can hold. The two values often differed drastically. Most of the calculations used in rankings, as far as I could tell, seemed to rely on the flood pool rather than the conservation pool as a means to preserve consistent measurements. That’s what I tried to use too.
It still didn’t answer which "largest" I should use so I decided to examine both: size as defined by square kilometres and volume as defined by cubic kilometres. Ponder that for a moment, a cubic kilometre of water!
LAKE VOLTA. by Fraser Morrison, on Flickr
via Creative Commons Attribution-NonCommercial-NoDerivs 2.0 Generic (CC BY-NC-ND 2.0) license
Lake Volta in Ghana had the largest area that I could find, the 8,482 km² mentioned previously (other sources listed it slightly differently, an issue I found with all bodies of water examined). That made it larger than the land area of the U.S. states of Rhode Island (2,706 km²) and Delaware (5,060 km²) combined, or more than fifty times the size of the District of Columbia. That’s a seriously large man-made lake.
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The damming of the White and Black Volta Rivers in 1965 caused the displacement of literally tens of thousands of people. On a more positive side, Volta’s Akosombo Dam generated electricity for most of Ghana and created a thriving fishing industry.
HX9V_DSC03096_Farewell Lake Kariba by Allan_Grey, on Flickr
via Creative Commons Attribution-ShareAlike 2.0 Generic (CC BY-SA 2.0) license
As I think about it, volume would probably be a more important indicator of size than area. A reservoir exists to store fresh water, and the more it can store for the needs of a surrounding population, the better. The largest volume of any artificial lake is Lake Kariba which straddles the Zambia and Zimbabwe border, with a storage capacity of 181 km³.
That’s an almost unimaginably large number as I considered it some more. Sure, it pales in comparison to an ocean, however, this particular body of water was created by people.
The lake filled what was known previously as the Kariba Gorge when the Zambezi River was dammed in 1958. Today its shores appear to be a great location for African safaris based on the online sources and photos I encountered as I researched it further.
Shoreline of Lake Sakakawea at Fort Stevenson State Park, North Dakota by loyaldefender2004, on Flickr
via Creative Commons Attribution 2.0 Generic (CC BY 2.0) license
I then turned my attention to the United States to see how it compared — not very favorably as it turns out versus the monster-sized international contenders.
North Dakota’s Lake Sakakawea on the Missouri River took the prize for largest area in the US.
Its 1,546 square kilometres seemed impressive until placed against Lake Volta’s 8,482 km².
On a completely irrelevant tangent, Wikipedia included an essentially meaningless statement which fascinated me anyway because I’m drawn to odd claims:
The creation of the lake displaced members of the Fort Berthold Indian Reservation from the villages of Van Hook and (Old) Sanish… one name that had been proposed [for a new town of displaced residents] was Vanish (a portmanteau of the two previous towns’ names).
I so desperately wanted to confirm that claim — everyone knows how much I love a good portmanteau — however Wikipedia offered the statement without attribution. I found one possible source although it offered little evidence that Vanish was anything other than a tongue-in-cheek proposal. I guess it would have been too good to believe that Van Hook and Sanish would vanish to (nearly) form Vanish.
The media wittily called the new town Vanish, a play on Sanish’s name and its unavoidable fate, but there’s no “Vanish, ND” on the maps today. When you lay the map… over nearby towns to figure out which one this is, you realize that the government was far less witty than the newspapers. The powers-that-be named the new town… New Town.
Lake Mead by Kath B, on Flickr
via Creative Commons Attribution-NonCommercial 2.0 Generic (CC BY-NC 2.0) license
Lake Mead is the US’s volume leader at 35.7 km³ which would hardly make a dent in Lake Kariba’s 181 km³ even though it’s still a massive amount of water.
Lake Mead formed behind the Hoover Dam on the Colorado River and straddles the border between Arizona and Nevada. The lake also served as a good example of difference between capacity measurements, conservation pool vs. flood pool. It’s depth has fluctuated wildly during protracted drought cycles and has flirted with critical shortage levels in recent years.
I thought about including examples from other nations represented by 12MC readers. The area/volume dichotomy doubled my writing requirements and I began to lose interest.