Counting Down the Largest Lake Islands in the World, Part I (#5-#1)

It’s the second half of our countdown of the ten largest lake islands around the world. Depending on how one defines an island from a geologic or hydrologic standpoint, the list of islands that make up the top ten is open to interpretation, and it is thus possible to assemble a number of different top ten islands for this list.

As mentioned in Part I (which you can visit here), to qualify for this particular list, in addition to lying within lakes, the island cannot be one artificially detached from the mainland by a manually-regulated canal. As well, the island must lie within a ‘true’ lake – the water body that surrounds it must be a single hydrological lake unit whose water level rises and falls as one (this condition will come into play in the second half of this list).  Artificial islands that are semi-connected to the mainland via dams and causeways are also not included. These conditions disqualify a number of landmasses for this particular list, but these islands will be still covered within the list for comparative purposes.

5. Isle Royale, Lake Superior, United States – 541 km2(209 sq mi)


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Though the top ten list may be dominated by Lake Superior’s neighbour to the east, Lake Huron, Superior does place its own entry in the form of Michigan’s Isle Royale.  Located much closer to the Ontario mainland than it is to the rest of Michigan across the lake (22 km/14 mi versus 90 km/56 mi), Isle Royale has nevertheless been a legal part of the United States since 1783 when it was awarded to the fledgling republic by Great Britain in the 1783 Treaty of Paris (fur traders in the region had already brought attention to the copper deposits that lay on the island, and the Americans successfully lobbied for Isle Royale as a result).  Still, the British would continue to govern the island unofficially until 1812, and the United States would not take firm possession over Isle Royale until treaties were reached with the local Ojibwa people in 1842.

It was at the same time that the first geologic surveys of Isle Royale were being conducted as part of a state-wide survey, and these surveys brought to light just how plentiful the veins of copper were on the island; deposits created within the cracks of ancient lava flows over a billion years old and later exposed by the scouring actions of continental ice sheets.  A small mining boom began on the island, but there was a general lack of success, leading to the island fading back into isolation. Isle Royale was generally left to loggers, cottagers, and fishers who noticed the plentiful amounts of fish that inhabited the shallow offshore waters.  These same waters would claim a number of ships over the years, and today these shipwrecks are protected as part of Isle Royale National Park.  The park was created in 1940 in response to the declining fish stocks and boreal forest stands, but in doing so a contentious relationship was established between the US National Park Service and the small number of families who continue to maintain property on the island.  In 1976, the government formally declared Isle Royale a wilderness area, effectively ceasing all non-park-related economic activity.

Isle Royale is also home to the world’s longest-running predator-prey study that revolves around its populations of moose and wolves that descended from a small group of moose that swam to the island in the early 1900s and a single pair of wolves that crossed an ice bridge from Ontario in 1949.  Ever since, the numbers of each species have fluctuated wildly from year to year as they compete against both each other and the harsh winter climate for space in the limited island habitat.

4. Samosir, Lake Toba, Indonesia – 630 km2 (240 sq mi)


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And now this list arrives at its first disputed member.  Located in the middle of North Sumatra’s Lake Toba is Samosir.  If taken as an island, Samosir is the world’s largest island within another island.  The catch?  Samosir only became an island in 1906 thanks to the dredging of a narrow canal by Dutch colonial authorities across the narrow 1 100 m (3 720 ft) isthmus that joined the large volcanic island to the rest of Sumatra.  The canal itself is only 10 m (33 ft) wide, as shown in this photo.  Even if one were to make the argument that Samosir qualifies since this dredged canal is now a permanent channel that requires no maintenance such as employing pumps and locks, the tiny size and shallow nature of the channel may lead some to preclude Samosir from the list.  For the purposes of this article, however, it’s enough to qualify.

A very blurry look at the canal separating Samosir from surrounding Sumatra.

Samosir, which takes up most of the Lake Toba basin, is the result of a catastrophic volcanic eruption that occurred approximately 73 000 years ago.  Perhaps the most violent volcanic eruption of the past 25 million years, the Lake Toba catastrophe destroyed an area of 20 000 km2 (7 700 sq mi) and ejected an astronomic 2 800 km3 (670 cu mi) of material – an eruption more than 230 times that of Krakatoa.  The mammoth effect of the eruption on the global climate and living conditions on the planet is hypothesised to have resulted in a decade-long volcanic winter than produced a genetic bottleneck amongst the then-small human population, with perhaps 600 to 10 000 females globally surviving the incident.  The huge caldera created in the middle of Sumatra then in-filled with Lake Toba, with the resurgent dome that emerged from the caldera floor forming Samosir.  Though the date of the last known eruption on Samosir is unknown, continued volcanic activity is evidenced by the lack of vegetation.

3. Olkhon, Lake Baikal, Russia – 730 km2 (280 sq mi)


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The tectonically-active Lake Baikal in southern Siberia is perhaps best known for being the deepest lake on Earth, or for perhaps being the largest lake by water volume on Earth.  It also happens to be home to the largest lake in Asia.  The lake is where the proposed Amur Plate may be breaking away from Eurasia, creating a rift valley similar to the East African Rift where Africa is splitting in two.  The split is hardly linear, however.  The lake itself is comprised of three separate basins, and Olkhon lies astride the boundary between the northern and central basins; a giant chunk of land trapped between two faults and separated from Baikal’s west shore by the 1.7 km (1.1 mi) Small Sea Strait.

The highest point on Olkhon, Mount Zhima, rises 1 276 m (4 186 ft) above the lake bottom, reaching 818 m (2 884 ft) above sea level.  Olkhon contains taiga forests on the east shore and steppe and grasslands on the west shore facing the mainland.  A solitary 1 500 souls, mostly Buryat, live on Olkhon, which was only hooked up to the power grid in 2005.  The isolation has actually led to the island becoming quite the tourist destination, especially among campers.  50 000 people visit the island every year, and there are shops, restaurants, and lodging to service them.

Eastern and Southern Flevoland, IJsselmeer, Netherlands – 948 km2(366 sq mi)


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It may be cheating to include Flevoland, as it is 1) artificial, 2) exists entirely below sea level, and 3) only continues to exist due to an enormous system of dykes and dams.  For those reasons, it’s not included in the list.  Still, as the world’s largest artificial island, Flevoland is a remarkable example of how humans have been able to engineer landscapes.

The Dutch have been reclaiming polders of land from the North Sea for nearly a millennium, providing themselves with thousands of square kilometres (one-fifth of the entire country) of valuable land for settlement and agriculture.  At same time, they have been saddled with the task of keep ocean waters from flooding the reclaimed land and the low-lying country surrounding it.  As early as the seventeenth century, proposals were made to drain the shallow Zuiderzee, the large arm of the North Sea that formed from a 1287 flood and had extended well into the heart of the Netherlands ever since.  While bits and pieces had been taken from it over the centuries, it was a 1916 flood that set the Dutch government to reclaim the entire Zuiderzee as part of the great project known as the Zuiderzee Works.

Zuiderzeeworks

The new lands, lakes, and dykes created as part of the Zuiderzee Works.  Source: Scipius, http://commons.wikimedia.org/wiki/File:Zuiderzeeworks.png.  Licensed under the Creative Commons Attribution-Share Alike 3.0 Unported licence.

Taken from an 1891 proposal designed by Cornelius Lely, the then-Minister of Transport and Public Works, construction on the Zuiderzee Works began in 1920, with the Wieringermeer Polder completed ij 1930.  The Zuiderzee was completely dammed in 1932 with the completion of the Afsluitdijk, transforming the water body from a saltwater arm of the North Sea into a freshwater lake fed by the Ijssel River; as such, it was renamed the IJsselmeer.  Now closed off from the sea, the IJsselmeer was to be drained piece-by-piece.  The first post-dam polder reclaimed was the Noordoostpolder in 1942, followed by Eastern Flevoland in 1957 and Southern Flevoland in 1962.  While the Noordoostpolder was attached to the mainland, the Flevolands (named for the Roman-era Lake Flevo that formerly occupied the centre of the Netherlands) would be kept apart from the mainland by a series of small water bodies that would allow pre-existing coastal towns to keep their access to the sea, meaning that the Flevolands would become one large artificial island.  Another proposed polder, the Markerwaard, was never constructed, although the dam that was intended to contain it was completed.

Since 1986, the Flevolands, along with the Noordoostpolder, have comprised the Dutch province of Flevoland, the country’s smallest province.  Eastern and Southern Flevoland share a single hydrological infrastructure, although a dyke splits them in half so that one polder can be saved from flooding should something happen to the other one.  Over 330 000 people have settled in the Flevolands; over half of those people live in the city of Almere in Southern Flevoland.  Constructed in 1976 and continually expanded ever since, the city serves to relieve population pressures in nearby Amsterdam and is expected to grow further to 350 000 residents by 2030.  The capital of the province is Lelystad in Eastern Flevoland, constructed in 1967 and named for Cornelius Lely.

While most of the rest of Flevoland is dedicated to agriculture (the orderly grid of planned farmland stands out starkly in satellite imagery amidst the chaotic patchwork of European farms that date back hundreds of years), a large portion of Southern Flevoland called the Oostvaardersplassen has been left alone.  Originally set aside in 1968 for future use as an industrial area, the new land, still filled with shallow pools of water, was quickly colonised by such a diverse array of flora and fauna that it was decided to set it aside as a wetland and nature preserve.  Today, it is one of the largest protected wetlands in Europe, and government is actively encouraging its expansion.  Deer and cattle have been introduced to further replicate natural processes that would have occurred on the European mainland prior to the introduction of large-scale agriculture.

Sääminginsalo,Saimaa, Finland – 1 069 km2 (413 sq mi)


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Sääminginsalo_island

A map highlighting Sääminginsalo, whose outline can be hard to determine in satellite imagery due to the heavily indented coastline.  Source: Dacnoh, http://commons.wikimedia.org/wiki/File:S%C3%A4%C3%A4minginsalo_island.png.  Licensed under the Creative Commons Attribution-Share Alike 3.0 Unported licence.

The next disputed member of the list is Sääminginsalo, a chunk of land surrounded by the great lake system of Finland’s Southern Savonia region known as Saimaa.  Hydrologically speaking, Saimaa itself is not so much a single lake as it is a chain (perhaps ‘maze’ is a better term) of lakes joined by canals, channels, and small rivers.  While there are elevation changes between some of the lakes, there are no elevation changes present in the waters surrounding Sääminginsalo, which would seem to affirm its status as the largest of the 14 000-plus islands that dot the glacially-formed Saimaa.  However, the eastern side of Sääminginsalo is only detached from the mainland via the construction of three canals in the 1750s: Pistalankanava, Nurmitaipaleen kanava, and Raikuun kanava.  While the first two canals would appear to pass the standard used to accept Samosir on the list, Raikuun kanava is even smaller than the canal separating Samosir from Sumatra, and is maintained in a state that is very artificial in appearance.  Only canoes and small boats can pass through, and the long-term permanence of the channel can be called into question since parts of the channel are so overgrown that they could be called wetland.  Since 2001, the Finnish government has recognised Sääminginsalo as an island.  Consider this island #3A on the list.

Soisalo, Saimaa, Finland – 1 638 km² (632 sq mi)


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13 km (8 mi) north of Sääminginsalo, also bordering Saimaa, is the traditional answer to the question of Europe’s largest lake island.  Soisalo is not artificially cut off from the rest of Finland via canals; all of the water in the six lakes that surround it is there naturally.  Most tourist guides will refer to Soisalo as Finland’s largest island.  The surrounding lakes, however, are not level; there is a 6 m (20 ft) elevation drop between the lakes that border Soisalo to the north and the lakes of Saimaa to the south.  Essentially, the various lakes are connected by wide, slow-moving rivers, and since Soisalo is not the product of fluvial deposition, it therefore cannot technically be an island despite being surrounded by water.  It’s an odd situation, to be sure.  Wikipedia includes it in its list of the largest lake islands, but also follows it with a proviso.  World Island Info, however, excludes it.  Regardless of the technicalities of island status, the Saimaa region truly is one of the most beautiful areas of Europe.

2. Île René-Levasseur, Lac Manicouagan, Canada –2 000 km2 (770 sq mi)


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Of all of the islands on this list, Île René-Levasseur may have the most distinctive appearance.  Located inside of a 214 million-year-old meteor crater, the island forms a near-circle in the middle of Quebec’s Lac Manicouagan and is readily visible from space.  René-Levasseur marks the location of another manmade engineering project, but in this case, it was the lake that is artificial, not the island.

Prior to 1970, Lac Manicouagan was two separate lakes, each tracing the outline of the ancient 85 km (53 mi) wide crater, the sixth-largest crater on Earth.  In the late 1950s, Hydro-Québec, the Quebec government-owned electric utility, began developing the remote centre and northern areas of the province for hydroelectricity.  The first project was the seven-dam Manic-Outardes complex, in which the Manicougan River and the Rivière aux Outardes were harnessed for power.  The largest dam in the complex was the Daniel-Johnson Dam, the world’s largest multiple-arch buttress dam named for the Quebec premier who died on the day of the dam’s opening that he was scheduled to preside over.  The reservoir created by the dam enlarged the original Lac Manicouagan to the point that it absorbed the neighbouring Lac Mouchalagan and covered the crater rim.  The resulting island formed in the middle of the crater was named for the dam’s chief engineer, who also died just days before the edifice’s completion.

Île René-Levasseur is almost entirely uninhabited, save for 52 cottagers with government-approved leases, and is occupied by large stands of valuable old-growth boreal forest.  As such, it has become a battleground between activists looking to preserve the island as a large park, the Montreal-based congomerate Kruger, for whom the island’s stands represent 35% of their attributed lumber volume on Quebec’s North Shore, and Innu looking to stop outside logging in their indigenous territory.  Currently, only the northeastern portion of the island is protected as a nature reserve.

1. Manitoulin Island, Lake Huron, Canada – 2 766 km2 (1 068 sq mi)


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Finally, we reach the end of the list with the undisputed largest island within a lake in the world: Ontario’s Manitoulin Island, which lies at the north end of Lake Huron, home to two other islands in the top ten as seen in Part I.  Overall, Manitoulin is the 171stlargest island on the planet, but when it comes to lake islands, no other island compares (second-place Île René-Levasseur is nearly 28 percent smaller than Manitoulin).  The low-lying island is itself dotted with 108 separate lakes, including the largest lake within a freshwater island within a lake (the 104 km²/40 sq mi Lake Manitou), and many of those lakes have islands of their own, including Lake Mindemoya’s Treasure Island, the world’s largest island in a lake in an island in a lake.

12 600 people live year-round on Manitoulin, which is one of Northern Ontario’s top vacation destinations.  The population increases greatly in summer with a large influx of cottagers and outdoor recreationists looking to enjoy the island’s scenery, including its winding roads, lakes, bays, and trails.  The island is joined to the mainland on its north shore by a one-lane wooden swing bridge via the intermediate Goat Island; the bridge was also used for rail traffic until the 1980s.  For much of the 19thcentury, the island was set aside as a reserve for Anishinaabe people in advance of the white population settling the lands to the south and east, but the reserve was dissolved in 1862 and the most of the land was divided for non-native settlement.  Today, the Anishinaabelive in six reserves scattered throughout Manitoulin and comprise about 38 percent of the island’s population.

Further Reading

Barnum, D.C. (2002).  The Purpose of the Isle Royale Families and Friends Association.  Isle Royale Families and Friends Association, August 2002.  Available at http://www.isleroyalefamilies.org/aboutus.htm.  Accessed 5 August 2012.

Calder, J. (2005).  Largest Lake Islands of the World.  World Island Info, 9 October 2005.  Available at http://www.worldislandinfo.com/LAKEV1.htm.  Accessed 3 August 2012.

CopperCountry.com (n.d.).  Isle Royale Geology and History.  Available at http://www.coppercountry.com/article_42.php.  Accessed 5 August 2012.

Hawaiian Volcano Observatory (2005).  Supersized eruptions are all the rage!  28 April 2005.  Available at http://hvo.wr.usgs.gov/volcanowatch/archive/2005/05_04_28.html.  Accessed 5 August 2012.

Howard, S.J. (1998).  History.  Isle Royal National Park.  Available at http://www.nyx.net/~sjhoward/Isle_Royale/.  Accessed 5 August 2012.

Hurskainen, T. (2012).  Raikuun kanava/Raikuu kanal.  Suomen kanavat.  Available at http://kanaler.arnholm.nu/suomi/finland/raikuuf.html.  Accessed 6 August 2012.

International Lake Environment Committee (2008).  Manicouagan Reservoir.  Available at http://www.ilec.or.jp/database/nam/nam-26.html.  Accessed 6 August 2012.

Lewis, M.L. (2012).  Lakes on Islands in Lakes: Toba and Taal in Indonesia and the Philippines.  GeoCurrents, 29 March 2012.  Available at http://geocurrents.info/geonotes/lakes-on-islands-in-lakes-toba-and-taal-in-indonesia-and-the-philippines#ixzz22k4DuHeb.  Accessed 5 August 2012.

National Park Service (2012).  Isle Royale National Park.  Available at http://www.nps.gov/isro/index.htm.  Accessed 5 August 2012.

Pilke, A. (2010).  Suomen suurimmasta saaresta kiistaa.  YLE Uutiset, 3 August 2010.  Available at http://yle.fi/uutiset/suomen_suurimmasta_saaresta_kiistaa/1877921.  Accessed 6 August 2012.

Provincie Flevoland (2012).  Oostvaardersland.  Available at http://www.flevoland.nl/wat-doen-we/grote-projecten/oostvaarderswold/english/.  Accessed 6 August 2012.

Radio-Canada (2001).  Réserve écologique Louis-Babel.  La Semaine Verte.  Available at http://www.radio-canada.ca/actualite/semaineverte/020721/reservelouisbabel.html.  Accessed 6 August 2012.

Stichtind Deltawerken Online (2004).  Zuyderzee Flood (1916).  Available at http://www.deltawerken.com/Zuider-Zee-flood-%281916%29/306.html.  Accessed 6 August 2012.

Vucetich, J.A. (2012).  About The Project: Overview.  Wolves & Moose of Isle Royale.  Available at http://www.isleroyalewolf.org/overview/overview/at_a_glance.html.  Accessed 5 August 2012.

Way to Russia (2011).  Where to Go: Olkhon Island on Baikal Lake.  6 July 2011.  Available at http://www.waytorussia.net/Baikal/Destinations/Olkhon.html.  Accessed 5 August 2012.

Weber, G. (2007).  Toba Volcano.  Basel: Andaman Association.  Available at http://www.andaman.org/BOOK/originals/Weber-Toba/textr.htm.  Accessed 5 August 2012.

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