TURKANA LAKE

Coordinates: 3°35′N 36°7′E

Lake type            Saline, monomictic, alkaline, endorheic

Primary inflows Omo River, Turkwel River, Kerio River

Primary outflows             Evaporation

Catchment area                130,860 km²

Basin countries Ethiopia, Kenya

Max. length        290 km

Max. width         32 km 20 mi

Surface area       6,405 km2 2,473 sq mi

Average depth  30.2 m

Max. depth        109 m

Water volume   203.6 km³

Surface elevation             360.4 m

Islands  North Island, Central Island, South Island volcanic

Settlements       El Molo, Loyangalani, Kalokol, Eliye Springs, Ileret, Fort Banya.

The lake was named Lake Rudolf in honour of Crown Prince Rudolf of Austria by Count Sámuel Teleki de Szék and his second-in-command Lieutenant Ludwig Ritter Von Höhnel, a Hungarian and an Austrian,on 6 March 1888. They were the first Europeans to have recorded visiting the lake after a long safari across East Africa. Natives who live around Lake Turkana include the Turkana, Rendille, Gabbra, Daasanach, Hamar Koke, Karo, Nyagatom, Mursi, Surma and Molo peoples. For the location of many of these peoples, refer to the dialect map in the article.

J. W. Gregory reported in The Geographical Journal of 1894 that it had been called 'Basso Narok'. This means "Black Lake" in the Samburu language. Likewise, Lake Stefanie is "Basso Naibor" in Samburu, meaning "White Lake". The Samburu are among the dominant tribes in the lake Turkana region when the explorers came." What the native form of this phrase was, what it might mean, and in which language is not clear. The lake kept its European name during the colonial period of British East Africa. After the independence of Kenya, the president, Mzee Jomo Kenyatta, renamed it in 1975 after the Turkana, the predominant tribe there.

At some unknown time, the lake acquired an alternate name as the Jade Sea from its turquoise colour seen approaching from a distance. The colour comes from algae that rise to the surface in calm weather. This is likely also a European name. The Turkana refer to the lake as Anam Ka'alakol, meaning "the sea of many fish". It is from the name Ka'alakol that Kalokol, a town on the western shore of Lake Turkana, east of Lodwar, derives its name. The previous indigenous Turkana name for Lake Turkana was Anam a Cheper. The area still sees few visitors, being a two-day drive from Nairobi. The lake is also an imaginary boundary of the Rendille and Borana and Oromo to the Turkana land. The area is primarily clay-based and is more alkaline than seawater.

MALAWI LAKE

Lake Malawi is between 560 kilometres 350 mi and 580 kilometres 360 mi long, and about 75 kilometres 47 mi wide at its widest point. The total surface area of the lake is about 29,600 square kilometres 11,400 sq mi. The lake has shorelines on western Mozambique, eastern Malawi, and southern Tanzania. The largest river flowing into it is the Ruhuhu River, and there is an outlet at its southern end, the Shire River, a tributary that flows into the very large Zambezi River in Mozambique.

The lake lies in a valley formed by the opening of the East African Rift, where the African tectonic plate is being split into two pieces. This is called a divergent plate tectonics boundary. It is variously estimated at about 40,000 years old or about one to two million years. The lake is about 350 kilometres 220 mi southeast of Lake Tanganyika, another of the great lakes of the East African Rift.

There is a rocky island about 3 kilometres from the western shore of the lake, across from Nkopola. named Boadzulu Island. The exact coordinates are 14°15'2.2"14.2506° south and 35°8'33.1" 35.1425° east. The island is uninhabited and is remarkable for the large number of cichlids which live in the surrounding waters.

European discovery and colonization

The Portuguese trader Candido José da Costa Cardoso was the first European to visit the lake in 1846.[8] David Livingstone reached the lake in 1859, and named it "Lake Nyasa".Much of the African region surrounding this lake was soon claimed by the British Empire and formed into the colony of Nyasaland. Although the Portuguese took control of the eastern shore of this lake, the island of Likoma was used as a mission station by the Universities' Mission to Central Africa, and as a result, Likoma and the nearby islet of Chizumulu were incorporated into Nyasaland rather than to Mozambique. Today, these islets form lacustrine exclaves: Malawian land surrounded by Mozambiquian waters.citation needed

On August 16, 1914, Lake Malawi was the scene of a brief naval battle when the British gunboat SS Gwendolen, commanded by a Captain Rhoades, heard that World War I had broken out, and he received orders from the British Empire's high command to "sink, burn, or destroy" the German Empire's only gunboat on the lake, the Hermann von Wissmann, commanded by a Captain Berndt. Rhoades's crew found the Hermann von Wissmann in a bay near "Sphinxhaven", in German East African territorial waters. Gwendolen disabled the German boat with a single cannon shot from a range of about 1,800 metres 2,000 yd. This very brief gunboat conflict was hailed by The Times in England as the British Empire's first naval victory of World War I. until that time, the lakeshore that is now in Tanzania had been a part of German East Africa.citation needed

Borders

The largest portion of the area of the lake is in Malawi. However, about a quarter of the area belongs to Mozambique. This area includes the waters surrounding the Malawian islets of Likoma and Chizumulu, which are this lake's only two inhabited islets. The islet of Likoma is dominated by a large stone and brick Anglican cathedral that was built by missionaries in the early 20th century. A notable feature of both islets is their significant number of baobab trees. The islets support a population of several thousand people, who in addition to being fishermen, grow plants such as cassavas, bananas, and mangoes for food.

LAKE KIVU

The lake covers a total surface area of some 2,700 km2 and stands at a height of 1,460 metres 4,790 ft above sea level. Some 1 370 km2 or 58% of the lake's waters lie within DRC borders. The lake bed sits upon a rift valley that is slowly being pulled apart, causing volcanic activity in the area, and making it particularly deep: its maximum depth of 480 m (1,575 ft) is ranked eighteenth in the world.

The world's tenth-largest inland island, Idjwi, lies in Lake Kivu, as does the tiny island of Tshegera, which also lies within the boundaries of Virunga National Park; while settlements on its shore include Bukavu, Kabare, Kalehe, Sake and Goma in Congo and Gisenyi, Kibuye and Cyangugu in Rwanda.

Native fish include species of Barbus, Clarias, and Haplochromis, as well as Nile Tilapia. Limnothrissa miodon, one of two species known as the Tanganyika sardine, was introduced in 1959 and formed the basis of a new pelagic zone fishery. In the early 1990s, the number of fishers on the lake was 6,563, of which 3,027 were associated with the pelagic fishery and 3,536 with the traditional fishery. Widespread armed conflict in the surrounding region from the mid-1990s resulted in a decline in the fisheries harvest.

Chemistry

Lake Kivu is a fresh water lake and, along with Cameroonian Lake Nyos and Lake Monoun, is one of three that experience limnic eruptions. Analysis of Lake Kivu's geological history indicates sporadic massive biological extinction on millennial timescales. The trigger for lake overturns in Lake Kivu's case is unknown but volcanic activity is suspected. The gaseous chemical composition of exploding lakes is unique to each lake; in Lake Kivu's case, methane and carbon dioxide due to lake water interaction with a volcano. The amount of methane is estimated to be 65 cubic kilometers (if burnt over one year, it would give an average power of about 100 gigawatts for the whole period). There is also an estimated 256 cubic kilometers of carbon dioxide. The methane is reported to be produced by microbial reduction of the volcanic CO2. The risk from a possible Lake Kivu overturn is catastrophic, dwarfing other documented lake overturns at Lakes Nyos and Monoun, because of the approximately two million people living in the lake basin.

Cores from the Bukavu Bay area of the lake reveal that the bottom has layered deposits of the rare mineral monohydrocalcite interlain with diatoms, on top of sapropelic sediments with high pyrite content. These are found at three different intervals. The sapropelic layers are believed to be related to hydrothermal discharge and the diatoms to a bloom which reduced the carbon dioxide levels low enough to precipitiate monohydrocalcite.

Scientists hypothesize that sufficient volcanic interaction with the lake's bottom water that has high gas concentrations would heat water, force the methane out of the water, spark a methane explosion, and trigger a nearly simultaneous release of carbon dioxide. The carbon dioxide would then suffocate large numbers of people in the lake basin as the gases roll off the lake surface. It is also possible that the lake could spawn lake tsunamis as gas explodes out of it.

The risk posed by Lake Kivu began to be understood during the analysis of more recent events at Lake Nyos. Lake Kivu's methane was originally thought to be merely a cheap natural resource for export, and for the generation of cheap power. Once the mechanisms that caused lake overturns began to be understood, so did awareness of the risk the lake posed to the local population.

An experimental vent pipe was installed at Lake Nyos in 2001 to remove gas from the deep water, but such a solution for the much larger Lake Kivu would be considerably more expensive. No plan has been initiated to reduce the risk posed by Lake Kivu.[dubious – discuss] the approximately 500 million tonnes of carbon dioxide in the lake is a little under 2 percent of the amount released annually by human fossil fuel burning. Therefore the process of releasing it could potentially have costs beyond building and operating the system.

LAKE VICTORIA

Lake Victoria during its geological history, went through changes ranging from its present shallow depression, through to what may have been a series of much smaller lakes. Geological cores taken from its bottom show Lake Victoria has dried up completely at least three times since it formed. These drying cycles are probably related to past ice ages, which were times when precipitation declined globally. Lake Victoria last dried out 17,300 years ago, and it refilled beginning about 14,700 years ago. Geologically, Lake Victoria is relatively young – about 400,000 years old – and it formed when westward-flowing rivers were dammed by an upthrown crustal block.

This geological history probably contributed to the dramatic cichlid speciation that characterises its ecology, as well as that of other African Great Lakes, although some researchers dispute this, arguing while Lake Victoria was at its lowest between 18,000 and 14,000 years ago, and it dried out at least once during that time, there is no evidence of remnant ponds or marshes persisting within the desiccated basin. If such features existed, then they would have been small, shallow, turbid, and/or saline, and therefore markedly different from the lake to which today's species are adapted.

The shallowness of Lake Victoria, its limited river inflow, and its large surface area compared to its volume make it vulnerable to the effects of climate changes.

Hydrology and limnology

Lake Victoria receives 80% of its water from direct precipitation. Average evaporation on the lake is between 2.0 and 2.2 metres 6.6 and 7.2 ft per year, almost double the precipitation of riparian areas. In the Kenya Sector, the main influent rivers are the Sio, Nzoia, Yala, Nyando, Sondu Miriu, Mogusi and the Migori. Combined, these rivers contribute far more water to the lake than does the largest single inflowing river, the Kagera River, which enters the lake from the west.

Lake Victoria and the Great Rift Valley

The only outflow from Lake Victoria is the Nile River which exits the lake near Jinja, Uganda. In terms of contributed water, this makes Lake Victoria the principal source of the longest branch of the Nile, however, the most distal source of the Nile Basin, and therefore the ultimate source of the Nile, is more often considered to be one of the tributary rivers of the Kagera River the exact tributary remains undetermined, and which originates in either Rwanda or Burundi. The uppermost section of the Nile is generally known as the Victoria Nile until it reaches Lake Albert. Although it is a part of the same river system known as the White Nile and is occasionally referred to as such, strictly speaking this name does not apply until after the river crosses the Uganda border into South Sudan to the north.

The lake exhibits eutrophic conditions. In 1990–1991, oxygen concentrations in the mixed layer were higher than in 1960–1961, with nearly continuous oxygen supersaturation in surface waters. Oxygen concentrations in hypolimnetic waters i.e. the layer of water that lies below the thermocline, is noncirculating, and remains perpetually cold were lower in 1990–1991 for a longer period than in 1960–1961, with values of less than 1 mg per litre < 0.4 gr/cu ft occurring in water as shallow as 40 metres compared with a shallowest occurrence of greater than 50 metres in 1961. The changes in oxygenation are considered consistent with measurements of higher algal biomass and productivity. These changes have arisen for multiple reasons: successive burning within its basin, soot and ash from which has been deposited over the lake's wide area; from increased nutrient inflows via rivers, and from increased pollution associated with settlement along its shores.

The extinction of cichlids in the genus Haplochromis has also been blamed on the lake's eutrophication. The fertility of tropical waters depends on the rate at which nutrients can be brought into solution. The influent rivers of Lake Victoria provide few nutrients to the lake in relation to its size. Because of this, most of Lake Victoria's nutrients are thought to be locked up in lake-bottom deposits. By itself, this vegetative matter decays slowly. Animal flesh decays considerably faster, however, so the fertility of the lake is dependent on the rate at which these nutrients can be taken up by fish and other organisms. There is little doubt that Haplochromis played an important role in returning detritus and plankton back into solution. With some 80% of Haplochromis species feeding off detritus, and equally capable of feeding off one another, they represented a tight, internal recycling system, moving nutrients and biomass both vertically and horizontally through the water column, and even out of the lake via predation by humans and terrestrial animals. The removal of Haplochromis, however, may have contributed to the increasing frequency of algal blooms, which may in turn be responsible for mass fish kills.

RAINY LAKE

Earliest documentation of the lake's name is "Tekamamiwen" shown as "Lac de Tecamamiouen" on the Ochagach map c. 1728, as "Lac Tacamamioüer" on the 1739 de l'Isle map, as "Lake Tecamaniouen" on the 1757 Mitchell Map and as "Lake Tekamamigovouen" on the Thomas Jefferys' 1762 Map of Canada. Pierre Gaultier de Varennes, sieur de La Vérendrye cites that the name was a corruption from the Cree "taki-kimiwen", meaning "It always is raining", referring to the Rainy River, though the language does not quite support that claim. He also cites that the lake was also known as "Ouichichick" Ojibwe word Gojijiing or Cree Kocicīhk, both meaning "at the place of inlets". Early documents lists the portion of Rainy Lake east of the Brule Narrows as "Cristinaux Cree Lake"or as "Little Lake."
Recreation on Rainy Lake
Voyageurs National Park
On Rainy Lake, Voyageurs National Park maintains an extensive network of over boat-in camping sites, hiking trails, and designated snowmobile trails for winter use.
Fishing
The lake is popular for sport and recreational fishing for species such as Walleye, Northern pike, Muskellunge, Largemouth and Smallmouth bass, which are all considered excellent freshwater sportfish. Rainy Lake is home to the annual Canadian Bass Championship, which has occurred every summer since 1996. The lake is dotted with many small islands on both the Canadian and American sides; they are the sites of numerous fishing cabins, small fishing resorts, and vacation homes. Tourism is an important part of the local economy.
Governance
The level of Rainy Lake is controlled at the hydro-electric power houses of the international dam that spans the Rainy River between International Falls and Fort Frances, at two water-control dams located at Kettle Falls where the outflow from Namakan Lake enters Rainy Lake, and at the Sturgeon Falls Generating Station located on the Seine River. The companies that own and operate the powerhouses Boise Inc. on the U.S. side and H2O Power Limited Partnership on the Canadian side are responsible for maintaining lake level and flow changes from the dams within normal ranges, subject to regulatory oversight by the International Rainy Lake Board of Control IRLBC. The IRLBC is a board of the International Joint Commission IJC, which is a bi-national organization created out of the International Boundary Waters Treaty of 1909 for the purposes of handling boundary water issues between the United States and Canada.

LAKE ONTARIO

Geography

Lake Ontario Basin

View from Fort Ontario, Oswego, New York

Historic cannon at Fort Niagara; Toronto across the lake

Lake Ontario is the easternmost of the Great Lakes and the smallest in surface area (7,340 sq mi, 18,960 km2), although it exceeds Lake Erie in volume (393 cu mi, 1,639 km3). It is the 14th largest lake in the world. When its islands are included, the lake has a shoreline that is 712 miles (1,146 km) long. As the last lake in the Great Lakes' hydrologic chain, Lake Ontario has the lowest mean surface elevation of the lakes at 243 feet (74 m) above sea level; 326 feet (99 m) lower than its neighbor upstream. Its maximum length is 193 statute miles (311 kilometres; 168 nautical miles) and its maximum width is 53 statute miles (85 km; 46 nmi). The lake's average depth is 47 fathoms 1 foot (283 ft; 86 m), with a maximum depth of 133 fathoms 4 feet (802 ft; 244 m). The lake's primary source is the Niagara River, draining Lake Erie, with the St. Lawrence River serving as the outlet. The drainage basin covers 24,720 square miles (64,030 km2). with all the Great Lakes, water levels change both within the year (owing to seasonal changes in water input) and among years (owing to longer term trends in precipitation). These water level fluctuations are an integral part of lake ecology, and produce and maintain extensive wetlands.TheA lake also has an important freshwater fishery, although it has been negatively affected by factors including over-fishing, water pollution and invasive species.

Baymouth bars built by prevailing winds and currents have created a significant number of lagoons and sheltered harbors, mostly (but not limited to) Prince Edward County, Ontario and the easternmost shores. Perhaps the best-known example is Toronto Bay, chosen as the site of the Upper Canada (Ontario) capital for its strategic harbour. Other prominent examples include Hamilton Harbour, Irondequoit Bay, Presqu'ile Bay, and Sodus Bay. The bars themselves are the sites of long beaches, such as Sandbanks Provincial Park and Sandy Island Beach State Park. These sand bars are often associated with large wetlands, which support large numbers of plant and animal species, as well as providing important rest areas for migratory birds. Presqu'ile, on the north shore of Lake Ontario, is particularly significant in this regard. One unique feature of the lake is the Z-shaped Bay of Quinte which separates Prince Edward County from the Ontario mainland, save for a 2-mile (3.2 km) isthmus near Trenton; this feature also supports many wetlands and aquatic plants, as well as associated fisheries.

Major rivers draining into Lake Ontario include the Niagara River; Don River; Humber River; Trent River; the Cataraqui River; the Genesee River; the Oswego River; the Black River; and the Salmon River.

Geology

The lake basin was carved out of soft, weak Silurian-age rocks by the Wisconsin ice sheet during the last ice age. The action of the ice occurred along the pre-glacial Ontarian River valley which had approximately the same orientation as today's basin. Material that was pushed southward by the ice sheet left landforms such as drumlins, kames, and moraines, both on the modern land surface and the lake bottom, reorganizing the region's entire drainage system. As the ice sheet retreated toward the north, it still dammed the St. Lawrence valley outlet, so that the lake surface was at a higher level. This stage is known as Lake Iroquois. During that time the lake drained through present-day Syracuse, New York into the Mohawk River, thence to the Hudson River and the Atlantic. The shoreline created during this stage can be easily recognized by the (now dry) beaches and wave-cut hills 10 to 25 miles (15 to 40 km) from the present shoreline.

When the ice finally receded from the St. Lawrence valley, the outlet was below sea level, and for a short time the lake became a bay of the Atlantic Ocean, in association with the Champlain Sea. Gradually the land rebounded from the release of the weight of about 6,500 feet (2,000 m) of ice that had been stacked on it. It is still rebounding about 12 inches (30 cm) per century in the St. Lawrence area. Since the ice receded from the area last, the most rapid rebound still occurs there. This means that the lake bed is gradually tilting southward, inundating the south shore and turning river valleys into bays. Both north and south shores experience shoreline erosion, but the tilting amplifies this effect on the south shore, causing loss to property owners.A

LAKE ERIE

Geographic features;

See also: Lake Erie Basin

(Lake Erie 42.2° N, 81.2) has a mean elevation of 571 feet above sea level. It has a surface area of 9,910 square miles 25,667 km with a length of 241 statute miles 388 km; 209 nmi and breadth of 57 statute miles  92 km; 50 nmi at its widest points.

It is the shallowest of the Great Lakes with an average depth of 10 fathoms 3 feet 62 ft; 19 m and a maximum depth of 35 fathoms 210 ft; 64 m For comparison, Lake Superior has an average depth of 80 fathoms 3 feet 483 ft; 147 m, a volume of 2,900 cubic miles 12,100 km3 and shoreline of 2,726 statute miles 4,385 km. Because it is the shallowest, it is also the warmest of the Great Lakes, and in 1999 this almost became a problem for two nuclear power plants which require cool lake water to keep their reactors cool. The warm summer of 1999 caused lake temperatures to come close to the 85 °F (29 °C) limit necessary to keep the plants cool. Also because of its shallowness, and in spite of being the warmest lake in the summer, it is also the first to freeze in the winter. The shallowest section of Lake Erie is the western basin where depths average only 25 to 30 feet 7.6 to 9.1 m; as a result, "the slightest breeze can kick up lively waves," according to a New York Times reporter in 2004. The "waves build very quickly", according to other accounts. Sometimes fierce waves springing up unexpectedly have led to dramatic rescues; in one instance, a Cleveland resident trying to measure the dock near his house became trapped but was rescued by a fire department diver from Avon Lake, Ohio:

In a tug of war against the waves, the two were finally hauled out by rope. After being trapped for an hour-and-a-half, Baker was back on dry land, exhausted and battered but alive.

—Tatiana Morales, CBS News, 2004

The Niagara River empties Lake Erie into Lake Ontario. This water has just passed over Niagara Falls.

This area is also known as the "thunderstorm capital of Canada" with "breathtaking" lightning displays. Lake Erie is primarily fed by the Detroit River from Lake Huron and Lake St. Clair and drains via the Niagara River and Niagara Falls into Lake Ontario. Navigation downstream is provided by the Welland Canal, part of the Saint Lawrence Seaway. Other major contributors to Lake Erie include the Grand River, the Huron River, the Maumee River, the Sandusky River, the Buffalo River, and the Cuyahoga River. The drainage basin covers 30,140 square miles 78,000 km2.

Point Pelee National Park, the southernmost point of the Canadian mainland, is located on a peninsula extending into the lake. Several islands are found in the western end of the lake; these belong to Ohio except for Pelee Island and eight neighboring islands, which are part of Ontario.

Major cities along the Lake Erie include Buffalo, New York; Erie, Pennsylvania; Toledo, Ohio; Port Stanley, Ontario; Monroe, Michigan; Sandusky, Ohio; and Cleveland, Ohio.

Partial map of the Lake Erie Islands

Islands

See also: Lake Erie Islands

Islands tend to be located in the western side of the lake and total 31 in number (13 in Canada, 18 in the U.S.). The island-village of Put-in-Bay on South Bass Island attracts young crowds who sometimes wear "red bucket hats" and are prone to "break off cartwheels in the park" and general merriment. Kelleys Island was depicted by the Chicago Tribune as having charms that were "more subtle" than Put-in-Bay, and offers amenities such as beach lounging, hiking, biking, and "marveling at deep glacial grooves left in limestone." Pelee Island is the largest of Erie's islands, accessible by ferry from Leamington, Ontario and Sandusky, Ohio. The island has a "fragile and unique ecosystem" with plants rarely found in Canada, such as wild hyacinth, yellow horse gentian (Triosteum angustifolium), and prickly pear cactus, as well as two endangered snakes, the blue racer and the Lake Erie water snake. Songbirds migrate to Pelee in spring, and monarch butterflies stop over during the fall.

Water levels

Lake Erie has a lake retention time of 2.6 years,the shortest of all the Great Lakes. This means that the lake water is renewed from upstream sources every three years. The lake's surface area is 9,910 square miles (25,667 km2). Lake Erie's water level fluctuates with the seasons as in the other Great Lakes. Generally, the lowest levels are in January and February, and the highest in June or July, although there have been exceptions. The average yearly level varies depending on long-term precipitation. Short-term level changes are often caused by seiches that are particularly high when southwesterly winds blow across the length of the lake during storms. These cause water to pile up at the eastern end of the lake. Storm-driven seiches can cause damage onshore. During one storm in November 2003, the water level at Buffalo rose by 7 feet (2.1 m) with waves of 10–15 feet (3–4.5 m) for a rise of 22 feet (6.7 m). Meanwhile, at the western end of the lake, Toledo experienced a similar drop in water level. Lake water is used for drinking purposes.

Historic High Water. The lake fluctuates from month to month with the highest lake levels in October and November. The normal high-water mark is 2.00 feet (0.61 m) above datum (569.2 ft or 173.5 m). In the summer of 1986, Lake Erie reached its highest level at 5.08 feet (1.55 m) above datum.[27] The high water records were set from 1986 (April) through January 1987. Levels ranged from 4.33 to 5.08 feet (1.32–1.55 m) above Chart Datum.

Historic Low Water. Lake Erie experiences its lowest levels in the winter. The normal low-water mark is 1.50 feet (0.46 m) below datum (569.2 ft or 173.5 m). In the winter of 1934, Lake Erie reached its lowest level at 1.50 feet (0.46 m) below datum. Monthly low water records were set from July 1934 through June 1935. During this twelve-month period water levels ranged from 1.50 feet (0.46 m) to the Chart Datum.