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62-431: The city features a resort on the shores of Lake Kivu , with several hotels and three sandy beaches. The area is also known for water sports . The northern shore of the lake on which Goma and Gisenyi lie is a flat plain featuring lava formations from the eruptions of nearby Mount Nyiragongo . In contrast to Goma, Gisenyi escaped the lava flows of both the 1977 and the 2002 eruptions, which destroyed between 15 and 40% of

124-421: A limnic eruption occurred at Lake Nyos, triggering the sudden release of about 100,000–300,000 tons (some sources state as much as 1.6 million tonnes) of CO 2 . This gas cloud rose at nearly 100 kilometres per hour (62 mph) and spilled over the northern lip of the lake into a valley running roughly east–west from Cha to Subum. It then rushed down two valleys branching off to the north, displacing all of

186-637: A depth of 300 metres (1,000 ft). Until 2004, extraction of the gas was done on a small scale, with the extracted gas being used to run boilers at the Bralirwa brewery in Gisenyi . As far as large-scale exploitation of this resource is concerned, the Rwandan government has negotiated with a number of parties to produce methane from the lake. In 2011 ContourGlobal , a UK-based energy company focused on emerging markets, secured project financing to initiate

248-577: A further 25 MW and are currently negotiating a PPA with the Rwanda Electricity Group which may see 8 MW of power despatched to the Grid six months after the PPA has been signed. This concession is on the site of the original pilot plant known as KP1. In addition to managing gas extraction, KivuWatt will also manage the electrical generation plants and on-sell the electrical power to

310-470: A lake much older than the commonly cited 15,000 years. Lake Kivu is the home of four species of freshwater crab , including two non-endemics ( Potamonautes lirrangensis and P. mutandensis ) and two endemics ( P. bourgaultae and P. idjwiensis ). Among Rift Valley lakes , Lake Tanganyika and Lake Victoria are the only other with endemic freshwater crabs. In 2018, over 400 cases of potential illegal fishing were recorded on Lake Kivu. According to

372-428: A large cloud of CO 2 , which suffocated 1,746 people and 3,500 livestock in nearby towns and villages, the most notable one being Chah , which was abandoned after the incident. The limnic eruption not only devastated human and livestock populations but also had a profound impact on the diverse aquatic life, including tilapia, crabs, snails, and frogs, leading to a significant loss of biodiversity in and around

434-413: A large-scale methane extraction project. The project is run through a local Rwandan entity called KivuWatt , using an offshore barge platform to extract, separate, and clean the gasses obtained from the lake bed before pumping purified methane via an underwater pipeline to on-shore gas engines . Stage one of the project, powering three " gensets " along the lake shore and supplying 26 MW of electricity to

496-406: A modern combined-cycle generating plant , that amount of methane would generate around 40,000 megawatts for an entire year, which is equivalent to the power output of six Grand Coulee Dams operating at peak springtime power. The lake also holds an estimated 256 cubic kilometres (61 cu mi) of carbon dioxide which, if released in an eruption event, could suffocate all of the inhabitants of

558-450: A permanent installation at Nyos. In 2011, two additional pipes were installed by Michel Halbwachs and his French-Cameroonian team to assure the complete degassing of Lake Nyos. Following the disaster, scientists investigated other African lakes to see if a similar phenomenon could happen elsewhere. Lake Kivu , 2,000 times larger than Lake Nyos, was also found to be supersaturated, and geologists found evidence for outgassing events around

620-426: A small earthquake, but as witnesses did not report feeling any tremors on the morning of the disaster, this hypothesis is unlikely. Whatever the cause, the event resulted in the rapid mixing of the supersaturated deep water with the upper layers of the lake, where the reduced pressure allowed the stored CO 2 to effervesce out of solution. It is believed that about 1.2 cubic kilometres (0.29 cu mi) of gas

682-448: A total surface area of some 2,700 km (1,040 sq mi), making it Africa's eighth largest lake. The surface of the lake sits at a height of 1,460 metres (4,790 ft) above sea level. This lake has a chance of suffering a limnic eruption every 1000 years. The lake has a maximum depth of 475 m (1,558 ft) and a mean depth of 220 m (722 ft), making it the world's twentieth deepest lake by maximum depth, and

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744-401: A wave of at least 25 metres (82 ft) that would scour the shore of one side. It is not known what triggered the catastrophic outgassing. Most geologists suspect a landslide, but some believe that a small volcanic eruption may have occurred on the bed of the lake. A third possibility is that cool rainwater falling on one side of the lake triggered the overturn. Others still believe there was

806-507: Is 0.71 g C m d (≈ 260 g C m a ). A study of evolutionary genetics showed that the cichlids from lakes in northern Virunga (e.g., Edward , George , Victoria ) would have evolved in a "proto-lake Kivu", much older than the intense volcanic activity (20,000-25,000 years ago) which cut the connection. The elevation of the mountains west of the lake (which is currently the Kahuzi-Biega National Park , one of

868-477: Is 1,800 m (5,900 ft) across and 208 m (682 ft) deep. The area has been volcanically active for millions of years—after South America and Africa were split apart by plate tectonics about 110 million years ago, West Africa also experienced rifting, although to a lesser degree. The rift is known as the Mbéré Rift Valley , and crustal extension has allowed magma to reach

930-572: Is one of three lakes in the world, along with Lake Nyos and Lake Monoun , that undergo limnic eruptions (where overturn of deepwater stratified layers releases dissolved carbon dioxide (CO 2 )). The lake's bottom also contains methane ( CH 4 ), meaning if a limnic eruption occurs, the lives of the two million people living nearby would be in danger. Lake Kivu is approximately 42 km (26 mi) long and 50 km (31 mi) at its widest. Its irregular shape makes measuring its precise surface area difficult; it has been estimated to cover

992-442: Is unknown, but volcanic activity and changes in climate are both suspected. The gaseous chemical composition of exploding lakes is unique to each lake. In Lake Kivu's case, it includes methane ( CH 4 ) and carbon dioxide (CO 2 ), as a result of lake water interaction with volcanic hot springs. The amount of methane contained at the bottom of the lake is estimated to be 65 cubic kilometres (16 cu mi). If burned in

1054-543: Is weakening. A geological tremor could cause this natural levee to give way, allowing water to rush into downstream villages all the way into Nigeria and allowing large amounts of carbon dioxide to escape. Lake Nyos lies within the Oku Volcanic Field , located near the northern boundary of the Cameroon Volcanic Line, a zone of volcanoes and other tectonic activity that extends southwest to

1116-662: The Rwandan genocide , the provisional government was based in the city. Gisenyi is the city where Laurent Nkunda — accused by the United Nations of having led an army that illegally recruited Congolese child soldiers — is being held, pending a determination on the DRC's extradition request. 1°42′S 29°15′E  /  1.700°S 29.250°E  / -1.700; 29.250 Gisenyi's campus of Kigali Independent University had an enrollment of 3413 students in

1178-695: The White Nile . About 13,000 to 9,000 years ago, volcanic activity blocked Lake Kivu's outlet to the watershed of the Nile. The volcanism produced mountains, including the Virungas , which rose between Lake Kivu and Lake Edward, to the north. Water from Lake Kivu was then forced south down the Ruzizi. This, in turn, raised the level of Lake Tanganyika , which overflowed down the Lukuga River . Lake Kivu

1240-504: The 2012-2013 academic year. The students were pursuing programs in the faculties of Economics and Business Studies, Social Sciences, and Law. University of tourism Technology and Business studies(UTB) previously called RTUC also has a Gisenyi campus. The town has about 30 public and private schools, including nursery, primary and secondary schools. Lake Kivu Lake Kivu is one of the African Great Lakes . It lies on

1302-639: The Animal Research and Technology Transfer at the Rwanda Agricultural Board, fish production in Kivu Lake dropped from 24 199 tonnes in the 2017–2018 fishing season to 16 194 tonnes in 2019–2020, which Deputy Director Solange Uwituze attributed to fishing methods that affect fish reproduction. Between May and July 2020, Rwanda Police Marine Unit operations reported 27 cases including 10 arrested poachers for illegal fishing on

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1364-547: The DRC, though Gisenyi is growing quickly. In 2011, a new multistorey shopping mall began construction over an old bus station. As of 2011, the main roads of the town are paved, and sidewalks are nearing completion for most of them as well. Gisenyi has two borders with Goma, the "Petite Barrière" and the "Grand Barrière". These names are a little misleading because the Petite Barrière is physically larger and features much higher traffic volumes. About 6,000 people crossed

1426-748: The Democratic Republic of the Congo, and Gisenyi , Kibuye , and Cyangugu in Rwanda. Lake Kivu is a fresh water lake and, along with Cameroonian Lake Nyos and Lake Monoun , is one of three that are known to undergo limnic eruptions (where overturn of deepwater stratified layers releases dissolved carbon dioxide). Around the lake, geologists found evidence of massive local extinctions about every thousand years, presumably caused by outgassing events. The trigger for lake overturns in Lake Kivu

1488-519: The Mt. Cameroon stratovolcano . The field consists of volcanic maars and basaltic scoria cones . Lake Nyos is located south of the dirt road from Wum , about 30 km (19 mi) to the west, to Nkambé in the east. Villages along the road in the vicinity of the lake include Cha , Nyos, Munji, Djingbe, and Subum. The lake is 50 km (31 mi) from the Nigerian border to the north, and lies on

1550-593: The Northwest Province and the Nigerian states of Taraba and Benue . The Cameroonian government, speaking through Gregory Tanyi-Leke of the Institute of Mining and Geological Research, acknowledges the weakening wall, but denies that it presents any immediate threat. A United Nations team led by Olaf Van Duin and Nisa Nurmohamed of the Netherlands ' Ministry of Transport and Public Works inspected

1612-522: The Petite Barrière daily during 2011. On the Gisenyi side, a large customs and immigration office was built with a large capacity, not yet matched by the Congolese facilities. Similarly, the road to the Petite Barrière is paved on the Rwandan side but not on the Congolese side. The Grande Barrière is paved on both sides and receives more of the heavy truck traffic. It is also a diplomatic border. During

1674-429: The Rwandan government under the terms of a long-term Power Purchase Agreement (PPA). This allows KivuWatt to control a vertically integrated energy offering from point of extraction to point of sale into the local grid. Extraction is said to be cost-effective and relatively simple because once the gas-rich water is pumped up, the dissolved gases (primarily carbon dioxide, hydrogen sulphide and methane) begin to bubble out as

1736-413: The air and suffocating 1,746 people within 25 kilometres (16 mi) of the lake, mostly rural villagers, as well as 3,500 livestock. The villages most affected were Cha, Nyos, and Subum. Scientists concluded from evidence that a 100 m (330 ft) fountain of water and foam formed at the surface of the lake. The huge amount of water rising suddenly caused much turbulence in the water, spawning

1798-683: The border between the Democratic Republic of the Congo and Rwanda , and is in the Albertine Rift , the western branch of the East African Rift . Lake Kivu empties into the Ruzizi River , which flows southwards into Lake Tanganyika . In 1894, German officer and colonial ruler Gustav Adolf von Götzen was the first European to discover the lake. In the past, Lake Kivu drained toward the north, contributing to

1860-559: The carbon dioxide levels low enough to precipitate monohydrocalcite. Scientists hypothesise 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, though the entry of 1 million cubic meters of lava during the January 2002 eruption had no effect. The carbon dioxide would then suffocate large numbers of people in

1922-497: The dam over three days in September 2005, and confirmed that the natural lip had weakened. Van Duin believed that the dam would breach within the next 10 to 20 years. One possible means of averting such a catastrophe would be to strengthen the lake wall, though this would take much time and money. Engineers could also introduce a channel to allow excess water to drain; if the water level were lowered by about 20 m (66 ft),

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1984-432: The earth. The fumes then dissolve in the natural springs encircling the lake, ultimately rising to the surface of the water and leaching into the lake. But with advanced in technology now there are machinery placed at the bottom of the lake to remove the gases, so as to make the inhabitants of the area free from danger. The lake waters are held in place by a natural dam composed of volcanic rock . At its narrowest point,

2046-435: The former. The centre of Gisenyi lies by foothills at the northeast corner of the lake, and low-density expansion is taking place in the hills, which are expected to be safe from future eruptions. Gisenyi is also home to Bralirwa , which manufactures various local beers — Primus , Mützig , Amstel and Guinness — as well as a range of Coca-Cola –branded soft drinks. Gisenyi is a small town compared to neighbouring Goma in

2108-479: The lake about every thousand years. The eruption of nearby Mount Nyiragongo in 2002 sent lava flowing into the lake, raising fears that a gas eruption could be triggered, but it was not, as the flow of lava stopped well before it got near the bottom layers of the lake, where the gas is maintained in solution by the water pressure. In 2005, Isaac Njilah, a geologist at the University of Yaoundé , suggested that

2170-478: The lake and leaks carbon dioxide (CO 2 ) into the water, changing it into carbonic acid . Nyos is one of only three lakes known to be saturated with carbon dioxide in this way, and therefore prone to limnic eruptions (the others being Lake Monoun , also in Cameroon, and Lake Kivu in the Democratic Republic of Congo and Rwanda ). In 1986, possibly as the result of a landslide, Lake Nyos suddenly emitted

2232-477: The lake basin area would be threatened. Cores from the Bukavu Bay area of the lake reveal that the bottom has layered deposits of the rare mineral monohydrocalcite interlaid 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

2294-478: 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

2356-401: The lake bed, charging the waters of Lake Nyos with an estimated 90 million tonnes of CO 2 . Lake Nyos is thermally stratified , with layers of warm, less dense water near the surface floating on the colder, denser water layers near the lake's bottom. Over long periods, carbon dioxide gas seeping into the cold water at the lake's bottom is dissolved in great amounts. Most of the time,

2418-467: The lake is stable and the CO 2 remains in solution in the lower layers. However, over time, the water becomes supersaturated , and if an event such as an earthquake or landslide occurs, large amounts of CO 2 may suddenly come out of solution. Although a sudden outgassing of CO 2 had occurred at Lake Monoun in 1984, a similar threat from Lake Nyos was not anticipated. However, on August 21, 1986,

2480-403: The lake suggested that outgassings could occur every 10–30 years, though a recent study shows that release of water from the lake, caused by erosion of the natural barrier that keeps in the lake's water, could in turn reduce pressure on the lake's carbon dioxide and cause a gas escape much sooner. Several researchers independently proposed the installation of degassing columns from rafts in

2542-617: The lake. Lake Nyos Lake Nyos ( / ˈ n iː oʊ s / NEE -ohs ) is a crater lake in the Northwest Region of Cameroon , located about 315 km (196 mi) northwest of Yaoundé , the capital. Nyos is a deep lake high on the flank of an inactive volcano in the Oku volcanic plain along the Cameroon line of volcanic activity. A volcanic dam impounds the lake waters. A pocket of magma lies beneath

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2604-406: The lake. Though not completely unprecedented, it was the first known large-scale asphyxiation caused by a natural event. To prevent a recurrence, a degassing tube that siphons water from the bottom layers to the top, allowing the carbon dioxide to leak in safe quantities, was installed in 2001. Two additional tubes were installed in 2011. Today, the lake also poses a threat because its natural wall

2666-593: The lake. The introduced species are three cichlids, the longfin tilapia ( Oreochromis macrochir ), blue-spotted tilapia ( O. leucostictus ) and redbreast tilapia ( Coptodon rendalli ), and a clupeid, the Lake Tanganyika sardine ( Limnothrissa miodon ) The sardine is referred to locally as ' Ndagala ' or 'Isambaza'. The exploitable stock of the Lake Tanganyika sardine was estimated at 2,000–4,000 metric tons (2,000–3,900 long tons) per year. It

2728-433: The lake. These use a pump to initially lift water from the bottom of the lake, heavily saturated with CO 2 , until the loss of pressure begins releasing the gas from the diphasic fluid, at which point the process becomes self-powered. In 1992 at Monoun, and in 1995 at Nyos, a French team directed by Michel Halbwachs demonstrated the feasibility of this approach. In 2001, the U.S. Office of Foreign Disaster Assistance funded

2790-435: The lakeshore. The water temperature is 24 °C (75 °F), and the pH is about 8.6. The methane is reported to be produced by microbial reduction of the volcanic CO 2 . A future overturn and gas release from the deep waters of Lake Kivu would result in catastrophe, dwarfing the historically documented lake overturns at the much smaller Lakes Nyos and Monoun. The lives of the approximately two million people who live in

2852-515: The lakeside human population but from an ecosystem standpoint, the introduction of planktivorous fish may result in important modifications of plankton community structure. Recent observations showed the disappearance during the last decades of a large grazer, Daphnia curvirostris , and the dominance of mesozooplankton community by three species of cyclopoid copepod: Thermocyclops consimilis , Mesocyclops aequatorialis and Tropocyclops confinis . The first comprehensive phytoplankton survey

2914-403: The largest reserves of eastern lowland (or Grauer's) gorillas in the world), combined with the elevation of the eastern rift (located in eastern Rwanda) would be responsible for the drainage of water from central Rwanda in the actual Lake Kivu. This concept of "proto-lake Kivu" was challenged by lack of consistent geological evidence, although the cichlid's molecular clock suggests the existence of

2976-554: The local grid, has since been completed. The next phase aims to deploy nine additional gensets at 75 MW to create a total capacity of 101 MW. In addition, Symbion Power Lake Kivu Limited was awarded a Concession and Power Producing Agreement (PPA) in 2015, to produce 50 MW of power using Lake Kivu methane. The project is expected to commence construction in 2019, with first power (Phase 1 - 14 MW) to be produced in first quarter 2020. The plant will be fully operational in 2021. Symbion Power has purchased another concession for

3038-518: The natural dam of volcanic rock that keeps in the lake's waters could collapse in the near future. Erosion has worn the dam away, causing holes and pockets to develop in the dam's upper layer, and water already passes through the lower section. Meanwhile, landslides have reduced dam strength on the outside. Seismic activity caused by the lake's volcanic foundation could thus cause the lake wall to give way, resulting in up to 50 million m (1.8 billion ft ) of water flooding downhill into areas of

3100-658: The northern slopes of the Massif du Mbam , drained by streams running north, then northwest, to the Katsina-Ala River in Nigeria which is part of the Benue River basin. Lake Nyos fills a roughly circular maar in the Oku Volcanic Field , an explosion crater caused when a lava flow interacted violently with groundwater . The maar is believed to have formed in an eruption a maximum of 12,000 years ago, and

3162-437: The pressure on the wall would be reduced significantly. Despite the risks from carbon dioxide and collapse of the lake's retaining wall, the area is being resettled. Settlers cite the wish to return to ancestral lands (although some are newcomers) and the great fertility of the land as reasons for their return. Nyos: Η τελετή της αθωότητας [Nyos: The ceremony of innocence] (2016), a novel by Basileios Drolias focusing on

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3224-560: The process of releasing it could potentially have costs beyond simply building and operating the system. This problem associated with the prevalence of methane is that of mazuku , the Swahili term "evil wind" for the outgassing of methane and carbon dioxide that kills people and animals, and can even kill vegetation when in high enough concentration. Lake Kivu has recently been found to contain approximately 55 billion m (1.9 trillion cu ft) of dissolved biogas at

3286-443: 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. The approximately 510 million metric tons (500 × 10 ^ long tons) of carbon dioxide in the lake is a little under 2 percent of the amount released annually by human fossil fuel burning. Therefore,

3348-431: The surface along a line extending through Cameroon. Mount Cameroon also lies on this fault line. Lake Nyos is surrounded by old lava flows and pyroclastic deposits. Although Nyos is situated within an extinct volcano, magma still exists beneath it. Approximately 80 kilometres (50 mi) directly below the lake resides a pool of magma , which releases carbon dioxide and other gases; the gases then travel upward through

3410-485: The thirteenth deepest by mean depth. Some 1,370 square kilometres (529 sq mi) or 58 percent 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. The world's tenth-largest island in a lake , Idjwi , lies in Lake Kivu. Settlements on the lake's shore include Bukavu , Kabare , Kalehe , Sake and Goma in

3472-414: The wall measures 40 metres (130 ft) high and 45 metres (148 ft) wide. Lake Nyos is one of only three lakes in the world known to be saturated with carbon dioxide—the others are Lake Monoun , also in Cameroon, and Lake Kivu on the border between the Democratic Republic of the Congo and Rwanda . A magma chamber beneath the region is an abundant source of carbon dioxide, which seeps up through

3534-459: The water pressure gets lower. This project is expected to increase Rwanda's energy generation capability by as much as 20 times, and will enable Rwanda to sell electricity to neighbouring African countries. The firm was awarded the 2011 Africa Power deal of the year for innovation in the financing arrangements it obtained from various sources for the KivuWatt project. The $ 200 million power plant

3596-493: Was introduced to Lake Kivu in late 1959 by the Belgian agronomist Alphonse Collart. An attempt to introduce the similar Lake Tanganyika sprat ( Stolothrissa tanganicae ) at the same time was unsuccessful. At present, Lake Kivu is the sole natural lake in which L. miodon , a sardine originally restricted to Lake Tanganyika, has been introduced initially to fill an empty niche. Prior to the introduction, no planktivorous fish

3658-706: Was operating at 26 MW in 2016. The fish fauna in Lake Kivu is relatively poor with 28 described species, including four introduced species . The natives are the Lake Rukwa minnow ( Raiamas moorii ), four species of barb ( ripon barbel , Barbus altianalis , East African red-finned barb , Enteromius apleurogramma , redspot barb , E. kerstenii and Pellegrin's barb , E. pellegrini ), an Amphilius catfish, two Clarias catfish ( C. liocephalus and C. gariepinus ), Nile tilapia ( Oreochromis niloticus ) and 15 endemic Haplochromis cichlids. Another c. 20 possibly undescribed species of cichlids are known from

3720-438: Was present in the pelagic waters of Lake Kivu. 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. The widespread armed conflict in the surrounding region from the mid-1990s resulted in a decline in the fisheries harvest. Following this introduction, the sardine has gained substantial economic and nutritional importance for

3782-501: Was released in 2006. With an annual average chlorophyll a in the mixed layer of 2.2 mg m and low nutrient levels in the euphotic zone, the lake is clearly oligotrophic . Diatoms are the dominant group in the lake, particularly during the dry season episodes of deep mixing. During the rainy season, the stratified water column, with high light and lower nutrient availability, favour dominance of cyanobacteria with high numbers of phototrophic picoplankton. The actual primary production

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3844-416: Was released. The normally blue waters of the lake turned a deep red after the outgassing, due to iron -rich water from the deep rising to the surface and being oxidised by the air. The level of the lake dropped by about a metre and trees near the lake were knocked down. The scale of the 1986 disaster led to much study on how a recurrence could be prevented. Estimates of the rate of carbon dioxide entering

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