|• location||Loma Mountains, Guinea Highlands, Sierra Leone, West Africa|
The Rokel River (also Seli River; previously Pamoronkoh River) is the largest river in the Republic of Sierra Leone in West Africa. The river basin measures 10,622 square kilometres (4,101 sq mi) in size, with the drainage divided by the Gbengbe and Kabala hills and the Sula Mountains. The estuary which extends over an area of 2,950 square kilometres (1,140 sq mi) became a Ramsar wetland site of importance in 1999.
The Rokel rises in the 900 metres (3,000 ft) high interior plateau of the Loma Mountains, in the Guinea Highlands of north central Sierra Leone, flows southwest about[ vague ]240 miles (390 km) through hill ranges and, together with a smaller, parallel stream called Port Loko Creek, feeds into the Rokel estuary before entering the Atlantic Ocean. The estuary, after it joins the Bankasoka River, is also called the Sierra Leone River, is 25 mi (40 km) in length and has a width of 4–10 miles (6.4–16.1 km). Freetown and Pepel are the two ports located on the shores of the estuary. As the estuary widens and joins the Atlantic its width is about 11 km (6.8 mi). The southern shore is the deepest and forms a natural harbour, which is reported to be the third largest in the world.
Mangrove swamps and the mud flats are the dominant ecosystem (accounting for 19% of the mangrove forest in the country) 10,622 square kilometres (4,101 sq mi) in size, with the drainage divided by the Gbengbe and Kabala hills and the Sula Mountains. The Rokel drops 15 metres (49 ft) at the Bumbuna waterfalls. Mangrove species recorded are Rhizophora , Avicennia , Laguncularia , and Conocarpus , which cover an area of 34.23 hectares (84.6 acres). Sierra Leone's capital city of Freetown lies at the entrance to the Sierra Leone River, about 25 miles (40 km) from the port of Pepel.noted around the river's ria. The river basin measures
Rokel River and its tributaries are defined as the "Rokel River Group" for geological study. The geological formation in this group is reported to be of the Tabe formation with glacial sediments dominating its eastern edge and are exposed along the river in some stretches; the geological formation noted in the river is granite rocks. The formation is broadly categorized as folded sedimentary rocks. It is also reported that its orogeny belongs to the Pan African thermo-tectonic age of about 550 Ma. 15 metres (49 ft) providing for building a hydroelectric project.Geologically it is a tectonically controlled basin with formations of Precambrian, Infra-Cambrian and Pleistocene age. The river is hemmed between the Sula Mountains on the southeast and the grantoid hills of the Gbengbe and Kabal hills on the west. The notable cascade in the river is known as the Bumbuna water falls where the river drops by
John MacCormac, an Irish businessman, settled on Timbo Island in 1816 and started exporting African Oak from the Rokel River. 2,950 square kilometres (1,140 sq mi), was listed as Ramsar site of wetland importance in 1999. The site is bounded by Cape Point on the western side of the Freetown, by the Bunce River on one of its banks, and the Tagrin Point where areas of the Rokel joins at the southern end of its mouth.The trade was quite substantial for a while but eventually went into decline. Iron ore and alluvial gold mining began in the late 1920s and early 1930s, while the Bumbuna Falls hydroelectric project is underway. The Yalunka people established their capital, Falaba, near the source of the Rokel. The estuary, which extends over an area of
The Rokel river flow has been measured at three gauge stations. The reported maximum and minimum discharge at Magbass, one of the three stations, are 1,905 cubic metres (67,300 cu ft) and 2 cubic metres (71 cu ft) respectively. There are many projects developed in the river basin which derive their water supply requirements from this river.
The iron ore mining at Marampa is dependent on pumped water supply from the river. A Rokel River Water Rights Agreement (Ratification) Act was signed with the developers of the mines; the mines are in operation since 1933 to 1975 by Sierra Leone Development Company (DELCO) and Astro Minerals from 1983. The water agreement provides “exclusive and preferential rights to the use of the Rokel waters by special agreement” for a period of 89 years from 1 January 1938. The environmental impacts on the downstream users and disposal of tailings from the mining operations have not been addressed. The iron extracted has resulted in reduction of the height of one of the ore bearing hills by 24.4 metres (80 ft).
Gold mining in the Sula Mountains and in the Rokel river sediments was an extensive operation undertaken since 1929 in the river and its tributaries after gold was found in the mountains. Steam sediment studies were carried out for assessing the mineral concentration of arsenic. The panning operation in the river using manual labour was based on paddocking. This alluvial gold mining operation has been described as environmentally destructive as forest denudation for the purpose of mining caused extensive erosion of the hills and consequent sedimentation of the river and its tributaries.
The Bumbuna Dam has been developed on the river by building a 93 metres (305 ft) high dam in the narrow reach of the river, which has created a lake that stretches 30 kilometres (19 mi) upstream. The Magbass Irrigation Project was implemented downstream of the dam. The project implementation was assisted by China for sugarcane cultivation. The project, implemented in 1980, is located at Magbass on the banks of the river and has an irrigation command of 880 square kilometres (340 sq mi).
The flora in the estuary consists of mangrove forest. The avifauna in the area consists of 10,000 birds of 36 species (1995 record). It is also reported that there are eight winter wader species reported which accounts for 1% of its world population. The eight species of palaearctic migrant waders recorded are:
Liberia is a sub-Saharan nation in West Africa located at 6 °N, 9 °W. It borders the north Atlantic Ocean to the southwest and three other African nations on the other three sides, Sierra Leone to the northwest, Guinea to the northeast and Ivory Coast to the east.
Sierra Leone, officially the Republic of Sierra Leone, informally Salone, is a country on the southwest coast of West Africa. It is bordered by Liberia to the southeast and Guinea to the northeast. Sierra Leone has a tropical climate with a diverse environment ranging from savanna to rainforests, a total area of 71,740 km2 (27,699 sq mi) and a population of 7,092,113 as of the 2015 census. The capital and largest city is Freetown. The country is divided into five administrative regions which are subdivided into sixteen districts. Sierra Leone is a constitutional republic with a unicameral parliament and a directly elected president. Sierra Leone is a Muslim-majority country at approximately 78%, though with an influential Christian minority at about 21%. Muslims and Christians in Sierra Leone are extremely tolerant of each other, and all the major Muslim and Christian holidays are officially national holidays in the country.
Sierra Leone is located on the west coast of Africa, between the 7th and 10th parallels north of the equator. Sierra Leone is bordered by Guinea to the north and northeast, Liberia to the south and southeast, and the Atlantic Ocean to the west.
The economy of Sierra Leone is that of a least developed country with a gross domestic product (GDP) of approximately US$1.9 billion in 2009. Since the end of the Sierra Leone Civil War in 2002 the economy is gradually recovering with a GDP growth rate between 4 and 7%. In 2008 its GDP in PPP ranked between 147th and 153rd (CIA) largest in the world.
There are a number of systems of transport in Sierra Leone, a country in West Africa, which possess road, rail, air and water infrastructure, including a network of highways and several airports.
Kazanka is a river in the Russian Federation, a left tributary of the Volga. The Kazanka begins near the village of Bimeri in Arsk District and flows into the Kuybyshev Reservoir in Kazan, near the Kazan Kremlin. Other towns on the Kazanka are Arsk and historical Iske Kazan. The river is 142 kilometres (88 mi) long, and has a drainage basin of 2,600 square kilometres (1,000 sq mi). The main tributaries are the Iya, Kismes, Shimyakovka and Sula. Historically, the Bulak river flowed into Kazanka until it was separated by a dam in 1957. The maximum river discharge is 299 cubic metres per second (10,600 cu ft/s), and the minimal mineralization is 400–1000 mg/l. In Tatarstan, Kazanka has a status of a natural monument.
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Tonkolili District is a district in the Northern Province of Sierra Leone. Its capital and largest city is Magburaka. The other major towns include Masingbi, Yele, Mile 91, Bumbuna, Yonibana, Matotoka. Mathora, Magbass and Masanga. Tonkolili District is home to the largest sugar factory in Sierra Leone, and one of the largest sugar factories in West Africa, that is located in the town of Magbass. Tonkolili District had a population of 530,776. The district occupies a total area of 7,003 km2 (2,704 sq mi) and comprises eleven chiefdoms.
The Maranhão mangroves is a mangrove ecoregion of northern Brazil. It supports half of the shorebird population of the country. The combination of flat land, heavy rainfall and high tides causes the mangroves to extend up to 40 kilometres (25 mi) inland, where they are interspersed with other rainforest species.
The Sierra Leone River is a river estuary on the Atlantic Ocean in Western Sierra Leone. It is formed by the Bankasoka River and Rokel River and is between 4 and 10 miles wide (6–16 km) and 25 miles (40 km) long. It holds the major ports of Queen Elizabeth II Quay and Pepel. The estuary is also important for shipping. It is the largest natural harbour in the African continent. Several islands, including Tasso Island, Tombo Island, and the historically important Bunce Island, are located in the estuary.
Railway stations in Sierra Leone include:
Bumbuna is a town in the central of Tonkolili District in the Northern Province of Sierra Leone. The town lies about 30 miles from the district capital of Magburaka and approximately 124 miles northeast of Freetown.
There are 84 kilometres of railway in Sierra Leone, all of which is private and of a narrow gauge, 1,067 mm.
The Wouri estuary, or Cameroon estuary is a large tidal estuary in Cameroon where several rivers come together, emptying into the Bight of Biafra. Douala, the largest city in Cameroon, is at the mouth of the Wouri River where it enters the estuary. The estuary contains extensive mangrove forests, which are being damaged by pollution and population pressures.
Lake Sonfon, also known as Lake Confon, is a fresh water mountain lake in Diang, Sierra Leone of religious and cultural significance. The nearest towns are Kabala that is 60 km to the north and Benugu that is 40 km to the south. It is located in the hills of the Sula Mountains at an altitude of 549 m (1,801 ft) above sea level. Sonfon drains from its southern end, which forms the start of the Pampana River, and is fed by seven small streams with its water level varying considerably during the year. The Lake has a maximum depth of 8 m (26 ft) and with an area of 8.2 km2 (3.2 sq mi) is Sierra Leone's largest inland lake.
The Bumbuna Dam is a concrete-face rock-fill dam on the Seli River near Bumbuna in Tonkolili District, Sierra Leone, and 350 kilometres (220 mi) from the capital of Freetown, the main consumer. The country's first hydroelectric dam, it supports a 50-megawatt (67,000 hp) power station.
The Bankasoka River is a river in Sierra Leone.
The geology of Sierra Leone is primarily very ancient Precambrian Archean and Proterozoic crystalline igneous and metamorphic basement rock, in many cases more than 2.5 billion years old. Throughout Earth history, Sierra Leone was impacted by major tectonic and climatic events, such as the Leonean, Liberian and Pan-African orogeny mountain building events, the Neoproterozoic Snowball Earth and millions of years of weathering, which has produced thick layers of regolith across much of the country's surface.
The Lion Mountains are a mountain range in Sierra Leone. The range stretches 30 kilometres (19 mi) on the Freetown Peninsula by the Atlantic Ocean, southeast of the capital Freetown. The mountains are part of the Western Area Forest Reserve, a nature reserve with a hunting ban, established in 1916. The highest point is Picket Hill at 888 metres (2,913 ft).
Bumbuna II Hydroelectric Power Station is a planned 143 megawatts (192,000 hp) hydroelectric power station in Sierra Leone. The power plant is under development by a consortium of renewable energy IPPs and investors, led by Joule Africa Limited. The energy generated here will be sold to Electricity Distribution and Supply Authority (EDSA), the electricity utility company of Sierra Leone, under a 25-year power purchase agreement.