Chilwa Lake
| Chilwa Lake | ||
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| Geographical location | Southeast Malawi | |
| Tributaries | Sambani, Phalombe | |
| Drain | no | |
| Islands | Chisi Island , Thongwe | |
| Places on the shore | Mecanhelas | |
| Data | ||
| Coordinates | 15 ° 18 ′ 0 ″ S , 35 ° 42 ′ 0 ″ E | |
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| Altitude above sea level | 627 m | |
| surface | approx. 600 km² | |
| Maximum depth | 2 m | |
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| Satellite image of the border region with the lakes there | ||
The Lake Chilwa located in the southeast of Malawi on the border with Mozambique .
geography
It is the second largest lake in Malawi and extends about 60 kilometers north-south and 40 kilometers east-west. The lake is at an altitude of 627 meters. It has seven tributaries, but no outflow, but it is believed that a certain amount of water is exchanged with Lake Chiuta in the north and around 100 to 300 square kilometers, depending on the season, via the swamps or underground . The two lakes are separated from each other by a 15 to 25 meter high sand barrier that was probably formed 10,000 years ago.
The hilly Chisi Island is located near the western shore of the lake, while the smaller Thongwe Island is in the middle of the lake .
Hydrology
The Chiuta Lake may in turn merge with the Amaramba Lake in Mozambique , which is drained by the Lugenda . Lake Chilwa is very shallow, the water depth is 1 to 2 meters. The area of the entire water area is around 2250 square kilometers, but is heavily dependent on the inflow. A distinction is made between open water areas, marshland and seasonally flooded areas. At the end of the dry season in October 2006, their size, measured by satellite images, was 828, 303 and 687 square kilometers, respectively. After a prolonged dry season, the surrounding marshland and parts of the lake can dry out. In 1995 the entire Lake Chilwa was dry after two years in a row it had rained only 775 and 748 millimeters. When the water level is low, the salt content is increased. The bank areas consist mainly of reeds ( Typha domingensis, a cattail species), from which ropes are tied to which fishing nets can be attached.
use
Lake Chilwa is rich in fish, with a long-term average of 15,000 tons being fished each year, which is (on average between 16 and 43 percent) 22 percent of the country's fishing yield. The productivity is 80 to 160 kg / ha. Three fish species together make up 85 percent of the yield: the cichlid Oreochromis shiranus chilwae , local name “Makumba”; an African predatory catfish , local name "Mlamba"; and the small barb Enteromius paludinosus , local name "Matemba". All three species are able to regenerate their populations even at different water levels.
The Chilwa Basin is an early settlement area for the Nyanja, Yao , Nguni and Lomwe ethnic groups , who, according to written sources, had been farming in the floodplains since the 19th century, but probably before. The British colonial authorities tried with little success to enforce the swampland as a protection zone. From the 1950s, parts of the area were established locally as irrigation farming. Studies by the FAO do not suggest abandoning arable farming, but rather a partial agricultural use and the involvement of the population in measures to protect the wetlands.
By the early 1970s, six irrigation programs for intensive agricultural use had been established, with an average size of 500 hectares for 1,300 to 1,500 farmers each. Individual villages were resettled within the area for this purpose, but there were hardly any new settlers from outside. The projects were supported by a Taiwanese aid organization and by IFAD . The main crops are rice, corn, peanuts and tobacco; various types of vegetables are grown for personal use. According to an estimate of 2000, 77,000 people lived in around 300 settlements in and largely on the wetlands of Lake Chilwa. With 162 inhabitants per square kilometer, the region has one of the highest population densities in Malawi. Since then, increasing land use has measurably reduced species diversity.
Flora and fauna
Around 160 species of water birds, including 41 species of migratory birds, live around Lake Chilwa. With traps, snares or fall nets with rice or millet as bait, waterfowl are caught for personal consumption and for sale in markets. A Danish project has been trying to regulate catch quotas since 2003. Birds are an important source of protein in times of low fishing. An estimated 1.2 million birds are caught each year. These include pond claws , whistling geese and Hottentot ducks . The breeding season is from January to July, the hunting season is the rainy season from December to February. In 2001, 29 bird sanctuaries were established in which hunting is prohibited all year round. Work was still underway in 2006 to set up a statutory hunting administration.
The fish fauna of Lake Chilwa comprises 27 species. Most important for the fishery are the small carp fish Enteromius paludinosus , which grow to about 12 cm long , the predatory catfish Clarias gariepinus and the two 25 and 45 cm long tilapia species Oreochromis shiranus chilwae and Coptodon rendalli . Other species are the cichlid Astatotilapia calliptera and the tetra Hemigrammopetersius barnardi . The crustaceans Diaphanosoma excisum, Tropodiatomus kraepelini, Daphnia barbata, Moina micrura, Ceriodaphnia cornuta and Mesocyclops leukarti were found in the zooplankton . The benthic invertebrate fauna contains Nilodrum brevibucca , N. brevipalpis , Ecnomus sp., Dipseudopsis sp., The apple snail Lanistes ovum , the plate screw Bulinus globosus and the horn snail Biomphalaria sp.
Since 2006 the area as is UNESCO - Biosphere Reserve reported.
Individual evidence
- ↑ M. Ngochera, W. Namoto and OC Mponda: Analysis of Catch and Effort Data for the Fisheries of Lake Chiuta 1976-1999. (PDF; 594 kB) Fisheries Bulletin No. 51, Department of Fisheries, Lilongwe 2001
- ↑ [1] ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. Image of boat in shallow water
- ↑ Lisa-Maria Rebelo, MP McCartney and CM Finlayson: Characterization of two large inland wetlands in southern Africa. International Water Management Institute ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (PDF; 622 kB)
- ↑ [2] afrika.info, August 27, 2012
- ^ PAM van Zwieten and F. Njaya: Environmental Variability, Effort Development, and the Regenerative Capacity of the Fish Stocks in Lake Chilwa, Malawi. ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. FAO Fisheries Technical Paper, 2003
- ↑ Pauline E. Peters: Informal Irrigation in Lake Chilwa Basin. Stream-bank and Wetland Gardens. ( Memento of the original from June 10, 2010 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. University of Wisconsin-Madison, October 2004
- ↑ Anne E. Ferguson and Wapulumuka O. Mulwafu: Irrigation reform in Malawi: exploring critical land-water intersections. ( Memento of the original from December 2, 2008 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 201 kB) International Conference on African Water Laws: Plural Legislative Frameworks for Rural Water Management in Africa. January 26-28, 2005, Johannesburg
- ^ Roy Bhima: Subsistence use of waterbirds at Lake Chilwa, Malawi. (PDF; 723 kB) In: GC Boere, CA Galbraith and DA Stroud (eds.): Waterbirds around the World. The Stationery Office, Edinburgh 2006, pp. 255-256
- ↑ Friday J. Njaya: Review of management measures for Lake Chilwa PDF
- ↑ International Lake Environment Committee: Lake Chilwa ( Memento of the original from July 15, 2007 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ List of UNESCO Biosphere Reserves , UNESCO.de, as of June 30, 2011, accessed on February 29, 2012
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