Rukwa Valley Zone
The Rukwa Valley lies between the Lyambalyamfipa escarpment on the western side and the Lupa escarpment on the eastern side and stretches north-westwards from Lake Rukwa. The area is characterized by extensive flat plains with mean annual rainfall ranging from as high as 1,250 mm in the northern part and reducing southwards to as low as 800 mm on the leeward side of the Lyambalyamfipa escarpment. The elevation varies from 1,000 - 1,100 m in the northern section of the valley to 800 - 900 m along the shores of Lake Rukwa. The valley soils are predominantly sandy loams with moderate to good drainage. The higher parts of the valley are mostly covered in tropical wooded grassland, while the lower parts close to the lake are dominated by extensive grassland consisting of grasses, reeds, and rushes of both permanent and seasonal types. The lake shores are water logged with extensive swamps especially around the northern lake shore and the Ugalla River valley. Major crops grown include maize, paddy, fruits, finger millet, sorghum, and cassava. Livestock keeping, fishing, and lumbering are also commonly practiced in the area.
Lake Rukwa is the main hydrological feature of the Rukwa valley zone. The northern and western shores of the lake are covered by extensive wetlands that include both permanent swamps and temporary floodplains. The swamps are dominated by Cyperus papyrus and Phragmites mauritianus, among other species. Other permanent or semi-permanent swamps, extending over about 39,000 ha, cover the south-western shores of the north basin and the section between the north and south basins of the lake. A significant part of the valley’s flood plain (53,000 ha) is an extensive wetland system, which drains the Katavi Plains through a network of several rivers and small lakes (Chada and Katavi) into Lake Rukwa. Nearly all of the flood plains and wetlands system form part of the Katavi-Rukwa ecosystem, a protected area with unique biodiversity and wildlife.
The Rukwa valley zone is home to the Katavi National Park which extends over an area of about 4,471 km2 and is the third largest National Park in Tanzania. It is a very remote park that is less frequently visited than other Tanzanian National Parks, though there is significant potential for tourist numbers to increase in the near future. The Park, together with Rukwa and Lukwati Game Reserves on its south-eastern fringes and the surrounding hunting blocks, constitutes one of the biggest and richest wildlife areas in Tanzania. Due to its remoteness, low human populations density, and poor infrastructure, the Katavi National Park contains some of the least disturbed ecosystems in the country.
Human-wildlife conflicts are common at the periphery of the protected areas with wildlife (e.g., baboons, elephants, and bush pigs) inflicting crop damage. There is also a problem of encroachment on protected areas by pastoralists from the neighboring villages in search of water and pasture for their livestock, especially during the dry season. Conflicts between the park and surrounding communities mainly escalate during the dry season due to reduction in water availability and pasture. The main conflict is between the park and upstream irrigators at Mwamkulu, Ngungwi and Kakese villages who abstract water to irrigate rice farms.
Fishing is a very important socioeconomic activity in the Rukwa valley zone and is mostly concentrated around Lake Rukwa and the major rivers feeding it. Fisheries are an important source of food, household income, and livelihood for the poor riparian communities. In the fishing areas around Lake Rukwa, fishing generates high economic returns to local fishermen. The occupation and related industries provide employment to many locals. The artisanal fisheries support a significant number of workers in related industries, such as those who repair boats and fishing gear. In addition, a high number of women are involved in the processing and selling of fish. Fishing in the Lake is confined to shallow water because fishermen use dug-out canoes from plunks of trees. Most of the money obtained from the sales by the small scale fishermen is spent on alcohol which explains the high levels of poverty observed in the fishing villages.
Fish stocks are under considerable threats from overexploitation, illegal fishing practices, and habitat destruction. Beach seining is reported to be the most destructive fishing method used in the inshore areas of Lake Rukwa. Fisheries authorities have tried to control the practice, but their efforts failed due to insufficient human and financial resources. Unregulated fishing activities are also contributing towards environmental degradation through rampant deforestation to meet the high demand for wood used in smoking fish.
The zone is predominantly rural and is characterized by poor socioeconomic infrastructure. Agriculture is the most important socioeconomic activity employing about 85% of the population in the zone. Other activities include Livestock keeping, Fishing, and small business. Irrigation is the major water use in the zone. Several small to medium scale irrigation shemes are scattered in different parts of the zone with the majority lying on the western and extreme northern corner of the zone. Industrial water use is minimal due to the absence of any major industries in the area. Major water resources issues pertain to pollution of water bodies by the Gold mines in Chunya and Mlele.