The United Republic of Tanzania

Internal Drainage Basin

Internal Drainage Basin
Water Resources Management is undertaken by the Basin Water Office which is under the Basin Water Board. The Board is chosen by the minister responsible for Water according to Water utilization (control and Regulation) Act no. 42 of 1974 and its subsequent amendments No. 10 of 1981, No 17 of 1989, No 8 of 1997. 
The basin is situated in the semi-arid region of Tanzania. The mean annual rainfall range from 500 mm/yr at Bahi to 900mm/yr in the highlands of Mbulu district. Rainfall varies greatly from year to year. 
The Internal Drainage Basin is described by rivers/streams draining into a group of inland water bodies (lakes) that are located around the north-central part of the country. The system, mainly of troughs and faults runs southward from lake Natron at the border with Kenya to central Tanzania in the Bahi depression and varies in width from 30-90 km. Total basin area on the Tanzanian side is about 153,800 km2. The major drainage systems in this basin includes:- Lake Eyasi System, which drains areas in North Tabora Region and East Shinyanga by the Wembere and Manonga river systems, Lake Manyara System and Bubu complex where important features are the Bubu and Bubu swamps. Several other small independent lakes and swamps with no outlet existing in this basin include Lake Basuto and Lake Natron. 
Internal drainage basins of Lake Eyasi, Manyara and Bubu Complex