Autor Abeyou wale .................. Bahir Dar University, Bahir dar Ethiopia. .............abeyou_wale@yahoo.com

Lake Tana (also spelled T'ana, Amharic: ጣና ሐይቅ Ṭānā Hāyḳ,"Lake Tana," an older variant is Tsana, Ge'ez ጻና Ṣānā; sometimes called "Dembiya" after the region to the north of the lake) is the source of the Blue Nile and is the largest lake in Ethiopia. Located in the north-western Ethiopian highlands, according to the Statistical Abstract of Ethiopia for 1967/68, the lake is approximately 84 kilometers long and 66 kilometers wide, with a maximum depth of 15 meters, and an elevation of 1,840 meters. Lake Tana is fed by the Little Abay, Reb and Gumara Rivers and its surface area ranges from 3,000 to 3,500 km² depending on season and rainfall. The lake level has been regulated since the construction of the control weir where the lake discharges into the Blue Nile, which regulates the flow to the Tis Abay falls and hydro-power station (from Wikipedia). From Wikipedia, the free encyclopedia

My MSc Work at ITC, the Netherlands.

Daily lake rainfall has been estimated through few procedures that are the inverse distance squared interpolation, inverse distance linear interpolation and Thiessen polygons. For interpolation, data for the period 1992-2003 from Bahir Dar, Chawhit, Zege and Delgi stations.

Lake Tana long-term monthly rainfall interpolation by linear invers distance interpolation (1992 -2003) Lake Tana areal rainfall

Lake Tana Bathymetry by Abeyou Wale Lake Tana Bathymetry