water Article Water Balance for a Tropical Lake in the Volcanic Highlands: Lake Tana, Ethiopia Muluken L. Alemu 1,2, Abeyou W. Worqlul 3 , Fasikaw A. Zimale 1 , Seifu A. Tilahun 1 and Tammo S. Steenhuis 1,4,* 1 Faculty of Civil and Water Resources Engineering, Bahir Dar Institute of Technology, Bahir Dar University, P.O. Box 26 Bahir Dar, Ethiopia;
[email protected] (M.L.A.);
[email protected] (F.A.Z.);
[email protected] (S.A.T.) 2 Ethiopian Construction Works Corporation, P.O. Box 21951/100 Addis Ababa, Ethiopia 3 Texas A&M AgriLife Research, Temple, TX 76502, USA;
[email protected] 4 Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA * Correspondence:
[email protected]; Tel.: +1-607-255-2489 Received: 3 September 2020; Accepted: 24 September 2020; Published: 30 September 2020 Abstract: Lakes hold most of the freshwater resources in the world. Safeguarding these in a changing environment is a major challenge. The 3000 km2 Lake Tana in the headwaters of the Blue Nile in Ethiopia is one of these lakes. It is situated in a zone destined for rapid development including hydropower and irrigation. Future lake management requires detailed knowledge of the water balance of Lake Tana. Since previous water balances varied greatly this paper takes a fresh look by calculating the inflow and losses of the lake. To improve the accuracy of the amount of precipitation falling on the lake, two new rainfall stations were installed in 2013. The Climate Hazards Group Infrared Precipitation Version two (CHIRPS-v2) dataset was used to extend the data.