1. Department of Soil and Water Management, Amhara Regional Agricultural Research Institute, Bahir Dar P.O. Box 08, Ethiopia
2. Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
3. Faculty of Civil and Water Resources Engineering, Bahir Dar Institute of Technology, Bahir Dar University, Bahir Dar P.O. Box 26, Ethiopia
4. International Water Management Institute, Accra PMB CT 112, Ghana
5. Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA