Emmanuel Okalany
Projects Assistant
Regional Universities Forum for Capacity Building in Agriculture
Uganda

Biography
Emmanuel is Projects Assistant at RUFORUM's M&E Unit. He holds M.Sc. Geomatics and Natural Resources Evaluation from University of Florence, Italy and B.Sc. Agricultural Land use Management from Makerere University. He worked with Centre for Development Research in BOKU University, Austria as Course Tutor for International Training Course on Organic Agriculture. His research interests are soil science, climate change, GIS and remote sensing.

Abstract
Assessing Agricultural Drought using Remote Sensing and GIS: The Case of May Gabat watershed, Northern Ethiopia

Co-Author: Maria Cecilia Anabela Morales Poclava, Researcher, Laboratory of GIS and Teledetection, Instituto Nacionale de Tecnologìa Agropecuaria

Agricultural drought is the most adverse climate change risk accounting for over 80% losses in biological and agricultural yields worldwide. In the last decade, over 60% losses in agricultural yield and over one million deaths have been caused by drought in Ethiopia. This study focused on use of remotely sensed data and GIS to assess the susceptibility of May Gabat watershed to agricultural drought. Irrigation water requirement (IWR), Available Water Capacity (AWC), land cover, and ground water levels were used as separate raster layers. Ground water levels were estimated using Topographic Wetness Index (TWI) derived from ASTER DEM using SAGA GIS. The four parameters were reclassed, weighted, and summed as raster layers to derive susceptibility classes. The whole area suffers from agricultural drought indicated by positive values of IWR with the largest area covering 48% with deficit of 700-800mm/year. 53% of the area has annual AWC between 40-50cm, values less than soil water requirements of the dominant crops in the area. 95% of the study area has TWI values less than 50% of the optimum. Over 90% of the area is heavily terraced, reducing the impact of runoff in the land of very steep slopes. When classified and rated, 52% of the area was less susceptible to agricultural drought while 40% is moderately to highly susceptible. In the 52%, water deficit is countered by deep colluvial soils on low lands with high AWC and TWI farther strengthened by terracing, contour farming, and drought tolerant vegetation. The 40% of the area is dominated by bare and shallow soils on steep slopes.