Watch Free Online HD Moviesjoy. Located in the central part of the Blue Nile Basin, the Gezira Irrigation Scheme is the biggest gravity irrigation scheme under one management in the world, counting an area of almost 900,000 hectare. Fertile soils and sufficient water resources were the reason for its establishment more than 90 years ago. But today the scheme’s efficiency is low due to a deteriorated infrastructure and institutional and financial limitations. Strong efforts are needed to revive the food basket of Gezira in Sudan.