Managing the Mega Irrigation Beast: Gezira, Egypt
Mega irrigation projects are the big elephants in the room. Located along many of the world’s large rivers in arid areas—the Indus, the Ganges, the Nile, the Amu Darya—they are spread over several hundred thousand to millions of hectares. For example, Pakistan’s Indus Basin Irrigation System is one of the largest integrated irrigation systems and extends up to 14 million hectares. But these systems are faced with challenges of an entirely different order than those facing other water systems.
First is their sheer size, spread over hundreds of kilometres. It is all but easy to distribute water equally, fairly or even reasonably. The chances that water is stolen or plainly diverted along the way are significant. Damage may occur too. Canals may be breached, and weirs may malfunction—all leading to a ripple effect in the lower part of the system. The downstream may also be flooded and waterlogged if there is too much water in the mega system. All these factors make mega irrigation systems difficult to handle.
Mega irrigation systems leave a substantial footprint on the entire landscape—not only the canals and drains but also on the roads, bridges, urban settlements and residential property. They determine what happens in agriculture as well as other sectors. But the management of large irrigation systems is not usually spatial.
Terry Feuerborn