GEF

Unit 3  |  Water Use and Human Water Systems 75 Land flooding resulting from damming rivers has harmed human populations. The World Commission on Dams (WCD) estimates that 40-80 million people worldwide have been directly displaced by flooding from dam construction. Indigenous communities have been especially hard-hit, as they often do not have clear legal title to their land and are frequently excluded from negotiations over dam planning and construction. 3.3  Agriculture, Irrigation, and Groundwater Of all the uses of water by people, agriculture places by far the largest demand on water resources, being responsible for roughly 66 percent of global water withdrawals and 84 percent of water consumption. However, these figures mask sizable differences between countries. For example, in Egypt, water withdrawals for agriculture are responsible for over 85 percent of total use, while in Canada, agriculture makes up about 12 percent of total water withdrawals. There are many factors influencing these differences, includ- ing the percentage of the economy dedicated to agriculture, regional climatic variation, and the efficiency of water infra- structure. What is certain is that without sustainable water use in agriculture, it will be impossible to develop sustainable water use to meet other needs. A major issue surrounding water use for agriculture is the growing demand of irrigation on limited groundwater resources. In water-stressed countries such as India, economic growth has relied on tapping shrinking aquifers to support crops. Currently, over 80 percent of agriculture in India is dependent on groundwater. In the most heavily populated regions of the country, groundwater is being depleted three times faster than it is replenished, according to recent studies. INDIGENOUS Originating in and charac- teristic of a particular region or country. GROUNDWATER Any form of fresh water supply, such as aquifers located underground, often supplying wells, springs, and agricultural irrigation. AQUIFERS Underground layers of porous rock that allow the movement of water between layers of non-porous rock.