Development of a digital global map of irrigation areas
Irrigation is by far the largest water use sector at global level, with about 70% of water withdrawal and about 90% of water consumption. In several developing countries, irrigation represents up to 95% of all water uses. In arid regions, irrigation is the prerequisite for crop production. In semi-arid and humid areas, irrigation serves to increase yields, to attenuate the effects of droughts or, in the case of rice production, to minimize weed growth. Average yields are generally higher under irrigated conditions. Although globally only 18 % of the cultivated area is irrigated 40 % of the global food production comes from irrigated agriculture. Therefore irrigated agriculture plays an important role in food production and food security.
Major efforts have been made in the last decade by the international community to assess the different elements of the water balance and predict current and future water needs for the different use sectors. Because there are too many water abstraction points, irrigation water use itself cannot be measured at larger scales. Instead models are used to simulate water requirements on irrigated fields. A high quality data set showing the global distribution of irrigated areas is therefore a major requirement to improve the reliability of global studies on water and food.
The goal of the project is to develop a digital global map of irrigation areas by 1) collecting statistical and spatial information on irrigated areas and 2) developing tools to derive a global map of irrigation areas which combines sub-national irrigation statistics with geo-spatial information on the location and extent of irrigation schemes. The database and the map are updated regularly as soon as new information becomes available. The map and its documentation are made available to the public.
Keywords: irrigation, database, global map, land cover, water use, agriculture
Participants: Stefan Siebert, Petra Döll
Cooperating institutions: Food and Agriculture Organization of the United Nations (FAO), Rome, Italy
Duration: since 1999 (ongoing)
Funding entity: state funds, FAO
Contact: hydrology@em.uni-frankfurt.de
