Groundwater use for irrigation – a global inventory

Abstract

Irrigation is the most important water use sector accounting for about 70% of the global freshwater withdrawals and 90% of consumptive water uses. While the extent of irrigation and related water uses are reported in statistical databases or estimated by model simulations, information on the source of irrigation water is scarce and very scattered. Here we present a new global inventory on the extent of areas irrigated with groundwater, surface water or non-conventional sources, and we determine the related consumptive water uses. The inventory provides data for 15 038 national and sub-national administrative units. Irrigated area was provided by census-based statistics from international and national organizations. A global model was then applied to simulate consumptive water uses for irrigation by water source. Globally, area equipped for irrigation is currently about 301 million ha of which 38% are equipped for irrigation with groundwater. Total consumptive groundwater use for irrigation is estimated as 545 km<sup>3</sup> yr<sup>−1</sup>, or 43% of the total consumptive irrigation water use of 1 277 km<sup>3</sup> yr<sup>−1</sup>. The countries with the largest extent of areas equipped for irrigation with groundwater, in absolute terms, are India (39 million ha), China (19 million ha) and the United States of America (17 million ha). Groundwater use in irrigation is increasing both in absolute terms and in percentage of total irrigation, leading in places to concentrations of users exploiting groundwater storage at rates above groundwater recharge. Despite the uncertainties associated with statistical data available to track patterns and growth of groundwater use for irrigation, the inventory presented here is a major step towards a more informed assessment of agricultural water use and its consequences for the global water cycle

Global Experiences on Wastewater Irrigation: Challenges and Prospects

“…Compared to surface water resources, the use of groundwater is increasing because of climate change, population growth and excessive water consumption, and as shown in Fig. 18.3d , irrigation is not exempt from this issue (Doll et al 2012 ;Green et al 2011 ;Siebert et al 2010 ). This leads to greater pressure on groundwater resources.…”

Comparing potential recharge estimates from three Land Surface Models across the western US

“…It plays a central part in irrigated agriculture and sustaining ecosystems (Giordano, 2009;Siebert et al, 2010), and enables human adaptation to climate variability and change (Taylor et al, 2013). Globally it accounts for 1/3rd of all fresh-water withdrawals, for domestic (36%), agricultural (42%) and industrial purposes (27%) (Döll et al, 2012;Taylor et al, 2013).…”

Joint Operation of Surface Water and Groundwater Reservoirs to Address Water Conflicts in Arid Regions: An Integrated Modeling Study

“…Meanwhile, in arid and semi-arid regions of the world where surface water is not abundantly available, groundwater (GW) abstraction is often required for irrigation purposes. According to Siebert et al [4], the total area irrigated by groundwater is nearly 114 million hectares globally. In most arid and semi-arid regions, irrigation with groundwater has experienced a considerable increase over the past few decades mainly due to the growing demand for agricultural products and the changing climate [5].…”