The USGS estimates that ~40% of all freshwater withdrawals are for irrigated agriculture. Total withdrawals are about 118 billion gallons per day (Bgal/d).[1,2]
Excluding thermonuclear power plants, freshwater irrigation accounted for ~62% of total freshwater withdrawals.[3]
Including the categories of livestock (on-farm) and aquaculture in agriculture and excluding thermonuclear, agriculture accounted for about two-thirds of all freshwater withdrawals.[4]
Dieter, C.A. et al., (2018) Estimated Use of Water in the United States in 2015, U.S. Geological Survey, Table 2A, p. 10. [Total freshwater withdrawals for irrigation = 118 billion gallons per day (Bgal/day). Total for all eight categories of use = 281 Bgal/day. 118 / 281 = 42.0%]
Shaddox, T. W., et al., (2022). Water use and management practices on US golf courses. Crop, Forage & Turfgrass Management, 8(2), e20182. [Note that the USGS includes golf courses and horticultural nurseries in irrigated water amounts, though they do not quantify it. According to Shaddox et al., total golf course usage equals about 1.69 million acre-feet or about 0.5% of total freshwater usage (1.69 / 315) and about 1.3% of irrigation usage (1.69 / 132). According to USDA figures, nurseries make up no more than 0.1% of irrigated cropland. For all stats based on USGS figures, we assume that irrigation = agriculture, while also reducing final estimates impacted by golf course usage by about 1 or 2 % and generally being conservative with estimates.]
For 62% figure, see, Dieter, p. 26 and calculation 118 / (281 – 95.1) = 63.5% (adjusted to 62% for golf courses). Almost all thermonuclear withdrawals are surface water used for cooling and then returned to the source. Consumptive use of freshwater by thermonuclear is about 4% of thermonuclear usage. [Dieter, Table 12, p. 43]
Calculation: 118 + 2 + 7.55 = 127.55. 127.55 / (281 – 95.1) = 68.6%.
About 80% of U.S. consumptive freshwater use is attributed to agriculture.[1-4]
Of the freshwater withdrawn for irrigation, ~62% is consumed (and not returned to the immediate water environment).[5,6]
Glenn Schaible & Marcel Aillery (2012) Water Conservation in Irrigated Agriculture: Trends and Challenges in the Face of Emerging Demands, USDA Economic Research Service, EIB 99, Abstract. [“U.S. agriculture accounts for 80-90 percent of the Nation’s consumptive water use (water lost to the environment by evaporation, crop transpiration, or incorporation into products).”]
Rehkamp, S., & Canning, P. (2018). Measuring embodied blue water in American diets: an EIO supply chain approach. Ecological Economics, 147, 179-188. [“…about 80% of the consumptive water use in the United States can be attributed to agriculture.”]
Konar, M., & Marston, L. (2020). The Water Footprint of the United States. Water (Basel), 12(11), 3286. https://doi.org/10.3390/w12113286 [“Between 74–93% … of all blue water consumed in the US is for irrigated agriculture and livestock production.” at p. 3. “Blue water is water from a source, such as a reservoir, river, lake, or aquifer.” at p. 2.]
Richter, B. D., et al., (2020). Water scarcity and fish imperilment driven by beef production. Nature Sustainability, 3(4), 319–328, table 1, p. 321. [Crop irrigation (75%) + Livestock Watering (2%) = 77%.]
Dieter, C.A. et al., (2018) Estimated Use of Water in the United States in 2015, U.S. Geological Survey, Table 7, p. 27. [Although the USGS provides amount of water consumed by irrigation and by thermonuclear power, it does not estimate consumption for other categories, nor does it estimate total consumption. Portion of irrigation withdrawal that is consumed = 73.2/118 = 62%.]
Water Footprint Calculator (2022) Water Use, Withdrawal and Consumption. https://www.watercalculator.org/footprint/water-use-withdrawal-consumption/
Surface water and groundwater are withdrawn in almost equal parts.
Surface Water – The USGS estimates that irrigation withdraws 60.9 billion gallons per day (Bgal/d) of fresh surface water. That’s ~52% of agriculture’s total withdrawals.[1]
Groundwater – Irrigation withdraws 57.2 Bgal/d of groundwater. That’s ~48% of agriculture’s total withdrawals.[2]
Dieter, C.A. et al., (2018) Estimated Use of Water in the United States in 2015, U.S. Geological Survey, Table 3A, p. 14. [60.9 / 118 = 51.6%.]
Dieter, C.A. et al., (2018) Table 4A, p. 16. [57.2 / 118 = 48.47%.]
Critically, irrigation makes up about two-thirds of total groundwater withdrawals.[1]
Dieter, C.A. et al., (2018) Estimated Use of Water in the United States in 2015, U.S. Geological Survey Table 4A, p. 16. [Total groundwater withdrawals for all categories = 82.3 billion gallons per day. 57.2 /82.3 = 69.5%.]
The unsustainable depletion of U.S. groundwater is well documented.[1-4]
Groundwater depletion is viewed as a threat to agriculture.[5] It is also a threat to the public supply of water, of which almost 40% is sourced from groundwater.[6] Additionally, ~13% of the population relies on its own water supply (mostly wells) and this is almost entirely groundwater.[7] Groundwater depletion due to irrigation is having dramatic consequences in the southwest where thousands of wells are drying up.[8]
Ecosystems are also negatively impacted as depletion of groundwater contributes to reduced base flow to springs, streams, and other surface water bodies, loss of wetlands, all of which can damage aquatic ecosystems and the animals that rely on them.[9]
US Geological Survey (2018) Groundwater Decline and Depletion https://www.usgs.gov/special-topics/water-science-school/science/groundwater-decline-and-depletion#overview [Defines groundwater depletion as “long-term water-level declines caused by sustained groundwater pumping.”]
Konikow, L. F., (2013). Groundwater depletion in the United States (1900− 2008), U.S. Geological Survey, No. 2013-5079.
Konikow, L. F., & Bredehoeft, J.D. (2020) Groundwater Resource Development: Effects and Sustainability, Groundwater Project, Guelph, Ontario, Canada, 2020, pp. 14-17.
Rojanasakul, Mira, et al., (August 28, 2023) America Is Using Up Its Groundwater Like There’s No Tomorrow. New York Times.
Lopez, J. R., et al., (2022). Sustainable Use of Groundwater May Dramatically Reduce Irrigated Production of Maize, Soybean, and Wheat. Earth’s Future, 10(1), Abstract.
Dieter, C.A. et al., (2018) Estimated Use of Water in the United States in 2015, U.S. Geological Survey, Table 5, p. 20. [15.2 Bgal/d from groundwater of 39 total]
Dieter, C.A. et al., (2018), p. 22 and Table 6, p. 23. [Groundwater = 98%]
Ella Nilson (November 2022) Wells are running dry in drought-weary Southwest as foreign-owned farms guzzle water to feed cattle overseas, CNN, https://www.cnn.com/2022/11/05/us/arizona-water-foreign-owned-farms-climate/index.html [Arizona wells drying up with large farms irrigating alfalfa]
Konikow, L. F. (2015). Long-term groundwater depletion in the United States. Ground Water, 53(1), 2–9, p. 2. [“Groundwater depletion can have a number of detrimental effects. These include reduced well yields, increased pumping costs, needs to drill deeper wells, irreversible land subsidence, reduced base flow to springs, streams, and other surface water bodies, and loss of wetlands. Depletion effects can, in turn, lead to land-use changes. Reduced groundwater discharge can damage aquatic ecosystems.”]
As the USDA explains, “Irrigation allows for agricultural production in arid regions where precipitation is insufficient to meet crop water requirements.”[1] These areas are more likely to be water stressed.[2]
Scientists project increased water shortages in many areas without restrictions on irrigation practices but acknowledge that “food security is complicated by several factors including, (1) some crops, or parts of crops, are used to produce biofuels, (2) large portions of some field crops, such as corn, are exported, and (3) much irrigated area is used for animal feed, only some of which is related to human food consumption.”[3]
Hrozencik, R. Aaron and Marcel Aillery (2021). Trends in U.S. Irrigated Agriculture: Increasing Resilience Under Water Supply Scarcity, USDA Economic Research Service, EIB-229, Abstract.
U.S. Government Accountability Office (2019) Irrigated Agriculture, Technologies, Practices, and Implications for Water Scarcity, GAO-20-128SP, p. 15.
Brown, T. C., et al., (2019). Adaptation to future water shortages in the United States caused by population growth and climate change. Earth’s Future, 7(3), 219-234, p. 228.
The top 5 states accounted for ~55% of the nation’s total freshwater withdrawals for irrigation.[1]
Dieter, C.A. et al., (2018) Estimated Use of Water in the United States in 2015, U.S. Geological Survey, Table 7, p. 27.[Total 5 states withdrawals 64.4 Bgal/day /118 Bgal/day == 54.5%]
The top 5 states accounted for ~56% of the nation’s consumption of irrigation water.[1]
Dieter, C.A. et al., (2018) Estimated Use of Water in the United States in 2015, U.S. Geological Survey, Table 7, p. 27. [Total 5 states consumption = 41 Bgal/d / 73.2 Bgal/d == 56%]
The 17 conterminous Western States cumulatively accounted for 81% of the nation’s total irrigation withdrawals. By water source, it was 91% of total surface-water irrigation withdrawals and 71% of total groundwater irrigation withdrawals.[1]
One experienced research team calculated that crop irrigation in the 17 Western States is responsible for 86% of the total water consumption in those states. Total domestic use (in residences) in those same states is responsible for just 7% of consumption.[2,3]
Dieter, C.A. et al., (2018) Estimated Use of Water in the United States in 2015, U.S. Geological Survey, p. 28.
Richter, B. D., et al., (2020). Water scarcity and fish imperilment driven by beef production. Nature Sustainability, 3(4), 319–328, Table 1.
Richter, B.D. et al., (2023). Alleviating water scarcity by optimizing crop mixes. (2023). Research Square, p. 3.
Per capita in the U.S. in 2015, about 390 gallons of water were withdrawn daily for agricultural use. This includes water withdrawn for irrigation, livestock, and aquaculture.[1]
This compares to per capita daily withdrawal of 82 gallons for domestic use, defined as “indoor and outdoor uses at residences.”[2]
Dieter, C.A. et al., (2018) Estimated Use of Water in the United States in 2015, U.S. Geological Survey, p. 28. [Calculation: Irrigation + Livestock + Aquaculture = 127.55 billion gallons per day. Based on population of 325,000,000 as noted in USGS report. 127,550,000,000 / 325,000,000 = 392 gallons per day.]
Dieter, C.A. et al., (2018) p. 22. [“…the national average per capita use was 82 GPCD (gallons per capita per day)”]