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Irrigated agricultural acreage has grown, shifting eastward, while western irrigated acreage has declined

Wednesday, September 27, 2023

U.S. irrigated agriculture has seen regional changes in the past two decades, influenced by a variety of factors. From 1997 to 2017, total U.S. irrigated agricultural acreage increased by 1.7 million acres. Irrigated acreage grew primarily in the eastern United States, where agriculture production is historically rain-fed, and declined in the West, where a generally arid climate necessitates irrigation for most crops. In the East, increased frequency and severity of drought have driven farmers to move from rain-fed to irrigated production. In the West, farmers have begun to take irrigated land out of production as surface water supplies dry up, and they face increasing competition for water from growing urban centers. This chart was drawn from the USDA, Economic Research Service report Trends in U.S. Irrigated Agriculture: Increasing Resilience Under Water Supply Scarcity, published in December 2021.

Irrigation water delivery organizations play important role in conveying water in the western United States

Tuesday, September 5, 2023

Water is withdrawn from surface and groundwater sources for agricultural, industrial and municipal use. Farmers in the United States source water for irrigation by diverting it from on-farm surface water bodies like rivers or streams, directly pumping groundwater, or receiving water via the canals and ditches of water delivery irrigation organizations. In the four regions of the western United States (consisting of the Northwest (Idaho, Oregon, and Washington), Pacific (California and Nevada), Southwest (Arizona, New Mexico, Utah), and Eastern Rockies (Colorado, Montana, Wyoming) regions) irrigation water delivery organizations accounted for almost 60 percent of the water that is withdrawn for all uses in an average year. In contrast, in the High Plains (Kansas, Nebraska, North Dakota, Oklahoma, South Dakota, and Texas) and Southeast (Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, and South Carolina), where surface and ground water resources for irrigation are available without large-scale coordination, these organizations conveyed water that amounted to about 3 percent of all water withdrawn in an average year. Irrigation water delivery organizations play a particularly large role in the Southwest, where in 2019 they conveyed 11 million acre-feet of water, which is 73 percent of the 15 million acre-feet withdrawn for all uses in an average year. This chart appears in the ERS report Irrigation Organizations: Water Inflows and Outflows, published in August 2023.

Irrigation organizations in Pacific region more likely to trade water with other irrigation organizations

Monday, August 21, 2023

Irrigation water delivery organizations play a key role in delivering water to farms, ranches, and nonagricultural users in the United States. Results from the 2019 Survey of Irrigation Organizations (SIO) show that 2,477 organizations in western regions were directly involved in delivering water to farms. About 70 percent of the water withdrawn from freshwater sources for irrigation in the western regions of the United States is managed by irrigation water delivery organizations. In most regions, organizations that allow transfers internally between their users were more common than organizations engaging in external trades with other entities. Some of these organizations trade water by leasing it to or from other irrigation organizations, municipalities, environmental groups, or other interested parties. In the Pacific region, 17 percent of organizations engage in these external leases, compared to between 3 and 7 percent in other regions in the western United States. Water exchanges may also occur internally between water users within a delivery organization’s own water delivery system, if allowed by the organization. Internal transfers between users in an organization occurred in 5 percent of organizations in the Pacific and between 8 and 11 percent of organizations in other regions of the western United States. This chart appears in the USDA Economic Research Service publication Irrigation Organizations: Water Inflows and Outflows, published in August 2023.

Federal projects provide nearly half of water conveyed by large irrigation water delivery organizations

Thursday, August 10, 2023

Irrigation water delivery organizations are entities such as irrigation districts and ditch companies that supply farmers, ranchers, and other users with water. These organizations draw water from several different sources. Water from Federal water projects and direct diversions from surface water bodies make up the majority of inflows to these organizations. Yet there is substantial variation across organizations based on size. Large water delivery organizations, (which supply water to more than 10,000 acres) tend to contract water from Federal water storage facilities rather than draw from natural surface sources such as rivers. However, small water delivery organizations (supporting less than 1,000 acres) draw a much higher proportion of their water inflows from surface sources. These differences reflect the historical development of irrigation organizations, with larger organizations developing in tandem with or as part of top-down approaches to provide water for irrigation, while small organizations developed from the ground up as small private ventures or community-led efforts. This chart appears in the USDA Economic Research Service publication Irrigation Organizations: Water Inflows and Outflows, published in August 2023.

Drought conditions have improved in much of the Western United States compared with the last two years

Wednesday, July 19, 2023

As of July 2023, drought conditions have improved across much of the Western United States (consisting of Arizona, California, Colorado, Idaho, Kansas, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, South Dakota, Texas, Utah, Washington, and Wyoming) compared not only with earlier in the year, but also with 2021 and 2022. According to the U.S. Drought Monitor, on July 11, 2023, 3 percent of land in the Western States was classified as experiencing extreme or exceptional drought, with an additional 8 percent classified as severe. This is down from June 2023, when 18 percent of land in Western States was classified as in extreme or exceptional drought. Significant precipitation and snowpack accumulation over the 2022–2023 winter and spring has reduced the prevalence of drought in the area, notably in California. However, conditions remain dry in Kansas and Nebraska where severe or worse drought conditions affect 55 and 48 percent of land, respectively. Data reported by U.S. Drought Monitor show Western drought conditions intensified during summer 2021, then gradually subsided between October and December 2021. They intensified again during the first half of 2022 before starting to subside again. For agriculture, drought means diminished crop and livestock outputs and reduced profitability if adaptive measures such as irrigation are not used. Drought also reduces the quantity of snowpack and streamflow available for diversions to irrigated agricultural land. These impacts can reverberate throughout local, regional, and national economies. Find additional information on the USDA, Economic Research Service’s Newsroom page Drought in the Western United States.

Primary role of groundwater management organizations varies

Wednesday, July 12, 2023

Groundwater management organizations are local entities that influence on-farm groundwater use through statutory, regulatory, or other powers. USDA, Economic Research Service (ERS) researchers studying irrigation identified two broad categories of groundwater organizations during a 2019 survey: those that influence only on-farm groundwater use (“groundwater only”) and organizations that both influence on-farm groundwater use and deliver surface water to farms (“groundwater and delivery”). More than 75 percent of “groundwater-only” organizations monitor groundwater conditions and collect pumping data. A smaller proportion of “groundwater and delivery organizations” monitor groundwater conditions or collect pumping data (approximately 38 percent and 34 percent, respectively). Charging pumping or water rights fees is a relatively common function among “groundwater and delivery organizations,” with 55 percent of these organizations charging fees compared with 40 percent of “groundwater only” organizations. Issuing permits for the development of new wells is also a common management function, particularly among “groundwater only” organizations. About 61 percent of “groundwater only” organizations engage in permitting, while 8 percent of “groundwater and delivery organizations” do. According to USDA data, about 65 percent of all irrigated U.S. acreage relied on groundwater as a primary or secondary source of water in 2018. This chart appears in the ERS report Irrigation Organizations: Groundwater Organizations, published in April 2023.

Groundwater organizations see nitrate contamination as top concern

Monday, May 15, 2023

Thirty percent of groundwater organizations cite nitrate contamination as a groundwater quality concern. Nitrates can come from animal manure and chemical fertilizers that leach into groundwater. When groundwater pumping exceeds the volume of groundwater recharge, the concentration of contaminants like nitrates can increase. Nitrate contamination is a concern on more than half of the groundwater-fed irrigated acreage within groundwater organization service areas. USDA’s Survey of Irrigation Organizations collected information on the estimated 735 local entities that manage on-farm groundwater use through statutory, regulatory, or other powers. While nitrate contamination was the most common groundwater quality concern reported, contamination by salinity, other nutrients, and heavy metals are a concern for 27, 19, and 18 percent of groundwater organizations, respectively. Contaminated groundwater can harm crops or make the water unusable for irrigation entirely. This chart appears in the Economic Research Service report Irrigation Organizations—Groundwater Organizations published in April 2023.

Degraded water quality, declining well capacity affect many groundwater organizations

Wednesday, April 19, 2023

The top two concerns raised by groundwater organizations related to groundwater depletion are degraded water quality and declining well capacity. Groundwater organizations are the local entities that influence on-farm groundwater use through statutory, regulatory, or other powers. In the United States, there are an estimated 735 such organizations that manage roughly 60 percent of all groundwater-fed irrigated acreage in the country. A national survey of these organizations found that 31 percent of them reported degraded water quality and 30 percent reported declining well capacity in 2019 as groundwater depletion concerns. These two issues affect about 53 and 59 percent of the acreage within organization service areas, respectively. When groundwater pumping exceeds the volume of groundwater recharge, the quality and quantity of the remaining water declines. For example, saltwater intrusion caused by groundwater depletion is a concern for many coastal and inland aquifers, since high salinity levels can hinder the growth of most common crops. Well capacity is another important groundwater depletion concern, since it limits the amount of water that can be applied to a crop within a given time, which can reduce irrigated crop yields and farm profits. Groundwater depletion has affected several of the nation’s most economically important aquifers, including the High Plains (Ogallala) and Central Valley aquifers. Additionally, 14 percent of groundwater organizations reported abandoned wells as an issue and 25 percent reported stream interaction issues, in which depleted groundwater can reduce streamflow and harm associated ecosystems. This chart appears in the Economic Research Service economic brief Irrigation Organizations: Groundwater Management, published in April 2023.

Drought conditions in Western States in summers of 2021, 2022 were the most intense in 20 years

Tuesday, September 27, 2022

As of September 19, 2022 the U.S. Drought Monitor (USDM) classified more than 18 percent of land in the Western States as experiencing extreme or exceptional drought. Data reported by USDM show that drought in the Western States during the summers of 2021 and 2022 exceeded the intensity of all past droughts in the region since 2000. Drought conditions in the Western States gradually subsided in the latter months of 2021 but began intensifying again during the first half of 2022. The USDM categorizes drought in a region according to soil moisture, streamflow, and precipitation levels. Regional designations are primarily based on historical weather patterns. For agriculture, drought can mean diminished crop and livestock outputs, as well as reduced farm profitability. Drought also reduces the quantity of snowpack and streamflow available for diversions to irrigated agricultural land. These impacts can reverberate throughout the local, regional, and national economies. Find additional information on the USDA, Economic Research Service’s newsroom page Drought in the Western United States.

Most formal drought plans for irrigation organizations specify rules for drought-induced water restrictions

Wednesday, April 6, 2022

Guidelines for implementing drought-induced water restrictions on water deliveries and pumping are the most common component in the formal drought plans of irrigation organizations. In the 2019 Survey of Irrigation Organizations, USDA asked groundwater organizations and water delivery organizations, such as irrigation districts and ditch companies, questions about their formal drought planning. Around one-fifth of all organizations had a formal, written drought plan. Between 69 percent and 73 percent of water delivery organization plans and 80 percent of groundwater organization plans included details about drought-induced water restrictions as a component of their plans. Land fallowing provisions and off-year water storage strategies typically occurred in fewer than 20 percent of plans for most organizations. About one-third of large delivery organization plans included provisions for price increases and water supply augmentation during drought by purchasing additional water. This chart was drawn from the USDA, Economic Research Service report Irrigation Organizations: Drought Planning and Response (EB-33), published January 6, 2022.

Irrigated cropping patterns in the United States have evolved significantly since 1964

Friday, March 25, 2022

Irrigated cropping patterns have shifted significantly in the United States during the past 50 years. In 1964, alfalfa hay and cotton were the most widely irrigated crops, but acreage under those crops has stayed relatively constant since then. Meanwhile, irrigated acres planted in corn for grain and soybeans have increased substantially. In 1964, farmers planted less than 2 million acres of irrigated land in corn for grain. By 2017, irrigated acreage planted in corn grew to more than 12 million acres, making corn for grain the most commonly irrigated crop. Over the same period, irrigated acreage planted in soybeans also increased substantially, from fewer than 1 million acres to nearly 10 million acres. The growth in irrigated corn and soybean acreage reflects, in part, increasing demand for these crops as feedstock sources for bioenergy production and feed for livestock operations, both domestically and abroad. Irrigated corn and soybean expansion also reflects a broader eastward shift in irrigated production acreage over the past five decades. This chart was drawn from the USDA, Economic Research Service report “Trends in U.S. Irrigated Agriculture: Increasing Resilience Under Water Supply Scarcity,” published December 28, 2021.

Use of surface or groundwater for irrigation depends on regional water availability, legal institutions, and infrastructure investments

Monday, March 14, 2022

Surface and groundwater are the two primary water supply sources for irrigated agriculture. Groundwater is pumped from aquifers, while surface water is diverted from natural streams, rivers, and lakes. The predominance of surface versus groundwater use varies regionally. Groundwater is the most common source of water applied for irrigation in the Mississippi Delta, Northern Plains and Southern Plains regions. The prevalence of groundwater-fed irrigated agriculture in the Northern and Southern Plains relates to the regions’ historically abundant groundwater resources. The High Plains Aquifer, the largest aquifer in North America and also known as the Ogallala Aquifer, underlies significant portions of the Plains regions. The Mississippi Delta region also has abundant groundwater resources that are relatively shallow, making groundwater-based irrigation less expensive. Irrigated agriculture relying on surface water is most prevalent in the Mountain and Pacific regions. The extent of surface water use for irrigation in these regions reflects past Federal, State, and local investments in water conveyance and storage infrastructure, as well as characteristics of the regions’ legal institutions which grant water rights based on historical beneficial use rather than ownership of land along streams and rivers. This chart was drawn from the USDA, Economic Research Service report “Trends in U.S. Irrigated Agriculture: Increasing Resilience Under Water Supply Scarcity,” published December 28, 2021.

Use of irrigation systems vary by crop

Wednesday, March 2, 2022

Irrigation methods vary by crop because of differences in production practices, crop value, water source, and soil characteristics. Irrigation application methods can be broadly categorized as either gravity or pressurized systems. Pressurized irrigation systems apply water under pressure through pipes or other tubing, while gravity irrigation systems use field slope to advance water across the field surface. In general, pressurized irrigation systems are more efficient than gravity irrigation systems under most field settings, as less water is lost to evaporation and seepage. Rice has the largest share of acres irrigated by gravity systems, which is related to the flooding requirements of most rice production systems in the United States. Peanuts have the largest proportion of acres irrigated by pressurized systems. Peanut cultivation is concentrated in the Southeastern United States (i.e., Alabama, Georgia, and Florida), where the prevalence of sandy, well-drained soils makes gravity irrigation methods generally unsuitable because of seepage losses. Pressurized systems are also prevalent among high-value specialty crops, such as vegetables and orchards. Pressurized irrigation systems, particularly low-flow micro irrigation systems, are generally more expensive than gravity irrigation systems, precluding their use among lower value crops. Pressurized systems are also more prominent among crops concentrated in regions more reliant on groundwater, including irrigated corn across the Eastern and Central United States. This chart was drawn from the USDA, Economic Research Service report “Trends in U.S. Irrigated Agriculture: Increasing Resilience Under Water Supply Scarcity,” published December 28, 2021.

Large organizations deliver 80 percent of off-farm irrigation water

Thursday, February 17, 2022

Irrigation delivery organizations, such as irrigation districts, ditch companies, mutuals and acequias, provide water to farms and ranches and can vary in size. The USDA 2019 Survey of Irrigation Organizations collected data about them in the 24 States where these organizations are most common. Analysis of the survey data indicated that most irrigation organizations are small or medium in scale based on the number of agricultural acres they serve. An estimated 44 percent serve fewer than 1,000 irrigable acres, and 40 percent serve between 1,000 and 10,000 acres. However, most land and off-farm irrigation water are supplied by large delivery organizations, which serve more than 10,000 acres. While they represent only 16 percent of organizations, they serve 78 percent of irrigated acres with off-farm water and deliver 80 percent of off-farm water. This chart appears in the ERS report Irrigation Organizations: Drought Planning and Response, release January 2022.

Per acre water use in irrigated farmland shows a declining trend

Wednesday, January 19, 2022

The importance of irrigation for the U.S. agricultural sector has evolved significantly over the past century. Irrigated acreage in the country has grown from fewer than 3 million acres in 1890 to more than 58 million acres in 2017. The expansion of irrigated acreage during this period reflects Federal, State, and local investment in irrigation infrastructure to deliver surface water to farms and ranches. Additionally, this expansion is partly due to advancements in well drilling and pumping technologies, which have facilitated growth in groundwater-based irrigated agriculture. Since 1969, the amount of water used per acre irrigated has decreased substantially. The average water use per acre irrigated was more than 2 acre-feet (1 acre-foot = 325,851 gallons) in 1969, which declined to nearly 1.5 acre-feet by 2018. Efficient water application technologies, such as the transition from gravity-based to pressurized irrigation systems, have driven the reduction in water use per acre of irrigated land. This chart was drawn from the USDA, Economic Research Service report “Trends in U.S. Irrigated Agriculture: Increasing Resilience Under Water Supply Scarcity,” published December 2021.

The distribution of U.S. irrigated acreage has shifted eastward since mid-20th century

Tuesday, January 4, 2022

Regional distribution of U.S. irrigated acreage changed significantly from 1949 to 2017. Trends in irrigated cropping patterns, technological advances, water availability, and changing growing-season weather drove this evolution. The arid Mountain and Pacific regions consistently irrigated the most farmland until 2007, when irrigated acreage in the Northern Plains region surpassed acreage in the Pacific region. Irrigated acreage in the Mountain and Pacific regions remained relatively constant over the 70-year period, despite increasingly limited opportunities for additional water development and increasing competition for water from non-agricultural sectors. The Northern Plains region has experienced the most substantial increase in irrigated acreage, expanding from less than 2 million acres in 1949 to nearly 12 million acres in 2017. The expansion of irrigated acreage in the Northern Plains is related to advances in groundwater pumping technologies, the diffusion of center pivot irrigation application systems, and the region’s abundant aquifer resources. The Southern Plains region experienced similar growth in irrigation until the 1980s, when dwindling groundwater supplies resulted in irrigated acreage declines. The Mississippi Delta and Southeast regions also have expanded irrigated acreage since 1949 reflecting, in part, changing cropping patterns, abundant aquifer water supplies, and producer responsiveness to changing precipitation levels during growing seasons. This chart was drawn from the USDA, Economic Research Service report Trends in U.S. Irrigated Agriculture: Increasing Resilience Under Water Supply Scarcity, published December 2021.

Irrigation delivery organizations use a variety of methods to calculate on-farm water use

Monday, December 13, 2021

Irrigation organizations use a variety of methods to calculate on-farm water use so they can accurately track water use within their delivery systems. The methods used to calculate on-farm water use partially determine ways organizations can price water deliveries. For example, implementing volumetric water pricing is difficult unless organizations can directly meter on-farm water use. According to data collected in the USDA’s 2019 Survey of Irrigation Organizations, about 44 percent of irrigation water delivery organizations use direct metering to calculate on-farm water use, and about 42 percent of organizations use time-of-use estimation to determine water deliveries. The time-of-use method estimates the volume of water delivered based on the duration of deliveries and the characteristics of the conveyance infrastructure. About 17 percent of organizations calculate water deliveries based on self-reporting from irrigated farms and ranches. Many organizations use more than one method to determine on-farm water use. This chart was drawn from the USDA, Economic Research Service report Irrigation Organizations: Water Storage and Delivery Infrastructure, published October 2021.

Large irrigation organizations are most likely to own water storage infrastructure

Monday, November 29, 2021

Water storage infrastructure includes dams and reservoirs that provide a way to store water across seasons and years to meet the demands of irrigators. According to data collected in the USDA’s 2019 Survey of Irrigation Organizations, less than 20 percent of water delivery organizations own and manage their own water storage reservoirs. The remaining water delivery organizations rely on natural streamflow or storage infrastructure owned by State or Federal agencies or other irrigation organizations. Large irrigation organizations, defined as those organizations that serve more than 10,000 irrigable acres, are the most likely to own water storage infrastructure. Almost 37 percent of large irrigation organizations have at least one water storage reservoir. Meanwhile, 21 percent of medium organizations and 10 percent of small organizations, have at least one reservoir. Storage infrastructure is particularly important in snowpack-dependent basins where the timing of spring runoff does not align with peak irrigation water demand. The role of water storage infrastructure will be critical as snowpack decreases, snowmelt runoff shifts to earlier in the growing season, and water demand increases. This chart can be found in the USDA, Economic Research Service report Irrigation Organizations—Water Storage and Delivery Infrastructure, published October 19, 2021.

Cost cited as major reason for not lining canals that carry water to farms, ranches in 2019

Wednesday, November 3, 2021

Irrigation organizations that deliver water to farms and ranches use main and lateral canals, tunnels, and pipelines to transport water from natural waterways, reservoirs, or other infrastructure to irrigated farms and ranches. Transporting water to farms and ranches can result in conveyance losses, or water that is unavailable for irrigation use because of evaporation or seepage. Lining water canals with quasi-impermeable materials, such as concrete or plastic membranes, can reduce conveyance losses as less water is lost to seepage. However, the cost of lining canals may be prohibitively high for many irrigation organizations. According to data collected in the USDA’s 2019 Survey of Irrigation Organizations, almost 76 percent of water delivery organizations cite expense as a reason for leaving conveyance infrastructure unlined. In some scenarios, lining canals may not be feasible or warranted. For example, unlined canals may beneficially recharge aquifers or soil and geologic attributes may minimize seepage losses. A smaller percentage of organizations cite those as reasons for not lining main and lateral canals. This chart can be found in the USDA, Economic Research Service report, Irrigation Organizations—Water Storage and Delivery Infrastructure, published October 19, 2021.

Use of pressurized irrigation systems in the western United States roughly doubled from 1984 to 2018

Monday, September 13, 2021

There are two methods to apply irrigation water to crops: gravity or pressurized irrigation systems. Gravity irrigation systems use on-field furrows, basins, or poly-pipe to advance water across the field surface through gravity means only. Pressurized systems apply water under pressure through pipes or other tubing directly to crops (e.g., sprinkler and micro/drip irrigation systems). Under many field conditions, pressurized irrigation systems use water more efficiently than gravity systems, as less water is lost to evaporation, deep percolation, and field runoff. Over the last 30 years, the number of acres irrigated using pressurized irrigation systems roughly doubled while the acreage irrigated using gravity systems declined substantially in the 17 Western States. In 2018, 72 percent of all irrigated cropland acres (28.96 million acres out of 40.31 million acres of total irrigated area) in 17 Western States used pressurized irrigation systems, up from 37 percent in 1984. This chart appears in the USDA, Economic Research Service topic page for Irrigation & Water Use, updated August 2021.