Water to Supply the Land: Irrigated Agriculture in the Colorado River Basin

Pacific Institute | May 9th, 2013

The Colorado River, recently named America’s most endangered river, supports millions of people in the American Southwest and northwest Mexico and helps irrigate millio

The Colorado River, recently named America’s most endangered river, supports millions of people in the American Southwest and northwest Mexico and helps irrigate millions of acres of land. Yet demands on the river already exceed the river’s average supply, a situation that is projected to get worse in coming years as climate change reduces runoff at the same time that fast-growing southwest cities demand more water. Irrigated agriculture currently consumes more than 70% of the water supply within the Colorado River basin, making it critical for more efficient water use. For the first time, new research from the Pacific Institute describes the extent of irrigated agriculture throughout the seven Colorado River basin states and two additional states in Mexico, the types of crops grown, and the amount of water used to grow these crops. In addition, the new report – Water to Supply the Land: Irrigated Agriculture in the Colorado River Basin – compares several agricultural management scenarios and the potential water savings and costs associated with each. Importantly, none of the scenarios remove agricultural land from production. More than 90% of pasture and cropland in the 256,000-square-mile Colorado River Basin requires irrigation, with about 60% of the irrigated acreage devoted to pasture, alfalfa, and other forage crops used to feed cattle and horses. These forage crops consume about 5 million acre-feet per year, equivalent to a third of the river’s annual flow. Employing innovative irrigation techniques more strategically and in more places – techniques that many farmers are already using – can help ensure agriculture in the basin states continues in the face of rising demand and climate change’s projected impact on supply. Modeling a series of agricultural water management conservation strategies – including regulated deficit irrigation, crop shifting, and advanced irrigation technologies – the Pacific Institute compared potential water savings and costs associated with individual scenarios. The analysis shows considerable water savings are possible. For example, almost a million acre-feet of water may be generated by irrigating alfalfa less often (a practice known as “regulated deficit irrigation”) throughout the basin in the U.S., at an estimated base cost of approximately $81 per acre-foot. Other scenarios, such as shifting to less water-intensive crops, also yield impressive water savings with relatively low costs and without reducing the total amount of irrigated acreage in the basin. For example, replacing about 10% of the basin’s irrigated alfalfa acreage with cotton and wheat could save about 250,000 acre-feet of consumptive water use each year, with estimated base costs of less than $40 per acre-foot. Total reductions in water withdrawals and applied water would be even greater.

Water Use Across the Conterminous United States, Water Years 2010–20, Chapter D of U.S. Geological Survey Integrated Water Availability Assessment—2010–20

U.S. Geological Survey (USGS) | January 15th, 2025

Key Points An estimated average of 223,594 million gallons per day (Mgal/d; 26,179 million cubic meters per month [Mm3/mo]) were withdrawn from freshwater sources fo

Key Points An estimated average of 223,594 million gallons per day (Mgal/d; 26,179 million cubic meters per month [Mm3/mo]) were withdrawn from freshwater sources for human use for crop irrigation, public supply, and thermoelectric power across the conterminous United States (CONUS) during water years 2010–20. Including saline water, withdrawals were 244,817 Mgal/d (28,677 Mm3/mo). Average withdrawals and consumptive use (1) for CONUS crop irrigation during water years 2010–20 were 105,497 and 75,698 Mgal/d, respectively; (2) for public supply were 35,440 and 4,219 Mgal/d, respectively; and (3) for thermoelectric power from fresh water were 82,656 Mgal/d and 2,904 Mgal/d, respectively. Across the CONUS, the source of water—whether groundwater, surface water, public supply, reclaimed wastewater, or a combination thereof—typically depends on the availability of these sources and on the category of use. The water-use categories of industrial, self-supplied domestic, mining, livestock, and aquaculture together accounted for 10 percent of water withdrawals in the United States in 2015. Although a small proportion nationally, these water-use categories can be locally important. Companion chapters: U.S. Geological Survey Integrated Water Availability Assessment—2010–20, Chapter A Water Supply in the Conterminous United States, Alaska, Hawaii, and Puerto Rico, Water Years 2010–20, Chapter B Status of Water-Quality Conditions in the United States, 2010–20, Chapter C  Climate Change and Future Water Availability in the United States, Chapter E  Integrated Water Availability in the Conterminous United States, 2010–20, Chapter F 

Water Use in California

Public Policy Institute of California (PPIC) | April 19th, 2023

What If California’s Drought Continues?

Public Policy Institute of California (PPIC) | August 20th, 2015

California is in the fourth year of a severe, hot drought—the kind that is increasingly likely as the climate warms. Although no sector has been untouched, impacts so

California is in the fourth year of a severe, hot drought—the kind that is increasingly likely as the climate warms. Although no sector has been untouched, impacts so far have varied greatly, reflecting different levels of drought preparedness. Urban areas are in the best shape, thanks to sustained investments in diversified water portfolios and conservation. Farmers are more vulnerable, but they are also adapting. The greatest vulnerabilities are in some low-income rural communities where wells are running dry and in California’s wetlands, rivers, and forests, where the state’s iconic biodiversity is under extreme threat. Two to three more years of drought will increase challenges in all areas and require continued—and likely increasingly difficult—adaptations. Emergency programs will need to be significantly expanded to get drinking water to rural residents and to prevent major losses of waterbirds and extinctions of numerous native fish species, including most salmon runs. California also needs to start a longer-term effort to build drought resilience in the most vulnerable areas.