Water and Irrigation in the Western U.S.

24 Jul 2023, Posted in All Posts, Blog Posts
western water

The western United States needs more water. The 2022-2023 winter season brought record amounts of snowpack and has filled reservoirs across the west, but it is a temporary respite from a problem that has plagued settlers since the 19th century.

Two-thirds of agricultural irrigation in the U.S. is in the western 17 states, where rainfall is not enough to sustain crops. Cities like Las Vegas and Los Angeles have begun to restrict water usage on unnecessary lawns and gardens, along with urging the public to limit personal water usage. Las Vegas has essentially outlawed having a lawn at all, but these attempts at reducing water are ignoring the largest water user: agriculture.

When American settlers first began moving across the country to settle in the West, there was widespread belief that the “rain will follow the plow.” People thought that once people started moving to the great plains and the rest of the West, the rainfall would increase. The idea was supported by western states eager for more settlers. Thousands of settlers ended up leaving the Great Plains states after finding that farming was almost impossible without expensive irrigation. Today, farmers use 80 percent of the available water in the Colorado River Basin, which supplies water for 40 million people across the West. Much of this water is put to important use, irrigating massive amounts of farmland in California, producing about half of the nation’s fruits and vegetables. 

Massive infrastructure projects have allowed the West to grow to this size. Almost every river in the western United States is extensively dammed for hydropower and to collect water for irrigation. There is only a single major undammed river in California. Many of these water projects are extremely useful feats of engineering, but others are expensive and inefficient.

California has the most productive farmland in the United States, but other states like Arizona lose massive amounts of water in transport and have inefficient farming. Like many of the western states, Colorado’s second most valuable crop type is hay and alfalfa. Alfalfa requires at least 20 inches of water per season and has an average yield value of $236 per ton. Strawberries and grapes on the other hand need a comparable amount of water and produce a yield value of $1,928 and $1,000 per ton, respectively. In other words, water is a much more productive use for some agricultural ventures than others. 

While the world still needs hay and alfalfa, it makes little sense to grow it in places with the most expensive water in the country. This inefficiency is made only more vexing when considering that the water is subsidized to many of these farmers growing crops in areas where it is not logical. Cotton farmers in Arizona received over $1 billion in subsidies over 10 years, despite being a nonessential crop and it costing the government more money to move water there than almost any other place. The recent Colorado River deal, while hailed by many as a way to protect the reservoirs, works by essentially paying many farmers not to farm. 

The real way to fix this issue isn’t necessarily massively expensive water projects or desalination plants –although this is a solution – but a change in efficiency and redistribution. Flood (also known as gravity) irrigation, widely used in much of the west, is often extremely inefficient and can be a waste of water. Other irrigation systems, such as spray (also known as pressure) irrigation, can lose more water to evaporation. However, new technologies are available that make this system less inefficient. Most efficient may be drip irrigation, which has been pioneered and perfected in the desert ecosystems of Israel.

Smaller farmers have been quicker to make this adjustment to more efficient spray systems, but larger farms, where the cost of irrigation pumping is spread across a much larger area, have been more reluctant to change. In 1994, 63 percent of farms in the West were using traditional inefficient irrigation, compared to 52 percent in 2013. The most efficient drip systems can save up to 50 percent more water than traditional irrigation but can cost upwards of $2,000 an acre. The Department of Agriculture offers an incentive to switch, but only at about $100 per acre. 

Moving all farms to more efficient irrigation systems would save an enormous amount of water. Farmers might save money in the long run by switching to a more efficient irrigation system, but government water subsidies mean that the increased water usage doesn’t cost very much. Not only does a change to western agriculture irrigation require further innovation, but also a policy change.

Water delivery for irrigation could also be improved significantly. Off-farm sources provide 40 percent of the water applied to irrigated cropland. Various water delivery organizations released more than 67 million acre-feet of water in 2019 to be used for irrigation, traveling through canals, pipes, groundwater infrastructure, and more. Of this 67 million acre-feet, 56 million acre-feet was used for irrigation or industrial purposes. Conveyance losses accounted for almost 11 million acre-feet. That’s roughly the same amount of water that 11 million households use in a year. Much of this water was lost in unlined canals. Significantly, 75.9 percent of irrigation organizations cited high costs as the reason for not lining canals with a membrane to prevent water loss. Canals in some places leak up to 50 percent of the water. 

Groundwater is also crucial for irrigation and drinking water in parts of the West, providing nearly 10 million people with water in the 17 western states. Groundwater is supposed to be a naturally replenishing resource, where new water from snow and rain will bring the groundwater to its natural table, but overuse for irrigation and cities is changing that too. Underground aquifers are being used much faster than they can be replenished across the western United States. Groundwater levels are decreasing six times faster than surface water levels, at over 4.5 million acre-feet per year. There is no real solution to this problem other than increased regulation around groundwater use, otherwise underground aquifers will disappear completely, taking potentially thousands of years to refill. 

The water crisis in the western states is more complicated than getting rid of pools or lawns in the cities, and it should be solved through changes in policy and industry efficiency instead of massive infrastructure projects taking water from the Mississippi and the Yukon. It is time for the 17 western states – in which the federal government is the majority land owner – to address the problem sustainably instead of continuing the quest for more water. Increased efficiency of farming practices, water transportation infrastructure, and water allocation practices can make the difference the west needs for a secure future. Restricting unnecessary uses of water in cities is a smart move, but should be complementary to changes in agriculture, which uses the vast majority of the water in the west. 

The federal and state governments together can play a pivotal role improving infrastructure and incentivizing better farming practices. There will likely be resistance from agricultural interests who enjoy the status quo, so changes will need to be made carefully and deliberately. Ultimately, everyone in the West understands the importance of water and that the current situation is unsustainable. Innovations like drip irrigation, dry farming, and improved desalination technologies are important, but ultimately, it is the small changes in efficiency that will make the biggest difference. 


Written by Owen Rogers, Public Policy Intern


The Alliance for Innovation and Infrastructure (Aii) is an independent, national research and educational organization. An innovative think tank, Aii explores the intersection of economics, law, and public policy in the areas of climate, damage prevention, energy, infrastructure, innovation, technology, and transportation.