Tag Archives: Irrigation

Study Finds We Vastly Underestimate Water Management’s Depletion of Freshwater


Here’s a frightening word of the day: “evapotranspiration.” It simply refers to water lost to the atmosphere by evaporation, or after being consumed and released into the air by plant life. It wasn’t so ominous last week, but it is this week because a new study in the journal Science puts it in a new context: unsustainable human use of freshwater.

Essentially, the study finds human have used 18 percent more of the planet’s freshwater than we previously thought, because we’ve underestimated the impact of our water-management systems, such as irrigation, dams and reservoirs. They cause more water to be lost to the atmosphere than would occur naturally, effecting precipitation patterns. Gather a lot of water in one place, like a reservoir, for instance, and more of it evaporates across the greater surface area exposed to air. The researchers studied the ratio of evapotranspiration to precipitation between 1901 and 2008, finding a significant increase in the latter half of the time period.

The additional 18 percent tips our water use into the unsustainable category given the increasing human population, the researchers warn. As Chelsea Harvey writes in her article about the study in The Washington Post, “The study highlights a critical need for better monitoring of our freshwater use and the ways our management techniques can affect the water cycle, as [study co-author Fernando] Jaramillo noted that the current effects of human water management ‘are even larger and more recognizable than the effects of atmospheric climate change.’”

Read more:

Alarming research finds humans are using up far more of Earth’s water than previously thought – The Washington Post

Local flow regulation and irrigation raise global human water consumption and footprint – Science

Related posts:

World Water Day: UN World Water Development Report Warns of Global Crisis by 2030

At the Point of ‘Peak Water,’ Our Foreseeable Future Grows Shorter

Mapping the World’s Most Water-Stressed Countries

Serious Water Conservation Demands Layered Approach and Emotional Commitment

Over-Salted: The Trouble(s) With Desalination

Study: Freshwater Shortage Will Double Climate Change’s Impact on Agriculture

Unchecked Emissions Will Drain Water Resources, Warns Leaked U.N. Report

Study Describes Vast Reserves of Water Under Ocean Floors

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Filed under Agriculture, Climate Change, Conservation, Dams and Hydropower, Drought, Environment, Groundwater, Rivers and Watersheds, Science, Sustainability, Water Resources, Water Shortage

Curtailing Big Ag’s Water Use in California

Image: iStockPhoto.com

When drought-struck California moved to curb consumers’ use of water, I wrote about agriculture’s massive and under-regulated use of water. On Friday the state moved to cut many farmers’ use of water, in terms of some of the older rights-holders who divert water from Central Valley rivers and streams. In spring, cuts were made to thousands of junior rights holders’ usage, including many growers. This is more than the state did when it curtailed Big Ag’s water use nearly 40 years ago, in 1977, the last time it made such a move. What it hasn’t done is to move strongly to curtail the industry’s waste of the water it’s allocated to use, which is to say …  it’s allowed to use most of it (about 80 percent).

Just for “fun,” here’s an annoyingly educational reminder that most Americans make the California drought worse by eating the food grown there. That’s not to say they should forego the glorious bounty and cramp the world’s 8th largest economy, but some would argue just that, more or less. Let’s say that some of Cali’s major crops — rice, almonds, avocados — should be grown where there is ample water because they need so damn much of it. Maybe not so much compared to raising beef, but still — a lot.

Another not-fun thing: Sucking up the groundwater is making the surface of California sink faster than ever before, and it’s going to cost a lot of money as infrastructure like bridges and roads suffers damage.

Related post:

It’s Long Past Time to Police Big Agriculture’s Water Waste

Read more:

Report: Feeding Ourselves Thirsty: How the Food Sector Is Managing Global Water Risks – Ceres (full report)

California Cuts Farmers’ Share of Scant Water – The New York Times

California Move to Restrict Water Pumping by Pre-1914 Rights HoldersLos Angeles Times

Drought-Ravaged California Orders Record Water Cuts on FarmersThe Guardian

The Untapped Potential of California’s Water SupplyPacific Institute and NRDC

California Is Literally Sinking Into the GroundMother Jones

Joseph Poland of the U.S. Geological Survey used a utility pole to document where a farmer would have been standing in 1925, 1955 and where Poland was then standing in 1977 after land in the San Joaquin Valley had sunk nearly 30 feet.

Joseph Poland of the U.S. Geological Survey used a utility pole to document where a farmer would have been standing in 1925, 1955 and where Poland was then standing in 1977 after land in the San Joaquin Valley had sunk nearly 30 feet. Image: U.S. Geological Survey

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Filed under Agriculture, Conservation, Drought, Groundwater, North America, Rivers and Watersheds, Water Shortage

It’s Long Past Time to Police Big Agriculture’s Water Waste

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When you observe water-stressed and drought-stricken areas around the world, you hear the same question being asked again and again: Who uses the most water? A common assumption leads people to blame the general population for its wasteful ways, heedlessly watering their lawns and washing their cars despite a water shortage. But the real answer, in most cases, is agriculture — and not by a small measure. It often accounts for 70% to 80% of total water use, and sometimes more.

Irrigation and other water uses in agriculture, especially where it is a major industry for domestic and export food production, such as California’s Central Valley, make other water uses look like drops in a bucket. According to a 2012 study by the Pacific Institute, the Golden State’s 38 million people use just 4% of its water, while agriculture, including the raising of both crops and livestock, uses 93%.

The reason this matters so much is that Big Agriculture wastes epic amounts of water and often fights efficiency measures on the basis of cost. California, to stick with that example, uses much less drip irrigation than other arid farming regions of the world. Generally, efficiency standards and enforcement are not in place, which allows massive amounts of water to leak out of systems. And much of the water used simply evaporates because it is not recaptured. This goes on while agricultural users pump out deep aquifers’ groundwater far faster than it can be restored naturally, especially in times of drought.

The types of agriculture matter for the scale of water usage, as well. California rice growers flood the fields, whereas another crop might need only sips of water, relatively speaking. Beef producers use about 2,500 gallons of water per pound (as opposed to 100 gallons of water per pound of grain).  Although costly, relocating water-intensive agriculture from water-stressed regions to places where water is most abundant would make sense. In the U.S., that might mean moving some practices from the Southwest to the Southeast. In China, it would mean moving farms  from the arid north to the wet south. But in many countries, business and political interests would keep it from happening as long as possible, and in the end, severe water shortage and escalating costs would force the issue.

Where you have a massive industry, you have a wealthy lobby with a lot of political power to influence government spending. Critics of California’s $7.5 billion drought bond known as Proposition 1, to be voted on in statewide elections on Tuesday (4 November; update — it passed by a two-to-one margin), note that it provides for new dams and water-storage measures that will benefit agriculture. But it’s not yet clear what might be asked in return. About $50 million of the $7.5 billion appears to be earmarked for agricultural efficiency. Will future measures mandate adequate technology and standards of efficiency? Ultimately, the nine-member California Water Commission will decide how funds from the Prop. 1  bond measure, if passed, will be spent.  They should know that the industries using nine-tenths of the state’s water should be doing a lot more to help ease the region’s water crisis.

Read more:

UPDATE: California Propositions 1 and 2 Sail to Resounding VictoriesSan Jose Mercury News

Prop 1: Water Quality, Supply, and Infrastructure Improvement Act of 2014 – Ballotpedia

Prop. 1, a False Framing of California’s Water CrisisSanta Barbara Independent

New Report Provides Insight to California’s Proposition 1 – Pacific Institute

Prop. 1 Aims to Relieve Drought — But Not This One – Los Angeles Times

Cows, Rice Fields and Big Agriculture Consumes Well Over 90% of California’s Water – AlterNet

Report Targets Waste, Inefficiency in Agricultural Water UseLos Angeles Times


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Filed under Agriculture, Conservation, Dams and Hydropower, Drought, Groundwater, Law, North America, Sustainability, Water Resources, Water Shortage

Study: Freshwater Shortage Will Double Climate Change’s Impact on Agriculture

Experts expect global warming to have a negative impact on crop yields, but shortages of water for irrigation could make for double the trouble, according to a study published yesterday.

As described in ScienceDaily, “given the present trajectory of greenhouse gas emissions, agricultural models estimate that climate change will directly reduce food production from maize, soybeans, wheat and rice by as much as 43 percent by the end of the 21st century. But hydrological models looking at the effect of warming climate on freshwater supplies project further agricultural losses, due to the reversion of 20 to 60 million hectares of currently irrigated fields back to rain-fed crops.”

The study’s lead author, Joshua Elliot, said the analysis is the first of its kind to feature an in-depth comparison of agricultural and hydrological models, which resulted in dramatically different results from other research.

“It’s a huge effect, and an effect that’s basically on the same order of magnitude as the direct effect of climate change,” Elliott, a research scientist with the Computation Institute’s Center for Robust Decision Making on Climate and Energy Policy (RDCEP), Argonne National Laboratory, is quoted as saying. “So the effect of limited irrigation availability in some regions could end up doubling the effect of climate change.”

The “good” news, if any, is that some areas will most likely see more precipitation, which could mitigate some of the effects of shortages, the study says.

The study, entitled “Constraints and potentials of future irrigation water availability on agricultural production under climate change” and conducted under the auspices of the Agricultural Model Intercomparison and Improvement Project, as part of the Inter-Sectoral Impacts Model Intercomparison Project, was published in Proceedings of the National Academy of Sciences.

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Filed under Agriculture, Climate Change, Environment, Research