food supply

(Illustration by Colin Mullin)

A new study found that regions in Texas and California have experienced severe groundwater depletion over the last century due to unsustainable irrigation techniques.

Bridget Scanlon, hydrogeologist in the Bureau of Economic Geology at the Jackson School of Geosciences, published a study in May on water depletion levels in the High Plains regions across Texas, Kansas and Nebraska and the Central Valley region of California. These two regions combined produce a large portion of the nation’s food supply. According to the study, Scanlon compared data from NASA’s Gravity Recovery and Climate Experiment satellites as well as ground-based estimates from well water data in order to determine the level of depletion across these regions. Over the last century, a disproportionate concentration of depletion has occurred in Texas and California, Scanlon said.

“I started focusing my research on impacts of irrigation and water resources when I realized that irrigation consumes 90 percent of freshwater resources,” Scanlon said. “These two regions have accounted for 50 percent of groundwater depletion in the last century.”

Robert Reedy, a research engineering and scientist associate in the Bureau of Economic Geology and co-author of the study, said the results of the research should be interpreted within a bigger picture.

“The food supply is not in danger,” Reedy said. “Agriculture would not go away in the case of depleted water. Productivity would decrease, so it would shift the balances, and prices would certainly go up if a certain supply went down. Part of the whole thing is just to see where all of this is headed.”

Scanlon said one of the most significant findings was the concentration of water depletion in specific parts of the Texas and Kansas areas in the High Plains region, which showed that water depletion was not uniform across one area.

“Most people think the High Plains aquifer is all the same type of system and everything is the same across the aquifer, but with this study we have really shown that spatially it’s quite variable,” Scanlon said. “About 35 percent of the depletion is focused in 4 percent of the land area, so in order to better manage it, we need to understand that.”

In California’s Central Valley, a complicated piping system has allowed areas to the south with less rainfall to be replenished with surface water from northern areas that receive more rain, Scanlon said.

“In California it’s a little bit different,” Scanlon said. “There’s a lot of rain in the Sacramento region but in Bakersfield to the south, the rainfall rate is much lower. California developed a large pipe infrastructure to transfer surface water between regions.”

Despite the effectiveness of the pipe structure, which takes surface water from rainfall, a similar system in the High Plains region would not be viable, Scanlon said. In addition to the process being expensive, Scanlon said Texas does not have all the infrastructure California has and it would be a much more involved process to transfer surface water to areas in need.

Changbing Yang, a research associate in the Bureau of Economic Geology, said there will be significant repercussions if more efficient and sustainable systems aren’t put into place in the High Plains.

“Bridget Scanlon’s study over groundwater depletion in the High Plains and Central Valley regions is significant,” Yang said. “In the High Plains, groundwater yield will decrease by two times if we continue to irrigate it as we have been.”

Part of finding the bigger picture in terms of regional agriculture is realizing that many people are unaware that they may be affected, Reedy said.

“The way the food market is set up in the country, a lot of people are unaware of the whole chain of events and everything that goes into it,” Reedy said. “Different groups of people are aware of certain aspects of what’s going around them in the world and others just don’t hear or understand some aspects of everyday life. Farmers are living on the land and doing the work and sometimes even they don’t know what’s going on except maybe in their own region.”

WASHINGTON — The first new case of mad cow disease in the U.S. since 2006 has been discovered in a dairy cow in California, but health authorities said Tuesday the animal never was a threat to the nation’s food supply.

The infected cow, the fourth ever discovered in the U.S., was found as part of an Agriculture Department surveillance program that tests about 40,000 cows a year for the fatal brain disease.

No meat from the cow was bound for the food supply, said John Clifford, the department’s chief veterinary officer.

“There is really no cause for alarm here with regard to this animal,” Clifford told reporters at a hastily convened press conference.Mad cow disease, or bovine spongiform encephalopathy (BSE), is fatal to cows and can cause a fatal human brain disease in people who eat tainted beef. The World Health Organization has said that tests show that humans cannot be infected by drinking milk from BSE-infected animals.

In the wake of a massive outbreak in the United Kingdom that peaked in 1993, the U.S. intensified precautions to keep BSE out of U.S. cattle and the food supply. In other countries, the infection’s spread was blamed on farmers adding recycled meat and bone meal from infected cows into cattle feed, so a key U.S. step has been to ban feed containing such material.

Tuesday, Clifford said the California cow is what scientists call an atypical case of BSE, meaning that it didn’t get the disease from eating infected cattle feed, which is important.

That means it’s “just a random mutation that can happen every once in a great while in an animal,” said Bruce Akey, director of the New York State Veterinary Diagnostic Laboratory at Cornell University. “Random mutations go on in nature all the time.”

The testing system worked because it caught what is a really rare event, added Mike Doyle, director of the University of Georgia’s Center for Food Safety.

“It’s good news because they caught it,” Doyle said.

Clifford did not say when the disease was discovered or exactly where the cow was raised. He said the cow was at a rendering plant in central California when the case was discovered through regular USDA sample testing. Rendering plants process animal parts for products not going into the human food chain, such as animal food, soap, chemicals or other household products.

There have been three confirmed cases of BSE in cows in the United States — in a Canadian-born cow in 2003 in Washington state, in 2005 in Texas and in 2006 in Alabama.

The Agriculture Department is sharing its lab results with international animal health officials in Canada and England who will review the test results, Clifford said. Federal and California officials will further investigate the case. He said he did not expect the latest discovery to affect beef exports.

The National Cattlemen’s Beef Association said in a statement that “U.S. regulatory controls are effective, and that U.S fresh beef and beef products from cattle of all ages are safe and can be safely traded due to our interlocking safeguards.”

Clifford said the finding shows that safeguards the U.S. government and other nations have put into place in recent years are working. In 2011 there were only 29 worldwide cases of BSE, a dramatic decline since the peak of 37,311 cases in 1992. He credited the decline to effect of feed bans as a primary means of controlling the disease.

There have been a handful of cases of variant Creutzfeldt-Jakob Disease — the human version of mad cow — confirmed in people living in the United States, but those were linked to meat products in the United Kingdom and Saudi Arabia, according to the Centers for Disease Control and Prevention.

Printed on Wednesday, April 25, 2012 as: First case of mad cow in six years appears in California to no alarm