Soaring Ethanol Production Pressures Water Supply

Soaring Ethanol Production Pressures Water Supply

October 2007

 If U.S. ethanol production 
continues to rise, the effect on water quality could be considerable and 
water supply problems could develop, says a new report today from the 
National Academy of Sciences' National Research Council. 
Increased pressure on local aquifers used to grow and refine corn into 
ethanol, high levels of nitrogen in groundwater from pesticides and 
fertilizers, and runoff pollution in streams and rivers are a few of the 
potential impacts, said the committee that wrote the report. 
Chaired by Dr. Jerald Schnoor, a professor of engineering at the 
University of Iowa, the six member committee examined policy options and 
identified opportunities for new agricultural techniques and technologies 
to help minimize effects of biofuel production on water resources.

Recent increases in oil prices together with subsidy policies have led to 
a dramatic expansion in corn ethanol production and high interest in 
further expansion over the next decade. 
Because of strong national interest in greater energy independence, in 
this year's State of the Union address, President George W. Bush called 
for the production of 35 billion gallons of ethanol by 2017, which would 
equal about 15 percent of the U.S. liquid transportation fuels. 
The committee found that agricultural shifts to growing corn and expanding 
biofuel crops into regions with little agriculture, especially dry areas, 
could change current irrigation practices and greatly increase pressure on 
water resources in many parts of the United States. 
The effects will vary by region. In the Northern and Southern Plains, corn 
generally uses more water than soybeans and cotton, while the reverse is 
true in the Pacific and mountain regions of the country. 
Water demands for drinking, industry, and such uses as hydropower, fish 
habitat, and recreation could compete with and constrain the use of water 
for biofuel crops in some regions.
 
Growing biofuel crops requiring additional irrigation in areas with 
limited water supplies is a major concern, the report warns. 
"Fundamental knowledge gaps" prevented the committee from making reliable 
assessments about the water impacts of future large scale production of 
feedstocks other than corn, such as switchgrass and native grasses. 
In addition, other aspects of crop production for biofuel may not be fully 
anticipated using the frameworks that exist for food crops. The water 
requirements of food crops may not translate directly into the 
requirements for biofuel crops. 
"For example, biofuel crops could be irrigated with wastewater that is 
biologically and chemically unsuitable for use with food crops, or 
genetically modified crops that are more water efficient could be 
developed," the committee said. 
The quality of groundwater, rivers, and coastal and offshore waters could 
be impacted by increased fertilizer and pesticide use for biofuels, the 
report says. 
High levels of nitrogen in stream flows are a major cause of low-oxygen or 
"hypoxic" regions, commonly known as "dead zones," which are lethal for 
most living creatures and cover broad areas of the Gulf of Mexico, 
Chesapeake Bay, and other regions. 
       
The report notes that there are a number of agricultural practices and 
technologies that could be employed to reduce nutrient pollution, such as 
injecting fertilizer below the soil surface, using controlled-release 
fertilizers that have water-insoluble coatings, and optimizing the amount 
of fertilizer applied to the land. 
The switch from other crops or noncrop plants to corn would likely lead to 
much higher application rates of highly soluble nitrogen, which could 
migrate to drinking water wells, rivers, and streams, the committee said. 
When not removed from water before consumption, high levels of nitrate and 
nitrite - products of nitrogen fertilizers - could have significant health 
impacts, warns the report. 
Excessive levels of nitrate in drinking water have caused serious illness 
and sometimes death. Once taken into the body, nitrates are converted into 
nitrites. The serious illness in infants is due to the conversion of 
nitrate to nitrite by the body, which can interfere with the 
oxygen-carrying capacity of a child's blood, according to the U.S. 
Environmental Protection Agency. This can be an acute condition in which 
health deteriorates rapidly over a period of days. Symptoms include 
shortness of breath and blueness of the skin. 
Nutrient and sediment pollution in streams and rivers could also both be 
attributed to soil erosion. High sedimentation rates carry financial 
consequences as they increase the cost of often-mandatory dredging for 
transportation and recreation. 
The committee observed that erosion might be minimized if future 
production of biofuels looks to perennial crops, like switchgrass, poplars 
or willows, or prairie polyculture, which could hold the soil and 
nutrients in place better than most row crops. 
The committee also identified other ways that farming could be improved, 
such as conservation tillage and leaving most or all of the cornstalks and 
cobs in the field after the grain has been harvested. 
For biorefineries, the water consumed for the ethanol production process - 
although modest compared with the water used growing biofuel crops - could 
substantially affect local water supplies, the committee concluded. 
A biorefinery that produces 100 million gallons of ethanol a year would 
use the equivalent of the water supply for a town of about 5,000 people. 
Biorefineries could generate intense challenges for the management of 
local water supplies, depending on where the facilities are located. 

The report held out the hope, however, that "use of water in biorefineries 
is declining as ethanol producers increasingly incorporate water recycling 
and develop new methods of converting feedstocks to fuels that increase 
energy yields while reducing water use." 
Jonathan Kaplan, director of the Sustainable Agriculture Project for the 
Natural Resources Defense Council, views the report in the context of a 
major Farm Bill that is now working its way through Congress. 
"The National Academy of Sciences report makes it clear that unless 
Congress acts decisively through the Farm Bill and comprehensive energy 
bill, increased biofuels production will increase water pollution from 
agriculture and intensify many regional and local water shortages." 
"The report also details many agricultural practices, technologies, and 
other biomass crops that could help reduce total water use and pollution 
while we increase the production of biofuels. But to deliver on the 
promise of biofuels, Congress must dramatically increase funding for Farm 
Bill conservation programs and reform them to get more conservation per 
dollar," Kaplan said. 
It is not enough to increase the volume of production, he said, "We also 
need to shift our biofuels policies to improve environmental and energy 
security performance." 
The study was sponsored by the McKnight Foundation, Energy Foundation, 
National Science Foundation, U.S. Environmental Protection Agency, and 
National Research Council Day Fund. 
To read the report, "Water Implications of Biofuels Production in the 
United States," visit 
http://books.nap.edu/openbook.php?record_id=12039&page=R1. 

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