Asked if she had been worried that the underground pipeline could leak, Bartlett said she hadn't even known it was a possibility.

CNN: Arkansas AG to investigate oil pipeline leak

About two dozen homes in Mayflower, in central Arkansas, were evacuated Friday as the crude oil, which originated in Canada and was bound for Gulf Coast refineries, crawled through yards and down streets spilled from a 2- or 3-inch gash in the underground Pegasus pipeline, officials have said.

CNN: Arkansas AG to investigate oil pipeline leak

But the Ogallala is completely interconnected underground and significant pipeline spills and wellhead catastrophes could affect more cropland and human health than any other disaster, including climate-induced droughts.

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The other portion of the pipeline had stirred concerns of Nebraskans worried about underground water supplies.

CNN: Keystone pipeline builder proposes new route

Traversing their land is a natural gas pipeline, 36 inches in diameter and 6 feet underground.

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Ostensibly, Obama made the decision to block the pipeline because of concern over contamination of the Ogallala Reservoir, a vast underground water source that makes much of Midwestern agriculture possible.

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