"Today, nearly 25,000 miles of petroleum pipelines exist within the Ogallala Aquifer, including 2,000 miles in Nebraska. These pipelines transport about 730,000,000,000 barrels of crude oil across the aquifer – each year, including nearly 100,000,000 barrels of crude oil transported across the aquifer in Nebraska. After this oil is refined into gasoline, diesel fuel, aviation gas and other products, pipelines transport much of it back across the aquifer for use on Nebraska farms, ranches and roads.
The Ogallala Aquifer — part of the High Plains Aquifer System — consists of braided layers of sand, gravel silts and clays deposited over the millennia. Water flows through the small “interstitial” spaces. Although it’s easy to think of the aquifer as an underground lake in a cavern across the surface of which oil might easily travel, that is not its nature. As shown in the photo at right, the makeup of the aquifer actually resembles a mechanical filter. Like dirt and other particles, oil has a very difficult time moving through this physical environment. Even the water itself moves very slowly — about one foot per day, according to USGS. Some hydrocarbon contaminants can dissolve in the water but that takes time and then movement is very slow and limited in extent. Even if there were a significant release from the pipeline in an area where the oil could reach groundwater, movement of hydrocarbon contaminants in groundwater would be neither broad nor regional.
Since 1930, 24,000,000,000 barrels of crude oil have been produced within the Ogallala Aquifer. In Nebraska, 500,000,000 barrels of crude oil have been produced from 2,000 oil wells drilled through the Ogallala Aquifer."