Groundwater decline in Nebraska in 2013 'unprecedented' [View all]

[Omaha Steve]

Source: Omaha World Herald

By Joe Duggan

LINCOLN — Groundwater in Nebraska dropped by “unprecedented” levels last year as farmers stepped up irrigation in response to record drought and heat in 2012.

Underground water tables declined in 90 of the state's 93 counties between spring 2012 and spring 2013, said Aaron Young, groundwater resources coordinator for the University of Nebraska-Lincoln. Aquifers dropped 2.5 feet on average.

“An average one-year decline of this magnitude has never been recorded before in the state,” Young said Wednesday, referring to groundwater monitoring that has been done since 1930.

Dean Edson, director of the Nebraska Association of Resources Districts, cautioned that one year of data does not signal a water crisis.

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Read more: http://www.omaha.com/article/20140206/NEWS/140209124/1016#groundwater-decline-in-nebraska-in-2013-unprecedented

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http://www.hpwd.com/aquifers/ogallala-aquifer

Ogallala Aquifer



The Ogallala aquifer (pronounced OH-GA-LA-LA) is one of the largest aquifer systems in the world. It stretches across all or portions of eight states generally from north to south to include South Dakota, Nebraska, Wyoming, Colorado, Kansas, Oklahoma, New Mexico, and Texas and underlies about 174,000 square miles. N.H. Darton is credited with describing and naming the formation in 1899 after the town of Ogallala, Nebraska.

The Ogallala aquifer lies relatively near the land surface in most of the above-described area with a maximum thickness of about 1,000 feet with a few hundred feet more the norm. Even in those areas of only a few feet of thickness, the aquifer can almost always be counted on to yield water to a well drilled into it. Some wells yield only a few gallons of water per minute, while others yield 1,000 gallons of water per minute or more. The Ogallala aquifer not only includes the portion of the Ogallala that is saturated with water, but may also include saturated portions of the overlying and underlying formations that are hydraulically connected to the Ogallala.

Water in the Ogallala Aquifer on the Southern High Plains flows from northwest to southeast at about 150 feet per year under natural conditions. This rate of movement can be altered by discharge from the aquifer by pumping wells.

Deposition of the Ogallala Formation began 10 to 12 million years ago during late Tertiary (Miocene/Pliocene) geologic time. Sand, gravel, silt, and clay eroded from upland areas to the west and north were deposited over the erosional land surface of the present-day High Plains by primarily eastward flowing streams. The surface on which the sediments were deposited would have been much like the present area located east of the High Plains escarpment characterized by low hills, relatively shallow valleys, and meandering streams.

FULL info at link.