It contains as much fresh water as the third largest of the Great Lakes, Lake Huron, and underlies 174, 000 square miles (450,000 km2)
From the University of Denver's Water Law Review:
The grain-growing region in the High Plains of America—known as America’s breadbasket—relies entirely on the Ogallala Aquifer. But long term unsustainable use of the aquifer is forcing states in the region to face the prospect of a regional economic disaster. As the High Plains states reach the verge of a major crisis, the states have taken different approaches to conservation with varying results.
The Ogallala Aquifer supports an astounding one-sixth of the world’s grain produce, and it has long been an essential component of American agriculture. The High Plains region—where the aquifer lies—relies on the aquifer for residential and industrial uses, but the aquifer’s water is used primarily for agricultural irrigation. The agricultural demands for Ogallala water in the region are immense, with the aquifer ultimately being responsible for thirty percent of all irrigation in the United States. The Ogallala Aquifer has long been unable to keep up with these agricultural demands, as the aquifer recharges far slower than water is withdrawn.Back in the day, 2008-ish, T. Boone Pickens was pretending he was all about wind power.
Aside from the obvious agricultural ramifications from the Ogallala’s depletion, recent studies have shown that groundwater depletion also has a severe effect on freshwater ecosystems in the region. Each state has had to confront the issue in their own way, but the depletion of the aquifer has become severe enough to warrant the attention of the federal government as well. At the state level, the focus has been on maintaining an orderly depletion of the aquifer rather than developing a plan for sustainable use. However, some states have achieved some level of success in slowing down the aquifer’s depletion. Kansas, for example, has recently achieved mild success by adopting a program that put conservation in the hands of the State’s farmers. On the other hand, Nebraska has seen more success than Kansas by being tougher on farmers and exercising its enforcement powers. The federal government has also set up financial and technical assistance for farmers who commit to conservation and is funding large-scale pipeline projects to bring in water to the more desperate areas of the High Plains.
The Ogallala Aquifer, also known as the High Plains Aquifer, underlies eight different states, stretching across America’s High Plains from South Dakota down to Northern Texas. It is an unconfined aquifer that is recharged almost exclusively by rainwater and snowmelt, but given the semiarid climate of the High Plains, recharge is minimal. In some areas, the water table is dropping as much as two feet a year, but recharge in the aquifer only averages around three inches annually.
The aquifer provides nearly all of the water for residential, industrial, and agricultural uses in the High Plains region. Irrigated agriculture is particularly straining on the aquifer as the region is responsible for one-fifth of the wheat, corn, cotton, and cattle produced in the United States. The High Plains actually leads the entire Western Hemisphere in irrigation with fourteen million acres irrigated annually, primarily in Nebraska, Kansas, and Texas. Accordingly, farming accounts for an astounding ninety-four percent of groundwater use in the region....MORE
He was actually making a play for the southern end of the Ogallala:
Beyond Wind Plan, Pickens Eyes Pipelines in Drought-Ridden U.S.
CEP's Live Blogging - "Notes from the T. Boone Pickens town hall meeting in Topeka"
T. Boone Pickens and Power Politics-Texas Style
"Boone Pickens unceremoniously drops wind from his energy plan"
