Liberal Area, Kansas June, 1996 Numerous central pivot irrigation operations can be seen in this near-vertical view taken over southwestern Kansas and the panhandle of western Oklahoma. The small city of Liberal, Kansas, near the Kansas/Oklahoma border, is just to the right of the center of the image. The runways of the Liberal Municipal Airport, located just to the northwest of the city, are also visible. Liberal is the trade center for this grain and livestock area. Oil and natural gas are also extracted in the region. Liberal and the surrounding agricultural regions are located on the Ogallala Aquifer, a vast underground water supply that stretches across the Great Plains from southern South Dakota to the panhandle of northern Texas. It is the largest underground water supply in the United States. The level of the water table is falling because irrigation systems, such as these visible throughout the image, are depleting the water system faster than natural processes can replenish it. Eventually this situation may well cause an economic hardship throughout this region of the Great Plains within the next decade or so