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Ground water is one of the United State's most important natural recourses. Approximately 40 percent of the water used by the public come from ground water, and 30 to 40 percent of agricultural water in the United States is supplied by ground water. The Ogallala aquifer is a uniquely important source of ground water. Over half the irrigated land in this country is fed by the Ogallala aquifer. The problem is, the aquifer is being depleted faster than it can replenish itself.

The Ogallala aquifer covers about 225,000 square miles, underlying eight states, making it one of the largest aquifer systems in the world. Farms and cities in South Dakota, Nebraska, Wyoming, Colorado, Kansas, New Mexico and Texas depend on the Ogallala for survival.

The Ogallala was once an expansive alluvial stretching eastward from the Rocky Mountains. As the gigantic mountains eroded to the size we see today, porous deposits of rock and gravel were washed down. The climate was different then, and gradually, the plain filled with water, like a giant sponge. When the climate changed, the rains grew less, glaciers retreated, and the erosion of the mountains slowed down. Now the rivers in the area began to cut down into the ground faster than it could than it could be deposited and cut off the alluvium from the runoff water from the Rocky Mountains, it's main source of recharge. The drier climate also hardened the surface of the plain, making a waterproof cover for the alluvium. Now, from this ancient formation, the water drawn is about three million years old.

The aquifer was discovered in 1899, and over the last 100 years, has been used extensively, mainly for irrigation of crops. With a low recharge rate due to the fact that it is cut off to most of the recharge means, the aquifer is currently losing over 1 foot per year. The climate plays a large part in the low recharge rate. The average rainfall varies across the aquifers great expanse, but a good example can be seen in Lubbock, Texas. In Lubbock, the average rainfall is 18 inches per year. The low rainfall is bad enough, but add in the semi-arid climate and persistent winds, and the evaporation rate in Lubbock is approximately 80 inches per year. Studies have shown that the natural recharge rate is somewhere between .35 and 3.24 inches per acre, in a year.

Ignorance and inefficient irrigation systems played a large part in the early depletion of the Ogallala. It wasn't until the 1950's, that people began to even suspect that the water

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