ogallala
...r is the largest “underground sponge” in the United States. It contains more than 977 trillion gallons, or three billion acre-feet of water. (Jack Lewis) the water contained in the aquifer is enough to fill Lake Huron plus one fifth of Lake Ontario. “If pumped out over the united states,” Lewis writes, The nature and the extent of the Problem Each year, at least 7.8 trillion gallons of water are drawn up from Ogallala Aquifer to irrigate the crops planted on the high plains. These crops are the main food source for our entire country. Tragically, irrigation is depleting the aquifer faster than it replenish itself, and that is the problem In fact, only the tiniest fraction of the water is ever replaced in the Ogallala Aquifer. If the water were ever fully depleted, the aquifer would need 6,000 years to refill naturally (zwingle 83). The only way the Ogallala can be replenished is by water seeping down through layers of soil until it reaches the aquifer. This water comes from the small amount of precipitation in the region, as well as from streams, reservoirs, canals, and irrigation (McGuire and Sharpe). How serious is the problem? Since 1930, the aquifers water has been reduced by 11 percent (Lewis). The volume of water has decreased because the use of irrigation has increased so much since World War II. In 1949, 2.1 million acres were under irrigation. In 1969, the amount of irrigated land rose to 9.0 million acres and in 1978 it rose to 13 million acres (McGuire and Sharpe). The Land is supplied by irrigation wells, and the number of wells has exploded over the decades from just 170 in 1930, to more than 150,000 today (Nebel and Wright 279). The biggest technological advance that has made this irrigation explosion possible is the center-pivot irrigation system. John Opie explains the system: The center pivot is a 1300-foot long pipe that is held eight feet off the ground by a row of seven or more towers on large wheels. Sprinklers are attached at regular intervals along the pipe, pointing up or down. One end of the pipe is set in the middle of a 160-acre quarter section around which the pipe and wheeled towers circle. (146) The water pumped through the pipe triggers a mechanism that causes the system to roll in a large circle. All of the crops within the circle receive a generous amount of water. If you were flying over the Great Plains between Minneapolis and Denver in the summertime, you would see thousands of green circles, showing how farmers have irrigated their land. With center-pivot irrigation, crop production on one acre increases 600 to 800 percent compared to dry land and 40 percent of American beef cattle feed on the grain and water of the Ogallala (Nebel and Wright 279). Center-pivot irrigation, however, has dramatically lowered the aquifers water level. Even though farmers have known for decades that this was happening, they have continued to pump and spray as much water as they felt was necessary. When a drought hit in the mid-1970s, the water level of the Ogallala began to lower drastically in some areas because of overuse and lack of replenishment. In some parts of Texas, water levels dropped as much as 200 feet. Farmers who lived above shallow parts of the aquifer could not pump enough water for their crops at that time. What makes the problem worse is that much of the water pumped from the Ogallala has been wasted. With center-pivot irrigation, 50 percent of the water evaporates before hitting the ground. Some farmers also over water their fields, thinking more water is better. Much of this extra water filters into streams and ends up in the Gulf of Mexico, instead of seeping back into the ground to replenish the aquifer (Sheaffer and Stevens 115). The problem is not just about wasteful irrigation, however. It is also about resistance to change. As Sheaffer and Stevens say in their book future water, “the real problems are attitudes Attitudes are held by an establishment that appears unwilling to change” (116) Farmers have thought of the Ogallala’s water as their private property, and it is difficult for them to give up their “rights.” In some places, farmers and cities are actually fighting over use of Ogallala water (Thorpe). The Solution: Sustainable Farming Practices Because people’s lives and the land itself are at stake, citizens in the plains state need to change their attitudes about the use of this resource. The key is following what are called “sustainable farming practices”. These practices promote the careful ...