# Center Pivot Irrigation and The Ogallala Aquifer

The Ogallala Aquifer is an underground water source used by many farmers and ranchers in the Great Plains region to utilize land that would be unable to be farmed for grain without its use. Center pivot irrigation systems are the main way in which this water is drawn up from underground and spread over the corn, wheat, or other crops to introduce enough moisture for them to grow productively. This method is common and has continually lowered the level of the water table and caused water reserves to drop. If we continue to draw water in this way, the level will continue to drop. By finding alternative ways to use the water in a more efficient manner after being extracted, the aquifer will be better suited to maintain itself in the future.

Since the 1950’s, farmers and ranchers have been pulling water from this mostly non-renewable aquifer and its level has been declining. With the advent of modern motors and increased pump technology, the agriculturists in the area were able to tap in an ancient and vast area of saturated ground, covering several modern states. The preferred method of irrigating in most of this area is the center pivot system. This method of irrigation involves strong pumps to bring water to the surface, and long, elevated piping on drive wheels that extend out from the center of the field. The pump system pushes water from the aquifer up and out the sprinklers, which continually make their way around the field, making a circle with the pump system at the center. Systems are common seen at a quarter mile long and watering 130 acres, all the way up to a half mile long and almost 500 acres of cropland. This is an effective way to change normally arid soils and land into productive cropland. This irrigation system is the most common on top of the Ogallala Aquifer and make up the biggest threat to its levels. Total storage of the aquifer has declined significantly, and since the development of this center pivot method, we have seen close to a 9% decline.

$\frac{266,700,000\text{acre-feet}}{2,900,000,000 \text{acre-feet}} = 0.091 \approx 9\text% \text{decline in total acre-feet}$

This is the total water declined from the aquifer from about 1950 until 2013, a drastic decline. Along with this loss of stored water, we see individual wells going dry and needing to be drilled deeper and deeper to get to the water. The most drastic of this water loss has occurred most recently. From 2011 until 2013, when the last data was taken, the decline in stored water was 36 million acre-feet.

$\frac{36,000,000\text{acre-feet}}{266,700,000 \text{acre-feet}} = 0.135 = 13.5\text% \text{water lost between 2011-2013}$

The most troublesome part of this comes from the fact that the rate at which we are using it is increasing. As you can see, almost one-seventh of the total water lost in the Ogallala Aquifer was just in the last few years. As we look back at one of the hottest summers the Western states have seen, it is unfortunate to see where the current levels sit. This massive economic area can and will be disrupted extensively if the agricultural community can’t find some sort of solution.

The first way in which we have made strides toward fixing the over taxation of the aquifer is by re-designing the center pivot systems themselves. This involves a dropping of the actual sprayer head to only a few feet above the crop heads themselves. The sprinkler nozzles then dispense water directly onto the crops and the soil beneath them. By reducing the space between the nozzles and the soil, you minimize the opportunity for moisture to evaporate before being useful. This also reduces the amount of misted water that could blow away from the crops due to wind.

Another, more difficult method of change for the region is the transition to crops that require less water than the traditional row crops, corn, soybeans, wheat and other big grains. The problems arise with this fix to the issue due to the loss of profits for the individual farmers and difficulty in sales of these less profitable crops. When the economy of a region relies heavily on the production of the major grains for animal feed, ethanol production, and syrup production, the incentive for private businesses and the farms they operate to change to sorghum and other species that have a smaller water requirement is minimal. In addition for loss profit in the sale of these different, more water efficient crops is the increase in labor for most of their production. For vegetables and many other common produce species, the amount of labor and non-machine drastically increases and the ability to utilize the massive fields of the high plains diminishes. These are just a few of the hurdles in reigning in the amount of water we are pulling out of the ground, and more need to be explored before we do enough damage to the Ogallala Aquifer.

With the aquifers continued use, you can see that at the present rate will cause continued problems in the area. With this source of water being so crucial to the agricultural economy of the region, we must utilize different methods to more efficiently use the water resources in the region. With agricultural production so important to our nations economy, and more specifically the great plains region, the conservation of the Ogallala Aquifer is vital to the longevity and economy of our high plains states. If we continue to withdraw water at this rate without giving it an opportunity to retain and replenish, we will find ourselves digging deeper and deeper until we lose access to this water source entirely. This scary thought dooms agriculture success in the region, as well as endangers communities from losing their drinking supply as well. We, as a community of agriculturalist need to make a conscientious effort to reduce and better utilize this natural resource so we can succeed as a society for many years to come.

1. Hornbeck, Richard, and Pinar Keskin. “The Historically Evolving Impact of the Ogallala Aquifer: Agricultural Adaptation to Groundwater and Drought.” American Economic Journal 2014.6 (2014): 190-219. Web.

2.Sophocleous, Marios. “Conserving and Extending the Useful Life of the Largest Aquifer in North America: The Future of the High Plains/Ogallala Aquifer.” Ground Water 50.6 (2012): 831-9. Web.

3. Basso, Bruno, Anthony D. Kendall, and David W. Hyndman. “The Future of Agriculture Over the Ogallala Aquifer: Solutions to Grow Crops More Efficiently with Limited Water.” Earth’s Future 1.1 (2013): 39-41. Web.

4.McGuire, V.L. “Water-Level Changes and Change in Water in Storage in the High Plains Aquifer, Predevelopment to 2013 and 2011-2013” U.S. Geological Survey Scientific Investigations Report 2014-5218 14 p.

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