Name__________________________________ #_____ Date____________ Hour____
Center #2: The Ogallala Aquifer
Part I: Reading and Responding
Directions: Read the background information and answer the questions that follow.
1. Define aquifer:
2. Read the paragraphs under the heading Threats to our Water Supply on p. 265 in the
green textbook; answer the questions that follow below.
3. Changes to groundwater supplies can lead to what types of environmental issues?
4. What is the name of the important aquifer in the United States?
5. Where is this important U.S. aquifer located?
6. Read the background information below, and then answer questions 7-13 on the next page:
Background Information on the Ogallala Aquifer:
The Ogallala Aquifer is the largest known aquifer in the world. It lies underground beneath eight states,
extending from South Dakota and Wyoming in the north to Texas in the south. Before depletion became a
problem, it held more water than all of the freshwater lakes, streams, and rivers on Earth.
The main cause for depletion is irrigation for farming. This area of the United States produces 20% of the
U.S.’s agricultural output. The government has encouraged this level of production with subsidies. For
example, it has supported growing cotton, a plant that requires large amounts of water, along with
providing crop-disaster payments and tax breaks that allow heavy groundwater use. In addition, while the
Ogallala Aquifer contains a large volume of water, it is replenished slowly- so much so that it is
considered a nonrenewable resource. Most of the present water is the same water that was stored at
the end of the last ice age. In some areas, the water is withdrawn at eight to ten times the recharge rate,
leading some experts to predict that the 25% of the aquifer will be depleted 2020.
Some solutions have been suggested in order to slow the rate of depletion. Farmers have had success
using more efficient irrigation systems, raising crops that require less water, and irrigating less land. In
Texas, employing better irrigation technology led to a 2-25% decrease in water use. Furthermore, as
resources have decreased, the cost of drilling and pumping costs have increased, causing an overall
decline in total irrigated area. Finally, better technology for all uses of water in the states on the Ogallala
Aquifer will help preserve this resource for years to come.
(Source:
http://images.google.com/imgres?imgurl=http://library.thinkquest.org/04oct/01590/global/ogallala.jpg&imgrefurl=http://library.thinkqu
est.org/04oct/01590/global/ogallala.html&usg=__uTmu0WeIzmYcppjfyvK84HtPJ04=&h=474&w=282&sz=60&hl=en&start=10&tbnid
=eIMau8fO2Cl83M:&tbnh=129&tbnw=77&prev=/images%3Fq%3Dogallala%2Baquifer%26gbv%3D2%26hl%3Den%26safe%3Dacti
ve%26sa%3DG)
7. List the eight states in North America that the Ogallala Aquifer lies beneath:
8. Define depletion (deplete):
9. What is the main reason for the depletion of freshwater in the Ogallala Aquifer?
10. Explain how humans are involved in the depletion of the Ogallala Aquifer:
11. List two solutions for slowing the depletion of the Ogallala Aquifer:
12. Is the Ogallala Aquifer a renewable or nonrenewable resource? Explain.
13. Define renewable resource:
14. Define nonrenewable resource:
Part II: “Graphing” the Aquifer
Directions:
1. Use Part I of this activity and the picture below to “graph” the Ogallala Aquifer on the United
States map on the next page.
2. Be sure to identify areas of different “saturated thickness” on the U.S. map, like those shown
on the map below.
3. Your completed map should be colorful and show the exact location of the Ogallala Aquifer
on a larger scale.
http://library.thinkquest.org/04oct/01590/global/ogallala.jpg