Aquifiers Case

1. Before visiting the site, define the term aquifer.

A body of permeable rock that can contain or transmit groundwater

2. Now, examine fig. 46. Under what states does the High Plains aquifer lie?

Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming

3. (a)What instigated irrigation in the High Plains? (b)From where is the water drawn?

a)the dust bowl or droughts b) High Plains aquifer

4. What does the Ogallala Formation (which composes the High Plains aquifer) consist of?

Unconsolidated gravel, sand, silt, and clay, also caliche, which is a hard deposit of calcium carbonate

5. Describe how the aquifer is recharged.

The dune sand quickly absorb rainfall which recharges the aquifer.

6. Look at figure 53. Where is the depth to water characteristically less?

Nebraska and Kansas

7. (a)When is the ground-water flow of an aquifer in equilibrium? (b) Is the High Plains aquifer in equilibrium? Why?

A) When the recharge and discharge of the aquifer are equal b) No, because of the withdrawal of large quantities of ground water by wells and redistribution of surface water in ditches and canals.

8. The website discusses the water source of the Platte River and where most of its water comes from. What affect can irrigation have on this river's water level?

The contours in western Nebraska bend upstream, which allows it to gain stream where in west central Nebraska the contours bend downstream and they lose stream.

9. Look at figure 56 which shows the saturated thickness of the aquifer. What region of the NE has the greatest thickness?

North Central Nebraska

10. Now look at figure 61. What do the maps show regarding the change in number of center pivots? Notice the void of irrigation systems in north-central NE and compare this region to the map in figure 56. If the aquifer is saturated in this area, why do we observe an absence of irrigation? (If you aren't familiar with NE check out the map at the following webpage: http://www.fws.gov/mountain-prairie/pfw/ne/ne3.htm).

The center pivot irrigation increased. Because of the