1. The zone of aeration is the area above the water table where the soil, sediment, and rock are not saturated. The open spaces at the zone of aeration are filled mainly with air. The zone of saturation is a zone where water that is not held near the surface penetrates downward until it reaches it. The upper limit of this zone is the water table. The open spaces at the zone of saturation are completely filled with water. The zone of saturation contains the groundwater.
2. Although we usually think of tables as being flat, the water table generally is not. The water table’s shape is usually a subdued replica of the surface topography, reaching its highest elevations beneath hills and decreasing in height toward valleys. The water table is right at the surface where there is a swamp and where there are lakes and streams the land surface is generally below the water table. The most important cause of the irregular surface of the water table is the slow movement of the groundwater.
3. An effluent stream is a stream channel that intersects the water table and is characteristic of humid regions. The groundwater from the zone of saturation feeds into the stream. An influent stream differs by a influent stream is a stream channel that is above the water table level and water seeps downward from the channel to the zone of saturation to produce an upward bulge in the water table. It is characteristic of deserts.
4. Porosity is the percentage of the total volume of rock or sediment that consists of pore spaces. Permeability is a measure of a materials ability to transmit water.
5. The difference between an aquiclude and an aquifer is that an aquiclude is impermeable layers composed of materials such as clay that hinder or prevent water movement, while an aquifer is permeable rock strata or sediment that transmits groundwater freely.
6. When a material has a high porosity but has a low permeability the material would not be a good aquifer.
7. Groundwater moves in looping curves because of the downward pull of gravity, and the tendency of water to move towards reduced pressure.
8. The important contribution to our understanding of groundwater made by Henry Darcy is that he established the relationship between slope and velocity. He established the equation which is known as Darcy’s Law. Darcy’s law says that in a material of given permeability, velocity increases as slope of the water table increases.
9. When an aquiclude is situated above the main water table, a localized saturated zone may be created. The term that is applied to such a situation is a perched water table.
10. The circumstance that might explain why one neighbor was successful and the other was not would be that the successful neighbor reached a perched water table. A perched water table is a localized saturated zone created by an aquiclude above the main water table.
11. The term artesian is applied to any situation in which groundwater rises in a well above the level where it was initially encountered.
12. In order for artesian wells to exist, two conditions must be present. These conditions are the water must be confined to an aquifer that is inclined so that one end is exposed at the surface, where it can receive water, and impermeable layers, both above and below the aquifer, must be present to prevent the water from escaping.
13. When the Dakota sandstone was first tapped, water poured freely from many artesian wells. Today these wells must be pumped. The reason for this was that thousands of wells were connected to the same aquifer and the water table depleted. The pressure decreased and pumps then had to be used.
14. The problem that is associated with the pumping of groundwater for irrigation in the southern part of the High Plains is that in years of average or below-average precipitation recharge is negligible because all or nearly all of the rainfall is evaporated or transpired. Only during wet years recharge is significant. Where there is intense irrigation, groundwater depletion is extreme. If pumping ceased, it would take thousands of years for the groundwater to be replenished.
15. As the result of excessive groundwater withdrawal, land subsidence occurred in the San Joaquin Valley.
16. In a particular coastal area the water table is 4 meters above sea level. Approximately, the fresh water reaches 160 meters below sea level.
17. The rate of natural groundwater recharge decreases as urban areas develop because of street, parking lots, houses, etc. which prevent water from seeping into the ground to recharge the groundwater.
18. The aquifer that would be most effective in purifying polluted groundwater is sand. This is because contaminate groundwater can travel long distances without being cleansed through the large openings in coarse gravel and cavernous limestone.
19. When a groundwater pollutant is classified as hazardous it is either flammable, corrosive, explosive, or toxic and just harmful to anything.
20. The source of heat for most hot springs and geysers is cooling igneous rocks. This is reflected in the distribution of these features by in the United States the great majority of hot springs and geysers are found in the West. This is because igneous activity has been most recent in the West.
21. Two common speleothems are stalactites and stalagmites. Stalactites are the icicle-like structure that hangs from the ceiling of a cavern. Stalagmites are the column-like form that grows upward from the floor of a cavern.
22. Speleothems form the zone of saturation. False because even though the formation of caverns take place in the zone of saturation, the deposition of dripstone is not possible until the caverns are above the water table in the zone of aeration. When streams cut their valleys and lower the water table the chamber is filled with air and cavern building can begin.
23. Areas whose landscapes largely reflect the erosional work of groundwater are said to exhibit karst topography.
24. Two ways in which sinkholes are created are the gradual dissolving of limestone from rainwater seeping downward that is freshly charges with carbon dioxide and suddenly when the roof of a cavern collapses under its own weight.