Groundwater Test Bank

Which of the following uses the largest percentage of the Earth's groundwater?

Irrigation

________ is a period of abnormally dry weather that persists long enough to produce a significant hydrologic imbalance.

drought

Which household function has the highest daily water consumption?

toilets

In what spaces or voids does most groundwater reside?

pore spaces and fractures

Which of the following materials is most readily dissolved by water?

calcite

Which of the following is not a factor that will influence infiltration of groundwater?

Acidity of precipitation

If gravity pulls infiltrating water downward, what force allows water to be pulled upward at the capillary fringe?

surface tension

The ________ is the point in the subsurface where 100% of the pore spaces are filled with water.

zone of saturation

How will the water table respond if part of it goes from being a dry spring to a wet spring?

water table will rise

How will the water table respond when there is a drought?

water table will fall

To be a gaining stream, the elevation of the water table must be ________ than that of the surface of the stream.

higher

What is permeability?

ability to transmit water

________ is the portion of groundwater that is retained as a film on particle and rock surfaces and in tiny openings in the subsurface.

specific retention

In order for an aquifer to be useful for reliable water extraction, what kind of porosity and permeability should it have?

High porosity, high permeability

What force pushes groundwater from pore space to pore space when below the water table?

hydraulic gradient

________ is when groundwater is being replenished. ________ is when groundwater is flowing back toward the surface.

recharge; discharge

Why is the aquitard a necessary part of any groundwater system?

It serves like the bottom of a bucket, allowing water in the aquifer above to be held in place

________ is a term used to describe how the water table around a pumping well becomes lowered and roughly conical in shape as water is taken from the subsurface.

cone of depression

What is the term used to describe the hypothetical line the water in a confined aquifer would rise to if it weren't trapped?

Potentiometric surface

A perched water table is normally located ________ the main aquifer and is an aquifer that is ________ than the main aquifer.

above; smaller than

A water tower sending water into your home is most like a ________ artesian well and if your pipes were not sealed ________.

nonflowing; water would sink back into the aquifer

What groundwater feature forms where the water table intersects with the Earth's surface, creating a natural outflow of groundwater?

spring

What geologic process is responsible for warming the water at nonvolcanic locations such as Hot Springs National Park, Arkansas, and Warm Springs, Georgia?

Normal geothermal gradient as groundwater circulates at depth

What is the source of much of water in geothermal features such as geysers and hot springs?

subterranean lakes

Why do geysers spout periodically and then go quiet?

steam builds up in empty chambers and is released, thus relieving pressure

Which environmental issue most commonly affects groundwater aquifers in coastal or island areas?

saltwater contamination

California's Central Valley is an important agricultural area for U.S. fruit and vegetable production. Because of the semiarid climate there, farmers must irrigate their crops. Which environmental problem do you anticipate as a result?

land subsidence

Which acid, found in most groundwater, is responsible for most karst topography worldwide?

carbonic

The general term used to describe cave deposits is ________.

dripstone

While on vacation, you visit a local Imax theater and see a movie about cave diving in the Yucatan Peninsula. In one of the caves, which is currently filled with water, you notice the divers swimming past some stalactites and stalagmites. If the water table is now above the level of the ceiling of the cave, what does the presence of the cave decorations indicate about past water table levels?

The water table was much lower, and the features were formed by water dripping from the ceiling into an air-filled chamber.