Mastering Geology Chapter. 14: Ground Water

In which ways do sinkholes form? Select all that apply.

- Limestone is dissolved by rainwater, the bedrock surface lowers, and groundwater that is flowing in the passages below washes away the soil. - A roof of an already formed cavern collapses under its own weight.

What features are caused by excessive groundwater withdrawal? Choose all that apply.

- a cone of depression - land subsidence

Of the rocks listed below, which has high permeability? Choose all that apply.

- conglomerate - sandstone

What share of Earth's liquid freshwater is groundwater?

96 percent

________ account(s) for the largest usage of groundwater in the United States.

Agriculture and irrigation

How does groundwater create caverns?

Caverns are created when acidic groundwater dissolves and carries away limestone.

Which one of the following concerning stalactites and stalagmites is NOT true?

Stalagmites form on the floors of caves below the water table.

Animation: Cones of Depression Part A How does the water table change around a pumping water well?

The water table elevation decreases.

Which of the following best describes how geysers erupt?

With a slight reduction in pressure, water in a saturated, natural conduit suddenly boils, sending a plume of steam and hot water into the air above the vent.

Where are the most extensive geothermal features in the world?

Yellowstone National Park, United States

Highly impermeable layers such as compacted clay or shale are known as ________.

aquitards

Which example best demonstrates groundwater's power as an erosional agent?

dissolution of limestone leading to sinkholes and caverns

Animation: Cones of Depression Part B What is the cone of depression?

the shape that the water table takes on near a pumping well

How do stalactites and stalagmites form? Select both correct processes.

- Stalagmites form when calcite-rich water falls to the floor from the ceiling, splattering minute amounts of calcite on the floor. After many such depositions, a stalagmite begins to take shape. - Stalactites form on the ceiling when water seeps through the ceiling and deposits calcite. Eventually a soda straw develops, which develops into a stalactite after many more depositions of calcite.

When rain falls on land, what factors influence the amount of water that soaks in? Select all that apply.

- the intensity of rainfall - the nature of the surface material - the steepness of the slope - the amount of vegetation on the surface

________ controls the ease (or difficulty) of groundwater transmission through a porous material.

Permeability

________ is the volume of voids or open space in a rock or unconsolidated material.

Porosity

GeoTutor: Groundwater and the Water Cycle Part A - Hydrologic Cycle Groundwater is one component of Earth's hydrologic cycle. Water is continuously transferred back and forth between Earth's different spheres. You will label the various components of the hydrologic cycle to understand these processes. Drag the appropriate labels to their respective targets.

The water cycle involves heat exchanges, which result in temperature changes. When water evaporates into the atmosphere, it takes up energy from its surroundings and cools the environment. When it condenses to form clouds, it releases energy and warms the environment. These heat exchanges influence our climate.

GeoTutor: Groundwater and the Water Cycle Part B - The Groundwater Cycle When water winds up underground, it becomes part of the groundwater cycle.Water can only be present underground in areas where rocks have porosity—spaces or voids within the rock material. Well-rounded coarse-grained sediments usually have higher porosity. For water to move underground, rocks need to have permeability, or connections between pore spaces.Water seeped into the ground becomes part of the zone of soil moisture in areas where the ground is covered with soil.Typically, soil moisture and the rocks below are part of the unsaturated zone —an area above the water table where rocks and soil are not completely filled with water. The depth of the unsaturated zone depends on climate, depth of soil, and the type of vegetation. This is the zone from which plant roots draw water.The water table is the boundary between the unsaturated zone above and the saturated zone below. The saturated zone is where rocks are entirely saturated with water. If there is a significant and useable amount of water present in the saturated zone, it is called an aquifer. Drag the appropriate labels of Group 1 to their respective targets and the appropriate labels of Group 2 to their respective targets. You do not need to use all labels.

The water table separates the unsaturated and saturated zones and the zone of moisture lies directly beneath the surface. The soil material shown has high porosity and permeability, allowing ground water to seep down and flow freely. You can see how all of the layers are connected and how they interact to form a subsurface system for freshwater storage.

The water table is ________.

a boundary between saturated rock below and unsaturated rock above

Depositional features created by dripping of water over great spans of time are called ________.

dripstone

The unsaturated zone ________.

lies above the water table

Animation: Cones of Depression Part C When will a cone of depression stop enlarging?

when the amount of water flowing toward the well equals the amount of water being pumped out of the well

Animation: Cones of Depression Part D When might a well, Well A, go dry?

when the cone of depression of a second well intersects the deepest part of Well A

The near-surface zone that contains some of the water that soaks into the ground is called the ________.

zone of soil moisture