Earth Science Chapter 6: Running Water and Groundwater

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Questions and Answers

What is the shape of the profile of a stream from head to mouth?

A steep curve

A zigzag shape

A smooth curve (correct)

A vertical line

What is a tributary?

A stream that empties into a lake

A stream that empties into another stream (correct)

A stream that empties into an ocean

A stream that empties into a river

What decreases downstream in a stream?

Gradient and velocity

Gradient, or slope, and channel roughness (correct)

Discharge and channel size

Gradient and discharge

What is the lowest point to which a stream can erode?

Ultimate base level Signup and view all the answers

What is the process by which a stream lifts loose particles?

Abrasion, grinding, and dissolving Signup and view all the answers

What is the term for the accumulation of sediment formed where a stream enters a lake or ocean?

Delta Signup and view all the answers

What is the process by which water moves into rock or soil through cracks and pore spaces?

Infiltration Signup and view all the answers

What is the term for the slope or steepness of a stream channel?

Gradient Signup and view all the answers

What is the primary work of a stream that forms a narrow V-shaped valley?

Downcutting towards base level Signup and view all the answers

What is the volume of water flowing past a certain point in a given unit of time?

Discharge Signup and view all the answers

What happens to the gradient of a stream as you move from its headwaters to its mouth?

It decreases Signup and view all the answers

What occurs when the discharge of a stream exceeds the capacity of its channel?

A flood occurs Signup and view all the answers

What is the purpose of artificial levees in flood control?

To contain the stream's waters during floodstage Signup and view all the answers

What is the process by which plants release water into the atmosphere?

Transpiration Signup and view all the answers

What is the balance in the water cycle that means the average annual precipitation over Earth equals the amount of water that evaporates?

Earth's water balance Signup and view all the answers

What determines how much groundwater can be stored?

Porosity Signup and view all the answers

What is the term for the land area that contributes water to a stream?

Drainage basin Signup and view all the answers

What happens when the water table intersects the ground surface?

A spring forms Signup and view all the answers

What is the characteristic of a stream that is near base level?

Downward erosion is less dominant Signup and view all the answers

How does groundwater move through the ground?

By twisting and turning through interconnected small openings Signup and view all the answers

Why is water in hot springs 6–9ºC warmer than the mean air temperature of the locality?

It's heated by cooling of igneous rock Signup and view all the answers

What is an artesian well?

Any formation in which groundwater rises on its own under pressure Signup and view all the answers

What is a potential environmental problem associated with groundwater overuse?

Land subsidence Signup and view all the answers

What is a naturally formed underground chamber?

A cavern Signup and view all the answers

What forms caverns at or below the water table?

Erosion Signup and view all the answers

What is the characteristic of features found within caverns formed in the zone of aeration?

Composed of dripstone Signup and view all the answers

What is the result of bedrock dissolving and caverns collapsing?

Formation of sinkholes Signup and view all the answers

What is characteristic of an area with karst topography?

Lack of good surface drainage Signup and view all the answers

What is travertine?

A type of limestone Signup and view all the answers

What is the term for a semi-circular valley formed by glacial erosion?

Cirque Signup and view all the answers

Study Notes

Profile of a Stream

A stream's profile is a smooth curve from its head to its mouth
Gradient decreases from the head to the mouth
Factors that increase downstream include velocity, discharge, and channel size
Factors that decrease downstream include gradient, channel roughness, and slope

Tributaries and Base Level

A tributary is a stream that empties into another stream
Base level is the lowest point to which a stream can erode
There are two types of base levels: ultimate (sea level) and temporary (local)

The Work of Streams

Erosion

Streams erode their channels through abrasion, grinding, and dissolving soluble material

Deposition

A stream's bedload is solid material too large to carry in suspension
Capacity is the maximum load a stream can carry
Deposition occurs when streamflow drops below the critical settling velocity of a certain particle size
Deposits are called alluvium
Deltas are accumulations of sediment formed where a stream enters a lake or ocean

The Water Cycle

Water constantly moves among the oceans, atmosphere, solid Earth, and biosphere
The water cycle involves evaporation, condensation, precipitation, infiltration, runoff, and transpiration

Streamflow

Streamflow is the volume of water flowing past a certain point in a given unit of time
Gradient is the slope or steepness of a stream channel
Channel characteristics include shape, size, and roughness

Changes from Upstream to Downstream

Gradient decreases from the head to the mouth, while discharge increases downstream

Groundwater

Distribution and Movement

Porosity is the percentage of pore spaces in a rock
Permeability is the ability to transmit water through connected pore spaces
Aquifers are permeable rock layers or sediments that transmit groundwater freely

Features Associated with Subsurface Water

Springs

A spring forms when the water table intersects the ground surface
Hot springs have water 6-9°C warmer than the mean air temperature of the locality
Geysers are intermittent hot springs where water turns to steam and erupts

Wells

A well is a hole bored into the zone of saturation
Artesian wells are formations where groundwater rises under pressure
Pumping can cause a drawdown of the water table and form a cone of depression

Environmental Problems

Overuse and contamination threaten groundwater supplies
Land subsidence can occur due to withdrawal of groundwater

Caverns

Caverns are naturally formed underground chambers
Caverns can be formed by dissolution of groundwater

Stream Valleys

Narrow valleys have a V-shape and show downcutting towards base level
Wide valleys are flat and show lateral erosion
Features of wide valleys include meanders, cutoffs, and oxbow lakes

Floods and Flood Control

Floods occur when the discharge of a stream exceeds its channel capacity
Measures to control flooding include artificial levees, flood control dams, and limits on floodplain development

Drainage Basins

A drainage basin is the land area that contributes water to a stream
A divide is an imaginary line separating the drainage basins of one stream from another

Types of Glaciers

Ice sheet: a large, continuous ice mass covering a vast area
Ice cap: a smaller, dome-shaped ice mass
Ice shelf: a thick, floating plate of ice extending from a glacier onto the sea
Iceberg: a floating piece of ice broken off from a glacier or ice shelf

Glacial Features

Drumlins: elongated, teardrop-shaped hills formed by glacial deposition
Eskers: long, narrow ridges of sediment deposited by glacial meltwater
Outwash plains: flat or gently sloping areas of sediment deposited by glacial meltwater
Kettles: depressions formed when blocks of ice break off from a glacier and melt
Cirque: a semicircular valley formed by glacial erosion
Arete: a narrow ridge of rock formed by glacial erosion
Horn: a steep, pyramidal peak formed by glacial erosion

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Description

Test your knowledge of Earth's water distribution, the water cycle, and the processes involved in it, including evaporation, condensation, precipitation, and infiltration. Learn about the movement of water among the oceans, atmosphere, solid Earth, and biosphere.