PHS 11 ch. 22 quiz

average stream speed increases

As a stream flows downslope, if discharge doubles but the cross-sectional area of the channel stays the same, what happens to the average stream speed?

Average stream speed stays the same.

As a stream flows downslope, if stream discharge doubles and the cross-sectional area of the channel also doubles, what happens to the average stream speed?

finer

As sediment travels in a downstream river, it changes by getting

widens

As streams move downslope, channel dimension generally

on the outside of each bend.

As water flows around a bending and looping river channel, maximum flow speed and erosion occurs

drops, making a cone of depression around the well.

As water is withdrawn from a well, the water table around the well

carry large sediment particles and a large volume of sediment.

Fast moving, turbulent streams are highly erosive, they can

small glacial lakes—kettle lakes.

Blocks of ice buried in a glacial moraine often result in the formation of

in the wind shadow of the leeward slope.

Blowing sand in a sand dune, settles

It weathers and erodes sediments, and then it deposits sediment.

Flowing surface water alters the landscape in what ways?

chemical weathering, hydraulic action, and abrasion.

Flowing water erodes stream channels by

land subsidence.

Cave formation in limestone does not involve

reaction of carbonic acid released into the groundwater.

Caves and caverns are formed in carbonate rock by

dentritic, radial, and trellis drainage patterns.

Common drainage networks include the

and drumlins.

Common glacial landforms created of drift include moraines,

streams enter a standing body of water.

Deltas form as

snow accumulates to form ice and the ice mass begins to flow under its own weight.

A glacier forms when

advancing.

A glacier grows and shrinks with the seasons. When a glacier is growing, we say it is

drift

Drumlins are made of

U-shaped valleys.

Erosion by alpine glaciers creates

Land subsidence can occur in areas underlain by thick sequences of poorly consolidated sediments. As water is pumped from an aquifer with layers of easily compressed water—bearing clays (low-permeability) interbedded with layers of sandy (high-permeability) rock, water slowly leaks out of the clay layers. As the clays become dewatered, they compact, and the land subsides.

From the 1930s to the 1970s, extensive groundwater pumping in the San Joaquin Valley of California caused the ground to subside by as much as 9 m. How does groundwater withdrawal contribute to land subsidence?

a mishmash of shapes and sizes.

Glacial debris is generally

composed of unsorted, angular rock fragments.

Glacial deposits are characteristically

rocks embedded in the ice.

Glacial striations are caused by

at its surface and in the center.

Glaciers flow downslope. A glacier moves fastest

melting and calving.

Glaciers lose mass by

s less than the amount of ablation each year.

Glaciers will retreat when the amount of accumulation

below the water table

Groundwater is water

a horn

Headward erosion of a group of cirques around a mountain may produce

flash floods.

Heavy rains in a desert environment can result in

Sand dunes form when airflow is blocked by an obstacle such as a rock or clump of grass. As the wind sweeps over this obstacle, wind speed decreases and sand grains fall out of the air and are deposited in the wind shadow. As more sand falls, a mound forms which further blocks the flow of air. With more sand and more wind a dune forms.

How are sand dunes formed?

Rainwater falling through the air becomes slightly acidic from chemical reactions with natural carbon dioxide in the air. When this slightly acidic rainwater comes in contact with limestone, the acidic water partially dissolves the rock. For caves and caverns to form, time is needed.

How do caves and caverns form in limestone?

Glaciers erode rock by scraping, plucking, and grinding underlying rock into sizes ranging from boulders to fine dust. Alpine glaciers erode cirques, horns, and aretes at their heads; U-shaped valleys and hanging valleys in their main courses; and fjords where glaciers end their journey at the sea. Continental glaciers erode the land surface that they cover, smoothing and rounding the entire underlying topography.

How do glaciers affect underlying rock?

Glaciers form in climates cold enough that snow recrystallizes into ice. As snow accumulates, the underlying ice thickens until it becomes so heavy that the forces of gravity cause the glacier to move downslope. Glaciers move by a combination of basal sliding and plastic flow.

How do glaciers form and how do they move?

At a stream's headwaters, a stream's energy is focused on downcutting. Downstream the focus changes to a sinuous side-to-side motion. This reflects how the stream minimizes its resistance to flow and dissipates its energy along the course. Meanders are the form a stream takes as it adjusts its energy so that it can carry away all the sediment that it produces.

How does energy relate to the way that streams meander?

Ninety-seven percent of Earth's water is in the oceans and about 2% is frozen in polar ice caps and glaciers. The remaining 1% consists of water vapor in the atmosphere, water in the ground, and water in streams and lakes.

Identify the locations of Earth's water, both oceanic and fresh.

be depressed around the well

If a water well is actively pumped, the water table will

heavier, coarse-grained sediment.

In a delta environment the first grains to settle are

far away from the mouth of the stream channel.

In a delta environment we find that fine-grained sediments settle

The cross-sectional area of the stream channel increased by the same percentage as the discharge, so stream speed does not change.

In a hypothetical stream flowing downslope, stream discharge doubles and the cross-sectional area of the channel also doubles. For this situation, what will happen to the stream's speed?

Stream speed will also double.

In a hypothetical stream flowing downslope, stream discharge doubles while the channel remains the same size and shape. For this situation, what will happen to the stream's speed?

the outer side of the meander.

In a meandering river, erosion is most notable on

the inner side of a meander.

In a meandering stream, deposition of sediment occurs on

in danger of being dismissed

In a prolonged drought, groundwater is

deeper wells must be dug.

In a severe drought, groundwater does not get recharged. To get to the groundwater

the level of the water table

In a well in an unconfined aquifer, the highest level that water can rise to is

a high velocity.

In general, a stream with a high discharge tends to have

dominated by limestone

In general, sinkholes are found in areas

The deposition of sediment in a delta environment is due to a stream's inability to transport sediment indefinitely. The settling of grain particles is directly related to inertia. Larger grains have more mass and more inertia; thus larger grains are the first to settle out. Smaller grains have less mass and less inertia and are the last to settle out.

In the formation of a river delta, why is it that coarser material is deposited first, followed by medium and finer material farther out?

Chemical weathering, hydraulic action, and abrasion.

In what three ways does flowing water erode a stream channel?

oceans

Evaporation and precipitation are greatest over the

Oceans

Evaporation and precipitation are in balance over the

evaporation produces nearly pure water vapor.

Evaporation from the oceans produces clouds that precipitate fresh water rather than saltwater because

glacial deposit.

A moraine is a

limestone

A rock that is readily attacked by chemical weathering is

large proportion of open pore spaces.

A rock with a high porosity will most likely have a

low permeability

A rock with very low porosity will most often have a

water-transmitting capability, or hydraulic conductivity.

A rock's permeability can be described by its

low hydraulic conductivity

A soil composed of flattened soil particles will most likely have a

high porosity

A soil composed of well-rounded sand grains of uniform size will most likely have

aquifer

A sub-surface region that holds and transmits water is called a/an

farthest point of a glacier's advance.

A terminal moraine marks the

gravity

All water—groundwater, surface water, and frozen water—flows downslope in response to

Unsaturated zone, saturated zone, water table, recharge area, and discharge area. The unsaturated zone is where pore spaces are partially filled with water, below this area is the saturated zone where all pore spaces are filled with water. The boundary between these two zones is the water table. Water enters an aquifer in a recharge area. Water leaves an aquifer at a discharge area—streams, artesian wells or springs, man-made wells, or as it enters a lake or ocean.

An aquifer is a reservoir of water beneath the ground surface. Describe five physical zones in an aquifer. (Hint: Consider in-flow and out-flow.)

till

An unsorted mixture of rock material that is deposited directly by melting ice is called

Sand dunes migrate. The whole mound of sand moves downwind as sand grains on the windward slope move up and over the crest of the dune to fall on the leeward slope. Sand removed from the back of the dune is redeposited on the front of the dune. Over time, this continuous process moves the entire dune.

Are sand dunes stationary or do they move and migrate?

will find a new route to its destination.

As a distributary channel in a delta becomes choked with sediment, the water in the channel

rises

As a large reservoir behind a new dam fills with water, the water table in the vicinity of the reservoir

Large and heavy sediment particles are the first to be deposited since they are too heavy to remain with the water flow. Small sediment particles, able to remain in the flow, are the last to be deposited.

As a river overflows its channel, sediment is deposited along the channel banks. What type of sediment is deposited first? What type is deposited last?

sinkholes, caves, and caverns.

Karst topography is dominated by

clear streams.

Laminar flow produces

Damage to roads, bridges, building foundations, pipelines, and other surface and subsurface infrastructure.

Land subsidence in the San Joaquin Valley of California is not just a historical occurrence, it is an ongoing problem. Other than water supply, what are some possible consequences of land subsidence?

over-pumping of groundwater and the compaction of clay layers.

Land subsidence is caused by

compacted clay layers cannot be expanded.

Land subsidence is generally not reversible because

hanging valleys, cirques, and roches moutonnees.

Landforms created by glacial erosion include

flat floodplain areas

Meandering streams are common in

migrate downstream.

Meanders

groundwater

Most of Earth's accessible fresh water is located in

polar ice caps and glaciers

Most of Earth's fresh water is located in

the oceans

Most of the world's water is in

physical abrasion.

Movement of water erodes stream channels. The main source of erosion comes from

wind

Of the three agents of erosion—water, wind and ice—the one with the ability to move only the smallest particles is

meandering

On a floodplain, stream flow is generally

fine-grained silts and clays.

On a floodplain, the sediment grains away from the main river channel are

underlain by unconsolidated sediments.

Over withdrawal of groundwater causes ground subsidence in areas

river access and rich soils.

People settle on floodplains because

on the inside bend of a curved stream channel.

Point bars typically form

continents

Precipitation exceeds evaporation over the

supply of freshwater

Rain or snow that falls on the continents is Earth's only

Ground surface made up of carbonate rocks is prone to erosion. When slightly acidic rainwater comes in contact with carbonate rocks, the carbonic acid partially dissolves the rock, creating unusual erosional features—Karst. More acidic rainfall, more Karst topography.

Rainwater becomes acidic as it falls through the air. How does this affect areas of Karst topography?

decrease

Riding down a river in an old canoe, if the discharge of the river does not increase and the river gets very wide and deep, the speed of the river will

increase

Riding down a river in an old canoe, if the discharge of the river increases a little and the width and the depth of the river stay the same, the speed of the river will

downhill due to gravity.

Rivers tend to flow

as wind moves sand from the back to the front of the dune.

Sand dunes form

blows sand from the back to the front of the dune.

Sand dunes form as wind

high porosity and high permeability.

Sandy soils tend to have

pressure.

Snow converts to glacial ice when subjected to

calcium-rich water dripping down from the cave ceiling.

Stalactites form from

gradient, channel geometry, and discharge.

Stream velocity is dependent on

stream with a very steep gradient.

Stream velocity is faster in a

turbulent flow.

Streams transport great quantities of sediment. The most effective transport of sediment occurs in

bedrock that show the direction of the glaciers flow.

Striations are long parallel scratches in

course lengthens and the delta grows.

The Mississippi River has a huge delta. With each year and each episode of deposition, the river

velocity

The ability to carry large particle sizes is dependent on the stream's

ablation.

The annual amount of snow lost by a glacier is called

Permeability

The capacity a material has for transmitting fluids is known as its

channel geometry.

The cross-sectional area and shape of a stream is called

Permeability

The degree to which a soil or rock allows groundwater to flow is called

terminal moraine.

The depositional landform at the farthest advance of a glacier is called a

striations, roches moutonnées, and drumlins.

The direction of ice flow can be determined by

cross-sectional area of a channel and the average stream velocity.

The discharge of a stream is directly related to the

water supply and demand

The dominant influence on the length of time a well will produce water is

solar energy

The driving force of our planet's hydrologic cycle comes from

delta

The dumped sediment from a stream flowing into standing water is called a

after it has reached a critical mass.

The flow of a glacier begins

hydraulic gradient, and hydraulic conductivity.

The flow of groundwater depends on

permeability and gravity

The flow of groundwater depends on

from where the water table is high to where it is low.

The flow of groundwater is

hydraulic conductivity and pressure.

The flow of groundwater is dependent on

stalactites

The formations of rock hanging from the roofs of caves are called

faster the flow

The greater the hydraulic gradient the

turbulent

The headwater flow of a mountain stream is generally characterized as

sandy soil

The infiltration of water is greatest in

sand dunes are larger than ripple marks.

The main difference between sand dunes and ripple marks is

stream discharge

The maximum sediment load of a stream depends on

discharge

The maximum volume of sediment a stream can carry is dependent on the stream's

water

The most important agent of erosion is

glacial action.

The most powerful agent of erosion is

at its surface.

The movement of a glacier is fastest

hydrologic cycle

The natural circulation of water—from ocean to air to ground to ocean and then back to the atmosphere—is called the

a confined aquifer under sufficient pressure.

The necessary condition to produce an artesian system is

rocky surfaces with no soil layer

The poorest absorber of water is

water

The principal cause of erosion and transportation of sediment in a desert environment is

zone of aeration

The region above the zone of saturation is called the

gradient, discharge, and channel geometry.

The speed of water in a stream is affected by

when stream speed is very fast.

The transport of large particle sizes is greatest

as outwash and till.

The two ways that glacial drift is deposited are

the letter "U."

The typical mountain valley that has been subjected to glaciation is shaped like

discharge

The volume of water that flows past a given point in a channel during a specified time is called

zone of saturation

The water table is found at the top of the

land subsidence.

The work of surface water does all of the following except

When accumulation exceeds ablation, the glacier advances—it grows. When ablation exceeds accumulation, the glacier retreats—it shrinks.

Under what conditions does a glacier front advance? Under what conditions does a glacier front retreat?

limestone aquifers

Underground rivers can exist in

common in mountainous regions.

V-shaped valleys are

porosity

Water able to be contained in the subsurface depends on

the Pacific Ocean.

Water from streams in northern Utah flow to

under pressure

Water in a confined aquifer is

groundwater

Water in the unsaturated zone is called

oceans

Water is vital to life on our planet. Most of Earth's water supply is in the

enters streams and lakes, seeps into the ground, flows to the ocean, or evaporates.

Water precipitated over land completes its cycle as it

runoff

Water that does not infiltrate into the ground or evaporate becomes

Ice does not become a glacier until it moves under its own weight. This occurs when the ice mass reaches a critical thickness of approximately 50 meters and the weight of the overlying ice causes the ice at the base to deform plastically and flow downslope.

What distinguishes a huge block of ice from a glacier?

Frictional drag is simply the slow down of movement due to the contact between two opposing surfaces. Frictional drag slows down a glacier's external movement. The glacier experiences this drag as it encounters the bedrock. So, movement is slowest at the base and at the sides of the glacier.

What is "frictional drag" and how does it affect the external movement of a glacier?

A stalactite is an icicle—shaped carbonate rock formed in caves from dripping water rich in calcium carbonate. As the calcium carbonate rich water drips downward, the water evaporates and the calcium carbonate precipitates.

What is a stalactite and how does it form?

The cross-sectional area and cross-sectional shape of a stream channel.

What is stream channel geometry?

Both can reveal the direction of ice flow. They differ in how they formed. A roche moutonnee is an erosional feature—eroded out of bedrock by continental glaciation, and a drumlin is a depositional feature formed of glacial till. Diff: 3

What is the difference between a roche moutonnee and a drumlin?

the polar ice caps or glaciers

What is the largest repository of fresh water?

sea level

What is the lowest level to which water can erode land?

Permeability is the ease with which water flows through a material. Permeability is affected by pore spaces—specifically the number, size, and interconnection of pore spaces.

What three factors affect permeability?

Porosity is the ratio of total volume of pore spaces in a soil or rock to total volume of soil or rock. Porosity is affected by the size, shape, and packing of particles.

What three factors affect porosity?

Gradient, the steeper the gradient the faster the flow; discharge, the greater the discharge the faster the flow; and channel geometry, (a) water flows slower in large, wide channels than in small narrow channels and (b) water flows faster in round deep channels than in flat shallow channels.

What three factors affect stream speed?

a spring

When a perched water table intersects the surface on a hillside, the result is

The well is drilled in an artesian system where water is brought up to the surface under its own internal pressure. For an artesian system to form, the well must be drilled where the elevation of the ground surface is lower than the elevation of the water table in the aquifer at the recharge area.

When a well is drilled into an aquifer, why does water flow out of the well spontaneously?

groundwater

When subsurface ground material is completely saturated with water, we call it

An increase in discharge will always mean that a larger volume of water is being transported by the stream. But an increase in discharge does not always mean that stream speed will increase. Increases in discharge and speed do not always have a direct correlation because changes in channel geometry and the cross-sectional area of the channel might also occur.

When the discharge of a stream increases, what happens to stream speed?

A delta forms where a stream enters a body of standing water and loses its ability to transport sediment. Large, coarse-grained sediments are the first to settle. Small, fine-grained sediments (able to be carried out to the farther reaches of the delta) are the last to settle. Thus sediment is deposited in order of decreasing weight, with heavy, coarse particles settling at and near the shoreline and light, fine particles settling farther offshore.

Where and how do deltas form?

in the oceans

Where does most rainfall on Earth finally end up before becoming rain again?

is higher than the surface of the stream.

Where groundwater discharges to a stream, the elevation of the water table next to the stream

slightly higher than the surface of the swamp

Where groundwater discharges to a swamp, the elevation of the water table next to the swamp is

polar ice cap and glaciers

Which has the longest residence time?

moraines

Which of the following are not produced by streams?

The ice mass must move under its own weight.

Which of the following is a necessary condition for an ice mass to be a glacier?

They are V-shaped and have rapids.

Which of the following is characteristic of mountain stream valleys?

U-shaped valleys

Which of the following is not a characteristic of continental glaciation?

land subsidence

Which of the following is not involved in cave formation in limestone?

The Grand Canyon

Which of the following landscapes were not carved by glaciers?

Striations are parallel scratches created by glaciers scraping the underlying bedrock. Aligned in the direction of ice flow, striations tell us the past movement of a glacier that has long since receded. By mapping striations on land once covered by continental glaciers, geologist can decipher the flow direction of the ice.

Why are glacial striations so important?

Clay is composed of tightly packed, small, flattened grain particles. Although voids between clay particles are small, clay is able to hold a lot of water. The movement of water, however, is impeded by poorly connected, small pore spaces.

Why does a clay rock body generally have a medium-to-high porosity but a poor hydraulic conductivity?

Quartz sandstone is predominantly composed of well-rounded, well-sorted sand particles. Because most of the sand particles are of the same size, the spaces between the sand particles are open and well connected. As such, water occupies the open spaces and easily moves between the spaces.

Why does quartz sandstone have a high porosity and a high permeability?

in the middle of the channel at the water's surface.

Within a stream channel, the speed of stream flow is greatest