Geology Final

What percentage of the Earth's water is in the form of groundwater?

0.62%

How many subdeltas have been formed by the Mississippi River in the last 6,000 years?

7

In terms of competence, if the velocity of the stream triples, the impact force of the water will increase ________ times.

9 times

What percentage of Earth's water is in the form of seawater?

97.2%

What is the geologic definition of a stream?

A channelized body of water flowing down gradient

What is an antecedent stream?

A stream that existed before uplift in a region

What is permeability?

Ability to transmit water

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

Acidity of precipitation

which of the following accounts for the largest usage of groundwater in the United States?

Agriculture and irrigation

What is the term for sediment deposited by streams?

Alluvium

How much of Earth's surface water exists in the oceans?

Almost all of Earth's surface water exists in the oceans.

Dam-Failure Floods

Artificial containment structures fail

Particles moving by saltation are transported in the _______ load.

Bed load

Which of the following is not one of the three basic stream channel morphologies? Meandering stream Straight channel Braided stream Bedrock channel

Bedrock channel

A ________ stream consists of a complex network of converging and diverging channels that weave around channel bars.

Braided stream

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

Calcite

________ is the maximum load of solid particles a stream can transport per unit time.

Capacity

Which acid is responsible for most karst topography?

Carbonic

________ is a measure of a stream's ability to transport particles based on size rather than quantity.

Competence

What feature is going to develop if a well is withdrawing more groundwater than an aquifer can naturally replace, resulting in a dimple in the water table?

Cone of Depression

which of the following is the best type of flood control?

Constricting a park in a flood plain

The ________ is an elevational point that divides an entire continent into large drainage basins.

Continental Divide

________ occurs when a rock is gradually dissolved by flowing water.

Corrosion

Which of the following statements about deposition and erosion around meander loops is true?

Deposition occurs where water is moving the slowest along the inside of the loop. Erosion occurs where water is moving the fastest along the outside of the loop.

_______ is a term used to describe how the water table around a well becomes lower as water is taken from the subsurface.

Drawdown

The general term used to describe cave deposits is ________.

Dripstone

Why does groundwater discharge to Earth's surface?

Earth's surface is irregular, and permeability decreases with depth within Earth.

True or False. As stream velocity slows, the smallest particles get deposited first.

False

True or False. Point bars are locations where erosion occurs whereas cutbanks are locations where deposition occurs.

False

True or False. The hydrologic cycle is off-balance because more liquid is brought in via comets and meteorites each year.

False

True or False. When discharge increases, the flow velocity will increase. However, the width and depth of the stream will decrease because the stream downcutting.

False

True or False. In a series of stream terrace levels, the oldest terrace is the one that is lowest in elevation.

False.

Suspended Load

Fine sediments that are held up by the water and carried throughout the water column

______ are flat areas along streams that are created by the deposition of alluvium and is subject to periodic inundation.

Floodplains

During what periods would streams see the greatest erosion and transportation of sediment?

Floods

Flash Floods

Floods with high precipitation in a short time

Which of the following locations is a likely place to find a braided stream?

Flowing from the terminus of a glacier

Delta

Form where streams enter large lakes or oceans

Levee

Formed by floodwaters on either side of a stream

Alluvial Fan

Formed by mountain streams emerging onto a flat plain

Ice-Jam Floods

Frozen material creates a temporary dam on a thawing river

A(n) ________ stream is a stream that is in equilibrium and is neither eroding or depositing material, but simply transporting it.

Graded stream

Which of the following is true regarding groundwater as you move deeper below the surface?

Groundwater moves over larger distances, over longer timescales.

What would increase flow velocity?

Having a narrow, deep channel

In which part of a stream's course would one typically find bedrock channels?

Headwaters

In order for an aquifer to use useful for human consumption, 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

In which country were geysers were first identified and described?

Iceland

Aquitard

Impermeable layer that prevents flow

Geyser

Intermittent hot springs that periodically eject water into the air with great force

Bed Load

Larger sediments that bounce, roll, or slide along the bottom

What beds would be easiest for a stream to erode?

Lined with silt

characteristics of a graded stream?

Meanders and Well-developed floodplain

What geologic process is responsible for warming the water at Hot Springs National Park?

Normal geothermal gradient

How does water get from the oceans onto land?

Ocean water evaporates to form gaseous water and moves into the atmosphere, where it condenses into liquid water and falls out of the atmosphere to land as rain.

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

What is the source of the majority of water in geothermal features?

Precipitation

Which of the following characteristics is not true or groundwater?

Rarely contains dissolved solids

What type of drainage pattern develops on highly jointed bedrock?

Rectangular

The Great Flood of 1993 in the Upper Mississippi River basin is an example of which type of flood?

Regional flood

Unconfined Aquifer

Rock or regolith that can store and transmit water and receives its recharge directly from the atmosphere

Confined Aquifer

Rock or regolith that can store and transmit water, but it contained between two impermeable layers

Which of the following has the highest permeability?

Sand

What is the ultimate base level?

Sea level

Regional Floods

Seasonal Floods

________ is the area at the headwaters of a stream where most of the sediment is derived.

Sediment Production

Which of the following materials would make the best aquitard?

Shale

What particle size is most likely to make up a stream's suspended load?

Silt (grain size between sand a clay)

What mineral substance is makes up most geyser deposits?

Sinter

Bar

Small deposits that form in the stream channel

Stalactites start out as hollow tubes called ________

Soda Straws

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

Spring

Which of the following can result from excessive pumping of groundwater?

Subsidence Saltwater contamination Reversing the direction of flow in the aquifer

What is the wetted perimeter of a stream?

The amount of flow in contact with the banks and bed of the channel

What would happen to atmospheric water if Earth were mostly covered with land?

The atmosphere would contain less water.

What is the longitudinal profile?

The cross-sectional area from the headwaters to the mouth

What is base level?

The downward limit of erosion

What is the knickpoint?

The edge of a resistant ledge over which a stream flows, becoming a waterfall

What does the hydrologic cycle describe?

The hydrologic cycle describes how liquid and gaseous water move between the ocean, atmosphere, and land.

What is the mouth of a stream?

The location where streamflow ends

What would happen to the oceans if surface runoff and groundwater flow did NOT occur?

The oceans would become smaller.

Which of the following is an erosional feature?

Tower karst

True or False. A typical rate of groundwater flow for many aquifers is approximately 4 cm/day.

True

True or False. In order for a stream to build and maintain a bird's-foot delta, a stream has to be carrying more sediment to the delta than is being removed by wave action.

True

True or False. Maximum velocity occurs when the stream is at the bankful stage.

True

True or False. Running water is the single most important erosional agent sculpting Earth's land surface.

True

True or False. Streams carry most of their sediment load in the form of suspended load.

True

True or False. The Nile River in Africa is a stream

True

True or False. Waterfalls are temporary features in the geologic record.

True

True or false. Lakes and streams are surface expressions of the water table.

True

True or false. The water in the majority of wells cannot rise above the level of the water table on its own.

True

Mudpot

Type of hot spring that contains boiling mud

Drainage Pattern: Rectangular

Underlying Geology: Fractured bedrock

Drainage Pattern: Radial

Underlying Geology: Topographic high in center of drainage pattern

Drainage Pattern: Dendritic

Underlying Geology: Underlying rock is relatively uniform

How does the use of water by humans affect the water table?

Use of water by humans increases discharge, resulting in lowered water tables.

How will channel velocity change along the longitudinal profile of a stream?

Velocity will start low and gradually increase toward the mouth due to increasing discharge downstream

Fumarole

Vent in the ground that emits steam

What geologic process is responsible for the geothermal features in Yellowstone National Park?

Volcanic activity

What is porosity?

Volume of pore space in a material

Hot Spring

Water in a basin that is 6-9° C warmer than the mean annual temperature of the location

Which of the following is a true statement about groundwater?

Water in a groundwater system is stored in subsurface pore spaces and fractures.

What is infiltration?

Water soaking into the ground

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

Water table will fall

How will the water table respond if it is a wet spring?

Water table will rise

Which of the following regions is famous for its artesian wells?

Western South Dakota

What is a flood?

When discharge in a river exceeds the river's capacity

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

Zone of Saturation

An artesian well must tap into ______.

a confined aquifer

Which of the following would produce a LOWER water table?

a decrease in the amount of recharge to groundwater an increase in the amount of discharge to surface water

karst topography

a landscape formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves.

bajada

an accumulation of sediment along the mountain front formed by coalescing alluvial fans.

A perched aquifer is located directly above a(n) __________.

aquitard

Where is most of Earth's freshwater found?

as ice at Earth's surface

What are the three types of loads carried by streams?

bed load, suspended load, dissolved load

Waterfalls are a characteristic of a ____.

bedrock channel

Bouncing is to sand as suspension is to_____________.

clay

The process that causes dissolution of limestone bedrock in a stream is ______.

corrosion

Describe the erosion occurring during headward erosion.

erosion backwards at the start of the stream

What are water gaps?

erosion through hills or ridges caused by a change in base level

True or false. Groundwater migrates from areas of low pressure to areas of high pressure.

false

true or false. Caves can only form in limestone.

false

stalactite

hangs from the ceiling of a cave

Which of the following represent the largest volume of freshwater found on Earth?

ice sheets and glaciers

Geysers are more common in the western United States because _____

igneous activity has occurred more recently in the area

Sliding is to gravel as dissolution is to_____________.

ions

Dissolved Load

ions in solution that are dispersed throughout the flow

Point bar

large deposits of sediment. deposition

cut bank

locations along a meandering stream where erosion occurs. little sediment deposit. erosion.

A __________ is separated from the groundwater system by the unsaturated zone.

losing stream (disconnected)

stalagmite

on the floor

Worldwide, the largest percentage of freshwater readily available to humans is stored in _______.

pore spaces between rocks and sediments

How can pieces of rock in contact with a stream bed move?

rolling, sliding, bouncing

parts of the bed load?

sand and gravel

Alluvial fans occur where a _____ exits the _____ and enters the _____.

stream, mountains, basin

The water table __________.

surface is a subdued version of the surface topography. mapped using wells.

Which ocean is Earth's largest?

the Pacific Ocean

Evapotranspiration moves water from _______.

the biosphere to the atmosphere

Which of the following is necessary to calculate hydraulic gradient?

the distance between two wells that penetrate the zone of saturation

What is suspended load?

the fine-grained particles that travel in the water column above the stream bed

The permeability of a material is directly related to which of the following parameters?

the grain size of the material

the quantity of groundwater that can be stored within sedimentary material is most directly controlled by which of the following parameters?

the porosity of the material

What is the water table?

the top of the saturated zone beneath Earth's surface

It is always difficult to pump groundwater from _____.

the vadose zone (unsaturated zone)

How would the water table be affected if Earth were made up of uniform, permeable material?

the water table would not exist.

true or false. Freshwater is less dense than saltwater.

true

true or false. If a groundwater well pumps enough water to draw down the water table, the drawdown will increase the slope of the water table, which will increase the velocity of groundwater.

true

true or false. Most caverns are created at or near the water table.

true

Good aquifers are...

typified by large size, high porosity and permeability, and if they are easy to tap into by being near the surface, so much the better.

In the __________, groundwater fills the pore space.

zone of saturation