Geology 112 Final

If a stream drops 15 meters in 15 kilometers, what is its gradient? Multiple Choice 100% 1 meter per kilometer 15 meters per kilometer 15 kilometers per meter none of these - not this one

1 meter per kilmeters

What is the discharge of the stream shown in the accompanying figure if the velocity is 1.5 meters per second?

1,500 cubic meters per second

Based on the accompanying hydrograph, what was the stream discharge when the data period shown in the graph ended? Multiple Choice 10 cubic meters per second 4 meters per second 4 cubic meters per second 9 cubic meters per second 1.8 meters per second

4 cubic meters per second

What is a floodplain? Multiple Choice A broad strip of land built up by sedimentation on either side of a stream channel. Covered with water during a flood. A body of sediment deposited at the mouth of a stream when the stream's velocity decreases. A ridge of sediment, usually sand or gravel, deposited in the middle or along the banks of a stream. Step-like landforms found above a stream.

A broad strip of land built up by sedimentation on either side of a stream channel. Covered with water during a flood.

What is a cutbank?

A cut bank, also known as a river cliff or river-cut cliff, is the outside bank of a water channel (stream), which is continually undergoing erosion.

Where the Nile River encounters the Mediterranean Sea, what has formed? A landslide A series of Waterfalls A delta All of these

A delta

What event triggered the main eruption of Mount St. Helens in May 1980 Multiple Choice Melting snow caused a huge steam eruption. Magma encountered groundwater and exploded. A landslide removed rocks and released pressure on the magma. All of these.

A landslide removed rocks and released pressure on the magma.

What is a point bar? Multiple Choice A new, shorter channel across the narrow neck of a meander A crescent-shaped meander cutoff A sandbar deposited along the inside of stream meanders due to lower velocity A flowing network of interconnected rivulets around numerous bars

A sandbar deposited along the inside of stream meanders due to lower velocity

Eruptions on the islands of Santorini in Greece and Krakatau in Indonesia resulted in: Multiple Choice collapse of a huge caldera that caused part of an island to disappear beneath the sea Incorrect a huge ash column and pyroclastic flows destructive waves that traveled across the sea all of these

All of these

Some scientists think that Yellowstone could cause a future disaster because: Multiple choice the area is part of a caldera scientists think that magma is still present at the depth past eruptions from yellowstone carried ash over a huge area of western North America Land near yellowstone is uplifting in some plaes and subsiding in others all of these

All of these

What typically happens when tributaries join the main river? Multiple Choice channel size increases water velocity increases the amount of discharge increases total sediment load increases all of these

All of these

Which of the following is true about levees? A) they are a reliable way to protect an area from flooding B) to be called a levee, a feature needs to be at least partly constructed by humans C) a levee can trap water on the floodplain after the flood has subsided D) none of these

C) A levee can trap water on the floodplain after the flood has subsided

If a stream-cut canyon is deep and narrow, which of the following is most likely to be true? A) rocks in the canyon walls are relatively hard and so easy to erode B) the stream is probably close to its base level C) downcutting is occurring faster than widening D) the stream contains mostly small clasts, such as silt

C) downcutting is occurring faster than widening

Which of the following types of eruptions is among the most deadly of natural disasters? Multiple choice Caldera-forming Basaltic shield-forming Geysers Scoria cone-forming

Caldera-forming

Which of the following statements about streams is NOT true? A) base level is the lowest elevation to which a stream can erode B) a steep stream high above base level generally will be eroding its channel C) some streams can simply transport material instead of eroding or depositing material D) rivers typically do not respond to a change in climate

D) rivers typically do not respond to a change in climate

What happens to the erosive power of a stream as velocity increases? Multiple Choice Erosion decreases. Erosion is not related to velocity. Erosion increases.

Erosion increases.

The discharge for a 100-year flood is the same for all streams and rivers. True or False

False

The area of origin of a river is the: Multiple Choice headwater mouth tributary

Headwater

What happens to water velocity downstream? It generally: Multiple Choice remains the same there is no way to tell because discharge cannot be determined increases decreases

Increases

The downfall of which ancient civilization in the Mediterranean closely followed the caldera-forming eruption at Santorini? Multiple Choice Minoan Spartan Persian Etruscan

Minoan

Which of the following is true about the base level of a stream: Multiple Choice The flat top of a mountain is the ultimate base level for most streams. Base level indicates the normal (or base) flow level before flooding. A mountain is close to its base level if bedrock is close to the surface. Base level generally is near the steepest part of a stream's profile. Most streams have lower gradient close to their base level.

Most streams have lower gradient close to their base level.

A stream or river that flows all year is referred to as: Multiple Choice perennial ephemeral a tributary

Perinnial

Yellowstone is still an active volcano. Which of these signs of volcanic activity has not recently occurred at Yellowstone? Multiple Choice Earthquakes Ground inflation Hydrothermal activity in the form of geysers and mud pots Small ash eruptions

Small Ash eruptions

An urban community developer redesigns a neighborhood so that the streets are narrower and more vegetation is planted. Also, the residents are now required to install rainwater catchment systems on their properties. What is the effect of this change on surface runoff? Multiple Choice Surface runoff will most likely not change Surface runoff will increase Surface runoff will decrease

Surface runoff will decrease

All of the following are lines of evidence written by Plato that support the hypothesis that Santorini is the location of the lost city of Atlantis except: Multiple Choice "Red, white, and black" rocks surrounded Atlantis - these colors may be volcanic rocks of Santorini Zeus, the God of sky and thunder, sent "lightening and thunder" onto the city Atlantis was a "city built of concentric rings" - likely a nested caldera An advanced civilization built Atlantis - likely the Minoans who lived on Santorini

Zeus, the God of the sky and thunder, sent "lightening and thunder" onto the city

A delta forms when: Multiple Choice a river slows and deposits sediment as it enters a lake or sea ocean waves, especially during storms, pile up sediment along the coast a steep mountain front collapses sending sediment out into the sea windblown dust slides down steep hillsides and into a lake

a river slows and deposits sediment as it enters a lake or sea

Which of the following influences whether a flood occurs? Multiple Choice the height of levees the amount of discharge urbanization (replacing farms or natural land with buildings) the width of the channel all of these are influences

all of these are influences

What is the pattern of discharge shown by this hydrograph? Multiple Choice discharge quickly increases and gradually decreases discharge gradually decreases and quickly increases discharges quickly decreases and gradually increases

discharge quickly increases and gradually decreases

The force behind a river's flow is: Multiple Choice Gravity its sediment load the shape of the river bed its velocity

gravity

Which of the following are NOT associated with a hurricane? Multiple Choice strong winds and heavy rainfall a mound of water (storm surge) pushed ahead of the storm high atmospheric pressure a relatively calm area in the center of the storm all of these are associated with a hurricane

high atmospheric pressure

Which of the following is properly called a flood? Multiple Choice when the entire bottom of the channel is covered with water when water is 1 meter below the top of the channel if water spreads out over the floodplain when a meander is cut off and forms a lake

if water spreads out over the floodplain

Which of the following typically decreases downstream in a river? Multiple Choice flow velocity discharge channel size maximum sediment grain size none of these

maximum sediment grain size

Which of the following is true about the formation and migration of meanders? Multiple Choice most floodplains do not preserve evidence of the former position of meanders flow velocity is highest when water takes a shortcut around the inside of a bend meanders migrate inward as sediment is deposited on the inside bend -Incorrect migration of meanders back and forth can help form a floodplain none of these

migration of meanders back and forth can help form a floodplain

The end of the river is the: Multiple Choice mouth headwater tributary

mouth

The cross-sectional area of the channel of a stream or river is calculated by: Multiple Choice multiplying the channel's width by its average depth multiplying the channel's depth by its average length dividing the channel's depth by its width adding the channel's width and average length

multiplying the channel's width by its average depth

The volume of water flowing through any part of a river per unit time is calculated by: Multiple Choice multiplying the velocity by the cross-sectional area of the river multiplying the velocity times the length of the river dividing the channel's width by its velocity dividing the channel's length by its cross-sectional area

multiplying the velocity by the cross-sectional area of the river

The Coriolis effect causes wind to have an apparent deflection to the: Multiple Choice east in the southern hemisphere west in the northern hemisphere east in both the northern and southern hemispheres none of these

none of these

Which of the following sediment sizes is likely to be transported mostly on the bottom of the stream bed? Multiple Choice pebbles and cobbles fine sand dissolved materials sticky clay particles

pebbles and cobbles

What flood control method captures surface runoff and delays its entrance into a stream? Multiple Choice levee retention pond flood wall urban planning

retention pond

Which of the following accompanies urbanization (replacing farms and open areas with cities)? Multiple Choice the discharge pattern of streams in the area does not change runoff occurs more quickly and produces a higher peak flow runoff becomes more spread out in time, increasing the amount of flooding runoff becomes more spread out in time, reducing the amount of flooding none of these

runoff occurs more quickly and produces a higher peak flow

The amount of sediment carried by a stream is the: Multiple Choice traction load suspended load saltation load sediment load

sediment load

A hydrograph shows: Multiple Choice the change in a river's discharge over time the beginning and ending elevations of a river the change in the sediment load of a river the length and width of a river

the change in a river's discharge over time

The term hundred-year flood signifies: Multiple Choice the size of a flood that is predicted to occur every year for 100 years continuously a general term for a very large flooding event the size of a flood that is predicted to have a 1 in 100 probability of occurring in a given year

the size of a flood that is predicted to have a 1 in 100 probability of occurring in a given year

What happens to a river as it flows through a delta and encounters the sea? Multiple Choice the discharge and water velocity increase the maximum sediment grain size carried by the river increases the total sediment load carried by the river decreases Correct all of these

the total sediment load carried by the river decreases