GEOL Module 10 Homework

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

The oceans would become smaller.

A drainage pattern that resembles the branching pattern of a deciduous tree is called ________.

dendritic

The process by which liquid water changes into water vapor is called ________.

evaporation

Which ocean is Earth's largest?

the Pacific Ocean

What is the primary energy source that drives the hydrologic cycle and most other cycles on Earth?

the Sun

Excessive groundwater withdrawals can cause ________.

the water table drops or declines in elevation

Double-click the Drainage Pattern C placemark. Which type of drainage pattern is this?

trellis drainage

Look at the four images of various river channels, and examine their unique characteristics and the dominant force or processes at work in each scene.

1. Braided alluvial channel - as a result of transporting coarse load. (IMAGE: the one with a ton of small rivers) 2. Meandering alluvial channel - as a result of transporting a lot of fine load in suspension. (IMAGE: the big thick windy river) 3. Non-meandering alluvial channel - as a result of transporting both coarse and fine load in suspension (IMAGE: the one with two big rocks in the river and smaller rock on the river bed) 4. Bedrock channel - as a result of erosion and undercutting. (IMAGE: the one with the deep river and tall rocks on each side)

Part A: Match the words in the left column to the appropriate blanks in the sentences on the right.

1. The geographical area where all surface water converges to one location is called its (drainage basin). 2. A delta forms at the (mouth) of a river, where the velocity of the water flow decreases and deposition is highest. 3. The volume of water flowing past a certain point in a given amount of time is a river's (discharge). 4. The (headwaters) of a river have a steep gradient, high channel roughness, and low water volume. 5. A stream with a low to moderate gradient, carrying most of its load in suspension, should be characterized by many curves and bends called (meanders). 6. A river with a well-developed (floodplain) has a flat low-lying channel and experiences flooding during periods of high discharge.

What is one effect of the current conflict in Darfur?

Agricultural production has decreased.

Which of the confluence sites placemarked in the Stream Load folder best displays a difference in suspended load?

C

Which of the placemarks in the Stream Drainage Patterns folder represents a radial drainage pattern?

C

How does the number of tributaries change for a stream that has had part of its flow captured (A in the example) and a stream that has pirated another stream (B in the example)?

The number of tributaries for the captured stream (A) decreases and the number of tributaries for the pirating stream (B) increases.

A tributary stream that has to flow for many kilometers before finding an opening where it enters the main river is called a ________.

Yazoo tributary

The Brahmaputra River is:

a braided stream due to its high sediment load.

What is a floodplain?

a flat surface next to a river channel

A perched water table develops when ________.

a horizontal aquitard above the regional water table lies below an aquifer Submit

What is the Sudanese government's "scorched earth" policy?

a policy of burning villages in an effort to combat rebellion

What is a natural levee?

a ridge of flood deposits next to a river channel

Double-click the Drainage Pattern E placemark. Use the visibility slider to adjust the transparency of the map overlay from opaque to transparent and back so that you can view the terrain as well as the stream channels. Which type of drainage pattern is this?

annular drainage

In what ways does a stream transport its load, and which part of the load moves most slowly? Select all that apply.

as a suspended load as a dissolved load as a bed load, which is the slowest mode of particle transport in streams

Where is most of Earth's freshwater found?

as ice at Earth's surface

What are the three types of beds that comprise a delta from bottom to top?

bottomset beds, foreset beds, topset beds

Double-click the Drainage Pattern F placemark. Which type of drainage pattern is this?

dendritic drainage

Double-click the Drainage Pattern D placemark. Which type of drainage pattern is this?

deranged drainage

Darcy's law allows for the calculation of ________.

discharge

The volume of water flowing past a certain point in a given unit of time is called ________.

discharge

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

Part E - Landforms Associated with Stream Incision Incised meanders and terraces are __________.

erosional features

What is the largest freshwater reservoir in the hydrosphere?

glaciers

Which component of the hydrologic cycle describes the recharge of water to the soil and groundwater systems?

infiltration

How does urbanization (paving, etc.) affect runoff and infiltration in a small, previously forested, drainage basin?

infiltration decreases; runoff increases

Which type of feature is Shegogue Lake?

meander scar

A network of recharge wells can help correct the problem of ________.

saltwater intrusion

A ________ is the icicle-like speleothem that grows down from the roof of a cavern.

stalactite

A stream is said to be a losing stream when ________.

the channel bottom is above the local water table

How many kilometers wide was the main channel of the river before the flood (1991)?

1.2

Which of the placemarks in the Stream Order folder is labeled with the most accurate stream order number?

2

How many kilometers wide was the floodplain that was submerged in the 1993 imagery? Include the pink regions, since they were recently under water when the image was captured.

6.7

What is the stream gradient of the Arkansas River between the two placemarks in the Stream Gradient folder?

7.22 meters/kilometer

Part B - Goosenecks of the San Juan River The Google Earth image and photo below, which depict the same location from different angles, show two features, labeled A and B, that were created by downcutting of the San Juan River. Choose the correct pair of terms from the choices below.

A) incised meanders, B) terraces

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

Agriculture and irrigation

What key factors are behind the conflict in Darfur?

All of the above are key factors behind the crisis in Darfur.

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

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

Which of the placemarks in the Stream Types folder represents an ephemeral stream?

B

________ is not part of the hydrologic cycle.

Calcium carbonate dissolving in soil water and groundwater

Which drainage basin in North America has the largest number of generating stations for hydroelectric power?

Columbia and Northwestern United States

What physical feature serves as the drainage divide on the western side of the Amazon River drainage basin?

Cordillera Central (Andes)

Which line contained in the Drainage Divide folder best represents a drainage divide?

D

What is the relationship between drawdown and the cone of depression associated with a pumping well?

Drawdown is the distance between the original water table and the water level in the well.

Which of the following placemarked locations in the Davis' Geomorphic Cycle folder best illustrates Davis' idea of an old age landscape?

E

Moving from the headwaters to the mouth, in most streams, which of the following is true?

Flow velocity generally increases.

What is groundwater, and how does it relate to the water table?

Groundwater is water that occupies the zone of saturation within the ground. The water table is the upper limit of the groundwater.

________ is a coefficient that takes into account the viscosity of the fluid and the permeability of the aquifer.

Hydraulic conductivity

How might a stream channel become braided?

If a large portion of a stream's sediment load consists of coarse material and the stream has a highly variable discharge, a stream channel can become braided.

Which of the following best describes a graded stream?

It is basically in equilibrium, neither eroding nor depositing material.

How does the formation of a natural levee impact flooding?

Natural levees raise the height of the stream channel, reducing the amount of flooding that will occur on the floodplain.

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

Porosity

How have rainfall patterns in Darfur changed over the past 50 years?

Rainfall has greatly decreased, leading to a series of droughts.

________ are characteristics of downcutting streams and a youthful stage of valley evolution.

Rapids and lots of whitewater

Which of these options accurately describes settling velocity?

Settling velocity is the speed at which a particle falls through a still fluid. This velocity is influenced by the size, specific gravity, and shape of the settling particle. Settling velocity has no effect on the dissolved load of a stream.

________ would have the largest capacity to naturally remove sewage pollutants.

Slightly clayey sand

________ generally constitutes the highest percentage of the annual sediment load moved by a stream.

Suspended load

Which of the following statements is best supported by the evidence found at the Knickpoint placemark?

The Niagara Escarpment is being eroded to the south and east by the Niagara River in the vicinity of Niagara Falls.

Which of the following can logically be concluded by speleothems/dripstone hanging from a cave roof?

The cave roof was above the water table when the speleothems formed.

Why is it difficult for farmers in Darfur to receive seeds?

The farmers fear militia violence and looting.

What is the source of heat for most hot springs and geysers, and how is this reflected in the distribution of these features?

The heat sources for most hot springs and geysers are magma bodies and igneous rocks. Thus, hot springs and geysers are often located where igneous activity occurs.

Part C - Stream features

Zone of Erosion: Waterfall Zone of Transportation: Cut banks and Point Bars Zone of Deposition: Delta + Alluvial Fan

What is a stream's longitudinal profile?

a cross-sectional view of a stream from the headwaters to its mouth

Which type of channel is likely to develop a sequence of steps and pools?

a steep channel cut into bedrock

What features are evident at placemarks B and D?

cutbanks

Which of the options below are types of floods? Select all that apply.

flash flood ice-jam flood dam-failure flood regional flood

The slope of a stream channel, expressed as the vertical drop of a stream over a specified distance, is called the/a________.

gradient

Which of the following methods of flood control is the cheapest and most effective?

nonstructural floodplain management

Which type of feature is Hampton Lake?

oxbow lake

Double-click the Drainage Pattern B placemark. Which type of drainage pattern is this?

parallel drainage

What does Darfur need more of in order to alleviate its crisis?

peace

Water-saturated muds have low ________ but can have greater ________ than well-cemented sandstone.

permeability, porosity

What features are evident at placemarks A and C?

point bars

What is the Sudanese Liberation Army's primary complaint?

poor infrastructure

Double-click the Drainage Pattern A placemark. Which type of drainage pattern is this?

radial drainage

________ are characteristics found in all good aquifers.

High porosity and high permeability

Which area in this list has the highest runoff?

an urban area

What is the best solution to address the problems caused by deforestation and desertification?

provide natural gas fuel for homes

Double-click the Drainage Pattern G placemark. Which type of drainage pattern is this?

rectangular drainage

Examine the words and/or phrases below and determine the relationship among the majority of words/phrases. Choose the option that does not fit the pattern.

waterfall

A stream begins at an elevation of 200 meters and flows a distance of 400 kilometers to the ocean? What is the average gradient?

0.5m/km

Part A - Erosion and deposition along a meandering stream (image drag drop answering)

1. (Top Left: pointing towards the dark blue part of the highlighted river) Maximum Acceleration (color of box: Pink) 2. (Top Right: pointing towards the lighter part of the highlighted stream) Minimum Acceleration (color of box: Pink) 3. (Bottom Left: pointing towards the edge of the curve of the stream) Erosion (color of the box: Purple) 4. (Bottom Right: pointing towards the sandy part of the riverbank) Deposit (color of box: Purple)

Part A - Stream Vocabulary Drag the terms in the left-hand column to the appropriate blanks on the right.

1. A(n) (incised meander) is a bend in a steep narrow bedrock valley. 2. The lowest level to which a stream can erode is called (base level). 3. A(n) (terrace) is the remnant of a former floodplain. 4. Examples of local base level include a stream or a(n) (lake). 5. A sweeping bend of a stream which is migrating laterally in a wide, flat valley is called a(n) (meander). 6. The flat, broad area surrounding a stream is referred to as a(n) (floodplain).

Which of the following must result in a lower base level for rivers and streams?

Sea level falls; land rises.

Which of the generalized channel paths seen in the Stream Capture folder most likely represents the previous outlet channel of the Murray River?

A

Which of the placemarks in the Stream Channel Patterns folder best resembles a braided stream pattern?

A

Which one of the following statements correctly describes how stream terraces can form?

A temporary base level is eliminated; the stream downcuts upstream from the old temporary base level, and the former floodplain is left well above the present elevation of the stream.

Making sure that the Mississippi River Map is deselected, evaluate the city elevations directly under the dot for each city location and the river height 0.25 km south of the north end of the transect line. (The elevation of the ground under your cursor is shown at the bottom of your screen.) Which of the following statements about the elevations of Alton, West Alton, and the Mississippi River is correct?

Alton is approixmately 20 m higher than West Alton.

The ________ River has the largest discharge of any in the world.

Amazon

Which of the following is a measure of a stream's ability to transport particles based on size, rather than quantity?

Competence

Which of the labeled placemarks in the Floodplain Landforms folder would have the highest active rate of deposition?

D

Which of the placemarks in the Deltas folder is located on the river that flows to the largest delta, as defined by the width of the largest part of the delta at the mouth of the river?

D

Which of the following choices correctly describes two processes that cut channels into bedrock?

During abrasion, the bed and the banks of the river are constantly bombarded by the particles carried in the water. During corrosion, soluble bedrock such as limestone is gradually dissolved by the flowing water.

The Congo River Basin, located primarily in the Democratic Republic of the Congo, is associated with which two natural regions?

Evergreen forest and savanna

Part B - Base level and stream valleys

Highest: - Narrow V-shaped valley (image) Middle: - Site of erosion / Site of deposition (image) Lowest: -Site of deposition/well developed floodplain)

Why do V-shaped valleys often contain rapids and/or waterfalls?

In many V-shaped valleys, resistant bedrock upstream creates rapids by acting as a local base level while downcutting occurs in less resistant bedrock downstream.

Based on the distribution and size of cities and the degree of urbanization in the Southwest, what area probably has the greatest demand for the river's water?

Los Angeles and southern California

Which major drainage basin in North America has the largest number of "extremely high" floods between 1985 and 2011?

Mississippi-Missouri

How has desertification changed the relationship between farmers and nomads in Darfur?

Nomads and farmers are now in conflict over limited agricultural land.

Part C - A Rincon in the Colorado River of Southern Utah Rank from oldest to youngest.

OLDEST EVENT 1. A stream migrates laterally across its floodplain developing meanders. This stream terminates at a lake, which is its base level. 2. The base level of the stream is lowered by crustal uplift and the river begins to incise downward. 3.Incised meanders form. YOUNGEST EVENT 4. A rincon forms by the cutoff of an incised meander, which shortens the river.

Part D - terraces of La Canada Alamosa Using the following photos, classify the observations according to whether they are "true," or " false."

TRUE - At least two episodes of downcutting have occurred. - Rounded gravels provide evidence that these flat-topped features are terraces. FALSE - The local base level for this stream is sea level. - Only one terrace is present at La Cañada Alamosa.

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

The atmosphere would contain less water.

What does the hydrologic cycle describe?

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

Which situations(s) would trigger the formation of incised meanders? Select all that apply.

The land on which the stream is flowing uplifts, causing the stream to begin downcutting. The base level of a stream drops, causing the stream to begin downcutting.

Which one of the following statements is TRUE concerning natural levees?

They are mostly fine sand and silt that build up during floods.

Using the example below, determine how flow will change as a result of stream piracy. The arrows indicate the original flow directions and the dotted line indicate where headward erosion has occurred.

Water would now flow from point A to point C.

Where is Darfur located?

Western Sudan

The type and amount of material carried in suspension are controlled by flow velocity and ________.

settling velocity

Look at the accompanying graph, and read the following statements regarding the time relationship between rainstorms and flooding. Based on this graph, which of the statements are true?

Flooding correlates with increased stream discharge. Peak stream flow happens after a storm.

________ describes the particle transport mode in streams intermediate between suspension and rolling along the bottom.

Saltation