EXAM 2

Question 1

Define stream load and explain what factors control it.

Answer 1

Stream load: materials that are carried and transported by a stream or river
Dissolved load: ions dissolved in the water
Suspended load: particles carried in suspension
Bed load: particles moved along the streambed

Factors:
Stream velocity
Volume of water flowing
Size and density of the particles
Slope of stream channel

Question 2

Why do stream sediments tend to be well sorted?

Answer 2

Stream sediments tend to be well sorted because the sorting process occurs as a result of the varying velocities of water within the stream

Faster-moving water: can transport larger and heavier particles

Slower-moving water: can only transport smaller and lighter particles

Differential transport leads to the sorting of sediment particles by size, resulting in well-sorted sediments.

Question 3

Explain how migration and enlargement of meanders contribute to floodplain development.

Answer 3

Meander migration and enlargement: Alter the shape and size of the river channel

As meanders migrate laterally and enlarge over time, they erode the outer banks and deposit sediment on the inner banks, creating a wider and flatter floodplain

Increases the capacity of the river to accommodate floodwaters

Reduces the risk of flooding in surrounding areas

Question 4

Describe some of the factors that cause rivers to be braided, rather than meandering.

Answer 4

High sediment supply: When a river has more sediment than it can transport, it deposits excess sediment, creating bars and islands within the channel

Variable discharge: Caused by factors like seasonal rainfall or glacial meltwater, can lead to fluctuations in channel capacity, promoting the formation of multiple channels

Steep channel gradient: Increases the energy available for sediment transport.

Question 5

What is a flood-frequency curve?

Answer 5

Flood-frequency curve: graph that illustrates the relationship between the magnitude of floods and their frequency of occurrence

Plots the discharge of a river against the probability of exceedance (chance of a flood of a certain magnitude occurring in a given year)

Essential for assessing flood risk and designing flood control measures

Question 6

What is recurrence interval and how is it determined?

Answer 6

Recurrence interval: Average time interval between floods of a particular magnitude or greater

Determined by analyzing historical flood data and constructing a flood-frequency curve

Recurrence Interval = (N + 1) / M, where N is the number of years of record and M is the rank of the flood event.

Question 7

Describe how urbanization can affect stream flooding.

Answer 7

Increasing the amount of impervious surfaces such as roads, buildings, and parking lots

These surfaces prevent water from infiltrating into the ground, leading to rapid runoff during rainfall events

Urban areas experience higher peak flows and more frequent flooding.

Question 8

Why does the Earth have seasons?

Answer 8

Earth’s axial tilt relative to its orbit around the Sun

As Earth orbits the Sun, different parts of the planet receive varying amounts of sunlight

Leads to differences in temperature and weather patterns

Question 9

In what way does climate change impact hurricanes?

Answer 9

Warmer ocean temperatures provide more energy for hurricanes to intensify, leading to stronger and more destructive storms

Rising sea levels increase the risk of storm surge and coastal flooding during hurricane landfalls.

Question 10

Describe the “greenhouse effect”.

Answer 10

Greenhouse effect: natural process that regulates Earth’s temperature by trapping heat in the atmosphere

Greenhouse gases (carbon dioxide [CO2], methane [CH4], water vapor [H2O]), absorb and re-emit infrared radiation emitted by the Earth’s surface

Warms the lower atmosphere and the surface of the Earth, making it habitable for life.

Question 11

The sun emits energy in what parts of the electromagnetic spectrum?

Answer 11

Electromagnetic radiation:
Ultraviolet (UV)
Visible light
Infrared (IR)

Question 12

The Earth emits energy in what parts of the electromagnetic spectrum?

Answer 12

Infrared radiation: result of the Earth’s surface and atmosphere absorbing solar energy and re-radiating it back into space

Question 13

What is ‘insolation’ and how does it vary with latitude and season?

Answer 13

Insolation: incoming solar radiation received by the Earth’s surface

Varies with latitude and season due to the curvature of the Earth and its axial tilt

At the equator, insolation is generally more intense throughout the year, leading to warmer temperatures

At higher latitudes, insolation decreases, resulting in cooler temperatures.

Question 14

Describe how global atmospheric circulation patterns affect climates at different latitudes.

Answer 14

These circulation patterns transport heat and moisture around the globe, shaping regional climates.

Question 15

What are the two main mechanisms by which the energy from the sun is transported from the equator toward the poles?

Answer 15

1. Atmospheric circulation (such as Hadley, Ferrel, and Polar cells)
2. Ocean currents (such as the Gulf Stream and the Antarctic Circumpolar Current)

Question 16

What drives the thermohaline circulation in the oceans, and how does this “conveyor” affect climate around the North Atlantic?

Answer 16

Thermohaline circulation: primarily driven by differences in temperature and salinity

Warm, less dense surface waters move towards the poles, where they cool and become denser, sinking to deeper ocean layers

Global “conveyor belt” of ocean currents helps regulate climate by redistributing heat around the Earth, particularly affecting climate in the North Atlantic region.

Question 17

What is upwelling and why does it occur?

Answer 17

Upwelling: process by which cold, nutrient-rich waters rise from the ocean depths to the surface

Occurs along coastlines where surface winds blow offshore, causing surface waters to move away from the shore and be replaced by cold, nutrient-rich waters from below

Supports high biological productivity and fisheries in coastal regions.

Question 18

El Nino and la Nina are naturally occurring variations in the climate. Describe the conditions that lead to El Nino and its effects on weather patterns in the Pacific.

Answer 18

El Niño: characterized by the warming of sea surface temperatures in the central and eastern Pacific Ocean, disrupting normal atmospheric circulation patterns

Occurs irregularly every 2-7 years and can lead to changes in weather patterns worldwide.

Effects of El Niño include droughts in some regions, heavy rainfall and flooding in others, and disruptions to marine ecosystems.

Question 19

What is the ‘Snowball Earth” hypothesis? Describe two of the feedback loops that it assumes.

Answer 19

The Snowball Earth Hypothesis: Earth experienced periods of extreme glaciation in its past, during which the entire planet was covered in ice

Feedback loops involving the following factors initiate and maintain these glaciations:

Ice-albedo feedback (reflectivity of ice)
Carbon dioxide levels

Question 20

What are the three components of Milankovitch cycles? Name and describe them in some detail.

Answer 20

Milankovitch cycles: long-term variations in Earth’s orbit and axial tilt that influence climate over tens to hundreds of thousands of years

Eccentricity: changes in the shape of Earth’s orbit

Axial tilt: changes in the tilt of Earth’s axis

Precession: changes in the orientation of Earth’s axis

*These cycles affect the distribution and intensity of solar radiation received by the Earth, influencing climate patterns such as ice ages.

Question 21

What are some expected changes to climate in New Hampshire in the coming decades? Be specific.

Answer 21

Warmer temperatures

Changes in precipitation patterns (including more intense rainfall events)

Increased frequency of heatwaves

Changes in the distribution of plant and animal species

Rising sea levels on coastal areas

Question 22

What are two primary factors that contribute to the uncertainty in climate change projections (like those from the IPCC)?

Answer 22

Complexity of Earth’s climate system:

Climate is influenced by numerous interconnected processes and feedback mechanisms, making accurate predictions challenging

Uncertainties in future human activities and emissions:

Uncertainties in future greenhouse gas emissions, technological advancements, and policy decisions contribute to uncertainty in future climate scenarios.

Question 23

Factors influencing slope stability - Geology and Rock Type

Answer 23

Different types of rock and soil have varying degrees of cohesion and internal strength, affecting their stability on slopes.

Question 24

Factors influencing slope stability - Slope Angle and Height

Answer 24

Steeper slopes are generally less stable than gentler slopes, especially when combined with greater height.

Question 25

Factors influencing slope stability - Vegetation Cover

Answer 25

Vegetation helps stabilize slopes by reinforcing soil with roots, reducing erosion, and absorbing excess moisture.

Question 26

Factors influencing slope stability - Water Content

Answer 26

Excess water can decrease soil cohesion, increase weight, and lubricate surfaces, making slopes more prone to failure.

Question 27

Factors influencing slope stability - Climate and Weathering

Answer 27

Climate conditions and weathering processes can weaken rock and soil over time, reducing slope stability.

Question 28

Factors influencing slope stability - Human Activities

Answer 28

Construction, mining, deforestation, and other human activities can alter natural slope conditions, increasing the risk of instability.

Question 29

What is “angle of repose”?

Answer 29

Angle of Repose: maximum angle at which loose material, such as sand, soil, or rock fragments, can remain stable on a slope without collapsing or sliding

Represents the equilibrium angle between the force of gravity pulling the material downhill and the resistance of the material to movement.

Question 30

Name and describe three different types of mass wasting.

Answer 30

Landslides: Rapid downslope movement of rock, soil, or debris along a discrete surface, often triggered by heavy rainfall, earthquakes, or human activities.

Slumps: Movement of material along a curved surface, typically characterized by rotational movement and internal deformation.

Rockfalls: Sudden detachment and free-fall movement of individual rock fragments or blocks from a steep cliff or slope.

Question 31

Describe why heavy rains increase the risk of landslides in some areas.

Answer 31

Saturation: Excessive rainfall saturates the soil, reducing its cohesion and increasing pore water pressure, making it more prone to failure.

Increased Weight: The added weight of water can increase the stress on slopes, especially on already unstable or weakened slopes.

Lubrication: Water acts as a lubricant, reducing friction between soil particles and rock surfaces, facilitating slope movement.

Erosion: Heavy rainfall can erode slope materials, undercutting the base of slopes and triggering mass wasting events.

Question 32

What human activities contribute to slope instability? Explain these activities create instabilities.

Answer 32

Deforestation: Removal of vegetation reduces slope stability by removing root reinforcement and increasing surface runoff, leading to erosion.

Construction and Excavation: Alteration of slopes through excavation, grading, or construction activities can disturb natural slope conditions, leading to instability.

Mining: Excavation and blasting associated with mining operations can weaken slopes, leading to slope failures and landslides.

Poor Land Use Practices: Improper land use practices such as overloading slopes with structures, roads, or landfills can increase stress on slopes and contribute to instability.

Question 33

Name and describe the methods that humans employ to prevent instabilities.

Answer 33

Vegetation Management: Planting and maintaining vegetation on slopes to stabilize soil with roots, reduce erosion, and absorb excess moisture

Engineering Structures: Constructing retaining walls, rock buttresses, or soil reinforcement structures to stabilize slopes and prevent erosion.

Drainage Systems: Installing drainage systems such as French drains or surface water diversion channels to reduce excess water infiltration and pore pressure buildup.

Slope Grading and Terracing: Modifying slope angles and creating terraces to reduce slope steepness and redistribute weight, improving stability.

Slope Monitoring and Early Warning Systems: Implementing monitoring techniques such as inclinometers, GPS, and rainfall gauges to detect changes in slope stability and provide early warnings of potential failures.

Question 34

Name and describe the major parts of a beach (beach face, berm, foreshore, backshore)

Answer 34

Beach Face: The sloping portion of the beach that extends from the water’s edge to the berm. It is continually reshaped by wave action and tides.

Berm: A raised area of sand or gravel running parallel to the shoreline, marking the highest point reached by normal high tides. It serves as a buffer against wave erosion during storms.

Foreshore: The area of the beach that is exposed during low tide and submerged during high tide. It experiences constant wave action and erosion.

Backshore: The upper portion of the beach that is only submerged during extreme high tides or storm surges. It is usually dry and subject to wind-driven processes.

Question 35

What causes waves? As waves approach a shoreline, they ‘break’. Why?

Answer 35

Waves: Primarily caused by the transfer of energy from the wind to the water’s surface

As wind blows across the ocean, it creates ripples that develop into waves

As waves approach the shoreline, they begin to feel the ocean bottom, causing the wave crests to become steeper and eventually break

Wave breaking occurs when the wave height exceeds the depth of the water, causing the wave to collapse and release its energy.

Question 36

What causes tides? What is the difference between neap and spring tides? What causes the so-called “King tide”?

Answer 36

Tides: primarily caused by the gravitational pull of the Moon and, to a lesser extent, the Sun, on Earth’s oceans

Neap tides: gravitational forces of the Sun and Moon are perpendicular to each other, resulting in lower high tides and higher low tides

Spring tides: gravitational forces of the Sun and Moon are aligned, resulting in higher high tides and lower low tides

King tides: (perigean spring tides) the Moon is at its closest point to Earth (perigee), amplifying the gravitational pull and causing especially high tides

Question 37

How do longshore currents impact shorelines? What is littoral drift?

Answer 37

Longshore currents: currents that flow parallel to the shoreline, transporting sediment along the coast

Littoral drift: movement of sediment along the shoreline due to the combined action of waves and currents

Longshore currents and littoral drift can impact shorelines by redistributing sediment, shaping beaches, and forming coastal landforms such as spits and barrier islands.

Question 38

What is a storm surge and what are its components?

Answer 38

Wind Setup: increase in sea level caused by strong onshore winds pushing water towards the shore.
Barometric Pressure Drop: decrease in atmospheric pressure associated with the storm, causing water to pile up.
Wave Setup: The increase in sea level caused by large waves riding on top of the storm surge.

Question 39

What is a wave-cut platform? How does it form?

Answer 39

Wave cut platform: gently sloping, flat surface eroded by wave action at the base of a cliff or headland

Forms through a process of abrasion and hydraulic action, where waves undercut and erode the base of the cliff, causing it to retreat inland

Over time, the exposed bedrock is worn down into a flat platform by continued wave action.

Question 40

Why do drowned valleys form?

Answer 40

Drowned valleys: form when sea level rises or land subsides, flooding river valleys that were previously exposed

As sea level rises, river valleys are inundated with seawater, forming estuaries or drowned river mouths

Process can be accelerated by glacial melting or tectonic activity.

Question 41

Name and describe two methods of coastal stabilization.

Answer 41

Beach Nourishment: Adding sand or sediment to eroded beaches to widen the shoreline and protect coastal structures.

Seawalls and Revetments: Hard structures built along the shoreline to deflect wave energy and prevent erosion of the coast.

Dune Restoration: Planting vegetation and building dunes to stabilize shorelines, absorb wave energy, and protect inland areas from storm surges.

Question 42

How does wave refraction work to erode points of land jutting out into the sea?

Answer 42

Wave refraction: occurs when waves approach a coastline at an angle, causing them to bend and concentrate their energy on headlands or points of land jutting out into the sea

Concentrated wave energy accelerates erosion on the sides of headlands, forming sea cliffs, sea caves, and other erosional landforms.

Question 43

Briefly describe the fate of the Hampton Beach community under the climate scenario coinciding with net zero by 2050?

Answer 43

Reduced risks of coastal erosion and flooding due to decreased sea level rise and storm intensity

Challenges related to:
sea level rise
increased temperatures
changes in precipitation patterns

Combat challenges with:
shoreline protection
flood defenses
infrastructure improvements.

Question 44

What is a glacier? How do glaciers form?

Answer 44

Glacier: large mass of ice that moves slowly over land under its own weight

Form through the accumulation and compaction of snow over many years

Successive layers of snow accumulate, weight of the overlying snow compresses the lower layers into dense ice

Ice becomes thick enough to flow downhill under the force of gravity, forming a glacier

Question 45

What are the differences between continental and alpine glaciers?

Answer 45

Continental Glaciers (ice sheets):
Vast ice masses that cover extensive areas of land
Found in polar regions such as Antarctica and Greenland
Characterized by their immense size and relatively flat topography

Alpine Glaciers (mountain glaciers):
Occur in mountainous regions
Confined to valleys or cirques
Smaller in size compared to continental glaciers
Often found in high-altitude areas
Flow down valleys, sculpting the landscape as they move

Question 46

What part of a glacier flows fastest? Slowest? Why?

Answer 46

Fastest-flowing: center/axis of the glacier (ice experiences the least resistance to flow)
- “zone of maximum flow” or “zone of velocity.”

Slowest-flowing: edges/margins (ice encounters frictional resistance from the valley walls or surrounding terrain)

*base of a glacier may also flow faster than the surface due to the presence of meltwater acting as a lubricant, reducing friction.

Question 47

Define and describe the following: striations, till, outwash, drift, moraine.

Answer 47

Striations: parallel scratches/grooves on bedrock surfaces caused by the movement of glaciers; formed as glaciers transport rock fragments and debris, which scrape and scratch the underlying bedrock as the glacier moves.

Till: unsorted and unstratified sediment deposited directly by glaciers; consists of a mixture of clay, silt, sand, gravel, and boulders, deposited as the glacier retreats or melts.

Outwash: sediment deposited by meltwater streams flowing from glaciers; usually well-sorted and stratified, consisting of sand, gravel, and finer sediment transported and sorted by meltwater.

Drift: all sedimentary deposits, including till and outwash, left behind by glaciers.

Moraine: accumulations of till deposited by glaciers; can be classified as:
- Lateral moraines: deposited along the sides of glaciers
- Medial moraines: formed where two glaciers merge
- Terminal moraines: deposited at the furthest extent of a glacier
- Recessional moraines: deposited as a glacier temporarily stalls during retreat

Question 48

How does a ‘wineglass valley’ form?

Answer 48

Wineglass valley (U-shaped valley): forms through the erosional action of glaciers

V-shaped river valley carved by the flow of water

Glacier erodes valley floor and walls through abrasion and plucking, widening and deepening the valley into a wineglass valley

After the glacier retreats, the valley may be further modified by other erosional processes such as rivers or weathering

Question 49

What is the “Water Budget Equation” and use it to explain the fall of the Aral Sea.

Answer 49

Water budget equation: method used to analyze the inflow, outflow, and changes in water storage of a particular system

Inflow - Outflow ± Changes in Storage = 0.

Aral Sea: received water from two main sources (Amu Darya and Syr Darya rivers).

Inflow of water into the Aral Sea drastically decreased due to water diversion for agriculture

Inflow of water into Aral Sea decreased

Increased evaporation due to higher temperatures and reduced surface area lead to higher outlow

Factors resulted in in negative change in storage, leading to dessication of Aral Sea

Question 50

In what region of the United States are water resources analogous to those of the Aral Sea? Briefly explain how the two are similar.

Answer 50

Colorado River Basin and Aral Sea Similarities:

Significant water diversion for agricultural irrigation and human consumption

Reduced inflow

Increased water demand due to population growth and economic development

Environmental degredation

Loss of biodiversity

Socio-economic impacts on local communities

Question 51

How do we commonly measure the quantity of “Renewable Fresh Water Resources” in a region and how is this quantification used to determine ‘Water Scarcity’?

Answer 51

Renewable freshwater resources indicators:
- Total annual precipitation
- Surface water runoff
- Groundwater recharge.

Water scarcity: determined by comparing availability of renewable freshwater resources to water demand of a region’s population and economy
- Occurs when water demand exceeds supply of renewable resources
- Regions facing high water scarcity may experience water shortages, competition for water resources, and socio-economic challenges related to water access and management

Water Stress Index: compares water withdrawals to renewable resources, or the Falkenmark Indicator (assesses water availability per capita)