Observing the Earth Exam #2

Earthquakes and the Earth's structure, Geologic Time, Freshwater: Streams, Lakes, Wetlands, and Groundwater, Water Resources

What is withdrawal?

any process that uses water and returns it locally

What is consumption?

processes that use water and return it far from its source

What is non-consumptive water use?

water that is used in a way that either returns the water immediately to its source or does not permanently remove it from the water cycle

What is the difference between consumptive and non-consumptive?

• Consumptive means to take and keep.

• Non-consumptive means to take and return.

What are the 3 major industries that use water?

domestic, industrial, and agricultural

How is agricultural water withdrawn and consumed?

• used to water crops and provide drinking water for livestock.

• water is usually withdrawn from rivers, lakes, reservoirs, and groundwater.

• much of it is consumed through evaporation and absorption by plants.

How is industrial water use withdrawn and consumed?

• used by factories, manufacturing plants, mining operations, and power plants.

• water is withdrawn from rivers, lakes, and groundwater.

• some water is consumed through evaporation or incorporated into products.

• some is treated and returned to rivers or other water sources.

How is domestic (household) water use withdrawn and consumed?

• used for drinking, cooking, baking, washing clothes, and flushing toilets

• water usually comes from municipal water systems or private wells.

• some water is consumed, such as water used for drinking and cooking.

• much of it goes down drains and is treated at wastewater treatment plans before discharged or reused.

What is an example of industrial water use?

A power plant withdraws river water to cool machinery and returns much of it to the river.

What is an example of agricultural water use?

A farmer pumps groundwater to irrigate a cornfield. Some water evaporates, and some is absorbed by the crops.

What is an example of domestic (household water use) ?

You take a shower. Water is withdrawn from the water supply, used, and then sent down the drain.

What are diversion systems?

a pipe, canal, or other infrastructure that transports water from its natural place and path in hydrologic cycle to a new place and path to serve human needs.

What do dams do?

trap and store seasonal precipitation

What are the advantages of dams?

• water storage

• flood control

• irrigation

• hydroelectric power

• recreation

What are the disadvantages of dams?

• disrupt ecosystems

• cause erosion

• displace people

• change the natural flow of rivers

What is ground water depletion?

the use of water faster than it is replenished

What is land subsidence?

• Land sinks because groundwater removal causes the ground to compact.

• Sinking of Earth’s surface

• Caused by loss of aquifer porosity

What is saltwater intrusion?

depletion of fresh ground water in coastal zones allows saline water to intrude

What are the effects of groundwater depletion?

• cone of depression

• land subsidence

• saltwater intrusion

What are regulated in the Clean Water Act?

It regulates pollutant discharges into U.S. surface waters and sets surface water quality standards.

What are biodegradable pollutants?

Pollutants that can decay or decompose naturally

What are the sources for biodegradable pollutants?

• sewage: wastewater and human activities

• disease organisms: human and animal waste

• phosphates and nitrate fertilizers: agricultural fertilizers and lawn fertilizers

What are non-biodegradable pollutants?

pollutants that do not decompose naturally and can remain in the environment

What are the sources for the non-biodegradable pollutants?

• PBTS (persistent, bio-accumulative, toxic substances): non-bio-degrable posions

• Organic industrial compounds: some pesticides, mine waste, and sediment

• Toxic organics: mine wastes, road salt, and lead mineral

• Mineral sediments: soil erosion and sediment runoff

What is point-source pollution?

Pollution that stems from a specific site such as a septic tank or gas spill

What is non-point source pollution?

stems from a broader area such as fertilizer, pesticide, runoff from lawns/farms

What is the definition of freshwater?

water that is relatively pure, with few dissolved salts

How much water on Earth is freshwater?

2.5% of total water

How much of freshwater is stored in ice caps and glaciers?

69%

How much of freshwater is stored in ground water?

30%

How much of freshwater is surface water?

1%

How is water stored in the hydrosphere?

water is stored in oceans, lakes, rivers, and other bodies of water.

How is water stored in the atmosphere?

water is stored in water vapor, clouds, and precipitation

How is water stored in the geosphere?

water is stored underground as groundwater and in soil.

How is water stored in the biosphere?

water is stored inside living organisms, including plants, animals, and humans.

What is the water cycle?

also known as the hydrologic cycle, it’s the continuous circulation of water among the hydrosphere, the atmosphere, the biosphere, and the geosphere.

What is evaporation?

Moves water from water bodies into atmosphere, cooling

What is precipitation?

sinks into the ground or runs off into rivers to form lakes or enter oceans, warming

What is runoff?

surface water flowing to the sea in streams and rivers

What is transpiration?

water evaporates directly from plants

What is infiltration?

water seeps into the ground

What is a perennial stream?

a stream that maintains some flow even during dry seasons.

What is an intermittent stream?

a stream that does not maintain some flow all the time and may be dry for long periods.

What is meander stream?

loops caused by lateral erosion

What is point bar stream?

depositional area, usually on “inside” of meander loop

What is oxbow lake stream?

meander that gets pinched off

What is braided stream?

network of interconnected channels

How is meander formed?

by erosion and deposition create winding river bends.

How is point bar formed?

sediment deposits on the inside of a river bend

How is oxbow lake formed?

a meander gets cut off from the main river

What is braided stream?

sediment buildup causes a river to split into multiple channels

What is a drainage basin?

an area of land that feeds into a river or stream

contiguous land that is all “downhill”

What is the largest drainage basin in the United States?

Mississippi River Basin

What is a delta?

deposition into aqueous environment

What is a distributaries?

fan of water channels in a delta

What is a flood plain?

• that portion of a river valley adjacent to the channel

• it’s built upward by sediment deposited during floods and is covered by water during a flood.

What are the different sections of a delta?

• delta top

• delta front

• prodelta

Why are deltas important?

Deltas are important because they create land, support wildlife, and provide good foil for farming.

How are lakes formed in different conditions?

Lakes form when natural processes create low areas or block water flow, allowing water to collect.

What is an oligotrophic lake?

• a lake that is poorly nourished

• blue, clear water

• low productivity, limited organisms

What is a eutrophic lake?

• A lake that has high nutrient supply

• often littered, green water

• high productivity, dense vegetation/algae

What is eutrophication?

• Eutrophication occurs when excess nutrients, such as nitrogen and phosphorus, enter a body of water and cause excessive algae growth.

• When the algae die, bacteria decompose them and use up dissolved oxygen, which can cause fish and other aquatic organisms to die.

What are wetlands?

areas that are water soaked or flooded for all or part of the year

What are the three types of wetlands?

• swamps

• bogs

• marshes

What are the functions of wetlands?

• biologically productive

• degrade pollutants

• mitigate flooding

• carbon storage

• habitat

Why are wetlands disappearing?

Wetlands are lost by both human and natural causes.

What is a water table?

• the top surface of the zone of saturation

• the water table separates the zone of saturation from the zone of aeration above.

What is an aquifer?

a body of rock that can yield economically significant quantities of groundwater; should be both porous and permeable.

What is the confined aquifer?

• an inclined aquifer sandwiched between layers of permeable rock.

• typically, the water in the lower part of the aquifer is under pressure from the weight of water above.

What is artesian well?

• a well drilled into a confined aquifer, in which the water rises without pumping and in some cases flows to the surface

How is an artesian well formed?

It forms when groundwater is trapped under pressure between impermeable rock layers, causing water to rise naturally when a well is drilled into the aquifer.

What is a non-confined aquifer?

It’s an underground water-bearing layer whose upper boundary is the water table and is open to the atmosphere through permeable soil and rock.

What are three types of deformation of rocks?

elastic, fracturing, and plastic

What is elastic deformation?

This type of deformation has the rock return to its original size and shape once the stress is removed and can cause an earthquake.

What is fracturing?

This type of deformation has vibrations that are formed that travel through Earth and are felt as an earthquake.

What is plastic deformation?

This type of deformation keeps its new shape when the stress is released and does not cause earthquakes.

What are the two types of movements in an earthquake?

Slippage and fracture

What is a slippage movement?

minor movement

What is a fracture movement?

larger movement

What is the focus of an earthquake?

the rupture point where energy is released

What is the epicenter of an earthquake?

the point on Earth’s surface directly above the focus

What are the two types of waves?

Body waves and Surface Waves

What are body waves?

travel through Earth’s interior

What are Surface waves?

slower waves

What are two types of body waves?

P wave and S wave

What is a P wave?

Fast, compressional, elastic wave, same direction in which it propagates

What is an S wave?

slower, shear wave, only moves through solids

What are the two types of surface waves?

Rolling waves

Love waves

What are Rolling Waves (Rayleigh waves)?

up and down rolling motion

What are Love waves?

side to side vibration

How does seismograph record seismic waves?

A seismograph records seismic waves by detecting and measuring ground vibrations caused by earthquakes.

What scales measure earthquake strength?

Mercalli scale and Richter scale

What is the Mercalli scale?

scale that measures damage

What is the Richter scale?

measures energy by the height of the largest wave

What is the moment-magnitude scale?

Measures energy as a function of movement and fault surface area

How are earthquakes located?

Earthquakes are located by comparing the arrival times of P-waves and S-waves at three different seismographs. Because the waves travel at different speeds, scientists can calculate the distance to the earthquake and use the three measurements to pinpoint its location.

What is triangulation?

the process of using three seismographs to determine the location of an earthquake

Where do most earthquakes occur?

at plate boundaries

Which plate’s boundary can cause significant earthquakes?

Convergent plate boundaries (especially subduction zones)

How do rocks and soil influence damages in an earthquake?

• Soft soil amplifies seismic waves and increases damage, while solid bedrock generally reduces shaking.