Geology 1401 Final Exam - Dworkin

soil moisture

38% of easily accessible surface freshwater is _________ ________________

true

52% of easily accessible surface freshwater is in lakes

true

79% of the world's freshwater is frozen (icecaps and glaciers)

hydrograph

A graph that shows discharge over time

river system

A network of connecting channels through which water is transmitted back to the ocean

potential surface

Differences in the elevation of the water table creates a pressure surface called...

rising floods

Due to heavy prolonged rain or melting snow. May last weeks or months

flash floods

High intensity rainfall causes flooding within a few minutes to hours

Meanders erode on the outside of the meander bend and deposit on the inside

How does the river channel change position?

1%

If a 100 year flood occurs, what is the chance of recurrence the next year?

water table

In an unconfined aquifer, the potential surface is the...

downhill

In what direction does ice flow?

drainage basin

Land area drained by one river system

volcanic activity, changes in the ocean circulation patterns, changes in the abundance of greenhouse gasses

Other factors that control climate

The Galveston Flood of 1900

September 8, 1900; a hurricane swept through Galveston Island; the result was the deadliest natural disaster in American history; the island was 9 feet above sea level at its highest point; the wind driven storm surge was 15 feet above sea level

Colorado, Wyoming, Utah and New Mexico

The Colorado River has headwaters in high mountains in...

floods

The inundation of normally dry land resulting from the rising and overflowing of a body of water

streams

The part of the hydrologic cycle that returns water to the oceans on the land's surface

mimics the ground surface

The shape of the water table...

glacial valleys

U-shaped landform created by alpine glaciers

Nile River

Which river is the longest in the world?

groundwater from aquifers is discharged into the streams

Why do rivers flow when it is not raining?

alluvial fan

a cone-shaped deposit of sediment crossed and built up by streams

natural levee

a curvy-linear mound of sand and gravel that parallels the river bank

moraine

a ridge of till that forms at the snout of a continental glacier

Bergschrund

a split or crevasse in the ice of a glacier, where the glacier detaches itself from the mountain's rock; forms at the back of a cirque

meander

a twisting winding course of looping stream bends

wind driven flood tides

affect coastal areas

the Earth was much colder in the past

alpine glacial features indicate that...

unconfined aquifer

an aquifer that is open to receive water from the surface

confined aquifer

an aquifer with an impermeable layer above it

dissolved load

atoms surrounded by water transported by the stream

erratics

boulders unlike the bedrock on which they lie

cirque

bowl shaped depression with a steep headwall

kettle lakes

depressions formed by melting of huge blocks of ice

false

discharge decreases downstream

drift

glacial deposits are all called ___________ because of the misconception that they were deposited by icebergs; material associated with glaciers

fjord

glaciated valley inundated by seawater

true

groundwater can flow uphill

pressure

groundwater flow is driven by...

eutrophic lake

highly nourished; high nitrogen and phosphorous input

20%

how much of our potable water is in groundwater?

3%

how much of the world's water is freshwater a.k.a. potable?

97%

how much of the world's water is in the ocean a.k.a. non-potable?

glacial theory

ice once covered large parts of the continents that are now ice free

flood frequency

in other words, how often does a particular river discharge occur?

oxbow lakes

isolated meander loops

evolution of lakes

lakes fill with sediment and organic material. They become marshes, swamps and then fill in completely

less often

large floods happen... more often or less often?

lake

large inland body of standing water that occurs in topographic depressions

man-made levees

man's influence: forces stream water to stay in the channel. Stream levels rise. Velocity increases

dams

man's influence: have a finite holding capacity. _______ failure causes catastrophic flooding.

channelization

man's influence: modifying a river's channel. Typically involves straightening and building concrete walls and floors

urbanization

man's influence: runoff is increased due to more impervious cover i.e. roofs, asphalt, cement

true

meander loops migrate throughout the floodplain

velocity x cross-sectional area

measurement of discharge

false - they are retreating

most of the world's alpine glaciers are still in tact

true

most sediment is transported during floods

suspended load

particles that are carried within the stream (fine grained - silt and clay)

bed load

particles that slide, roll or bounce (saltation) along the bottom of the stream (coarse grained)

tributaries, main trunk, deltas

parts of a river system

recharge zone

place where water enters the aquifer (environmentally sensitive)

discharge zone

places where groundwater flows out of the aquifer

oligotrophic lake

poorly nourished; not many nutrients; few plants; abundant O2

meander scars

positions where the river used to occupy

horn

pyramidal peak where three or more cirques intersect

entrenched meander

rapid uplift of the land causes rapid down cutting

false

rivers are static - they never change position

outwash

sand and gravel deposited in front of a glacier

point bar

sand or gravel deposited on the inside of a meander bend

esker

sinuous ridge of sand and gravel deposited by rivers under, on or within the ice

more often

small floods happen... more often or less often?

the 100 year flood

statistical assessment that a given event has a 1 in 100 chance of occurring in any year; 1% chance

true

stream competence (grain size) decreases downstream

the volume of water per time that passes through a stream

stream discharge is...

water and sediment

the 2 parts of streams are...

true

the Earth's climate has been different in the past

tributaries

the collection system; a dendritic pattern of smaller streams that feed water into the main trunk

deltas

the dispersing system; river water flows into a standing body of water

evaporation from ocean, precipitation, water returned back to the ocean (runoff)

the hydrologic cycle (3 steps)

main trunk

the major part of a river system that transports the water

true

the number of tributaries decreases downstream

the 100 year floodplain

the part of the floodplain that has a 1% chance in any year of being covered in water

floodplain

the portion of a river system that is covered by water during flood stage

the Earth is warming

the rapid melting of the remaining alpine glaciers indicates

cut bank

the steep walled part of the outside of the meander

false

the stream gradient (relief, slope) increases downstream

water table

the top of the saturated zone in an unconfined aquifer

Planetary Orbital Variations

these change the Earth's distance to the Sun; most probable cause of the advance and retreat of Pleistocene glaciers

flood frequency curve

this is constructed by monitoring a river over time

true

tributaries "V" downstream

false - only 1%

true or false: only 3% of potable is easily accessible

till

unsorted, unstratified sediment deposited in contact with a glacier

outwash plain

vast flat areas underlain by sand and gravel

false

velocity increases downstream

nile, amazon, yangtze

what are the 3 longest rivers in the world?

the variability of the amount of solar radiation received and the retention of that energy

what is the primary cause of temperature on Earth?

rivers

where is 1% of easily accessible freshwater?

Freak weather patterns in the Midwest

why did the 1993 Mississippi Flood occur?

false

you should always build your house on a floodplain