Geog Midterm

Front 1

streams

Back 1

flowing bodies of water continued to a channel drain excess water from land

-all bodies of water called streams regardless

Front 2

stream formation

Back 2

energy driving stream, flow comes from gravity water @ high elevations has potential energy

Front 3

sheetwash

Back 3

precipitation first flows downslope as action film of water

Front 4

dry wash

Back 4

empty stream channel

Front 5

stream gradient (slope)

Back 5

is a good predictor of how much energy it will have

Front 6

channel slope

Back 6

energy changes

if a channel get narrower the same amount of water has to go through a smaller space (faster)

Front 7

high elevation

Back 7

high elevation = high energy

Front 8

erosion (down vs. side)

Back 8

erosion down > erosion on side

faster slower

Front 9

base level

Back 9

lowest level to which a stream can cut ponds & lakes can serve as a local base level (new base level) form when water levels drop

Front 10

lowest base level

Back 10

sea level

Front 11

drainage basin

Back 11

the region drained by a river it is bound on all sides by high topography

Front 12

drainage divide

Back 12

the highland

Front 13

tributaries

Back 13

smaller channels drain into larger channel

Front 14

weathering and erosion

Back 14

weathering: is a physical and chemical break down of earth materials

products of weathering = sediments

Front 15

erosion

Back 15

is transport of materials fro one place to another

-streams erode by abrasion plucking dissolving etc. the sediments are moved in different ways

Front 16

stream transport

Back 16

solid sediments transported by water are modern in different ways depending on size

Front 17

3 types of stream transport

1. suspension

2. saltation

3. creep

Back 17

1. tiny particles float in water

2. medium sized particles move by bounding along the bottom

3. large objects slowly moved impact

Front 18

load

Back 18

additional material dissolved in water, all the materials are load

Front 19

deltas

Back 19

form as sediments is deposited @ the mouth of a stream

Front 20

deltas have a distinctive cross section

Back 20

1. coarse beds topsets: form on top

2. river beds foresets: dip into the water

3. very fine beds bottomsets: are on bottom

Front 21

alluvial fans

Back 21

form in dry regions when streams flow into dry valleys

Front 22

a river system consists of 3 zones

Back 22

zone 1: zone of erosion (water and sediment, productivity)

zone 2: zone transport (water and sediment)

zone 3: zone of deposition (sediment)

Front 23

discharge

Back 23

amount of water flowing through a stream per unit time

Front 24

competence

Back 24

maximum grain size a stream can carry

Front 25

capacity

Back 25

the total amount of sediment carried

Front 26

channel patterning

Back 26

the path a stream takes is a channel pattern

1. meandering streams

2. braided streams

Front 27

braided stream

Back 27

consist of small interweaving channels that are separated by sediment accumulations

-form in regions with high slopes, high sediment inout, where channel depth increases

Front 28

factors that affect braided streams

Back 28

erodibility - resistant substrates form deep meandering streams

suspended load - sticky days are resistant and prevent braided channels from flowing

Front 29

meandering streams

Back 29

characteristically wind across low gradient regions with soft substrates the Connecticut river CT and MA is a major meandering river in our region

Front 30

meandering streams form:

Back 30

as variations in the channel bottom cause the fastest flow to move back and fourth

Front 31

velocity increases

Back 31

on the outside of the bend because discharge in constant and water there travels farther

Front 32

cut bank

Back 32

steep sloped (causes it to form)

Front 33

point bars

Back 33

slow flow on the inside of the bend causes sediment deposition in point bars

Front 34

oxbow lake

Back 34

two cut banks eventually erode into each other cutting off the bend (makes an island)

Front 35

floods

Back 35

natural processes of overbank flow

Front 36

flood plain

Back 36

the low lying region beyond the bank

Front 37

flooding results

Back 37

from increased or concentrated precipitation within a drainage basin

Front 38

intense stroms (floods?)

Back 38

can bring so much rain it cant drain fast enough

Front 39

steep slopes: prevent?

Back 39

prevent water accumulation but may cause flooding downstream

Front 40

shallow slope

Back 40

may not permit water from draining fast enough

Front 41

infiltration rate

Back 41

how fast water is absorbed will also affect flooding

Front 42

poros material

Back 42

will per unit infiltration non porous ones will not