chapter 17 flowing water

Question 1

floodplains

Answer 1

the areas of flat land near a stream that experiences flooding on a regular basis

Question 2

stream

Answer 2

channel in which water flows down hill by the force of gravity

Question 3

drainage basin

Answer 3

a geographic region drained by a single trunk stream and its tributaries

Question 4

trunk stream

Answer 4

single large stream into which smaller tributaries merge

Question 5

tributary

Answer 5

stream that joins with other streams to form a larger stream

Question 6

drainage divide

Answer 6

a ridge or highland that separates drainage basins and defines their boundaries

Question 7

continental divide

Answer 7

a ridge or highland that separates drainage systems that empty into ocean basins

Question 8

internal drainage

Answer 8

drainage basins with no outlet to the ocean

Question 9

stream order

Answer 9

a system that ranks streams based on the number of tributaries flowing into them
first order stream- no tributaries

Question 10

intermittent stream

Answer 10

a stream that runs dry during part or most of the year

Question 11

ephemeral stream

Answer 11

a stream that flows briefly after heavy rainstorms

Question 12

permanent stream

Answer 12

a stream that flows all year

Question 13

exotic stream

Answer 13

a permanent stream that originates in a humid region and flows through an arid region ex. nile river

Question 14

fluvial erosion

Answer 14

erosion by running water

Question 15

headward erosion

Answer 15

the process by which a stream channel lengthens upslope through time, forming new rills (newly forming stream channels) and gullies (what rills develop into) by fluvial erosion

Question 16

stream discharge

Answer 16

the volume of water flowing past a fixed point within a stream channel

Question 17

calculating stream discharge

Answer 17

Q=A X v
stream discharge- Q
stream channel area- A
velocity- v

Question 18

abrasion

Answer 18

the process by which movement of one material wears away another material

Question 19

stream load

Answer 19

material that moves within stream channel

Question 20

three types of stream loads

Answer 20

dissolved- soluble minerals that are carried in solution by a stream
suspended- small particles that remain suspended in flowing water or wind
bed- material in stream channel that is too heavy to become suspended in the current

Question 21

saltation and traction

Answer 21

saltation- sand grains move in a bouncing or hopping motion

traction- larger rocks are moved by a dragging or tumbling motion

Question 22

stream competence and stream capacity

Answer 22

stream competence- size of fragments a stream can transport

stream capacity- total amount of material that a stream can carry

Question 23

stream gradient

Answer 23

refers to the steepness of a stream, or the drop in elevation of the stream channel in the downstream direction

Question 24

base level

Answer 24

lowest level a stream can reach

Question 25

knickpoint

Answer 25

a location where there is an abrupt increase in stream gradient over a short distance

Question 26

escarpment

Answer 26

long cliff face or steep slope

Question 27

plunge pool

Answer 27

bowl at the base of a waterfall created by abrasion of circulating rocks

Question 28

stream rejuvenation

Answer 28

a process in which a stream gains erosional energy as its base level is lowered relative to its drainage basin

Question 29

stream piracy

Answer 29

the diversion of one stream into another as headward erosion merges the two streams

Question 30

alluvium

Answer 30

sediments deposited on a floodplain

Question 31

aggradation

Answer 31

the buildup of sediments within a stream bed and along its floodplain

Question 32

braided streams

Answer 32

streams that form intertwining channels around sediments in the stream bed

Question 33

alluvial fan

Answer 33

a gently sloping accumulation of sediment deposited at the base of a mountain by an ephemeral stream in arid regions

Question 34

thalweg

Answer 34

the fastest flowing portion of the stream

Question 35

cut bank

Answer 35

the side of a stream where erosion exceeds deposition

Question 36

point bar

Answer 36

an accumulation of silt, sand, and gravel on a stream bank that forms where deposition exceeds erosion

Question 37

oxbow lake

Answer 37

a water filled abandoned channel that results when a meander is cut off from stream channel

Question 38

reservoir

Answer 38

an artificial lake created by a dam

Question 39

delta

Answer 39

an accumulation of sediments that forms where a stream reaches base level

Question 40

distributaries

Answer 40

a branching network of small streams in a delta

Question 41

subsidence

Answer 41

the lowering of land evolution through the compaction of sediments