Earth Sci 2Gg3 - Lecture 6 - Rivers

Front 1

What cycle are rivers part of, what do rivers do?

Back 1

part of the hydrologic cycle, transports water that has fallen onto land toward the oceans

Front 2

Runoff

Back 2

Precipitation flowing along the surface that has not infiltrated the soil

Front 3

Stream

Back 3

tributariesof rivers

Front 4

drainage basin

Back 4

thearea of surrounding land that is drained by that river

Front 5

Drainagebasin (for a lake)

Back 5

thearea of land that drains into that lake

Front 6

Divides

Back 6

aridge of higher land that separates which way rivers flow, theyformthe boundaries of drainage basins

Front 7

The ContinentalDivide

Back 7

located along thespine of the RockyMountains, separates which ocean the streams and rivers will eventually drain into

Front 8

RiverGradient

Back 8

the change in elevation over the distance the river flows, higher elevation = steeper gradient

Front 9

Bed Load

Back 9

Materialsthat roll, slide, or bounce along the bottom of river (e.g. sand, pebbles).

Front 10

Suspended Load

Back 10

Siltand clay particles carried in the water (90%)

Front 11

Dissolved Load

Back 11

Materialderived from chemical weathering of rock and sediment within the drainage basin

Front 12

Discharge

Back 12

The volume of water flowing past a pointin a river over a specific period of time.

Front 13

Discharge Formula

Back 13

Q= VA

Q= discharge, V= velocity, A = cross-sectional area

Front 14

alluvial fan

Back 14

Whenthe river slows at its mouth, it deposits on land

Front 15

delta

Back 15

When the river slows at its mouth, it deposits in water

Front 16

Braided Channel Pattern

Back 16

Alarge number of channels are evident.

Front 17

Anastomosing Channel Pattern

Back 17

Twoor more channels that have intervening

islands where sediment is temporarilystored.

Front 18

Meandering Channel Pattern

Back 18

Asingle channel that is shaped like a snake.

Front 19

cutbank

Back 19

Forms around the outside of the curves in

meanders due to erosion from fasting moving water

Front 20

point bar

Back 20

Deposition formed by slower moving water on inside of curves in meanders

Front 21

Riffle

Back 21

a shallow section of river where watermoves rapidly over a gravel bed

Front 22

Pool

Back 22

a deep section of a river where watermoves slowly

Front 23

floodplain

Back 23

thearea of flat land adjacent to a channel that is subject to natural flooding

Front 24

avulse

Back 24

During a flood water leaves the channel and cuts a new channel that forms a shorter route toa meander bend

Front 25

oxbowlake

Back 25

The abandoned looping section of the old channel forms during avulsion

Front 26

bankfull discharge

Back 26

the discharge at which pointwater first flows out of the channel

Front 27

Stage (measured in metres)

Back 27

Thelevel of the river surface.

Front 28

Flood Stage (measuredin metres)

Back 28

Thelevel the river surface must reach in order for it to cause property damage.

Front 29

Hydrograph

Back 29

Agraph showing changes in discharge or changes in stage over time.

Front 30

Recurrence Interval

Back 30

Theaverage time between floods of a certain size.

Front 31

Upstream floods

Back 31

occur in the upperpart of the drainage basin, produced by heavy rainfall ofshort duration over a relatively small area

Front 32

flashfloods

Back 32

suddenand involve a large increase in discharge, occurin areas of steep topography and little vegetation

Front 33

DownstreamFloods

Back 33

cover relatively large areas, produced by rain of long duration or by rapid melting of a snowpack

Front 34

Outburst floods

Back 34

causedby the sudden draining of lakes that were originally dammed by a glacier orother material