Geography Rivers Chapter

Front 1

Hydrology

Back 1

science of water, its global circulation, distribution and properties, specifically water at and below Earths surface.

Hint 1

science of...

Front 2

Fluvial

Back 2

Stream-related processes

Hint 2

none

Front 3

errosion

Back 3

the process of dislodging, dissolving or removing surface material by wind or water

Hint 3

wind water

Front 4

transport

Back 4

move to new locations

Front 5

deposition

Back 5

dropping of particles

Front 6

alluvium

Back 6

term for clay, silt and sand transported by running water

Front 7

base level

Back 7

level below which a stream cannot errode a valley furthur

Hint 7

the lowest level is sea level

Front 8

dynamic equilibrium

Back 8

a balance among force, form and process

Front 9

drainage basin

Back 9

spatial geomorphic unit occupied by a river system

Hint 9

where the water drains to..

Front 10

drainage divides

Back 10

ridges or dividing lines that control into which basin precipitation drains

Front 11

watershed

Back 11

catchment area of a drainage basin

Front 12

sheetflow

Back 12

water that moves downslope ina thin filmas overland flow, not concentrated in channels larger than rills

Front 13

continental divides

Back 13

ridge or elevated area that determines the drainage patter of drainage basins

Front 14

drainage pattern

Back 14

an arrangement of channels that is determined by slope, differing rock resistance, climatic and hydrologic variablity, relief of the land, and structural controls imposed by the landscape

Front 15

discharge

Back 15

measured volume of flow in a river that passes by a given cross section of a stream in a given unit of time

Front 16

hydraulic action

Back 16

work of water moving materials through the exertion of pressure and shearing force

Front 17

abrasion

Back 17

process whereby rock particles grind and carve the streambed

Front 18

dissolved load

Back 18

materials carried in chemical solution in a stream derived from minerals such as limestone and dolomite, or from soluble salts

Hint 18

in stream transport

Front 19

suspended load

Back 19

fine particles held in suspension in a stream. The finest particles are not deposited until the stream velocity nears zero

Front 20

bed load

Back 20

coarse materials that are dragged alonge the bed of the stream by traction or by rolling and bouncing motion of saltation, involved particles to large to remain in suspension

Front 21

traction

Back 21

a type of sediment transport that drags coarser materials alonge the bed of the stream

Front 22

saltation

Back 22

the transport of sand grains by stream or wind, bouncing the grains along the ground in assymetrical paths

Front 23

aggradation

Back 23

the general building up of land surface because of deposition of material

Front 24

braided stream

Back 24

a stream that comes to a maze of interconnected channels laced with excess sediments. braiding often occurs with a reduction of discharge that affects a streams, transportation ability or an increase in sediment load.

Front 25

meandering stream

Back 25

the sinuou, curving pattern common to graded streams, with the outerportion of each curve subjectedto the greatest erosive actionand the inner portion recieving sediment deposits

Front 26

undercut bank

Back 26

a steep bank formed along the outer portion of a meandering stream; produced by lateral, erosive, undercutting action of a stream.

Front 27

point bar

Back 27

the inner portion of a stream meander that recieves sediment fill

Front 28

oxbow lake

Back 28

a lake that was formerly part of the channel of a meandering stream; isolated when a stream eroded its outer bank, forming a cuttoff through the neck ofa looping meander

Front 29

gradient

Back 29

the drop in elevation from a stream's headwaters to its mouth, ideally forming a concave slope

Front 30

graded stream

Back 30

a condition in a stream of mutual adjustment between the load carried by a stream and the related landscape through which the stream flows, forming a state of dynamic equilibrium among erosion, transported load, deposition and the stream's capacity.

Front 31

nickpoints

Back 31

the point at which the longitudinal profile of a stream is abruptly broken by a change in gradient; for example, a waterfall, rapids or cascade

Front 32

floodplain

Back 32

a low-lying area near a stream or channel, subject to recurrent flooding; alluvial deposits gnerally mask underlying rocks

Front 33

natural levees

Back 33

long, low ridges that occur on either side of a river in a developed floodplain; depositional by productsof river-flooding episodes

Front 34

alluvial terraces

Back 34

level areas that appear as topographic steps above the stream, created by a stream as it occurs in arid landscapes where streams are intermittent

Front 35

delta

Back 35

a depositional plain formed where a river enters a lake or ocean; named after the triangular shape of the greek letter delta

Front 36

flood

Back 36

a high water level that overflows the natural banks along any portion of a stream

Front 37

hydrograph

Back 37

a graph of stream discharge over a period of time ata specific place on a stream. The relationship between stream discharge and precipitation input is illustrated on the graph