Geography As Rivers

Front 1

What is a river's long profile?

Back 1

The long profile shows how a river's gradient changes as it flows from its source to its mouth.

Front 2

What are the main inputs to a drainage basin?

Back 2

Precipitation (rain, snow, hail, dew)

Front 3

What are the main outputs to a drainage basin?

Back 3

Evaporation , transpiration (similar to evaporation but is the loss of water as a vapour from plant and tree leaves)- which is collectively known as evapotranspiration. The main way that water is lost from a drainage basin is river discharge.

Front 4

What is the definition of precipitation?

Back 4

Water that falls or condenses on the ground.

Front 5

What are the main stores in a river?

Back 5

Stores includepuddles, rivers, lakes (surface storage), glaciers, soil storage and groundwater storage along with water stored on vegetation (interception) followingprecipitation.

Front 6

What is a drainage basin?

Back 6

A drainage basin is an area of land drained by a river andits tributaries It includes waterfound in the water table and surface run-off. There is an imaginary line separating drainage basins calleda watershed. Usually, this is aridge of high land or mountains.

Front 7

What are the main transfers/ flows in a river?

Back 7

Flows include percolation, overland flow,infiltration, stemflow, throughflow and overland flow.

Front 8

What is 'Thedownward movement of water from the soil into rock' known as?

Back 8

Percolation

Front 9

What is the difference between 'infiltration' and 'throughflow'?

Back 9

Throughflow - When water travels through the soil towards ariver or the seaPercolation - The downward movement of water from the soilinto rock

Front 10

Where does the river the river have less gravitational potentialenergy and more kinetic energy so erosion shifts from vertical to lateralerosion?

Back 10

Middle-course

Front 11

What is a river's cross profile?

Back 11

River cross profiles show you a cross-section ofa river’s channel and valley at certain points in the river’s course. The

Front 12

Why is the cross profile in the upper course 'V' shaped?

Back 12

the valley and channel are narrow and deep as a result of the large amount of vertical erosion and little lateral erosion.

Front 13

What is fluvial erosion?

Back 13

erosion is erosion caused by streams, rivers,creeks, etc.

Front 14

What is the name for the maximum particle size that it is able to transport?

Back 14

Competance

Front 15

What is the definition of 'capacity'?

Back 15

The capacity is the maximum load a river can transport.

Front 16

What is headward erosion?

Back 16

Headward erosion is erosion at the origin of a stream channel, which causes the origin to move back away from the direction of the stream flow, and so causes the stream channel to lengthen.

Front 17

What are potholes?

Back 17

Potholes are cylindrical holes drilled into the rocky bed of a river by high-velocity water loaded withpebbles.

Front 18

What is a 'braided channel'?

Back 18

Braiding occurs when the river is forced to split into several channels (detributaries)separated by islands (eyots). It is a feature if rivers that are suppliedwith large loads of sand and gravel (sediment). It is most likely to occurwhen a river has variable discharges.

Front 19

Why do meanders occur?

Back 19

Meanders form where alternating pools and riffles developat equally spaced intervals. As the water travels through a pool where it is deeper, the water is more efficient, thus having more erosional power. However, energy is lost as the river flows over a riffle because of friction.

Front 20

What is alluvium?

Back 20

A deposit of clay, silt, and sand left by flowing floodwater in a river valley or delta, typically producing fertile soil.

Front 21

Why do deltas form?

Back 21

Deposition occurs as the velocityand sediment-carrying capacity of the river decrease on entering the lake or sea, and bedload and suspended material are deposited. Flocculationoccurs as fresh water mixes withseawater and clay particles coagulatedue to chemical reaction.

Front 22

What is a topset bed?

Back 22

The larger and heavierparticlesare the first to be deposited as the river loses its energy.

Front 23

What is a foreset bed?

Back 23

Mediumgraded particles travel a little further before they aredeposited as steep-angled wedges of sediment, forming the foreset beds

Front 24

What is a bottomset bed?

Back 24

The very finest particles travel furthest into the lake beforedeposition and from the bottomset beds

Front 25

What is rejuvenation?

Back 25

Rejuvenation occurs when the river’s base level falls (i.e. when sea level falls). This can be a consequence of either a fall in the amount of sea water or the land rising. result of the comings and goings of ice ages. The effect on rivers is to produce features called “knick points” (which can be seen as waterfalls and rapids), river terraces and incised meanders.

Front 26

What is an insized meander?

Back 26

Incised meanders are meanders which are particularly well developed and occur when a river’s base level has fallen giving the river a large amount of vertical erosion power, allowing it to downcut.

Front 27

Name the two types of insized meander and name the differences between them

Back 27

entrenched meanders are symmetrical and form when the river downcuts quickly. Due to the speed which the river downcuts, there is little lateral erosion giving them their symmetrical shape. Ingrown meanders are asymmetrical. They form when the river down-cuts at lower pace, so the river erodes laterally as well as vertically.

Front 28

What is a river terrace?

Back 28

A step that extends along the side of a valley and represents a former level of the valley floor. It results from rejuvination/ renewed downcutting. It generally has a flat top made up of sedimentary deposits and a steep fore edge, and it may be the remains of an old floodplain, cut through by the river and left standing above the present floodplain level.