River Environments

Question 1

Examples of stores (3)

Answer 1

• atmosphere; as water vapour or clouds
• the land; rivers, lakes, reservoirs
• sea; liquid and ice

Question 2

Examples of flows (9)

Answer 2

• evaporation
• transpiration
• evapotranspiration
• condensation
• precipitation
• overland flow
• infiltration and percolation
• throughflow
• groundwater flow

Question 3

transpiration

Answer 3

plants take up liquid water from the soil and ‘breathe’ it into the atmosphere as water vapour

Question 4

evapotranspiration (2)

Answer 4

• the loss of moisture from the ground by direct evaporation from water bodies and the soil
• also as transpiration from plants

Question 5

overland flow

Answer 5

when precipitation hits the ground and due to gravity eventually enters a stream, river or lake

Question 6

throughflow (2)

Answer 6

• this takes place between the ground surface and the top of the groundwater store
• as a result of gravity water slowly moves through the soil until it reaches a stream or river

Question 7

important differnces between hydrological cycle and drainage basin? (2)

Answer 7

• drainage basin is an open system, while the hydrological cycle is a closed system
• the amount of water in the drainage basin varies over time, while in the hydrological cycle the amount of water stays the same

Question 8

drainage basin (3)

Answer 8

• also known as the river’s catchment area
• has external inputs and outputs
• amount of water in basin varies over time

Question 9

inputs of drainage basin (3)

Answer 9

• energy from sun
• precipitation formed from moisture picked up outside of basin
• water from tributary drainage basins

Question 10

outputs of drainage basin (2)

Answer 10

• river’s discharge
• the water in its basin from which evaporation and transpiration take place, this water eventually falls as precipitation in another drainage basin

Question 11

discharge

Answer 11

the quantity of water flowing in a river channel at a particular location and time

Question 12

watershed

Answer 12

boundary between neighboring drainage basins

Question 13

estuary

Answer 13

mouth of river where it enters sea

Question 14

river regime

Answer 14

the seasonal variations in the discharge of a river

Question 15

storm hydrograph

Answer 15

records the changing discharge of a river after a rainstorm

Question 16

lag time (3)

Answer 16

• delay between peak rainfall and peak discharge (time from when rain falls until it reaches river)
• the shorter the lag time the quicker the water reaches the river channel
• short lag time causes the river discharge to rise steeply

Question 17

base flow

Answer 17

normal discharge of the river

Question 18

storm flow

Answer 18

additional discharge of the river as result of rainstorm

Question 19

Factors affecting river regime (why river regime may change) (6)

Answer 19

• amount and intensity of rain
• temperature can affect form of precipitation
• steep slopes will cause rapid surface runoff, so water will reach river more quickly
• the rock type (impermeable/permeable)
• vegetation and land use
• human intervention (dams and reservoirs)

Question 20

weathering

Answer 20

the breakdown and decay of rock by natural processes, without the involvement of any moving force

Question 21

mass movement (2)

Answer 21

• movement of weathered material down a slope due to the force of gravity
• the two main types are slumping and soil creep

Question 22

erosion

Answer 22

the wearing away and removal of material by a moving force, such as running water

Question 23

transport

Answer 23

the movement of a river’s load

Question 24

deposition

Answer 24

the dropping of material being carried by a moving force

Question 25

physical weathering

Answer 25

breaks down rocks into smaller and smaller pieces, by changes in temperature, freezing of rainfall and thawing in rock cracks

Question 26

chemical weathering

Answer 26

causes rocks to decay and disintegrate by slightly acidic rain seeping into porous rocks

Question 27

biological weathering

Answer 27

the roots of plants growing into cracks in the rocks and gradually splitting them apart

Question 28

slumping (3)

Answer 28

- form of mass movement - occurs when bottom of valey side slope is cut away by the river at its base - makes slope unstable so material slumps towards river

Question 29

soil creep (3)

Answer 29

- form of mass movement - weathered material moves down slope due to gravity - collects at bottom of valey side and is eroded by river

Question 30

hydraulic action (3)

Answer 30

- form of erosion - water hits river bed and banks with such force that material is carried away - usually happens when river's discharge is high

Question 31

abrasion (2)

Answer 31

- form of erosion - material carried by river rubbs against sides and floor of channel, this widens and steepens channel

Question 32

corrosion/solution (2)

Answer 32

- form or erosion - minerals in the rocks that form the sides of the river channel are dissolved by the water that flows past

Question 33

load (2)

Answer 33

- material that has been washed or fallen into river - also materials eroded from sides of channel