Geography Rivers As

Front 1

is a drainage basin an open or closed system?

Back 1

open

Front 2

what is an input of the hydrological system?

Back 2

precipitation, includes all the ways moisture comes out of the atmosphere.

Front 3

what is interception?

Back 3

a type of storage in the drainage basin. when precipitation lands on vegetation or other structures like buildings and concrete or tarmac surfaces, before it reaches the soil. this is a significant store in wooded areas. only temporary because the water evaporates quickly.

Front 4

what is a drainage basin?

Back 4

the area surrounding the river where the rain falling on the land flows into that river. also called the river's catchment.

Front 5

what is a watershed?

Back 5

the boundary of a drainage basin, any precipitation falling beyond this point enters a different drainage basin.

Front 6

what is vegetation storage?

Back 6

water that's been take up by plants. all the water contained in plants at any one time.

Front 7

what is surface storage?

Back 7

water in puddles, ponds and lakes

Front 8

what is groundwater storage?

Back 8

water stored either in soil, or in rocks.

Front 9

what is the zone of saturation?

Back 9

the area of soil or rock where all pored in the soil or rock are full of water. porous rocks that hold water are called aquifers

Front 10

what is channel storage?

Back 10

water held in a river or stream channel.

Front 11

what are the outputs of the drainage system?

Back 11

evaporation, river discharge and transpiration and river discharge.

Front 12

what are the flows and processes in the drainage basin?

Back 12

through flow, surface runoff, percolation, groundwater flow, stem flow, infiltration, throughfall, interflow, baseflow, channel flow

Front 13

what is surface run off?

Back 13

water flowing over the land, can flow over the whole surface or little channels. common in arid areas where torrential rain falls on hard baked land.

Front 14

what is throughfall?

Back 14

water dripping from one leaf to another

Front 15

what is stemflow?

Back 15

water running down a stem or tree trunk

Front 16

what is throughflow?

Back 16

water moving slowly downhill through the soil. faster through things like cracks in the soil or animal burrows.

Front 17

what is infiltration?

Back 17

water soaking up into the soil. influenced by soil type, soil structure and how much waters already in the soil

Front 18

what is percolation?

Back 18

water seeping down through the soil into the water table.

Front 19

what is groundwater flow?

Back 19

water flowing slowly below the water table through permeable rock.

Front 20

what is baseflow?

Back 20

groundwater flow that feeds into rivers through river banks and river beds.

Front 21

what is interflow?

Back 21

water flowing downhill through permeable rock above the water table.

Front 22

what is channel flow?

Back 22

the water flowing in the river or stream itself. also called the river's discharge.

Front 23

what does the water balance show?

Back 23

the balance between inputs and outputs.

Front 24

what happens in the wet seasons of the water table?

Back 24

precipitation exceeds evapotranspiration. creating water surplus,. the ground stores fill with water so there's more surface runoff and higher discharge, so the river levels rise.

Front 25

what happens in the dry season of the water table?

Back 25

precipitation is lower than evapotranspiration. ground stores are depleted as some water is used and some flows into the river channel, but isn't replaced by precipitation.

Front 26

what happens at the end of the dry season?

Back 26

there's a deficit of water in the ground. the ground stores are recharged in the next wet season.

Front 27

what is river discharge?

Back 27

the volume of water flowing in the river

Front 28

how does precipitation effect river discharge?

Back 28

more=higher

Front 29

how does hot weather effect river discharge?

Back 29

higher=lower because evaporation is higher

Front 30

how does removal of water affect discharge?

Back 30

reduces it

Front 31

what do hydrographs show?

Back 31

river discharge over a period of time

Front 32

what is peak discharge?

Back 32

this is the highest point on the graph, when the river discharge is at its greatest

Front 33

what is lag time?

Back 33

the delay between peak rainfall and peak discharge. the delay happens because it take time for the rainwater to flow into the river.

Front 34

what can a shorter lag time do?

Back 34

increase peak discharge because more water reaches the river during a shorter period of time

Front 35

what is the rising limb?

Back 35

part o the graph up to peak discharge. the river discharge increases as rainwater flows into the river.

Front 36

what is the falling limb?

Back 36

part of the graph after peak discharge. discharge is decreasing because less water is flowing into the river. a shallow falling limb shows water is flowing in from the stores long after its stopped raining.

Front 37

how do drainage basin characteristics effect the storm hydrograph? (size)

Back 37

larger drainage basins collect more water so have a higher peak discharge compared to smaller ones. but smaller basins have shorter lag times because precipitation has less distance to travel, so reaches the main channel quicker.

Front 38

how do drainage basin characteristics effect the storm hydrograph? (banks)

Back 38

steep-sided drainage basins have shorter lag times than shallower basins- water flows more quickly downhill into the river on steep slopes. this can also increase peak discharge

Front 39

how do drainage basin characteristics effect the storm hydrograph? (shape)

Back 39

circular basins are more likely to have flashy hydrographs than long narrow basins. because all points on the watershed are roughly the same distance from the point discharge is measured. this means a lot of water will reach the same point at he same time, increasing peak discharge.

Front 40

how do drainage basin characteristics effect the storm hydrograph? (streams)

Back 40

basins with lots of streams drain quickly, so have shorter lag times.

Front 41

how does the amount of water already in the basin affect lag time?

Back 41

if the grounds already waterlogged then infiltration is reduced and surface runoff increases. surface runoff is much faster than throughflow or baseflow, so rainwater reaches the river more quickly, reducing lag time.

Front 42

what does rock type affect on the hydrograph and why?

Back 42

peak discharge and lag time-

impermeable rocks don't store water or let water flow through them. this reduces infiltration and increases surface run off reducing lag time. peak discharge also increases as more water reaches the river in a shorter period.

Front 43

what does soil type affect on the hydrograph and why?

Back 43

lag time and peak discharge-

sandy soils allow a lot of infiltration, but clay soils have very low infiltration rates. low infiltration rates increase surface runoff, reducing lag time and increasing peak discharge.

Front 44

what does vegetation affect on the storm hydrograph and why?

Back 44

lag time and peak discharge

vegetation intercepts precipitation and slows its movement to the river channel, increasing lag time. interception=highest when there's lots of deciduous trees having their leaves.