Flashcards in Rivers Key Terms Deck (76)
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31
Infiltration rate
The rate of water absorption expressed in millimetres per minute
32
Interception
Process by which incoming precipitation is trapped by vegetation and buildings. Water is then transferred to the earth's surface or evaporated.
33
Interlocking Spurs
Protrusions of higher land characteristic of the upper sections of a river valley resulting from the river's winding course and more resistant rocks.
34
Isovel
A lining joining pointed of equal velocity in a river channel.
35
Knick point
A break of slope in the long profile of river due to rejuvenation. Because of the renewed down cutting a new long profile is created and where this intersects the former long profile a Knick point is created.
36
Lag time
The time between peak precipitation and peak discharge
37
Laminar flow
Horizontal movement of water
38
Levee
A bank of sediment along the edge of a river channel, deposited naturally with floodwaters. Often raised and strengthened artificially to contain floodwaters.
39
Load
Pebbles, particles and dissolved matter carried by a river
40
Long profile
A river course from its source in an upland area along its channel to its mouth.
41
Meander
A bend in a river with a sinuosity ratio of more than 1:5
42
Natural levee
An embankment on the sides of a river formed by the deposition of silt during flooding
43
Overland flow / surface run off
Process by which water moves downslope over the earth's surface in unconfined channels under the influence of gravity. Saturated overland flow occurs when excess water flows across the ground surface due to subsurface being saturated.
44
Percolation
Process by which water moves vertically downwards through soil and rock
45
Permeability
Ability of rocks, soil or sediment to permit water to flow through it. Permeable rocks allow water to pass through them via bedding planes and joints e.g. Limestone. Impermeable rocks like granite produce more run off and streams.
46
Point bar
Sediment deposited under water on the inside bed of a meander
47
Pools and riffles
The alternating pattern of deep pools and is reaches where a river flows across gravel bars. Distribution if regularly spaced with the distance between pools being 5-7 times greater than the channel width.
48
Porous rocks
Allow water to pass through them via pores e.g. Sandstone and chalk
49
Recessional limb
Part of the hydrograph showing the speed at which the discharge declines after a peak back to its pre storm level
50
Precipitation
Process by which water is transferred from the atmosphere to surface in the form of snow, sleet, hail, rain, fog. Input into drainage system.
51
Recharge
Water added to groundwater or soil to replace that lost by evaporation or transpiration
52
River regime
Variation in discharge from January to December
53
Rejuvenation
The state of a river when it's energy has been revitalised leading to an increase in erosional capability. Results from a fall in base level, due to fall in sea level or uplift of land.
54
Rising limb
The part of a flood hydrograph which shows how quickly floodwaters rise due to storm event
55
River cliff / Bluff
Erosional landform on the outside bend of a meander
56
Saltation
Bed load is transported by bounding motion of lighter particles
57
Sinuosity
The curving nature of the meander. The actual channel length divided by the straight line distance.
58
Soil moisture budget
The balance between moisture inputs and outputs in a soil over time.
59
Soil moisture deficit
A shortage of soil moisture. Evapotranspiration > precipitation- in summer
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