RIver Flashcards
1
Q
What is hydrological characteristics?
A
It is also called as ‘water cycle’ which is a cycle that involves the continuous circulation of water in the Earth-atmosphere system
2
Q
Evaporation
A
when liquid water turns to water vapour. (heat is involved)
3
Q
Condensation
A
when water vapour cools and turns back into liquid water
4
Q
Precipitation
A
rainfall
5
Q
Transpiration
A
the evaporation of water from plant leaves
6
Q
Interception
A
precipitation that does not reach soil, but is caught by the leaves and branches of trees
7
Q
Infiltration
A
the process where water on the ground enters the soil
8
Q
Surface runoff
A
water that flows on the surface of land
9
Q
Throughflow (OR Groundwater flow)
A
the movement of water sideways through the soil
10
Q
Stem flow
A
flow of intercepted water down the trunk or stem of a plant
11
Q
Perlocation
A
water moves downwards through the soil to the underlying rocks
12
Q
River flow
A
water flowing in a river
13
Q
Drainage Basin
A
the area of land drained by a river
14
Q
What are the features in drainage basin?
A
Mouth, Watershed, Confluence, Tributary, Source, Catchment
15
Q
Mouth
A
where the river flows into the sea, or sometimes a lake
16
Q
Watershed
A
the boundary dividing one drainage basin from another - a ridge of high land
17
Q
Confluence
A
the point at which two rivers join
18
Q
Tributary
A
a river which joins a large river
19
Q
Source
A
the upland area where the river begins
20
Q
Catchment
A
the area from which water drains into a particular drainage basin
21
Q
What are the features in ‘Flood Hydrograph’?
A
discharge, basin lagtime, peak flow, rising limb, recession limb, (overland flow, throughflow, baseflow)
22
Q
Rising Limb
A
the rising flood water in the river
23
Q
Peak Flow
A
maximum discharge in the river
24
Q
Recession Limb
A
falling flood water in the river
25
Basin Lagtime
the difference between the peak of the rainstorm and the peak flow of the river
26
Baseflow
normal discharge of the river
27
'peaky' graph in flood hydrograph means...
short lagtime
28
'flatter' graph in flood hydrograph means...
longer lagtime
29
What are the factors that affect the flood hydrograph?
Rock porosity and permeability (geology), Land use, Climate, Amount of vegetation, Relief
30
Rock Porosity and Permeability
'porosity rocks'
- have tiny spaces known as 'pores'
-this means water can go into the rock
'permeable rocks'
- also allow water to pass through them through 'cracks'
(e.g. sandstone, limestone)
+KW: infiltration, perlocation, ground waterflow
31
Land Use
-'grass' is 'permeable' and will let water soak in
- 'concrete' and 'tarmac' is 'impermeable' and won't let water in
- More impermeable surface = More surface runoff
+KW: infiltration, surface runoff, perlocation, throughflow
32
Climate
- the amount of rain will affect all flows and stores.
- if there is lots of rain the soil can become saturated reducing infiltration rates
- Lots of rain -> soil can become saturated, reducing infiltration rates
+KW: infiltration, surface runoff, perlocation, throughflow, precipitaion, antecedent conditions
33
Amount of Vegetation
- Lots of vegetation -> More interception, less surface runoff, infiltration into the soil and rocks
+KW: interception, precipitation, stem flow, transpiration, infiltrationw
34
Relief
- 'steep slopes' reduce the amount of 'infiltration', increasing 'surface runoff' and 'river flow'.
- they can also increase through flow
+KW: infiltration, throughflow, relief, lagtime
35
What is 'River Regime'?
it is the variability in a river's discharge throughout the year
36
Oceanic Rainfall/Evaporation
-many oceanic areas of Europe, rainfall is evenly distributed but high evapotranspiration in summer leads to low runoff
37
Tropical Seasonal Rainfall (monsoonal)
-in tropical areas, evapotranspiration tends to be stable (high) but summer rains cause a peak
38
Glacier Melt
-european mountain rivers have a high-water period (jul-aug) when glaciers feeding them melt most rapidly
39
What are the four 'Fluvial Processes'?
Erosion, Transpiration, Weathering & Mass Movement, Deposition
40
Erosion
the weathering away of the land
41
Transpiration
a river's load is carried downstream
42
Weathering & Mass Movement
the breaking down of rock and subsequent movement due to gravity
43
Deposition
when a river drops eroded material
44
4 Types of EROSION
Hydraulic Action, Attrition, Corrosion(solution), Abrasion
45
Hydraulic Action
-Moving water is forces into cracks in the river bed and river banks.
-The force breaks it apart.
-It is known as mechanical weathering.
46
Attrition
-Pieces of rocks carried by the river bump into one another.
-These then breakdown into smaller pieces.
47
Corrosion
-This is the chemical action of river.
-The acids in the water slowly dissolve the bed and the banks.
-This is a form of chemical weathering.
48
Abrasion
Sand and stones in the river scrape the bed and banks and wear them away.
49
4 Types of Transportation
Saltation, Suspension, Solution, Traction
50
Saltation
-The sediment bounces and skips along.
-More energetic rivers with higher velocities. Sand and small gravels.
51
Suspension
-Tiny particles one carried along distances in the flowing water.
-Suspension occurs in all but the slowest flowing rivers.
52
Solution
-Minerals from the rocks and dissolved in the water.
-Soluble materials such as calcium carbonate
53
Traction
-The largest material is dragged along the bed of the river or minerals from the rocks and dissolved in the water or medium particles bounce along the river bed.
54
How does a river DEPOSIT its load?
-This is where the river dumps or leaves behind material that it has been carrying. It deposits LARGER material first as this is the HEAVIEST to carry. The SMALLER the load, the further downstream it can be transported, so this is deposited much further downstream than the larger load.
-The river will deposit material when there is a fall in the SPEED/VELOCITY of the river or the AMOUNT of water (river discharge). This often occurs when the gradient changes at the foot of a mountain or when a river enters a lake or the SEA.
55
What is Weathering?
the breaking down of rocks in situ by the action of plants, animals and chemical processes.
56
3 Types of Weathering
Chemical, Biological and Mechanical
57
Chemical Weathering
rainwater is slightly acidic and overtime this wears away the rocks
58
Biological Weathering
this is when the actions organisms breaks up the soil/rock. This might be due to the roots of trees or other plants or burrowing mammals or even insects.
59
Mechanical Weathering
This is where changes in the moisture levels or temperature. There are many different kinds, freese-thaw weathering below and onion skin weathering.
60
MECHANICAL WEATHERING steps
1. water collects in water crack
2. water freezes and expands, forcing crack to widen
3. ice thaws, contracts and water gets deeper into cracks again
4. repeated expansion and contraction causes further cracks till rocks split
61
What is a MASS MOVEMENT?
a large scale downward movement of rocks and materials
62
Rotational Slip
occasional, rapid movements of rock and soil sliding along a steep slope. This occurs after periods of heavy rain, when the water saturates overlying rock, making it heavy.
63
Rock Fall
bits of rock fall off the slope, usually due to freeze-thaw weathering
64
Landslide
involves a whole segment of the cliff moving down-slope along a bedding plane
65
Mudflow
saturated soil (soil filled with water) flows down a slope
66
Cross Profile
the side view shape of a river including width
-Upper - verticaler (+bumpy)
-Middle - wider/deeper/smoother
-Lower - widest/deepest/smoothest
67
Meander
a bend in a river, caused by erosion
EROSION - wearing away of rock and sediment
DEPOSITION - the dropping of sediment
68
Upper Course
1) Upland Landforms
- rapids
- patholes
-V-shaped valley
-interlocking spurs
-waterfalls
V-shaped Valley and interlocking spurs
- vertical erosion
- high gravitational potential
- interlocking spurs -> river takes the easiest path (softer rocks) through the V-shape valleys
2) Waterfalls
- erosion of softer rock
- creates plunge pool
- the descending water erodes the softer rock
-erodes back to form a gorge
69
Middle Course
69
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