2370084
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Flashcards by clowaters, updated more than 1 year ago
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Created by Diane MAK
about 9 years ago
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Copied by clowaters
about 9 years ago
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| Question | Answer |
| Define: INFILTRATION | the downward movement of water through tiny pores in the soil |
| Define: GROUNDWATER | water stored at a depth in rocks |
| Define: SURFACE RUNOFF / OVERLAND FLOW | water that flows across the surface of the ground (not in a stream or river). This happens when the surface doesn't allow water to penetrate, such as when the ground is saturated or when the rock is impermeable. Surface runoff is the fastest process of water movement. |
| Define: DRAINAGE BASIN (catchment area) | an area of land drained by a main river and its tributaries |
| Define: WATERSHED | a boundary, often marked by a ridge of higher land, that separates one drainage basin from neighbouring ones |
| A drainage basin... drainage basin cycle | has a movement of water within it that is rather like a small-scale water cycle the drainage basin cycle involves stores and flows |
| Where is the Earth's water? | ≈ 97% Seas and Oceans ≈ 2% Ice and Snow (in arctic and alpine areas) ≈ 1% Fresh Water on Land or Water Vapour in the Atmosphere |
| Examples of Transfers (flows) | stemflow; infiltration; percolation; surface runoff (overland flow); throughflow; groundwater flow |
| Examples of Stores | interception by vegetation; surface storage; soil moisture storage; groundwater storage |
| Define: SOURCE | the beginning or start of a river; often at a higher altitude like the top of a mountain |
| Define: MOUTH | the point where the river comes to the end, usually when entering a sea or lake |
| Define: CONFLUENCE | the location where tributaries enter the main river channel; the point at which two rivers or streams join |
| Define: TRIBUTARY | a stream or smaller river which joins a larger stream or river |
| Define: ESTUARY | part of the mouth or or lower course of a river in which the river's current meets the sea's tide; the river's velocity decreases rapidly, depositing a majority, if not all, of its load |
| Define: DISCHARGE | the volume of water which flows through a river at a given time; it is measured in cumecs (cubic metres per second) |
| Define: the DRAINAGE NETWORK | the system of surface and underground channels that collect and transport the precipitation falling on the drainage basin |
| Factors affecting run off: (EIG p5 fig 1.5) | 1) rapid run off - steep slopes; impermeable rock (grit) 2) little run off - permeable rock; rivers have disappeared underground (clay) 3) woodland - slows rate of run off (clay) 4) urban area - speeds up rate of runoff |
| Runoff in woodland area | woodland can hold water and slow overland flow. However, once it is cleared for cultivation, run off will speed up |
| Runoff in urban area | rainwater hits solid surfaces such as roofs, pavements and roads. It is then quickly channelled into drains which speed its delivery into a stream or river |
| a typical drainage basin system (WW p279 fig 17.4) | |
| Define: HYDROGRAPH | a graph showing the discharge of a river at a given point over a period of time |
| Define: LAG TIME | the gap between the time of peak (max) rainfall and peak discharge (highest river level) |
| Causes of river flooding from weather | extreme weather conditions - a torrential thunderstorm, several days of continuous rainfall, or heavy snowfall melting while it rains increase the discharge of a river |
| Factors contributing to flooding | 1) although high summer temperatures increase evapotranspiration and reduce the amount of water available to reach a river, they can make the ground hard, reducing infiltration when it does rain 2) freezing conditions in winter can make the ground impermeable |
| Factors affecting the critical time lag of a storm: | the amount and the intensity of the rain - heavy rain will not sink into the ground; instead it will become overland flow or run off and quickly reach the river |
| Define: WETTED PERIMETER | where the water comes into contact with the river’s banks and bed |
| Processes of Transportation: | traction saltation suspension solution |
| Define: TRACTION | rolling stones/boulders along the bed (this needs the most energy) |
| Define: SALTATION | sand-sized particles bound along the bed in a “leap-frog” movement |
| Define: SUSPENSION | silt and clay-sized particles are carried with the water flow |
| Define: SOLUTION | some minerals dissolve in the water (this needs the least energy) |
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