482394
Description
Flashcards by katiehumphrey, updated more than 1 year ago
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Created by katiehumphrey
about 12 years ago
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| Question | Answer |
| processes of erosion | hydraulic action: force of water breaks rock particles away corrasion: rocks scrape against river channel wearing it away attrition: rocks smash into each other corrosion: water dissolves some rock e.g chalk/limestone |
| processes of transportation: the movement of eroded material | traction: large particles pushed along river bed by water saltation: pebble-sized particles bounce along riverbed suspension: small particles (silt) carried along by water solution: soluble materials dissolve in water |
| course of the river | upper - steep - narrow/shallow middle - medium - wider/deep lower - gentle - very wide/deep |
| features of a drainage basin | tributary: smaller river joins main river source: where river starts in upland area e.g mountains confluence: point where two rivers join mouth: river flows into sea or lake |
| causes of flooding | prolonged rainfall heavy rainfall snowmelt |
| flood managements | dams and reservoirs channel straightening man-made levees flood warnings preparation flood plain zoning |
| the hydrological cycle | shows how water moves around |
| infiltration | water soaks into the soil |
| percolation | water moves vertically down through soil and rock |
| throughflow | water in the soil flows downhill |
| groundwater flow | water in rock flows downhill |
| surface runoff | water flows overground |
| channel flow | the flow of water in a river |
| channel storage | water is held in a river |
| groundwater storage | water is stored underground in soil and rock |
| interception storage | water lands on things like leaves and doesn't hit the ground |
| surface storage | water is held in things like lakes, reservoirs and puddles |
| permeable rocks | rocks that absorb water: chalk |
| impermeable rocks | rocks that don't absorb water: granite |
| drainage basin | the area of land drained by a river |
| drainage basins are separated by a boundary called a watershed - ridges of high land |
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| a drainage basin |
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| tributary | smaller river that joins a main river |
| source | where the river starts, usually in an upland area |
| confluence | the point where two rivers join |
| mouth | where a river flows into the sea or a lake |
| weathering in a drainage basin | the breakdown of rocks where they are (material doesn't get taken away) |
| mechanical weathering | the breakdown of rock without changing its chemical composition - freeze-thaw |
| chemical weathering | the breakdown of rock by changing its chemical composition - carbonation weathering |
| biological weathering | the breakdown of rocks by living - plant roots grow into cracks on the surface, pushing them apart |
| hydraulic action | the force of water breaks rock particles away from the river channel |
| corrasion | eroded rocks scrape against river channel wearing it away |
| attrition | rocks smash into each other breaking them into smaller fragments |
| corrosion | water dissolves some rock e.g chalk/limestone |
| traction | large particles are pushed along the river bed by the force of the water |
| saltation | pebble-sized particles are bounced along the river bed by the force of the water |
| suspension | small particles like silt and clay are carried along by the water |
| solution | soluble materials dissolve in the water and are carried along |
| deposition | when a river drops eroded material - happens when a river loses velocity (slows down) |
| waterfalls and gorges are found in the upper course of a river |
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| interlocking spurs |
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| meanders: large bends in a river |
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| ox-bow lakes: formed from meanders |
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| flood plain | the wide valley floor on either side of a river which occasionally gets flooded |
| levees: natural embankments along the edges of a river channel |
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| deltas: low lying areas where a river meets the sea or a lake | rivers slow down when they meet the sea/lake and deposit material - it builds up, the channel is blocked and splits up into smaller rivers: distributaries |
| types of delta |
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| river discharge | the volume of water that flows in a river per second - measured in cumecs |
| storm hydrograph |
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| peak discharge | the highest discharge in the period of time |
| lag time | the delay between peak rainfall and peak discharge |
| rising limb | the increase in river discharge as rainwater flows into the river |
| falling limb | the decrease in river discharge as the river returns to its normal level |
| factors that increase discharge and make the hydrograph steeper | high rainfall intense rainfall impermeable rock previously wet conditions - saturated soil steep slopes less vegetation |
| factors that decrease discharge and make the hydrograph gentler | low rainfall light rainfall permeable rock previously dry conditions gentle slopes more vegetation |
| urban areas have drainage systems and are covered with impermeable materials increasing discharge so hydrographs are steep | rural areas have more vegetation and reservoirs decreasing discharge so hydrographs are gentle |
| human causes of flooding | deforestation - more water reaches river channel urbanisation - buildings are impermeable increasing surface runoff |
| hard engineering to reduce flooding | dams and reservoirs channel straightening man-made levees |
| soft engineering to reduce flooding | flood warnings preparation flood plain zoning |
| hard engineering | man made structures built to control the flow of rivers and reduce flooding |
| soft engineering | schemes set up using knowledge of a river and its processes to reduce the effects of flooding |
| flood in MEDC: River Eden, Carlisle, 8.1.2005 heavy rainfall | 3 deaths 3000 homeless 4 schools flooded some roads were damaged |
| flood in LEDC: River Ganges, India, July 2007 heavy rainfall | 2000 deaths 25 million homeless 44 schools destroyed 10,000km road destroyed |
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