Flashcards
River Environments
Cards in this deck (82)
- 1What is a HydrographRecords the changing discharge of a River
- 2What is discharge?The volume of water carried by a river at any one time. It is measured in Cumecs
- 3What is Discharge measured in?Cumecs (cubic metres per second moving past a particular point in the river)
- 4What is the bit with a positive gradient called on a hydrograph? What would a steep gradient imply?Rising Limb, it would imply a quick reaction time.
- 5Factors affecting Lag Timeprecipitation, temperature, land use, gradient of land, rock type, dams and reservoirs.
- 6What is lag time? What would a short lag time mean?The time between the peak rainfall and the peak discharge. A short lag time would mean that the river was 'flashy'- short reaction time.
- 7Define WeatheringThe breakdown of rocks in situ. Can be physical, chemical or biological
- 8Describe physical weatheringPhysical- temperature, freezing water= cracks
- 9Describe Chemical weatheringDecay and disintegrate due to slightly acidic rainfall.
- 10Describe Biological weatheringPlants growing in cracks, roots cracking rocks gradually splitting them apart.
- 11What is mass movement?Material moving downwards under the influence of gravity.
- 12Name the two types of Mass Movement.Slumping- bottoms of a valley side slope is cuts away by a river flowing at its base, mades the slope unstable.
- 13Soil creepweathered material moves slowly down under influence of gravity. Removed by river.
- 14Factors that affect erosion?Acidity of water, amount of debris in river load. Speed of flow of water, gradient. amount of water and frequency it passes an area, size of particles in the river load.
- 15Name the 4 methods of erosion.Corrasion, Attrition, Solution, Hydraulic action.
- 16Name the 4 methods of transport of a river load.Traction- boudoirs rolling, Saltation- small stones rolling, Suspension- small material suspended, Solution- dissolved material.
- 17Define DepositionThe laying down of material transported by the river. It happens in low energy environments
- 18Landforms in the upper course of a RiverV shaped Valley, waterfalls, gorges, rapids, potholes, plunge pools.
- 19How is a V shaped valley formedGradient is steep, stream narrow due to little water. Therefore, vertical erosion. Combined with mass movement causes V shaped valleys.
- 20How are waterfalls formed?Hard layer of rock over soft layer. soft layer wears away underneath hard layer creating overhang which eventually collapses. Plunge pool.
- 21How does a gorge form?As the overhang collapses in the formation of a waterfall, the process is repeated. This causes a gorge to form.
- 22Features of the Middle course of a RiverMeanders, Oxbow lakes, wider shallower valleys but deeper river.
- 23How do meanders form?Water flows fastest on the outside of a bend as it is the easiest route. Most erosion on the outside. River cliff forms, and collapses making the outer edge retreat. Inner edge of a bend= area of low energy = deposition--> slip off slopes. Create a bend shape.
- 24How do oxbow lakes form?The neck of a meander thinks until it breaks, this is caused by the lateral erosion. The loop is then left as stagnant water. Eventually deposition will seal of the oxbow lake from the rest of the river.
- 25How do rapids form?Bands of hard and soft rock. Soft rock erodes leaving protrusions of hard rock. Uneven surface= rapids.
- 26How do potholes form?Small pebbles get stuck in crack in the river bed. Pebbles get swirled around by the water eroding by corrosion and some hydraulic action until hole gets bigger and bigger.
- 27As distance from the source increases...-->gradient decreases
river gets wider and deeper
sediment/load size decreases
increasing lateral erosion
Average speed increases (slow on flat plains) - 28What is a drainage basin.The area drained by a river and all of its tributaries.
- 29Is a drainage basin an open or closed system?Open, water can enter and leave
- 30Define WatershedThe edge of a drainage basin (usually high ground)
- 31Define River ChannelWhere the river flows and has cut a channel.
- 32Define ConfluenceWhere two rivers/tributaries meet
- 33Define Tributarysmall stream or river that flows into a bigger river
- 34Define 'source'Where a river begins (usually high ground)
- 35Define 'mouth'Where the river meets the sea of a lake. (body of water)
- 36Define Drainage NetworkSystem of surface and underground channels that transport and collect precipitin falling in a drainage basin.
- 37Define infiltrationthe movement of water from the surface through the soil.
- 38Define PercolationThe movement of water through rocks deeper down to the top of the water table.
- 39Features in the lower course of a river?Flood plains, Deltas, Levees, Flat bottomed valleys.
- 40What is a flood plain?Area of flat land that gets flooded when it bursts its banks. Very rich soils because alluvium is deposited when flooded.
- 41How do levees form?When the river bursts its banks it deposits its largest load first, close to the banks of the river and deposits finer material such as clay further away from the river. This continues over time. Naturally rises river banks. Creates slopes.
- 42Domestic uses of water?Hygiene, Toilets, Drinking, cooking, washing clothes, watering plants.
- 43Industrial use of watermaking everything!, in factories as a coolant, harnessed for green energy.
- 44Agricultural uses of water?Producing food from livestock, keeping livestock alive, irrigating plants
- 45Reasons for increased demand for water?Agricultural demand, climate change, industrialisation, increased development, rising standard of living, population growth.
- 46Sources of water? (3 main ones)RIvers/lakes, reservoirs, aquifers/wells.
- 47Define water balanceThe comparison of the water supply to the water demand in each country.
- 48What does it mean to be a water deficit area?The water balance is negative- water demand exceeds the supply.
- 49What does it mean to be a water surplus area?supply of water exceeds the demand. The water balance is positive.
- 50Reasons for varying water qualityWealthy/Economy, Natural Resources, Education, Pollution, Disease/Health care, transport.
- 51Types of Agricultural pollution of water?silage, slurry, fertilisers and pesticides from farms, chemical waste from paper and pulp mils, deforestation (carries soil from this into river)
- 52Examples of Industrial Water pollution?Dumping of sewage sludge, coastal marches, water gown pollutants, oil slick, warm water from power stations can effect river ecosystems.
- 53Domestic Examples of water pollutionUntreated sewage, chlorinated pools, use of river for washing clothes and bathing.
- 54Describe the treatment of water process.Collection, Treatment, Purification, Chlorination, Aeration, Sedimentation, Filtration, Disinfection, Delivery.
- 55What is purification?Controls Biological growth in water treatment process.
- 56What is chlorination?same as purification (controls biological growth)
- 57Define AerationRemoving iron from water
- 58Define SedimentationRemoves suspended soils
- 59Define FiltrationRemoves finer sediments
- 60Define DisinfectionKills bacteria
- 61Physical Causes of floodingWeather, Rock type, Soil, Relief, Drainage Density, Vegetation.
- 62Human factors affecting/causing floods.Deforestation, Urbanisation, Agriculture, Climate Change.
- 63Environmental effects of floodingLandslides, soil erosion, soil contamination, vegetation/habitats destroyed, destruction of settlements.
- 64Effects of flooding on peopleDamage to property, casualties/ injuries, loss of possessions, contamination of water, loss of services, disease and stress.
- 65describe Dams: hard or soft? details?controls water through a settlement, hard
- 66Describe Levées: Hard or Soft?, detail?Hard, building up river banks, increases capacity.
- 67Describe Sluice gates: Hard or soft? Detail?Hard. Controls volume of water into channels.
- 68Describe Relief Channels: Hard or soft engineering? Detail?Provides alternative route for water to flow around a settlement in a storm. Hard.
- 69Describe Channel Straightening: Hard or Soft? Detail?Moves water quicker to mouth of river. Quicker through the town/settlement.
Hard. - 70Describe Mitigation: Hard or Soft? Detail?Soft, working with nature not agains it to minimise or avoid damage.
- 71Describe management scheme of preserving marshes and wetlands: H or S? Details?The flood plains are preserved therefore increased lag time/decreases flood risk. Soft.
- 72Describe scheme of No buildings near river; Hard or Soft? Detail?Decreases damage, increases permeable surfaces near the river.
- 73Describe warning systems: Hard or Soft? Details?Giving people warning so that they can self mitigate ahead of the event. Soft.
- 74Describe Prediction: Details? Hard or Soft?Helps to decide what needs to be done to mitigate. How much risk?
- 75InfiltrationThrough soil (i=first in alphabet-soil=first)
- 76Define Percolationwater moving through the rocks
- 77Vegetation interceptionwhen precipitation falls it is occasionally partially absorbed on the way down by the living things
- 78What does a closed system mean?water is not added or removed, the total amount of water in the system.
- 79what words come to mind when you think Tikashit personality
- 80drainage densitythe number or tributaries. Dense drainage means more likely to flood.
- 81River RegimeThe seasonal flow and discharge of a river and how it behaves throughout the year
- 82Factors affecting lag timesteep sided valley, little vegetation interception, impermeable rock, saturated/sunbaked/frozen land, channel network density, impermeable surfaces e.g. impermeable rock and concrete, drains in urban areas, temperature, land use, dams, water abstraction (when you take water out of the system for industry, domestic and agricultural use.
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- General Test on River Environments from the Edexcel IGCSE board
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- Francesca Wittmann
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