2585104
Beschreibung
Karteikarten von 09newkieran31, aktualisiert more than 1 year ago
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Erstellt von 09newkieran31
vor mehr als 9 Jahre
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| Frage | Antworten |
| Abrasion | Wearing of the shoreline by sediment carried by water flow. Erosion by scraping, scouring and rubbing of load in contact with banks and bed (Corrasion) |
| Afforestation | Planting trees in the catchment area of a drainage basin to increase interception storage and evapotranspiration |
| Aquifer | Porous and Permeable rocks that can store water |
| Antecedent Rainfall | Rain that falls on already saturated soil. Soil cannot take any more water so it becomes surface runoff. |
| Attrition | Reduction/rounding of particles of sediment carried in water by repeat collision with other sediment/banks |
| Bankfull | The state of flow of a river when it completely fills its channel (at capacity) |
| Bedload | Larger material, cobbles, pebbles and sand transported by saltation. |
| Braided stream | Interconnected channels separated by deposited material |
| Capacity | The total volume of sediment a river can carry |
| Calibre | Measurement of the long axis of sediment in a river |
| Catchment Area | The land that drains water into a particular river system |
| Channel Enlargement | Deepening/Widening of the channel to accommodate larger discharge and transport it faster |
| Channel Flow | Movement of water within the river channel |
| Competence | The maximum size (calibre) of load a river is capable of transporting |
| Condensation | Process that water vapour is converted into water |
| Corrasion | Erosion by friction of load in contact with banks/bed (Abrasion) |
| Corrosion | Dissolving of carbonate rocks (eg. Limestone) in water flow. |
| Cross sectional area | Channel depth x Chanel width |
| Dams | Barriers that hols back water and create a large reservoir behind them. |
| Defecit | A Shortage eg. soil moisture |
| Deltas | Formed when the amount of sediment delivered to the mouth of a river exceeds the amount taken away by waves, and so it is deposited. |
| Deposition | When the rivers competence is not great enough to carry the sediment, so it is dropped. |
| Discharge | Volume of water flowing in a river per second, measured in cumecs (Cubic metres per second) |
| Dissolved load | (Solution load) When weak acids in water flow dissolve material in solution. |
| Distributary | Small channel that leaves the main river on a delta (one of the braided channels) |
| Drainage Basin | The area in which water will flow into one particular river |
| Dreding | The removal of sediment from the river bed to increase channel depth |
| Eddies | Fast-flowing circular currents of water in the rivers flow |
| Evaporation | Transformation of water into water vapour by heat from the sun |
| Field capacity | Amount of water that can be held by the soil before rainfall becomes antecedent. |
| Evapotranspiration | Loss of water from a drainage basin into the atmosphere from the processes of evaporation and transpiration. |
| Flocculation | River load particles joining together on contact with salt in sea water, increasing weight and causing them to be deposited |
| Flood | A temporary excess of water that spills over onto the land |
| Flood Abatement | Reducing possibility of flooding by managing land use upstream. Eg. afforestation |
| Flood embankments | Building up of levees around river channel |
| Flood interception schemes | Intercepting the channel, diverting part of the flow for town/agricultural use and to move water to flood retention areas. |
| Flood proofing | Temporary protection against flooding. Eg. sandbags or Permanent Eg. Flood proof walls/flood gates |
| Flood relief channel | Constructed to redirect excess water ahead of a settlement |
| Flood walls | Increasing height of channel, preventing water spilling out over floodplain |
| Flood plain | Flat and broad valley floor created by successive flooding events depositing alluvium (sediments) |
| Frequency | How often flooding occurs |
| Gorge | Narrow, rocky, steep-sided valley, created by recession of a waterfall |
| Graded profile | Also called the long profile |
| Groundwater storage | Storage of water in permeable rock under subsoil |
| Groundwater flow | Movement of water through permeable rock under subsoil |
| Hard engineering | Flood management strategies that involve structural measures offering protection through engineering. |
| Helicoidal flow | Water flow pattern where the fastest current spirals across the channel in a corkscrew motion |
| Hjulstroms Curve | Graph showing relationship between velocity, erosion and deposition. |
| Hydraulic action | Force exerted by moving water on bed and banks of river |
| Hydraulic radius | Ratio of the cross sectional area of the channel and the length of its wetted perimeter |
| Hydrograph | Graph showing the discharge, depth and velocity of a given point of a stream at a particular time (normally during a storm) |
| Infiltration | Downward movement of water into soil |
| Infiltration rate | Speed (mm/s) at which water passes through ground into soil |
| Interception | Prevention of precipitation reaching Earth's surface by trees and vegetation |
| Interception storage | Total volume of water held on surface of vegetation |
| Knick point | Break of slope in the long profile. Often upper limit which downcutting from rejuvination has reached. Marked by rapids/waterfalls |
| Lateral erosion | Middle/lower sections where river has high energy especially if close to bankfull. Widens valley, especially strong on meanders, where hydraulic action undercuts river cliffs |
| Levees | Natural ridge formed by deposition of coarse material along channel edge. |
| Lining the channel | Lining river with concrete, making it smoother and reducing friction, allowing water to flow faster |
| Load | Material carried by river |
| Magnitude | Size of the food |
| Meanders | Bends in a river formed by helicoidal flow, with erosion on the outside and deposition on the inside |
| Naturalisation | Restoring rivers to a more natural state by removing hard engineering |
| Overland flow | Movement of water over surface of land, usually when ground is saturated or frozen |
| Peak rainfall | Time when maximum amount of rain was falling |
| Percolation | Gravity flow of water seeping into soil or rock |
| Point bar | Sediments laid down on the inside of a meander |
| Potholes | Formed by abrasion, pebbles carried by flow get stuck in crack, an eddied is formed and the pebbles grinds down in circular motion to form pothole |
| Precipitation | All moisture that reaches the Earth including rain, snow and dew |
| Profile | Changing height of a river from source to mouth, also called long profile |
| Rapids | Stretches of fast flowing water over rock and shallow riverbed |
| Realignment | Straightening/shortening of river course by removing meanders, increases gradient making water move faster |
| Regime | Annual pattern of river discharge |
| Rejuvination | Renewal of energy permitting accelerated erosion and transport. Rivers adjusting to new base level |
| River cliff | Outside of a meander, steep undercut bank |
| River restoration | Returning uplands to peat bog increasing absorption in soil |
| Roundness | Shape of sediment in a river, changes downstream as a result of attriction |
| Runoff | Water flowing over land surface as channel flow/overland flow |
| Saltation | Small stones bounce along channel bed |
| Sinuosity | Curving nature of a meander. Actual channel length divided by straight line distance |
| Sluice gates | Barriers that hold water back, some pump water in opposite direction |
| Soft engineering | Flood management strategies that are non-structural, more 'natural' |
| Soil moisture | Total amount of water, including water vapour in unsaturated soil |
| Solution load | Dissolved minerals transported within mass of moving water |
| Stemflow | Flow down plant trunks/stems following interception. |
| Stormflow | Water that reaches the channel through runoff. Combination of overland flow and rapid throughflow |
| Strata | Layers of rock |
| Surface storage | Total volume of water on surface in lakes etc |
| Surplus | More than is needed Eg. Soil moisture |
| Suspended load | Bulk of sediment transported by river. Reason most rivers are brown in colour in bankfull |
| Throughflow | Movement of water downslope within soil layer |
| Traction | Large stones rolled along river bed |
| Urbanisation | Increase in proportion of countries population living in urban areas |
| Velocity | Speed and direction at which a body of water moves (m/s) |
| Verticle erosion | Dominates upper reaches of river cutting into bed by abrasion and hydraulic action |
| Water budget | Relationship between inputs and outputs in drainage basin, shown as graph |
| Washland restoration | Wet lands allowed to flood at times of high discharge, to reduce impact elsewhere |
| Waterfalls | Steep or verticle part of the river, occur when hard rock lies across the river with soft rock downstream which erodes faster |
| Watershed | Boundary between two drainage basins, usually ridges of high land |
| Water table | Surface of saturated layer of soil/rock |
| Wetted perimeter | Portion of perimeter of a stream channel cross section that is in contact with the water |
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