Flashcards
River Discharge
Flashcards do conjunto (22)
- 1What is river discharge?...volume of water that flows in a river per second.
- 2How is river discharge measured?Cubic metres per second/ cumecs
- 3What are the three things river discharge is affected by?> Precipitation- more precipitation, the higher the discharge
> Hot weather- higher the temp, the lower the discharge due to higher levels of evaporation
> Removal of water from the river - 4What is a hydrograph?graph of river discharge showing the volume of water flowing at a certain point in a river changing over time. They often cover a relatively short period of time (hours/ days compared to weeks or months)
- 5Storm HG shows short periods of time, where as water balance HG shows......a whole year
- 6What is a storm hydrograph?shows river discharge around the time of a storm
- 7What physical factors of the drainage basin affect?Affect the lag time and peak discharge
- 8What does a large drainage basin result in regarding discharge?...catches more precipitation, so higher peak discharge compared to smaller basins.
- 9What does a smaller basin result in?shorter lag times because precipitation has less distance to travel, so reaches the channel quicker
- 10Steep-sided drainage basin regarding lag time...... shorter lag times than shallower basin- water flows quicker downhill into a river on steep slopes. Can increase peak discharge.
- 11How are circular basins in terms of hydrographs?more likely to have a 'flashy' hydrograph than long, narrow basins. This is because all points on the watershed are roughly the same distance from the point of discharge measurement. Means lots of water will reach the measuring point at the same point, increasing peak discharge
- 12Why do basins with lots of streams have shorter lag times?as they drain quicker due to high drainage density
- 13The amount of water in the drainage basin affects the lag time. What happens if the ground is waterlogged?infiltration is reduced and surface runoff increases. Surface runoff is much faster than throughflow or base flow, so rainwater reaches river quicker, reducing lag time.
- 14Rock types that effect lag time and discharge in a storm hydrograph?impermeable rock don't store water or let water flow through them. This reduces infiltration and increases surface runoff, reducing lag time. Peak discharge increases as more water reaches the river in a shorter period.
- 15How does the soil type affect lag time and peak discharge in a storm hydrograph?sandy soil allows a lot of infiltration, but clay soils have very low infiltration rates. Low infiltration rates increase surface runoff, reducing lag time and increasing peak discharge.
- 16How does vegetation affect lag time and peak discharge in a storm hydrograph?vegetation intercepts precipitation + slows its movement to the river channel, increasing lag time. Interception is highest when there's lots of vegetation
- 17How does vegetation affect lag time and peak discharge in a storm hydrograph?The more vegetation there is in a basin the more water is lost (through transpiration and evaporation directly from vegetation) before it reaches the river channel, reducing peak discharge
- 18How does precipitation affect lag time and peak discharge?intense storms will generate more precipitation and so greater peak discharge than light rain showers.
the type of precipitation also affects lag time e.g. snow thats fallen in winter storm can melt and slow into a river in spring, giving a very long lag time - 19How does temperature affect lag time and peak discharge?hot dry conditions and cold freezing conditions both result in hard ground. Reduces infiltrations and increasing surface runoff- reducing lag time and increasing peak discharge.
High temps can increase evapotranspiration so less water reaches the river channel reducing peak discharge - 20What human factors affect the storm hydrograph?> dependent if soil is exposed
> man-made drainage system - 21In urban soil is covered, explain how this affects?covered with man-made impeccable materials like concrete. Water can't infiltrate the soil, which increases surface runoff, so water slows more quickly into the river. This make lag time short and increases peak discharge. 1
- 22How do man-made drainage systems affect this?they affect the hydrograph in a similar way, water flows down drains into river before it can evaporate or infiltrate into soil, causing a shorter lag time and increased peak discharge
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- A Levels Geography (Rivers) FlashCards sobre River Discharge, criado por Alice Kimpton em 14-12-2015.
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- Alice Kimpton
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