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17 Cards in this Set
- Front
- Back
What is river discharge? |
River discharge is the volume of water that flows in a river per second. It's measured in cumecs cubic metres per second. |
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What does a hydrograph show? |
A hydrograph shows how the discharge at a certain point in a river changes over time. |
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What do storm hydrographs how? |
Storm hydrographs show the changes in a river discharge around the time of a storm. |
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What is peak discharge? |
The highest discharge in the peroid of the time you're looking at. |
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What is lag time? |
The delay between peak rainfall and peak discharge. |
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What is rising limb? |
The increase in river discharge as the rainwater flows into the river. |
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What is the falling limb? |
The decrease in river discharge as the river returns to it's normal level. |
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Why does lag time happen? |
Lag time happens because most rainwater doesn't land directly in the river channel -- there's a delay as rainwater gets into the channel. |
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What is surface run off? |
When water flows overland. |
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What is infiltration? |
Infiltration is the downwards movement of water that seeps into the soil or porous rock. |
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How does more surface runoff lead to a greater discharge? |
More surface runoff means a reduced lag time. This means discharge will be greater because more water gets to the river channel in a short amount of time. |
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List all the factors that affect river discharge. |
Amount of rainfall, Temperature, Previous Weather Conditions, Rock Type,Land use and relief. |
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How does temperature effect river discharge? |
Temperature can effect river discharge because hot dry conditions an cold,freezing conditions both result in hard ground -- this increases run off. Lag time decreased, so discharge increases.
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What type of rock infiltrates through pore spaces? |
Permeable rock infiltrates through pore spaces. |
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What rock does water flow along the cracks? |
Pervious rocks. |
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How does relief affect river discharge? |
Relief effects river discharge because more runoff occurs on steep slopes. Lag time decreases, so discharge increases. |
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How does urbanisation affect river discharge? |
Urbanisation can effect river discharge because urban areas have drainage systems and they're covered in impermable materials -- like concrete. This increases runoff. Lag time decreases, so discharge increases. |