How does precipitation effect the river discharge?
The more precipitation, the higher the discharge.
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How does hot weather effect the rivers discharge?
The higher the temperature, the lower the discharge due to the rate of evaporation is higher.
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How does the removal of water effect the rivers discharge?
This reduces the discharge as water is taken from the river (abstration).
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What do hydrographs show?
These show a rivers discharge over a period of time.
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What is the 'Peak Discharge'?
This is the highest point on the graph, when the river discharge is at its greatest.
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What is 'Lag Time'?
This is the delat between peak rainfall and peak discharge. This delay happens because it takes time from the rainwater to flow into the river.
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What can a shorter lag time cause?
This can increase peak discharge because more water reaches the river during a shorter period.
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What is the 'Rising Limb'?
This is the part of the graph up to peak discharge. The rivers discharge is increasing as rainwater flows into the river.
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What is the 'Falling Limb'?
This is the part of the graph after peak discharge. Discharge is decreasing because less water is flowing into the river. A shallow falling linb shows water is flowing in from the stores after its stopped raining.
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What is a storm hydrograph?
This is a graph that shows the amount of discharge around the time of a storm.
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What 5 factors affect the lag time and peak discharge?
Size of drainage basing, Steepness of drainage basin, shape of drainage basin, the amount of streams within a drainage basin and the amount of water already present in the drainage basin.
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How does rock type affect lag time?
Impermeable rocks do not store water, or let water flow through them. This reduces infiltration and increases surface runoff, reducing lag time.
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How does rock type affect peak discharge?
Peak discharge is increased as more water reaches the river in a shorter period of time.
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How does soil type affect lag time?
Sandy soils allow a lot of infiltration, but clay soils have very low infiltration. Therefore increasing surface runoff, reducing lag time.
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How does soil tyoe affect peak discharge?
Low infiltration rates in soil increase surface run off, so therefore will increase the peak discharge.
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How does vegetation affect lag time?
Vegetation intercepts precipitation and slows down its movement to the river channel. This therefore increases lag time.
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How does vegetation affect peak discharge?
The more vegetation there is in a drainage basin, the more water is lost (through transpiration and evaporation directly from the vegetation) before it reaches the river channel, reducing peak discharge.
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How does precipitation affect peak discharge?
Intense storms will produce more precipitation, so it will create greater peak discharges.
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How does temperature affect lag time?
Hot, dry conditions and cold, freezing conditions both result in hard ground. This reduces infiltration and increase surface runoff - reducing lag time.
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How does temperature affect peak discharge?
High temperatures can increase evapotranspiration, so less water reaches the river channel, reducing peak discharge.
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What man made structure affects the hydropgraph?
The man made drainage systems. These cause water to flow to rivers quickly without the chance of being evaporation or infiltrated, creating a shorter lag time and increasing peak discharge.
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Other cards in this set
Card 2
Front
What is river discharge measured in?
Back
Cubi meteres per Second. (Cumecs).
Card 3
Front
How does precipitation effect the river discharge?
Back
Card 4
Front
How does hot weather effect the rivers discharge?
Back
Card 5
Front
How does the removal of water effect the rivers discharge?
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