Definition Flashcards
Discharge
The amount of water / volume a river is carrying
Groundwater flow
Very slow water movement deep below the ground
Infiltration
When surface water is absorbed into the soil
Interception
When water droplets collect on trees and plants
Throughflow
Movement of water downhill through the soil
Surface run off
The movement of water across the land
Percolation
Water moving downwards through the soil into rocks below
Transpiration
Water vapour released by trees and plants
Hard engineering
Building of artificial structures to reduce, disrupt or stop the impact of river processes
Flood
Occurs when river discharge exceeds river channel capacity and water spills over the floodplain
Soft engineering
The use of the natural environment surrounding the river to work with the natural processes
Dam and reservoirs
Large structures which regulate (control) river flow. high rainfall = water can be stored in the reservoir (big lake). It can then be released when the rainfall is low
Embankments
Raised river banks. Raising the level = river channel can hold more water before flooding
Flood relief channels
A manmade river channel constructed to by-pass (go around) an urban area. High rainfall = sluice gates (barriers which control water flow) open to allow excess water to flow away into the flood relief channel and reduce the threat of flooding
Channel straightening
Cutting through meanders to create a straight channel. This speeds up the flow of water along the river so it passes through a location quickly, reducing the risk of flooding.
Flood plain zoning
This involves putting building restrictions (rules) in place on floodplains that are at risk of flooding. Areas at risk can be kept clear of building impermeable surfaces.
Flood warnings
Developing a system of alerting people to the risk of flooding.People then have time to plan, prepare or even evacuate if a flood is likely to occur.
Planting trees
Planting more trees helps to increase the amount of interception and transpiration. They help to slow down the time it takes for water to enter a river.
River restoration
Where the course of a river has been changed artificially, it can be restored to its original course. This reduces the discharge of the river, making it less likely to flood.
Silt
Fine sand, clay, or other material carried by running water and deposited as a sediment, especially in a channel or harbor.
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Alluvium
A deposit of clay, silt, sand, and gravel left by flowing streams in a river valley or delta, typically producing fertile soil.
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