Rivers and Flooding ✅ Flashcards
What is groundwater flow?
Water in rock flows downhill.
What is a drainage basin?
The area of land by a river where the water cycle takes place
What is transpiration?
The evaporation of water from plants
What is percolation?
When water moves vertically through the soil and rock
What is infiltration?
When water soaks into the soil
What is surface runoff?
When water flows above the ground
What is surface storage?
When water lies on the ground as puddles or lakes
What is interception?
When water droplets collect on trees or plants
What is through flow?
When water in the soil moves downhill
What is watershed?
A ridge of land or area which separates the drainage basins
What is a confluence?
The spot where a smaller stream or river feeds into a larger one
What happens at the source of the river severn?
The water emerges from the bog and becomes a flowing stream
What is erosion?
The wearing away of the river bed and banks by the moving water and the load that it carries
What is transportation?
The movement of pebbles, sand and mud down a river
What is Deposition?
When a river drops its load and it builds up on the bottom
What are the 4 processes of erosion?
Attrition, abrasion, solution and hydraulic action
What is attrition?
When the rocks and river knock together and wear away the banks
What is abrasion?
When the bank is worn away like sandpaper
What is solution?
When the water dissolves the rocks
What is hydraulic action?
When water is forced into the cracks in the bank
What are the 4 processes of transportation?
Suspension, solution, traction and saltation
What is suspension?
Small materials carried along the river
What is solution?
Dissolved material carried along the river
What is traction?
Large stones that roll along the riverbed
What is saltation?
When small pebbles bounce along the riverbed
How is the larger sediment deposited?
It is deposited first and it rolls along the river bed
How is the smaller sediment deposited?
It is carried further then deposited on the river bed or banks
What are interlocking Spurs?
The ridges of land that the river weaves past. The river flows past these chunks of land making a v shaped valley
How is a gorge formed?
When a waterfall retreats and the ledge collapses
How is an oxbow lake formed?
There is a meander in the river, which gets worn away from the fast river eroding
The river takes a shortcut and makes this shape: |> but it’s still attached
The > bit detaches and make an oxbow lake
What is a levee?
A raised river bank naturally formed that reduces flood risk
What is a delta?
When sediment is dropped at the river mouth and it builds up in layers
What is hard engineering?
Creating and using man-made structures to prevent or control natural processes usually very expensive such as dams, river straightening and changing the capacity of the discharge
What is discharge?
The volume of water flowing through the river channel
What is soft engineering?
Working with natural river processes to manage the flood risk without building structures
What are some examples of soft engineering?
Afforestation, River restoration, Floodplain zoning and flood storage plains
