Rivers Flashcards
What are the 4 types of erosion?
Hydraulic action, attrition, solution and abrasion
What is hydraulic action?
When the river forces air into cracks and gradually wears the bed away
What is abrasion?
Where rocks get carried along the bed by the river and erode the bed
What is attrition?
When rocks bump together eroding each other becoming smaller and smoother
What is solution? (Erosion)
When particles of rock dissolve into the river
What are the 4 types of river transport?
Traction, saltation, suspension and solution
What is traction?
When large boulders and rocks roll along the river bed
What is saltation?
When small pebbles and stones bounce along the river bed
What is suspension?
When light material gets carried along by the river
What is solution? (Transportation)
When dissolved minerals are transported
What are the three main parts of a river?
The upper, middle and lower course
What are the land forms found in the upper course?
V-shaped valleys, interlocking spurs, waterfalls, rapids
What land forms are found in the middle course?
Meanders, oxbow lakes
What land forms are found in the lower course?
Wide flood plains, meanders, oxbow lakes, leveés and deltas
How is an oxbow lake formed?
The meanders become tighter and the river erodes the outside of the beds and deposits on the inside. The river takes the shortest course through the meander and and the meander gets cut off front the river and forms an oxbow lake
What is a tributary?
A smaller river which flows into a larger river
What is a confluence?
Where two rivers meet
What is the mouth of the river?
Where it meets the sea
What is a drainage basin?
The area drained by a river and its tributaries
What is the watershed?
The imaginary line surrounding the drainage basin
What is the source of a river?
Where it begins
Case study: uk floods When? Where? Why? Impacts
June-July 2007
All across the uk
Anticyclone then low pressure weather system
5,000 homes flooded, 5 deaths
Case study: Mozambique floods When? Where? Why? Impacts
January 2013 Mozambique, Africa Rivers swelled and burst banks in rainy season 246,966 affected 117 deaths
River Thames sustainable management
The Thames barrier which is a moveable flood barrier, prevents London being flooded by high tide and storm surges
Hard engineering but effectie
