Ch10 River Processes Flashcards
Source
Where a river begins.It is normally located on high ground
Tributary
A smaller river that joins a larger one
Confluence
The point where to or more rivers join together
Mouth
The point where the river enters the sea
Course
The path a river flows along. The path I’d from the Source of the river to where it enters the sea at its mouth
Watershed
A Highland area that separates one drainage basin from another
Estuary
Part of a river mouth that is tidal. It is where the river water meets the sea
DP. (Dendritic)
°Most common type found in irish river basin, °patterns resemble a tree °normally occurs on gently sloping land,The tributaries flow from narrow valleys into the main river
DP Trellis
Drainage patterns occurs where tributaries meet the main river at right angles °they look like a rectangular grid
DP radial
°Dp form when tributaries flow from a circular or oval-shaped mountain °the tributaries flow outwards in all directions it resembles spokes from a wheel
DP parallel
Dp form when rivers flow alongside each other rather than joining together -due to shape of landscape, their coarse is straight with few or no tributaries joining them
Dp Deranged
Dp occurs where tributaries flow in a disorganised or aimless manner typically occurs in swamps or marshlands where the river has a low velocity.
What are the 4 main processes if river erosion
1 Hydraulic Action 2 Abrasion 3 Attrition 4 Solution
What is hydraulic action
°The sheer force of moving water °as water flows it crashes off riverbank and riverbed the force of collision enlarges joints in rock and breaks off fragments of rock °HA both widens and deepens the river channel
What is abrasion
Occurs as a rivers load(eroded material hits off the bed and banks of a river °Its most effective in times of flood when river is capable of carrying a larger load
What is attrition
Occurs as rocks and pebbles being carried by the river hit off each other
What is solution
Occurs when soluble rocks in the river channel are dissolved by weak acids in the water
What are the processes of river transportation
1 solution 2 suspension 3 saltation 4 traction
What is solution in transportation
Occurs when soluble rocks are dissolved and carried away in solution °accounts for a small percentage of rivers load transported and need little energy to transport
What is suspension
Occurs as clay and silt particles are lifted off the riverbed and carried as a suspended load,much of the rivers load is transported by suspension
What is saltation
Occurs when small pebbles and stones that are too heavy to be carried in suspension for a long time are bounced along the bed of the river
What is traction
Occurs when heavy materials such as large rocks are dragged along the riverbed °transportation requires great amount of energy and usually occurs when the river has a great level of volume and velocity
River deposition occurs when a river loses its velocity(speed the water travels)
•when a river slows down it loses energy.
•human interference can reduce speed of a river through construction of dams as it blocks the rivers coarse
River deposition when a river loses its volume(the amount of water in river channel)
•when a river loses some of its volume its energy is reduced
•during hot weather,evaporation reduces the rivers volume,causing deposition to occur
River deposition increased load
During heavy rainfall tributaries joining the main river can carry alot of sediment. The main river is unable to transport all of its load causing its channel to become clogged with sediment
