Drainage Basin, Fluvial Processes, Landforms Flashcards
Hydrological Cycle
Sequence of conditions through which water passes from vapour in the atmosphere through precipitation upon land or water surface and ultimately back into the atmosphere
Permeable vs Impermeable
Permeable surface are porrus and allow water to go through them
Impermeable doesn’t allow water to go through them, forcing it to run off
Tributaries
River or stream flowing into a larger river or lake
Watersheds
An area of ridge of land that separates waters flowing into different rivers, basins or seas
River basin
The land water flows across or under on its way to a river (think like a bathtub catches all the water that runs down its sides)
River mouth
The part of the river that flows into a lake, reservoir or ocean
Estuary
Tidal mouth of a river that flows into the ocean
Attrition
Boulders collide with other materials and the impact may breakdown both rocks into smaller pieces
Abrasion/Corasion
River pickes up rock and materials and rubs them along the river bed, breaking them down into smaller pieces through abrasion
Hydraulic Action
Sheer force of the water hits cracks in the river banks and pushes compressed air into cracks. Overtime the pressure splits apart the river banj
Solution
Independent of river discharge or velocity
Chemical composition in the water breaks down rocks like limestone
Water has carbonic and humic acid
Types of erosion
Attrition
Abrasion
Hydraulic action
Solution
Types of transportation
Traction, saltation, suspension, solution
Traction
Occurs when the largest cobbles and boulders roll or slide along the bed
Saltation
Occurs when pebbles, sand and gravel are temporarily lifted up by the current and bounced along the bed
Suspended
Very fine particles of clay and silt are dislodged and carried by turbulence in a fast-flowing river. The greater the turbulence and velocity the greater the quantity and size of the particles that can be lifted up
Solution
Water flowing within a river channel contains acids.
If the bedrock is readily soluble, like limestone, it is constantly dissolved in running water and removed in solution
Velocity
The speed of something in a given direction
Capacity
What the river is carrying
Competency
Maximum amount of load the river COULD carry
Load
what material the river is carrying
Bradshaw model
A geographical model which describes how a rivers characteristics vary between the upper and lower course of the river
Cross profile
The result of interaction with fluvial, weathering and slope movement processes
Landforms associated with rivers
V shaped valleys, waterfalls, meanders, rapids, oxbow lakes, braided channels, floodplains, levees, deltas
Flooding: Causes
Heavy rainfall
urbanisation
Overflow of river
Coastal flooding
Flooding: Effects
Can distribute large amounts of sediment and water over a large space
Erodes banks
Flood populated areas
Hydrographs
Means of showing the discharge of a river at a given point over a short period of time
Bifurcation Ratio
Shows the risk of flooding in a certain area
As the ratio is reduced, the risk of flooding within the basin increases
Drainage Density
Total length of all the streams divided by the area of the whole basin
Highest in areas where land surface is impermeable
Greater in areas with little vegetation cover
More precipitation = higher drainage density
Hydraulic Radius
The ratio between the area of the cross-section of a river channel and the length of its wetted perimeter
A larger ratio = the more effective the stream is at moving water. The use of the hydraulic radius helps to give an idea of velocity and friction in the water
Drainage Patterns
Dendritic
Parallel
Trellised
Radial
