Freshwater Flashcards
What is a drainage basin?
Any area of the Earth that drains towards a body of water such as a lake or a pond. Many combine to make a larger drainage basin, this process would then repeat into rivers and then can lead to large bodies of water such as the ocean.
How can human action influence the functioning of the system?
The further there is an effect up the system, this would effect people further downstream. If the people upstream were to not care for the drainage basin, this would affect the quality of water for the people downstream.
What is an open system?
This is where the systems receive inputs and transfer outputs of energy and/or matter across the boundaries between them. Most natural systems are open ones.
What is a closed system?
Where there is a transfer of energy but not matter between the system and its surroundings.
Define transpiration, interception, throughflow, percolation, infiltration, groundwater flow, evaporation, and surface runoff.
Transpiration- Water vapor is released through the stomata (pores) in the leaves.
Interception- Water is stored on leaves and branches of vegetation.
Throughflow- Water flows horizontally through the soil into the river.
Percolation- Water flows vertically through the soil and rocks.
Infiltration- Water seeps into the ground.
Groundwater flow- Water flows horizontally through the rock into the river.
Evaporation- Water turns from water droplets into water vapor.
Surface runoff- Water flows horizontally over the land into the river.
Define hydraulic action, abrasion, attrition and solution
Hydraulic action- The sheer power of the water as it smashes stains the river banks. The air becomes trapped in the cracks in the rock of the river bank and bed and causes the rock to break apart.
Abrasion- when pebbles grind along the river bank and bed in a sand papering effect.
Attrition- when rocks that the river is carrying knock against each other. They break apart to become smaller and more rounded.
Solution- when the water dissolves certain types of rocks, eg. limestone.
Define the four types of transportation
Traction- Large, heavy pebbles are ROLLED along the river bed. This is the most common near the source of the river as the load is larger.
Saltation- pebbles are BOUNCED along the riverbed, most commonly near the source.
Suspension- Lighter sediment is SUSPENDED (carried) within the water, most commonly near the mouth of the river.
Solution- the transport of dissolved chemicals. This varies along the river depending on the presence of soluble rocks.
Define Deposition and its causes
When the water looses energy, it drops any of the material it has been carrying.
Caused by shallow water, the end of the rivers journey (at the mouth of the river), when the volume of the water decreases.
Define the watershed, source, mouth, confluence, tributary, channel
Watershed- The area of high land forming the edge of a river basin.
Source- where a river begins.
Mouth- where a river meets the sea.
Confluence- the point at which two rivers meet.
Tributary- small rivers or streams that join and connect to the main river.
Channel- where the river flows.
Describe the features for the Upper Course
Where the river would start.
Slopes are steep.
The river channel is narrow and shallow here.
The river load is large- it has not been broken down by erosion yet.
When discharge is high, the vertical erosion erodes the river bed and larger sediments are transported by traction.
Describe the features for the Middle Course
The gradient becomes less steep.
The channel gets deeper and wider.
The sediment load of the river gets smaller as some has been eroded.
Small meanders and floodplain can be found in this part of the river.
Describe the features for the Lower Course
The final course of the river where the gradient is near-to-flat.
The sediment load is fine and small as erosion has broken down the rocks.
The channel is at its widest and deepest as it flows towards the mouth.
Deposition is the main process in this course.
The deposition creates large floodplains and deltas.
What factors have an impact on drainage basins?
Time- The variables which effect the drainage basin system would be the time of year. An example includes within the summertime, the baking of the soil may make the soil impermeable and therefor increase surface runoff. This means it is more likely for flash floods to occur.
Relief- Elevation of the channel affects the speed of which the river flows at. This would mean if the channel is fairly steep the gravity aids the velocity and therefor increases the discharge.
Describe the formation of a V-Shaped Valley and Interlocking Spurs
In the upper course, there is vertical erosion which takes place and forms V-Shaped valleys and interlocking spurs. The interlocking spurs are formed when there is hard rock, which would take longer to erode vertically and forms small meandered turns and therefor creates Interlocking Spurs.
Describe the formation of Rapids
This is where a process known as differential erosion takes place. It is where there is a mix of hard rock and soft rock on the riverbed and the soft rock would erode much faster than the hard rock meaning the hard rocks are the rapids. They would eventually erode away too however they would stay for much longer than soft rock.
