Hydrosphere Flashcards
(20 cards)
Physical factors affecting movement of water through drainage basin
X6
-type of precipitation (rain snow)
-duration of precipitation
-number of streams
-soil type
-relief
-temperature
Human factors affecting movement of water in a drainage basin
X6
-dams and reservoirs
-farming
-Urbanisation
-deforestation
-mining
-altering river channels
What is the lag time
The time between peak precipitation and peak discharge
What is discharge
The volume of water at a certain point in the river at a particular time
Formation of a v shaped valley
Due to a lack of energy the river erodes downwards
As it erodes the sides of the valley are exposed to freeze thaw weathering
This loosens the rock steepening the valley sides
The material moved into the river is transported away and further deepens the valley floor
Formation of a waterfall
X4
Where more resistant rock sits on top of less resistant
And as the river flows over the rock it erodes the less resistant
This causes undercutting leading to an overhang called a plunge pool
As the undercutting becomes more pronounced the harder rock collapses into the plunge pool
Formation of a meander
X3 para
In rivers water weaves around sediement creating deeper paths. This causes the river to swing from side to side causing the river to become curvy.
Where the river swings towards the bank erosion occurs (abrasion hydraulic action) this causes undercutting of the outside bank creating a river cliff.
Water moved faster on the outside bend of the river creating more erosive power. However there is more friction on the inside bend slowing the water down and allowing it to deposit materials creating a river beach.
Formation of an oxbow lake
X3 para
Form during flood conditions when a meander loop is breached as the river takes the shortest route.
The abandoned loop is sealed off by the freshly deposited alluvium.
The rivers new direct route allows for deposition on either bank further cutting off the meander.
type of precipitation explanation (physical factor)
rain will move more quickly through a drainage basin than snow which lays on the ground for a period of time before melting taking longer to reach the river
duration of precipitation explanation (physical factor)
prolonged rainfall will cause the land to become saturated and the water will flow overland when no more water can soak in
number of streams explanation
(physical factor)
within a drainage basin more streams results in a larger volume of water entering the river as they can transport the water to the trunk river more quickly and efficiently
soil type explanation (physical factor)
sandy soils are more porous and allow water to pass through more easily meaning water will take longer to reach the main river as it will flow via throughflow rather than as overland flow
relief shape explanation (physical factor)
precipitation falling onto steep slopes resulting in water flowing over land more quickly and reaching the river more quickly as a result. less infiltration occurs this increases the chance of flooding
temperature explanation (physical factor)
evaporation rates are higher in warmer areas meaning there is less water to reach the trunk river
dams and reservoirs explanation (human factor)
taking water from underground stores and rivers reduces the river volume and lower the water table, it also increased evaporation and evapotranspiration rates as more water is being stored in surface stores
farming explanation (human factor)
increased crop cover reduces infiltration since more water is being intercepted and more water is being transpired. water will reach the river more quickly once crops are harvested as there is less interception
urbanisation explanation (human factor)
removal of vegetation and replacing with impermeable surfaces (concrete) increases the rate of overlandflow.
deforestation explanation (human factor)
cutting down trees increases surface runoff since water is no longer being intercepted or stored. this means precipitation will reach the trunk of the river more quickly increasing river discharge and flood risk
mining explanation (human factor)
residue from mining silts up rivers which reduces their storage capacity it can also reduce vegetation cover meaning less water will be absorbed by the plants roots or intercepted meaning water will reach the river channel more quickly
altering river channels explanation (human factor)
straightening river channels increased the speed at which water flows increasing the chance of flooding further downstream as a result
