River Environments Flashcards
Examples of stores (3)
- atmosphere; as water vapour or clouds
- the land; rivers, lakes, reservoirs
- sea; liquid and ice
Examples of flows (9)
- evaporation
- transpiration
- evapotranspiration
- condensation
- precipitation
- overland flow
- infiltration and percolation
- throughflow
- groundwater flow
transpiration
plants take up liquid water from the soil and ‘breathe’ it into the atmosphere as water vapour
evapotranspiration (2)
- the loss of moisture from the ground by direct evaporation from water bodies and the soil
- also as transpiration from plants
overland flow
when precipitation hits the ground and due to gravity eventually enters a stream, river or lake
throughflow (2)
- this takes place between the ground surface and the top of the groundwater store
- as a result of gravity water slowly moves through the soil until it reaches a stream or river
important differnces between hydrological cycle and drainage basin? (2)
- drainage basin is an open system, while the hydrological cycle is a closed system
- the amount of water in the drainage basin varies over time, while in the hydrological cycle the amount of water stays the same
drainage basin (3)
- also known as the river’s catchment area
- has external inputs and outputs
- amount of water in basin varies over time
inputs of drainage basin (3)
- energy from sun
- precipitation formed from moisture picked up outside of basin
- water from tributary drainage basins
outputs of drainage basin (2)
- river’s discharge
- the water in its basin from which evaporation and transpiration take place, this water eventually falls as precipitation in another drainage basin
discharge
the quantity of water flowing in a river channel at a particular location and time
watershed
boundary between neighboring drainage basins
estuary
mouth of river where it enters sea
river regime
the seasonal variations in the discharge of a river
storm hydrograph
records the changing discharge of a river after a rainstorm
lag time (3)
- delay between peak rainfall and peak discharge (time from when rain falls until it reaches river)
- the shorter the lag time the quicker the water reaches the river channel
- short lag time causes the river discharge to rise steeply
base flow
normal discharge of the river
storm flow
additional discharge of the river as result of rainstorm
Factors affecting river regime (why river regime may change) (6)
- amount and intensity of rain
- temperature can affect form of precipitation
- steep slopes will cause rapid surface runoff, so water will reach river more quickly
- the rock type (impermeable/permeable)
- vegetation and land use
- human intervention (dams and reservoirs)
weathering
the breakdown and decay of rock by natural processes, without the involvement of any moving force
mass movement (2)
- movement of weathered material down a slope due to the force of gravity
- the two main types are slumping and soil creep
erosion
the wearing away and removal of material by a moving force, such as running water
transport
the movement of a river’s load
deposition
the dropping of material being carried by a moving force
physical weathering
breaks down rocks into smaller and smaller pieces, by changes in temperature, freezing of rainfall and thawing in rock cracks
chemical weathering
causes rocks to decay and disintegrate by slightly acidic rain seeping into porous rocks
biological weathering
the roots of plants growing into cracks in the rocks and gradually splitting them apart
slumping (3)
- form of mass movement
- occurs when bottom of valey side slope is cut away by the river at its base
- makes slope unstable so material slumps towards river
soil creep (3)
- form of mass movement
- weathered material moves down slope due to gravity
- collects at bottom of valey side and is eroded by river
hydraulic action (3)
- form of erosion
- water hits river bed and banks with such force that material is carried away
- usually happens when river’s discharge is high
abrasion (2)
- form of erosion
- material carried by river rubbs against sides and floor of channel, this widens and steepens channel
corrosion/solution (2)
- form or erosion
- minerals in the rocks that form the sides of the river channel are dissolved by the water that flows past
load (2)
- material that has been washed or fallen into river
- also materials eroded from sides of channel
