General Flashcards
What’s the river’s watershed?
The boundary of the drainage basin.
What is a river’s catchment?
The area surrounding where the rain falling on the land flows into that river. It’s also called a river’s drainage basin.
What happens to water falling beyond the watershed?
It enters a different drainage basin.
Are drainage basins open or closed systems?
Open.
What’s an input of a typical drainage basin system?
Precipitation.
Name the storage of a typical drainage basin system.
Interception, vegetation, groundwater, surface and channel.
Name the flows of a typical drainage basin system.
Throughfall, surface runoff, stemflow, infiltration, interflow, channel flow, percolation, groundwater flow, baseflow.
Put these flows in speed order: baseflow, throughflow, groundwater and interflow.
Throughflow (fast)
Interflow (medium)
Baseflow (slow)
Groundwater flow (very slow)
Name the outputs of a typical drainage basin system.
Transpiration, evaporation, evapotranspiration and river discharge.
What is the water balance worked from?
Inputs (precipitation) and outputs (channel discharge and evapotranspiration).
What’s the trend in wet seasons of the water balance?
Precipitation exceeds evapotranspiration creating a water surplus. The ground stores fill with water so there’s more surface runoff and higher discharge, so river levels rise.
What the trend of drier seasons of the water balance?
Precipitation is lower than evapotranspiration. Ground stores are depleted as some water is used and some flows into the river channel but isn’t replaced by precipitation.
What happens at the end of a dry season of the water balance?
There’s a definite of water in the ground.
When are the ground stores recharged in the water balance?
In the next wet season.
Define river discharge.
The volume of water flowing in a river.
Define peak discharge in relation to hydrographs.
The highest point on the graph, when the river discharge is at its greatest.
Define lag time in relation to hydrographs.
The delay between peak rainfall and peak discharge.
Define rising limb in relation to hydrographs.
Part of the graph up to peak discharge, river discharge increases as rainwater flows into the river.
Define falling limb in relation to hydrographs.
Part of the graph after peak discharge. Discharge is decreasing because less water is flowing into the river.
Name the seven physical factors that affect river discharge.
1) Drainage basin characteristics
2) The amount of water already present
3) Rock type
4) Soil type
5) Vegetation
6) Precipitation
7) Temperature
Name the human activities can affect the hydrograph.
1) Urbanisation
2) Man-made drainage systems
Explain how headward erosion affects a river.
Headward erosion makes the river longer. It happens near the river’s source as throughflow and surface runoff cause erosion at the point the water enters the river channel.
Explain how vertical erosion affects the river.
Vertical erosion deepens river channel it happens in the upper stages of a river.
Explain how lateral erosion affects the river.
Lateral erosion makes the river wider happens in the middle and lower stages of a river.
Name the five main ways in which river erosion happens.
1) Hydraulic action - force of water
2) Abrasion - rocks hitting the banks
3) Attrition - rocks hitting together
4) Cavitation - air bubbles implode causing shockwaves that break rock off bed and banks
5) Corrosion - chemical processes
Name the four transportation processes.
1) Traction - rolling
2) Saltation - bouncing
3) Suspension - carried
4) Solution - dissolved
Define deposition.
The process of dropping eroded material.
Why does deposition occur?
It occurs when the river loses energy, dropping some of its load.
