fluvial processes Flashcards
fluvial systems
- distributed network operating from very small to very large scale
- comprise physical and living
- transport water and sediments from areas of erosion to deposition
hydrological cycle
This is how water moves between reservoirs on the Earth. Without the cycle there would be no oceans, rivers, groundwater or life on earth.
surface water
flows occur when soils are saturated or when the rain is so heavy it cannot infiltrate the soil.
explain what hillslope-fluvial couple means?
water flows from the hills into the stream
overland flow
excess water from rainfall or snowmelt runs across the surface and can deliver large amounts of sediment
Drainage basin
- distributed channel network which eventually converge into a single channel
- drainage basin is an area from which a river or stream and their tributaries carry all the surface runoff
what separates drainage basins?
topographic highs, which are referred to as watersheds or divides
shape of a drainage basin affects its response to the catchment. How would dendritic basins compare to long narrow basins in a rainfall?
dendritic basins would respond quickly, long and narrow would be a slower response
whats it called where two 1st order streams meet?
2nd order stream
if a 3rd order stream meets a 1st order stream, what results?
still 3rd order
4th order stream occurs when?
two 3rd order streams meet
what is the main thing that influences stream velocity?
river gradient. higher = faster velocity. faster velocity = more erosion
ultimate vs local base level
- ultimate base level is the ocean because rivers flow into the ocean so they cant erode any lower than that.
- Local or temporary base levels may occur e.g. if there is a lake half way down the mountain the river is flowing down.
how does turbulence affect river velocity? where about is the greatest velocity of the river?
decreases it.
highest velocity in the middle of the surface.
greatest turbulence occurs where?
bed of the channel