What does channel form of lowland rivers depend on
Stream power, which is influenced by depositional environmental factors!
load
sediment size
slope
variability
bank stability
Scales of rivers
Large range of spatial and temporalscales that are present in a lowland river system
Such as physical scale e.g. ripples, which can become dunes or channel bars
The temporal scale of rivers is highly variable and changes with respect to depositional elements, this can be over days – such as in floods or geologicalscales – sea level changes can also have an influence
The depositional facies of lowland rivers
Range from gravel dominated or sand dominated with low or high sinuosity
Forms of rivers
Braided
Wandering (a mix of the two)
Meandering
o The forms of river change to accommodate stream power
Stream power changes
Stream power changes when there is any change to sediment load, sediment size, slope, bank stability or discharge variability
Discharge and sediment (load and size) of a river fluctuate throughout time and are also dependent on how downstream of a source they are
Meaning that rivers experience constant adjustment
As a result of this, rivers that are perfectly straight reflect the exact energy required to transport their bedload
Grande River in Amazon
The changing nature of this river suggests that there is insufficient power to transport all of the river’s sediments
There is a continuous adjustment in the flow pattern of the river.
The river changes downstream from braided to wandering to meandering with thick channels
