Final answer:
The gradient of a stream or river refers to the change in elevation over a horizontal distance, reflecting the steepness of the river's slope which impacts the current's speed and the channel's shape.
Step-by-step explanation:
The gradient of a stream or river is defined as the change in elevation for a given horizontal distance. In the language of mathematics, this is analogous to the concept of slope in a graph, where the term "gradient" is denoted as m and calculated as the rise (change in y-value) over the run (change in x-value).
In the context of a river or stream, the gradient is the vertical drop of the streambed over a specified horizontal distance. As a river flows from its source, the gradient influences the speed of the water and the sediment transportation, impacting the river's channel width and the current's speed.
A steeper gradient often means a faster current and less sedimentation, due to less time for sediments to settle, while a gentle gradient can lead to wider channels and a slower current with more sedimentation.