What is a waterfall and how does it form?
A waterfall is a river's steep fall over a rocky ledge into a plunge pool below (upper course). It forms when a river flows over a band of hard, resistant rock with a layer of softer, less resistant rock beneath it. The river erodes the softer rock through abrasion and hydraulic action. It undercuts the harder rock, which eventually collapses.
What is a meander? (definition + processes)
A meander is a winding in the course of a river (middle and lower course). Inside, most of the water's force is directed outside of the bend, resulting in lateral erosion and deposition.
Formation of an ox-bow lake
As a meander develops, its neck becomes narrower due to lateral deposition, eventually cutting it off completely. This leaves behind a horseshoe-shaped lake: an ox-bow lake (middle and lower course)
Delta definition + formation
When a river reaches the ocean, it loses velocity and deposits its load (eroded material transported by the water). The sediments build up and form a delta, and the river splits into many smaller channels called distributaries, creating large areas of wetlands.
What is an estuary?
An estuary is a place where a river joins the ocean. When the river water combines with the sea water, it becomes brackish
Confluence vs. Tributary (definitions)
1. A confluence is a point where two streams or rivers meet.
2. A tributary is a stream or a small river that joins a larger river
What is the wetted perimeter?
The wetted perimeter is where the water comes into contact with the river's banks and bed. This is where most of the friction occurs