Geography, Chapter 10: Rivers

Stages, Erosion and Transport

Source

The beginning or start of a river. This stage of the river is the youthful stage and often starts at mountain tops.

Course

The route a river takes to the sea.

Confluence

The point where two rivers or streams join together.

Mouth

The point where the river comes to the end, usually when meeting the sea.

Drainage basin

The area of land drained by the river.

Watershed

The are a of high ground which separates the two drainage basins.

Estuary

The point where the river becomes tidal, just before it reaches the sea.

Upper/Youthful stage

The beginning of a river. The land is steep with fast-flowing water. Lost of erosion happens here.

Middle/Mature stage

The river starts to slow down. There is more water. Erosion and some deposition happen here.

Lower/old stage

The river is moving more slowly. There is more water. Mainly deposition and not much erosion happens here.

Three stages of a river

Young, mature, old

Four processes of river erosion

Hydraulic action, abrasion, attrition, solution

Hydraulic action

The force of the fast-flowing water breaks up the bed and bank of the river, almost like a power hose.

Abrasion

Stones carried by the river (load) hit against the bed and bank of the river, wearing it away.

Attrition

When the stones roll along the bed or collide with each other. This makes river stones rounder and smoother over time.

Solution

When the river water dissolves the rocks over which it flows.

Four processes of river transport

Traction, saltation, suspension, solution

Traction

Larger stones are rolled or dragged along the driver bed

Saltation

Lighter stones are hopped along the river bed.

Suspension

The smallest rocks or soil grains are held up in the water. This makes the water cloudy.

Solution (Transsport)

Rock is dissolved in the water. The water can be clear but coloured.