The water cycle and river landforms

What is evaporation in the water cycle?

Liquid water changing into water vapour

Which process releases water vapour from plant leaves into the atmosphere?

Transpiration

Condensation occurs when water vapour does what?

Cools and changes into liquid droplets

Rain, snow, sleet and hail are all forms of which water-cycle process?

Precipitation

What does infiltration mean?

Water entering the soil from the ground surface

How is surface runoff best described?

Water flowing over the land towards a river

Which drainage-basin feature is the boundary separating one basin from another?

Watershed

A smaller river or stream that joins a larger river is called what?

Tributary

Which combination is most typical of a river's upper course?

A steep gradient, narrow channel and V-shaped valley

Hydraulic action erodes a river channel mainly through what mechanism?

Water forcing air into cracks and weakening the rock

When a river's load scrapes and wears away its bed and banks, which erosion process is occurring?

Abrasion

What is attrition in a river?

Rock fragments colliding and becoming smaller and rounder

Why does a V-shaped valley commonly form in a river's upper course?

Strong vertical erosion cuts down while weathering and mass movement shape the sides

Which sequence best explains the formation of a waterfall and gorge?

Softer rock erodes faster, an overhang develops and collapses, and the waterfall retreats

In a meander, where are erosion and deposition usually greatest?

Erosion on the outer bend and deposition on the inner bend

How does an oxbow lake usually form?

A meander is cut off and its ends are sealed by deposition

What is a floodplain?

A flat area beside a river formed largely by deposition during floods

Natural levees develop beside a river because floodwater does what?

Deposits heavier sediment first as it spills over the banks and slows

Under what conditions is a river delta most likely to form?

The river enters the sea and deposits sediment faster than waves and currents remove it

River deposition occurs when the river can no longer do what?

Carry all of its sediment load