Rivers

SEC ONE TEXTBOOK PAGE 101

What is a river?

A river is a natural watercourse, usually freshwater, flowing towards the sea.

Without the hydrological cycle, rivers cannot be formed.

Is this a river?

HYDROLOGICal CYCLE

HYDROLOGICal CYCLE

HYDROLOGICALHYDROLOGICAL

CYCLECYCLE

SURFACE RUNOFF

INFILTRATION

CONDENSATION

TRANSPIRATION AND EVAPORATION

PRECIPITATION

HYDROLOGICAL CYCLE

• Precipitation – water from clouds come to the Earth’s surface as rain, snow and hail• Transpiration – plants release water vapour into atmosphere

HYDROLOGICAL CYCLE

•Surface Run-off – rain that falls on Earth’s surface flows over land

• Condensation – water vapour rises, cools and changes into tiny water droplets

HYDROLOGICAL CYCLE

• Infiltration – water that soaks into the soil subsurface

• Percolation – water moves further down into the underlying soil after infiltration

HYDROLOGICAL CYCLE

•Throughflow – infiltrated water that flows sideways in the soil subsurface

• Interception – water is absorbed by trees

Water flows from highlands to lowlands due to the pull of gravity.

River System

River sourceRiver source: The place at which the river begins. Usually found in mountainous areas or highland.

TributaryTributary: Streams and rivers that join the main river

River course River mouthRiver mouth: The place at which a river ends into the sea

RIVER SYSTEM

• Source – the starting point of a river• Mouth – the ending point of a river• Drainage Basin – The area drained by a river and its tributaries

RIVER SYSTEM

•Confluence – the point at which a tributary joins the main river • Watershed – The boundary formed by the edges of the drainage basin