Water Cycle & Drainage Basin System Vocabulary

Flashcards covering key vocabulary related to the hydrological cycle, drainage basins, river regimes, and hydrographs, as presented in the IGCSE Geography Edexcel course notes.

Hydrological Cycle

A closed system where water is constantly recycled through stores and transfers.

Stores of the Hydrological Cycle

Places where water is held for a period of time within the hydrological cycle, such as the atmosphere, surface stores, aquifers, ice, snow, seas, and oceans.

Interception

How precipitation is prevented from reaching the ground, usually by being caught on leaves or branches.

Transfers of Water within the Hydrological Cycle

How water is moved around the hydrological cycle, including evaporation, condensation, transpiration, precipitation, overland flow, infiltration, percolation, throughflow, and groundwater flow.

Evaporation

The change of water from a liquid to a gas (water vapour) due to heat from the sun.

Condensation

Occurs when water cools and changes from water vapour into a liquid (water droplets).

Transpiration

Occurs when plants release water vapour from their leaves

Evapotranspiration

The combined transfer of water vapour from the Earth's surface and plants.

Precipitation

The transfer of water from the atmosphere to the Earth's surface in the form of hail, sleet, rain, or snow.

Overland Flow

Any water flowing across the Earth's surface.

Infiltration

When water is transferred from the surface into the soil.

Percolation

The transfer of water from the soil into the rocks and aquifers.

Through Flow

Occurs when water is transferred through the soil between the surface and the water table.

Groundwater Flow

The transfer of water through rocks.

Advection

The horizontal movement of water droplets and water vapour in the atmosphere.

Drainage Basin

The area of land drained by a river and its tributaries, also known as the catchment area of the river.

Input (Drainage Basin)

Any water entering the drainage basin system (precipitation).

Outputs (Drainage Basin)

Where water is lost from the drainage basin (evaporation, transpiration, and into the sea/lake).

Direct Channel Precipitation

Occurs when the waterfalls directly into a river.

Watershed

The boundary between drainage basins.

Source (River)

The point of the river which is furthest from the mouth; this is the point at which the river begins.

Confluence

The place where two or more streams/rivers meet.

Tributaries

Streams or rivers flowing into larger streams or rivers.

Mouth (River)

The place where a river enters the sea/ocean or sometimes a lake.

Channel Network

The main river channel and all of its tributaries.

Drainage Density

The number of tributaries in a drainage basin.

Discharge (River)

The amount of water passing a specific point on the river at a given time.

River Regime

A record of the changes in river discharge over a year.

Storm Hydrograph

Shows the changes in river discharge after a storm event over a short period, usually 24 hours.

Base Flow

The 'normal' level of river discharge, mainly from groundwater flow.

Peak Rainfall

The highest rainfall level during the storm.

Rising Limb

Shows the increase in the river discharge.

Peak Discharge/Peak Flow

The highest level of discharge.

Lag Time

The time difference between the peak rainfall and the peak discharge.

Recessional Limb

Shows the river discharge returning to normal flow.