Geography: 31 River Key Words

Hydrological cycle

The never-ending movement of water between the land, the sea and the atmosphere.

Precipitation

Moisture reaching the Earth's surface - rain, snow, sleet, hail, dew or frost.

Store

A place in a system where water is held for a time - for example a lake or the soil.

Transfer

A flow of water between one store and another.

Streamflow

The flow of surface water in a well-defined channel.

Base flow

The part of a river's discharge that is fed by groundwater.

Drainage basin

The area drained by a river and its tributaries, bounded by a watershed.

Watershed

The dividing line - usually high ground - between one drainage basin and the next.

Channel

The part of the valley floor occupied by the flowing water of a stream or river.

Channel network

The system of tributary streams joining increasingly larger channels in a basin.

Valley

A linear dip in the landscape formed by erosion, with a river at its lowest point.

Flood plain

The part of a valley floor a river spreads across during seasonal floods.

Erosion

The wearing down of the land by water, ice, wind and gravity.

Weathering

The chemical alteration and physical breakdown of rock where it stands (in situ).

Mass movement

Weathered rock moving downslope without the direct action of running water.

Impermeable

Rock that does not allow water to pass through it.

Velocity

The speed of the water flowing in the river channel.

Discharge

The quantity of water passing a given point on the river in a given period of time.

Landform

A physical feature with recognisable characteristics, formed by processes such as erosion or deposition.

Waterfall

A landform created by erosion, where water drops steeply or vertically over a cliff-like feature.

Interlocking spurs

Ridges projecting out on alternate sides of a valley, around which the river winds.

Meander

A pronounced bend in a river.

Oxbow lake

A crescent-shaped lake formed when a meander bend is cut off from the main channel.

Levee

A bank of sediment along the edge of a channel, deposited by floodwater.

Flood

When discharge exceeds the channel's capacity and water spills onto the floodplain.

Hydrograph

A graph on which a river's discharge is plotted against time.

River regime

The seasonal pattern of a river's discharge over the course of a year.

Abstraction

Removing water from rivers, lakes or groundwater for human use.

Dam and reservoir

A barrier built across a valley to interrupt river flow and create a man-made lake to store water.

Shortage/surplus

Where water supply is lower / higher than the demand from humans.

Water quality

A measure of how fit water is for human consumption. Polluted water has low water quality.