Cambridge International AS & A Level Geography 9696 – Glossary (Hydrology to Urbanisation)

Vocabulary flashcards covering key geography terms from Hydrology, Atmospheric Processes, Earth's Tectonics, Population & Migration, Water Resources, and Urbanisation topics.

abrasion

When the load of a river rubs against the riverbed and riverbanks, wearing them down over time.

afforestation

Planting trees in an area that has not recently had tree cover.

agricultural

Relating to farming.

antecedent moisture

The existing level of moisture in soil before precipitation occurs.

baseflow

The very slow movement of water through permeable rock towards a river channel.

bedrock

The solid rock beneath surface materials such as soil and sand.

bluffs

Steep cliffs along the side of a river, forming as erosion wears down river banks.

cavitation

A type of erosion where an air bubble in a crack implodes under pressure, weakening rock.

chalk

A soft sedimentary rock, a form of limestone.

clay

A soft mineral that forms soils and many sedimentary rocks.

condensation

The process of water vapour cooling and changing into liquid water.

corrasion

Erosion where the load rubs against and wears down the riverbed and banks.

dam

An artificial structure across a river which controls the flow of water.

deforestation

Cutting down trees and clearing an area of forest.

deposition

The process of a river losing energy and dropping the load it has been carrying.

discharge

The volume of river water flowing past a given point at a given time.

drainage basin

An area of land that is drained by a single river and its tributaries.

drainage density

The total length of the channels in a drainage basin divided by the total area of the drainage basin.

duration

In a hydrograph, the amount of time that precipitation lasts.

erosion

The process of material being removed from a riverbed and riverbanks.

evapotranspiration

The process of water moving back into the atmosphere by evaporation and transpiration.

falling limb

A part of a hydrograph showing when the discharge of a river decreases and the river level falls.

floodplain

A flat area of land beside rivers in the middle and lower course.

flood forecast

A prediction of the occurrence, magnitude and duration of a flood.

gauging station

A site on a river where a hydrologist measures the discharge of the river.

gorge

A narrow valley that forms when a waterfall retreats upstream.

granite

A hard igneous rock formed when melted rock under the Earth's surface cooled and solidified.

groundwater

The water stored in soil or permeable rock under the Earth's surface.

groundwater flow

The very slow movement of water through permeable rock towards a river channel.

hard engineering

Flood management techniques that work against nature.

helicoidal

A river flow pattern where the water moves in a corkscrew-like motion.

hydraulic action

When the force of moving water removes rocks and sediment from the riverbed/seabed and riverbanks.

hydrograph

A combined bar and line graph showing how a river responds to a period of rainfall.

infiltration

The process of surface water moving into the soil.

inputs

The processes which move water into a drainage basin.

intensity

The strength of a period of rainfall.

interception

The process of vegetation preventing precipitation from reaching the ground.

irrigation

The process of artificially supplying water for crops.

(recurrence) interval

The estimation of the amount of time between flood events of a particular magnitude.

lag time

In a hydrograph, the amount of time between peak rainfall and peak discharge.

laminar

A river flow pattern where the water moves in smooth and parallel lines.

(river) landforms

The physical features a river creates through the processes of erosion, transportation and deposition.

levee

Higher areas of land found beside a river.

limestone

A soft sedimentary rock, which is made of calcium carbonate.

load

The material that a river transports.

meander

A bend in a river, usually found in the lower or middle courses.

outputs

The processes which move water out of a drainage basin.

overland flow

The movement of water over the ground toward rivers.

oxbow lake

An isolated section of water that is left behind when a meander bend is cut off.

percolation

The downward movement of water from the soil into permeable rocks.

permeability

The ability of a rock or soil to allow liquid through it.

point bars

A gently sloping mound of sand, gravel and rocks found inside a river meander.

porosity

The quality of a rock or soil having tiny holes which allow water to pass through it.

precipitation

Water falling from the air onto the land, e.g., rain, snow, hail.

riffle-pool sequence

Alternating areas of deep, slow-moving water (pools) and shallow, fast moving water (riffles) on a riverbed.

rising limb

A part of a hydrograph showing when the discharge of a river increases and the river level rises.

river straightening

The process of removing meanders from river channels to allow water to move more quickly downstream and reduce the chance of flooding.

riverbank

The land on the edges of a river, which marks the sides of the river channel.

saltation

When small pebbles and stones appear to bounce along the riverbed/seabed.

sandstone

A soft sedimentary rock, composed of sand and other small sediments.

silt

Granular sand, clay and soil that a river carries and deposits.

(diversion) spillway

An artificial channel which a river can flow into when its discharge rises.

soft engineering

Flood management techniques that work alongside nature.

stemflow

The movement of water which has entered the drainage basin, such as precipitation, through the stems of plants into the ground.

suspension

When fine sediment particles, such as silt and clay, are carried along by the river/sea.

thalweg

The line of fastest flow in a river.

throughfall

The movement of water which has entered the drainage basin, such as precipitation, and drips from the plant canopy into the ground.

throughflow

The lateral movement of water through soil.

traction

When large boulders and rocks are pushed, dragged, or rolled along the riverbed/ seabed by the force of flowing water.

transfers

The processes which move water within the drainage basin.

transpiration

The process of water moving back into the atmosphere as plants lose water through their stomata.

turbulent

A river flow pattern, where the water moves in a swirling, chaotic motion around objects such as rocks.

urbanisation

An increase in the proportion of people living in towns and cities.

velocity

The speed of the water in a river, in a given direction.

water table

The boundary between the soil surface and the underground rocks which are permanently saturated with water.

waterfall

Water flowing over a ledge of harder rock.

wetland

An area of land where water covers and saturates the soil.

albedo effect

The amount of radiation a surface reflects back into space.

anthropogenic

Relating to humans.

carbon dioxide

A gas composed of one atom of carbon and two atoms of oxygen, present in the Earth's atmosphere and traps heat.

concentration

The amount of a particular gas in the atmosphere.

conduction

The process of heat moving from a high temperature area to a low temperature area.

convection currents

The movement of heat from one place to another by the mass movement of molten rock.

deficit

A state of net energy loss, where the amount of energy absorbed is less than the amount radiated.

dew

The moisture that forms on cool surfaces, usually overnight, when water vapour condenses.

diurnal

The difference in the balance of energy going into the atmosphere and the energy leaving the atmosphere during the day and night.

El Niño Southern Oscillation

A periodic climate pattern where the sea surface temperature and atmospheric pressure fluctuates across the equatorial Pacific Ocean.

energy budget

The balance between the energy going into the atmosphere and the energy leaving the atmosphere.

enhanced greenhouse effect

A process where increased greenhouse gases in the atmosphere trap more heat, warming the Earth.

eruption

The expulsion of lava, gases and other materials from a volcano.

excess

A state of net energy surplus, where energy absorbed is larger than energy radiated.

F gases

Human-made compounds which contain fluoride and trap heat in the atmosphere.

Ferrel cell

An atmospheric circulation pattern between 30–60° latitude, with warm air moving toward poles and rising.

fog

A thick cloud of small water droplets near the Earth's surface.

frontal uplift

A warm air mass meeting a cold air mass, rising and cooling to produce precipitation.

global warming potential

A measure of how much a greenhouse gas is estimated to contribute to global warming over a specific time.

greenhouse gases

Gases in Earth's atmosphere that trap heat by absorbing infrared radiation (e.g., CO2, CH4).

Hadley cell

An atmospheric circulation pattern between the equator and 30° latitude with rising warm air at the equator and sinking air at 30°.

hail

Small, hard balls of ice that fall as precipitation.

horizontal transfer

The sideways movement of energy through ocean currents from warmer to cooler water.