Chapter 4: Water and its Management

Vocabulary flashcards based on Chapter 4 'Water and its Management' lecture notes, covering the water cycle, water supply, desalination, pollution, and water-related diseases.

Global Water Distribution (Oceans and Seas)

Oceans and seas contain $97.2\%$ of all the Earth's water.

Freshwater Distribution

Only about $2.8\%$ of water on Earth is freshwater, consisting of $0.6\%$ groundwater, $2.1\%$ snow and ice, and $0.1\%$ rivers and lakes.

Precipitation

Moisture that reaches the surface in the form of rain, sleet, snow, or hail.

Surface run-off

Water from rainfall or snowmelt that flows over the ground.

Interception

Precipitation that does not reach the soil but is instead stopped by the leaves and branches of plants.

Infiltration

Process where precipitation soaks into sub-surface soils and moves into rocks through cracks and pore spaces.

Through-flow

The process by which infiltrated water flows through the soil.

Ground water flow

The process by which infiltrated water flows through the rocks.

Transpiration

The evaporation or diffusion of water from plant leaves.

Evaporation

The process where water from bodies of water changes from water droplets to water vapor due to heat.

Condensation

The process where water vapor is converted back into liquid droplets due to a decrease in temperature.

Potable water

Water that is safe to drink.

Aquifers

Water stored in porous rocks (such as limestone and sandstone) under the ground, often trapped between layers of impermeable rock.

Artesian aquifer

An aquifer in which the water is under pressure, causing it to rise to the surface without the need for a pump.

Reservoirs

An artificial lake used as a source of water supply, usually created behind a dam.

Desalination

The removal of salt from seawater to produce fresh water.

Distillation

A desalination method where water is boiled and released as vapor to leave salt behind, then condensed back into liquid.

Reverse osmosis

A desalination method involving the pumping of water at high pressure through a fine, semi-permeable membrane.

Multipurpose dam

A dam constructed for multiple uses, such as irrigation and the generation of electricity.

Bioaccumulation

The increase in concentration of a toxic substance in the tissues of organisms at successively higher levels in a food chain.

Biomagnification

The process where toxic concentrations increase higher up in the food chain, often causing the death of top consumers.

Eutrophication

Nutrient enrichment from fertilizers causing increased algae growth, which blocks sunlight and depletes oxygen, leading to the death of aquatic organisms.

Acid rain

Rain formed when sulphur dioxide ($SO_2$) and oxides of nitrogen ($NO_x$) react with water and oxygen in the atmosphere to form sulphuric and nitric acids.

Biological Oxygen Demand (BOD)

A measure used in sewage treatment to determine the amount of oxygen required by bacteria to break down organic matter.

Coagulation

A water treatment process where particles in the water are stuck together to settle to the bottom.

Water-bred disease

A disease where the carrier breeds in stagnant water and spreads the disease by biting victims; an example is malaria.

Water-borne disease

A disease spread by consuming contaminated water or using it for washing; examples include cholera and typhoid.

Vector

An organism that transmits a parasite or disease, such as the Female Anopheles mosquito for malaria.

Cholera

A bacterial infection caused by contaminated water that leads to severe diarrhea and dehydration.