Option A: Freshwater Vocabulary

Drainage Basin

Area of land drained by a river and its tributaries

Watershed

Boundary dividing two drainage basins

Hydrological Cycle

Continuous movement of water on, above, and below the surface

Infiltration

Movement of water into soil

Percolation

Movement of water through soil and rock

Groundwater

Water stored underground in rock crevices and pores

Evapotranspiration

Combined water loss from evaporation and transpiration

Throughflow

Water flowing through soil horizontally

Baseflow

Water that enters a river from groundwater

Overland Flow

Water that flows over land surfaces

Peak Discharge

Highest point of discharge after a rain event

Lag Time

Time between peak rainfall and peak discharge

Rising Limb/Falling Limb

Slopes on a hydrograph

Hard Engineering

Physical structures like dams or levees

Soft Engineering

Sustainable, natural methods like afforestation

Afforestation

Planting trees to reduce runoff and erosion

Water Scarcity

Lack of sufficient water to meet demand

Water Security

Reliable availability of clean water

Water Stress

When demand exceeds availability during a period

Biological Oxygen Demand (BOD)

Measurement of organic pollution

Turbidity

Cloudiness of water due to particles

Salinization

Accumulation of salts in soil or water

Desalination

Removing salt from seawater

Greywater

Recycled domestic wastewater (not from toilets)

Transboundary Water Conflict

Disputes between countries sharing water

Integrated Water Resource Management (IWRM)

Coordinated management of water, land, and resources

Water Stewardship

Responsible use and protection of water by all sectors

Virtual Water

Hidden water used to produce goods

Aquifer

Underground layer of water-bearing rock

Flash Flood

Sudden flood caused by heavy rainfall

Channelization

Engineering to alter river flow

Floodplain Zoning

Controlling land use in flood-risk areas

Sediment Load

Material transported by a river