What physical factors determine the supply of water?

G4 Water Key Idea 2.1

Rivers only 2% of surface freshwater

The parts of the water cycle

Global values of the water cycle

Climate determines where rain falls – Highs and Lows

Freshwater availability varies at different scales

Continent population and fresh water

Upland Wales – temperature and rainfall

Craig Goch Wales - a good reservoir site – why?

London SE England – Temperature and Rainfall

England and Wales – matching supply and demand.

Water Transfer – proposal (controversial)

Water Balance

Botswana – Rainfall Total, seasonality, variability

India – climate, river discharge, aquifers

Relief – river basins

Global warming will melt most Andean glaciers in the next 30 years, scientists say, threatening the livelihood of millions of people who depend on them for drinking water, farming and power generation.

Climate Change – ultimately reduced river flows in some areas

Aquifers and groundwater in the UK

Thames Basin - artesian

See pie chart c).

Water supply is not always top quality. Human impact.

Human impact on supply. Lake Chad.

Water scarcity – physical and economic.