The Sahel is a narrow belt of semi-arid land south of the Sahara desert. Rain falls in only 1 or 2 months of the year, and is very variable. Sometimes the rain comes in torrential downpours and is then lost as surface runoff, causing flooding.
Drought causes seasonal rivers and water holes to dry up and the water table to fall. Drought spells disaster for the nomads who graze animals and for subsistence farmers who rely on rain to grow millet and maize. Grasses die and soil erosion and desertification follow, due to overgrazing by animals.
Many of the countries in the Sahel are developing countries, such as Chad and Sudan. They have rapid growing populations which puts pressure in drought years on failing food supplies.
These semi-arid lands are a very fragile environment and water stress soon causes humanitarian crises. Famines happen regularly.
Three Gorges Dam (Large Scale)
The Three Gorges Dam will have 26 generators capable of generating 84.7 kWh of electricity a year. The dam will help to prevent seasonal flooding that annually threatens the lower reaches of the Yangtze River.
The project has required the relocation of roughly 1.4 million people from 1200 villages. However the dam has made problems as well. The lake has flooded 225 cultural and archaeologist sites and it interferes with logging, navigation and fish migration. It has created a loss of farmland and villages, the bed of the dam was not cleared properly and toxic waste may lie at the bottom of the lake.
The dam has gone on to become a large habitat for water birds and the hydroelectric power created attracts industries to the area.
The dam was incredibly expensive to build and it lies on a plate boundary, meaning it could fall down any time soon.
Dhaka, Bangladesh (Small Scale)
A slum community in Bangladesh has no safe water or toilets. But with the help of a company called Prodiplan, things are changing.
They are working with the community to help deliver water, sanitation and hygiene education.
Six deep tube wells have been constructed, saving people time and energy in collecting water.
Two new sanitation blocks provide toilets and water for washing.
People living in the slums are no longer ill.
They are able to run the facilities themselves as simple machinery is used and the project has helped them move slowly out of poverty.