SUSTAINABILITY
Water demand is rising and supplies can be unpredictable. If we use water faster than it is replenished, its use is not sustainable. It can also be expensive to store and distribute it effectively.
Large scale projects to increase water supply usually involve big dams. They are usually complex, multi-purpose projects.
Currently dams supply:
40% of the world's irrigated water
20% of the world's electricity
15% of all BLUE WATER
Blue Water - This is water that is stored in dams and then used for domestic purposes such as washing and cleaning.
Non-governmental organisations (NGO's) such as WaterAid or Practical Action, often develop small scale sustainable solutions to local problems in LEDC's.
They set up low cost projects using APPROPRIATE or INTERMEDIATE technology (this means that it is appropriate to the geographical conditions of the local area and within the technical ability of the local community).
This is done so the local community can take pride in what they do, feel part of the decisions and operate and maintain it themselves.
The main schemes involve:
Rainwater harvesting (see the diagram).
Protecting springs from contamination in order to reduce diseases.
Developing gravity fed piped schemes so people can easily access water.
Building hand dug wells or TUBE wells (when the water is too deep to get to it by hand).
Sanitation projects such as low-cost pit or composting toilets.
Large Scale Management
Are there any snags?
Some small scale solutions don't work because they can be inefficient. In many African countries, huge numbers of people suffer from HIV/AIDS and people may be too ill to operate them. But, in general, intermediate technology works well and is often more sustainable than the large-scale schemes.
Access to clean water can make a huge difference to people's lives. In the past people (usually women) often had to walk long distances to get water.
Now they can have safe drinking water, and water for cooking, washing and personal hygience.
Small Scale Management
A rainwater harvester