Dam Solutions - Water Use

Agriculture, irrigation and water supply

Thirsty crops ...
Worldwide the agricultural sector is the largest consumer of freshwater, accounting for some 70% of all water withdrawals and more than 90% in many developing countries.

Most of this is withdrawn in Asia, where most of the world's irrigated lands are found. Cotton, rice and sugar are amongst the thirstiest crops (PDF: 948 KB) in the world, requiring between 2,000 - 10,000 litres of water per kilogram grown.

.. and inefficient irrigation
The importance of irrigation in food supply is undeniable; 40% of the world's food is produced from the 17% of land that is irrigated. However, poorly designed irrigation systems and inappropriate field application methods mean that a lot of water is wasted. And even where there is no alternative to using water for irrigation, there are alternatives to new storage dams or transfer schemes that produce the same amount of food or fibre using less water, for example:

• Improved management of surface irrigation systems e.g. downstream control systems, channel maintenance.
  
  
• Selection of better field application practices e.g. 'bed and furrow' irrigation, or drip irrigation instead of flood irrigation.
  
  
• Encouraging a cropping pattern that is adjusted to the local climatic conditions e.g. growing sorghum instead of rice or wheat in drought prone areas.
  
  
• Enhancing local water storage in pond or lakes through small structures, connecting channels and measures to encourage groundwater recharge, such as the traditional 'tank' system in Southern India.
  
  
• Adopting water harvesting techniques can provide an alternative to large reservoirs, or reduce the volume of new storage required.

Industrial and domestic water use
Although farming is responsible for the majority of water withdrawals globally, in Western Europe, where rainfall is usually adequate or sometimes even too much, water withdrawals for industry and domestic use can account for more than 50% of the total. As with agriculture, there are still substantial savings that can be made in industry and domestic water use for example:

Supply-side options include:

• Leakage reduction programmes, which stabilise and reduce losses from piped systems.
  
• Rainwater harvesting through rooftops, tanks and other methods.
  
• Infiltration techniques to maintain groundwater levels in areas that have short but intensive rainy seasons.
  
• Reuse and recycling of water.
  
• Desalinisation, although current techniques are both expensive and energy intensive.

Demand-side options include:

• Establishing rights for users to use or trade their water allocations, thus enabling water to be used more productively.
  
• Realistic pricing to recover the full financial and environmental costs of water, and the creation of thus avoiding hidden subsidies and waste.
  
• Technical (water efficient) standards for industrial and household equipment e.g. washing machines.
  
• Respect for existing legislation and control of water use.
  
• Education and awareness raising of consumers on water saving.