Introduction:

• Water resources are limited and they are vital for economic development, crucial for food security, national security and energy security.
• As per the recent study the water demand is likely to increase about 73 percent in irrigation sector, followed by industrial and domestic sectors.
• There are spatial and temporal variations of water availability. For example, 75 percent of the rainfall in India occurs in 4 months with higher precipitation in North east region and lowest in Rajasthan.
• India's per capita availability of fresh water is low when compared to countries like Brazil, Australia, USA, UK, Bangladesh and China.
• There is increasing trend of lower low productivity per unit use of water raising concern in context of India's growing population.
• Irrigation is the major input cost amounting to about 70 percent of total input cost. Increasing water use efficiency leads to reduction in input cost and leads to better savings.
• More than 70 percent of the people either directly or indirectly dependent on agriculture and monsoon plays an important role in the economy.
• The conventional irrigation water use, such as through canal and flood irrigation has an efficiency of about 55 to 60 percent but the efficient technologies like micro irrigation techniques has an efficiency of about 90 percent.

Certain Terms associated with water use:

• Water conveyance efficiency takes into account the conveyance and transit loss, and is determined as the ratio of water delivered to farm or irrigated plot over the water supplied or diverted from river or reservoir.
• Water application efficiency focuses on the attention of suitability of the method of application of water to the crops, and is measured by the ratio of quantity of water delivered to the field.
• Water use efficiency is the ratio of water consumptively used to the quantity of water delivered.
• Water storage efficiency is the ratio of water stored in the root zone during irrigation and the water needed in the root zone prior to irrigation.
• Water distribution efficiency evaluates the degree to which the water is uniformly distributed throughout the root zone.

Steps to be taken :

• Rehabilitation and restoration of damaged and silted canal system to enable it to carry designated discharge.
• Conjunctive usage of surface and ground water, especially in areas where there is a threat to water logging.
• Adopting micro irrigation systems lie drip and sprinkler mechanisms for irrigation wherever possible.
• Revision of cropping patter in the event of change in water availability.
• Constitution of water user associations and transfer of management to them as mentioned in the National Water Policy.
• Introducing night irrigation practices to reduce the evaporation losses.
• Proper and timely system maintenance.
• Assuring timely and optimum irrigation for minimizing water loss and water logging.
• Conservation of monsoon flows in rivers, mush of which go as waste to the sea.
• Construction of check dams, barriers, ponds and lakes will enhance the conservation of water resources.
• Rainwater harvesting must be promoted by following TamilNadu model as it increases the level of ground water.