Rainwater harvesting and water-saving technologies

Abstract

Water is an important life giving natural resource. Yet, human kind not done enough to replenish, conserve and safeguard sources of water supply. On contrary, we face the real prospect of reduced supply of water be- cause of climate change and global warming. Irrigation is the major source of water and it consumes about 80 % of the current water utilization in India. It is estimated that with increasing demand from other competing sec- tors, the share of water is likely to reduce by 10 to 15 in the next two decades. In addition, shrinking water re- sources due to falling ground water-tables, silting of reservoirs and pollution of water resources from untreated domestic waste, industrial effluents and agro-chemicals are threatening the sustenance of existing levels of ag- ricultural production. At the national level, the ground water contributes to about 50 % in the irrigated areas and its intensive development has been one of the key-driving elements in ushering the green revolution but over ex- ploitation of ground water has led to several other problems affecting the sustainability of the production base. Its unscientific exploitation is creating problems and leading to many areas in the country being classified as dark and grey blocks. The per caput water availability is declining continuously and likely to reach the stress and even scarcity levels in some regions in the next few years. There are variety of irrigation water saving tech- nologies that can improve the water use efficiency and productivity of water. These include in-situ water conser- vation, water auditing, increasing in irrigation efficiency adoption of improved irrigation methods and conjunctive use. Even a marginal improvement in the water use efficiency in irrigation sector will result in saving of substan- tial quantity of water which can be utilized either for extending the irrigated area or for diverting the saving to other sectors of water use. It is now widely recognized that water, especially irrigation water is finite and a vulner- able resource. There is also a wide consensus that water development and management should be based on a participatory approach, involving all stakeholders.