Though water covers nearly 75 per cent of the earth’s surface, fresh water that can be utilised for irrigation, household and industrial purposes is only about 0.5 per cent. A scarce natural resource, it is the sustainer of life and ecology. India occupies 2 per cent of the world’s land area, supports over 16 per cent of its population and has only 4 per cent of its renewable water resources. We receive total annual precipitation of about 4,000 billion cubic metres (BCM). After loss through evaporation, etc, the total water availability is about 1,869 BCM. Discounting for topographical characteristics and hydrological constraints, as also the need to allow a certain amount of water for ecological flow, the quantity of usable water is 1,123 BCM.
With the total availability of water being limited, its per capita availability decreases in direct proportion to the increase in population. From 5,177 cubic metres in 1951, when India’s population was 361 million, it is likely to fall to 1,140 cubic metres in 2050, when the population is projected to be 1,640 million. This suggests the scale of the water scarcity crisis that faces us today.
Irrigation, industry, power generation, household and other needs raise competing demands on water. With development and growth leading to urbanisation, the demand for water is constantly rising. As the requirement of food between now and 2050 is likely to increase by 70 per cent, the projected demand of water for irrigation is likely to increase. The widening gap between demand and supply is likely to result in severe deficits in most of our river basins. The intended river inter-linking projects, if realised, can give an additional utilisable yield of about 210 BCM.
The Accelerated Irrigation Benefit Programme and the Bharat Nirman Project helped accelerate the creation of irrigation potential, which in March 2012 stood at 110 million hectares (mha), against the ultimate irrigation potential of 140 mha. India has been able to attain a storage capacity of 253 BCM. For food security, livelihood and equitable and sustainable development, we have to augment this capacity, utilise the already created irrigation potential and improve efficiency.
Large temporal and spatial variation in rainfall, and consequently in river flow and ground water aquifers, is an important feature of Indian water resources. The effect of climate change on the hydrological cycle could result in a further intensification of spatial variation in precipitation, snow-melt and water availability.
Ground water, constituting about 38.5 per cent of available water resources, meets nearly 55 per cent of irrigation, 85 per cent of rural and 50 per cent of urban and industrial needs. It is a community resource, but perceived to be individual property and exploited inequitably without sustainability. As a result, aquifers in 15 per cent of assessment blocks are overexploited. It is estimated that in 20 years, 10 crore people will face water scarcity.
A low awareness of overall water scarcity and water’s economic value results in wastage and inefficient use. Also, many natural water bodies and drainage channels have been encroached upon. Anthropogenic pollution caused by the use of chemical fertilisers and pesticides, and the discharge of untreated industrial effluents threaten rivers and fresh ground water ecosystems. Inadequate sanitation and lack of sewage treatment are also polluting water resources. Ground water in many areas is also found to be contaminated by geogenic arsenic, fluoride, nitrate and iron. The National Water Policy (NWP) expresses the need to treat water resources as a national resource and advocates an overarching federal law for water resources development and management. An effort to enact such a law has not found favour with the states. The NWP also accords importance to a participatory approach among stakeholders for efficient management of water resources. Panchayati raj institutions, water users’ associations, NGOs, schools, etc, can help create an understanding about the looming water scarcity and the need to adopt judicious daily water-use practices.
Irrigation accounts for over 70 per cent of the total water usage and hence the greatest need to adopt good practices is in this sector. The old habit of flooding the fields for a good crop has been proved counterproductive. Plants need only a specific degree of moisture to yield the right crop. There is a need to compute water requirements of different crops, apply water accordingly and adopt drip and sprinkler systems. Water management and the use of appropriate technology are critical to avoid wastage. The lining of canals and common water channels is essential, besides their maintenance.
Replenishable fresh water is increasingly becoming a scarce natural resource. Treated tap water is accessible to only 30.8 per cent of the rural population who have to depend on wells, hand pumps, ponds and tanks and women have to carry pitchers on their heads over long distances. The ever-elusive targets of piped water supply to every household have to be pursued with determination. The National Water Mission was conceived with the objective of conservation of water, minimising wastage and ensuring equitable distribution, both across and within states, through integrated water resources management. It has, inter alia, the goal of promoting citizen and state actions for water conservation, augmentation and preservation. A basic change in our attitude to water, rainwater harvesting and ground water recharge is needed. We can either conserve and save water, or perish.
The writer is a former Union minister for water resources.