Jul 10, 2008

India - Save every drop

The Indian Meteorological Department (IMD) has forecast a normal monsoon for 2008. This is good news. A good monsoon will help Indian agriculture sustain a 4 per cent growth rate, rein in food price inflation and improve food security for the poor. However, the way we use a good monsoon is in need of urgent change. For millennia, the Indian farmer has used rainwater to raise his main kharif crop, making agriculture risk-prone. Mid-season or terminal dry spells during the monsoon period often result in halving of crop yields. Canal irrigation was thought to be an answer to this problem. But even after 200 years of canal building, less than 15 per cent of Indian farmlands benefit from canal irrigation. The rest is either rain-fed or supported by some 20 million farmer-owned irrigation wells. In sustaining well-irrigation lies the future of Indian farming. Thanks to groundwater development, Indian agriculture today is far less susceptible to the vagaries of the monsoon. Irrigated rabi wheat has become the most important crop in large swathes of India. In West Bengal, irrigated boro rice has helped break its agrarian gridlock. In the semi-arid west and south, a booming dairy economy is sustained by lightly irrigated fodder millets during summer. Contrary to popular thinking, the marginal farmer is at the forefront of the groundwater revolution. During 1970-1995, marginal and small farms increased their groundwater-irrigated area by 400 per cent. Large farms increased it by only 60 per cent. Governments at the Centre and in the states keep investing heavily in dams and canals. These projects have guzzled crores of rupees, claimed most monsoon run-off areas but have added nothing to the irrigated areas since 1990. We need to rethink our use of the monsoon for improved water security. This is especially true in the hard rock aquifer areas of peninsular India — 65 per cent of our land mass — where dry-land agriculture depends increasingly upon crop-saving supplemental irrigation from over 11 million open dug wells. In 86 million hectares of India's rain-fed areas, mid-season or terminal droughts regularly take their toll on kharif crops. Traditionally, the Indian farmer has used his dug well only for taking out water from the aquifer. This needs to change. Managed properly, dug wells can be excellent devices for putting monsoon floodwaters into the aquifers to be retrieved during dry spells to save crops. Scientists scoff at the idea because Americans and Australians do not use dug wells for recharge. But they overlook the fact that westerners do not have the millions of dug wells that we have and we do not have the vast uninhabited swathes that they have. We must design our recharge strategy around what we have. Our dug wells are often built as collector wells with a huge capacity for storage.

For instance, in Kolar and Coimbatore, they are over 10 metres in diameter and 30-50 metres deep. Farmers commonly make several lateral bores inside them to access surrounding water-bearing formations. When recharged, such wells can also dispatch water to those water-bearing formations. What hard-rock India needs is a new mindset of managing dug wells as dual-purpose structures, for taking out water when needed, and putting water into the aquifers when surplus is running off during a good monsoon. Presently, water available for recharge is estimated after allowing for the requirements of existing and planned surface reservoirs. We need to take up an intensive project to rethink the ways to harness a good monsoon. First, extensive groundwater recharge should get priority claim on reservoir water after power generation. Second, farmers must be exposed to the benefits of recharging wells with monsoon floodwaters rather than turning it away from wells as they have always done. Third, farmers should be helped to desilt floodwaters before recharge. Fourth, they should be encouraged to desilt their wells every 3-5 years. Fifth, economic incentives should be offered to villages that take to recharge. Sixth, funds from schemes like NREGS should be allocated for deepening existing wells and digging new wells provided they are recharge-enabled. Finally, instead of regulating well-digging, groundwater laws should elicit farmer participation in the recharge campaign. If all 11 million dug wells in hard-rock India are recharge-enabled, during a good monsoon, these can add 25-30 billion cubic metres of water to the aquifers, and provide crop-saving supplemental irrigation. Over the years, a sustained recharge campaign can drought-proof kharif crops and also sustain some rabi or summer irrigation. It will also increase lean season flows in rivers, revive wetlands and reduce the high fluoride contamination in groundwater, which is a public health hazard in hard-rock areas. The economics of recharge are highly attractive too. It costs just around Rs 5,000 to modify a dug well for recharge and support supplemental irrigation on 2-2.5 hectares. Compare this with the estimated Rs 2 lakh it costs to cover one hectare by canal irrigation. At the national level, a groundwater recharge campaign can pay for itself many times over simply by reducing farm power subsidies. In recent decades, India has emerged as the world's largest groundwater user. Nowhere else in the world are hard-rock aquifers under vast areas so intensively used as here. There is a dire need to rethink our 'monsoon strategy' in the wake of this reality. (The writer is a principal scientist with Inter-national Water Management Institute, Sri Lanka.)

No comments: