Reversing groundwater decline could ease water crisis


Posted: 13 May 2003

Recent research, validated by experts from the International Water Management Institute, has shown how modifying existing irrigation schemes can recharge groundwater on a vast scale - improving food security, reducing farmer's vulnerability to drought, and helping to alleviate South Asia's growing water crisis.

"As a result of this strategy, declining water tables have been arrested, pumping costs for irrigation have been reduced, and agriculturalproductivity has been improved," says Dr. Tushaar Shah of the IWMI-Tata Water Policy Programme - a new initiative to introduce research knowledge into the policy planning process.

A 10-year pilot project has transformed an earthen irrigation system into a highly productive groundwater recharge system, simply by switching from providing irrigation during the dry season to providing canal irrigation only during the monsoon.

The project - focusing specifically on the Lakhaoti Branch Canal system in North India's Uttar Pradesh state - was carried out by the state government, and evaluated by researchers from IWMI, Roorkee University, the Water and Land Management Institute (WALMI) of Uttar Pradesh, and the state's irrigation department

When the monsoon raises river flows, surplus water is diverted through the system to provide farmers with irrigation for wet crops such as rice. Seepage water from the canals and fields recharges the underlying aquifers. That stored water is then pumped back up for a second cropping season post-monsoon.

This system ensures farmers are no longer at the mercy of monsoon rains, which sometimes fail to provide enough water when and where it is needed. They are guaranteed sufficient water to irrigate both a monsoon and a post-monsoon crop.

Government benefits

There are also benefits for national and state governments. "From a government point of view, one of the most attractive advantages of thisapproach is that the 'infrastructure' - earthen canals and groundwater aquifers - already exist and can be modified at very low economic andenvironmental cost, compared to planning and building dams, tanks, or other water storage facilities," concludes Dr Tushaar Shah.

The research suggests the system can be replicated in other regions where there are viable aquifers and surplus river flows during the monsoon. Locations where the construction of a dam or reservoir threatens to cause environmental damage or incur huge financial costs would also benefit.

The direct benefits of the Uttar Pradesh pilot project include a 26 per cent increase in average income per hectare for farmers and a big decrease in the average depth of groundwater from 12 metres below ground in 1988 to 6.5 metres in 1998.

Other benefits included annual pumping cost savings of 180 million rupees (US$3.8 million), annual energy savings of 75.6 million kWh, a 15 per cent increase in the cropped area for rice and a halving of the water conveyance losses.

For more information see Innovations in Groundwater Recharge, issue 1 of the Water Policy Briefing series.