The Hindu Business Line : Demand management of groundwater vital: Study

A study of the A-K basin (Araniar-Kortaliyar) in North Chennai, a major water source for the city, has highlighted the need for rigorous monitoring of the entire basin, managing demand and controlling water abstraction to enable long-term recovery of the aquifer.

Demand management should go hand-in-hand with the more common approach of augmenting supply, according to participants at a workshop to discuss the findings of the study on demand management of ground water in over-exploited areas in Chennai.

The study funded by the UK Department of International Development (DFID) also pointed out the need for legislations and policy measures to ensure efficient and cost-effective use of water among competing users such as agriculturists, industry and households, and exploring options for recharging the aquifer.

In this regard, the experts said that recommendations for sustaining water availability in this aquifer, such as constructing check dams, had been ignored for decades and legislations to regulate ground water use had not been enforced.

For instance, according to Mr Louis Menezes of the Centre for Poverty Alleviation, a partner in the study, even in the 1960s, the United Nations Development Programme had suggested the construction of five check dams in the basin, but it was only 1993 that three were constructed and even these are not operational now.

"Legislations form the bedrock of a policy," he said, but legislations to regulate ground water were not being enforced. The more-than-decade-old proposal for a Chennai-basin plan for managing water is yet to be implemented. Unplanned urbanisation continues with irrigation tanks being destroyed.

According to Mr Kandaswamy Bharathan of VRV Consultants, another partner, a study of the economic aspects of water use showed that among the options to augment water resources, rainwater harvesting was the cheapest at Rs 4 a cubic metre. Check dams cost Rs 11 a cubic metre, recycling waste water for industrial use cost Rs 36 a cubic metre, which the industries were willing to pay, and desalination cost about Rs 45 a cubic metre.

Mr John Petrie, Water Resources Specialist of the UK-based Black & Veatch Consulting, which led the study, said that the A-K Basin aquifer was not being recharged, though water was being drawn continuously. While Metrowater was monitoring the lower portion of the basin where it has its well fields, water was being diverted from the surface for other uses. It is possible that the change in water levels could also be due to usage in other parts of the basin.

The entire basin needs to be monitored and drawal has to be regulated. Artificial recharge structures such as rainwater harvesting, injection wells and check dams are needed. The study also focussed on the socio-economic aspects and the impact of drought on the water users for framing equitable measures for water distribution.

Presenting the findings, Dr Elizabeth Mann, an independent consultant with Black & Veatch, said that drought affected the livelihood of the poor — both in rural and urban areas — more than the rich. The poor fared worse in access to ground water, quality of water, impact on livelihood, affordability and health.

In the rural areas, the livelihood of marginal farmers with less than five acres land was affected more than that of the landless, who could get employment in factories or neighbouring urban centres.

In the city, the `human asset' was crucial for ensuring access to water. Water mostly from tankers had to be carried into the house from the streets, and often up the stairs. So the most affected were households in which the able-bodied were not present or out at work when water was available. The elderly in high-rise tenements, women-headed households and daily wage earners were hit.