Saturday, April 21, 2007

City running out of ground water - Deccan Herald - Internet Edition

City running out of ground water - Deccan Herald - Internet Edition: "
The groundwater situation is in a critical condition in Devanahalli, Doddaballapur, Nelamangala, Bangalore East (Whitefield and adjoining areas) and Hoskote, according to officials from Department of Mines and Geology. Planning to invest in property in Bangalore? Make sure that there is adequate surface water supply and a provision for rain water harvesting because groundwater resources in both the Bangalore Urban and Rural districts are already in the red.In several residential areas, especially in Bangalore North and East, borewells are dry or on the verge of drying. Ironically, these areas, recording meteoric rise in land prices, are among the 'most critical' areas as far as groundwater is concerned.

“The situation has worsened in the last three years. The average annual rainfall in the district is only 600 mm to 700 mm per year. Because of the drought in 2001, 2002 and 2003, groundwater recharge has been very low. Bangalore is entirely dependent on rainfall because it is built on a plateau, on different hydrological basins of South Pinakini and Cauvery rivers,” another officer from the Department of Mines and Geology said. “It’s time the government declared a five-year holiday to exploitation of groundwater.”


According to the report on groundwater resources of Karnataka in March 2004 (the last five-yearly report on groundwater resources) by the Department of Mines and Geology, though the total annual groundwater recharge in Devanahalli was 6,496.65 hectares per metre (HAM), the gross groundwater draft for all uses was 14,294.31 HAM. In Bangalore North, the total annual groundwater recharge was 6,943 HAM and the overdraft was 13,132.21 HAM. In Bangalore South, the groundwater recharge was 6543.16 HAM and the overdraft was 11,856.63 HAM.

“The figures show that people have not only over-exploited groundwater, but have also drilled into the static water reserve, which should be used only in emergency situations,” said a department official.


Jagadiswara said...

This has reference to the news items in the Hindu dated 26th March 2007 and the Deccan Herald dated 21st April 2007 on the need for people’s movement for taking up rainwater harvesting and artificial groundwater recharge at household level to overcome water shortages and groundwater depletion in Bangalore and its suburbs.

The observation by the Department of Mines and Geology that the groundwater draft in Devanhalli, Bangalore North and Bangalore South areas is nearly twice the groundwater recharge is quite disturbing. The suggestion by the Department that the Government should ban further exploitation of groundwater cannot be implemented. The best course of action would be to artificially increase groundwater recharge to equal the draft.

The present strategy is to take up groundwater recharge at house-hold level. Although recharge by each household is quite low, it is hoped that sizeable groundwater could be recharged by involving lakhs of households. Besides impracticality of involving such large numbers, this can lead to deterioration of groundwater quality.

Managed Aquifer Recharge (MAR) is the best alternative for achieving large-scale groundwater recharging without deteriorating water quality. This method consists in injecting large quantities of treated rainwater, tank water and imported river water directly into deep aquifers at selected wells under the supervision of experts. MAR is presently being successfully implemented in the arid and semiarid tracts of most developed countries in the world. The same alone gives best results for Bangalore and its suburbs.

One worthy thing the Department of Mines and Geology can do is to prepare and make available locality-wise detailed groundwater maps of Bangalore and its suburbs showing groundwater availability, level of groundwater development, groundwater potential zones and groundwater quality. Such maps will help both planners and people to prioritise urban sprawl to localities holding abundant groundwater of good quality.

dinesh kumar said...

It is true that groundwater reserves are getting over-exploited in many arid and semi arid areas and more so in large towns and cities with concentrated water demands. But, the suggestion to balance the abstraction with increased recharge sounds rather strange. These are text book solutions. Where is the water for recharging the aquifers?

Also, what is the compulsion for using very expensive treated rainwater for recharging? Instead, people can directly use the water from the natural system after treatment (if at all available).

Our groundwater experts seem to forget the fact that the resource is over-exploited because of poor availability of freshwater on the surface.

Declaring holiday to groundwater exploitation is a good idea, provided the corporation is able to supply sufficient quantum of imported water to the users