Date:14/07/2008 URL: http://www.thehindu.com/2008/07/14/stories/2008071454020400.htm

Karnataka - Bangalore

Groundwater not managed properly in 82 taluks

T.S. Ranganna

Of them, 65 are over-exploited blocks

Bangalore: Karnataka, the second most drought-prone State in the country after Rajasthan, has not managed its groundwater reserves properly in at least 82 taluks, according to Jawaid Akhtar, chairman, Technical Committee on Rainwater Harvesting.

Quoting a report of the Central Groundwater Board in the preface to the user’s manual and trainer’s manual on rainwater harvesting, brought out by the Karnataka Urban Infrastructure Development and Finance Corporation (KUIDFC), he said the State had a total annual replenishment groundwater resource of 15.93 billion cubic metres (BCM), a year with a net draft of 10.71 BCM.

Of the 82 taluks where groundwater was poorly managed, the board said 65 taluks were over-exploited blocks (withdrawal being more than 100 per cent of the available resources), three were critical (withdrawal being 90 to 100 per cent of what was available with long-term decline in groundwater level) and 14 were semi-critical (withdrawal being 70 to 90 per cent with declining pre or post-monsoon water levels).

Bangalore and Kolar districts had the maximum number of over-exploited and critical blocks. Districts that over-utilised groundwater included Bangalore, Kolar, Chamarajanagar, Tumkur, Chitradurga, Davangere, Bellary, Haveri and Gulbarga.

Semi-critical blocks existed in Belgaum, Bijapur, Bidar, Koppal, Chitradurga, Dakshina Kannada and Hassan districts. During 1978-96, a sharp decline was recorded in the water levels in Bangalore (5.4 metres), Chitradurga (8.44), Dharwad (5.4), Bijapur (3.03), Bellary (5.93), Kolar (5.2) and Tumkur (5.96) districts.

Excessive groundwater withdrawal was one of the causes for increasing water quality problems. This had led to salinity in Bijapur, Belgaum, Raichur, Bellary and Dharwad districts, and excess fluoride in Tumkur, Kolar, Bangalore, Gulbarga and parts of Bellary and Raichur districts.

There was high dependency on groundwater resources for irrigation, commercial, industrial and domestic use in most parts of Karnataka. On the other hand, recharge initiatives were inadequate, resulting in depletion of groundwater resources with increasing problems in quality. Large-scale rainwater harvesting across the State was, therefore, the need of the hour, the report said.

Mr. Akhtar said the corporation had taken up the initiative to advocate rainwater harvesting in the State. The corporation was spreading awareness on rainwater harvesting and making sure it was implemented in all urban centres. To make this vision a reality, it wanted to mandate rainwater harvesting for residences, commercial buildings, industrial complexes, public buildings and parks.

The technical committee, which he headed, developed a user’s manual that reached out to the general public, making them aware of the basics of rainwater harvesting. The other, a trainer’s manual, was directed towards practitioners and implementing agencies of rainwater harvesting systems. The Energy Resources Institute played a major role in developing the manual. It would serve as a guide for training the district-level officials and Nirmiti Kendras in implementing it.