Chandrashekar, Hanumanthaiah
Paper number: 1270
ASSESSMENT OF GROUNDWATER POLLUTION POTENTIAL THROUGH REMOTE SENSING AND GIS
TECHNIQUE
A CASE STUDY FOR ANEKAL TALUK, BANGALORE URBAN DISTRICT, INDIA.
H. Chandrashekar ', G. Ranganna and C. Nataraju
% Dayananda Sagar Institute of Technology, Bangalore-78, Karnataka, India.
xt UGC-DSA Centre, Bangalore University, Bangalore-01, Karnataka, India.
E S. J .College of Engineering, Mysore-06, Karnataka, India.
Groundwater is regarded to be the most valuable resources. Groundwater quality is affected by virtually every
activity of the society thereby making groundwater protection complicated. The protection of groundwater is always
cheaper than restoring already polluted aquifer. DRASTIC index methodology helps in the assessment of
groundwater pollution potential.
DRASTIC index uses a set of seven hydrogeological parameters viz., D-depth to Groundwater table; R-recharge due
to rainfall; A-aquifer media; S-soil media; T-topography; I-impact of vadose zone; C-hydraulic conductivity. These
parameters are weighed with respect to their relative importance.
All the DRASTIC parameter layers in spatial formats are put into GIS. The layers were assigned weights and ratings
and they are combined interactively in the computer system.. The DRASTIC index map was generated on a minute
grid and seven categories of groundwater pollution potential zones were identified.
The Drastic Index represents the relative measure of groundwater pollution potential, which helps planners and
administrators in broadly screening areas for waste disposal sites. Pollution potential map also helps in evaluating
alternatives for directing the financial resources and land use activities to the appropriate areas.
INTRODUCTION:
The importance of water for sustaining human, animal and plant life needs no emphasis. Human health and welfare,
agricultural growth, industrial development and ecobalance are all at critical stage, unless water and land resources
are managed more efficiently now than in past. Even today more than 90% Indian population is primarily dependent
on groundwater. So, it is essential to conserve groundwater quantity as well as quality.
A statergy for the protection of groundwater must be aimed at protecting aquifers from becoming contaminated
preventive efforts should be directed first at land use activities that pose a higher risk of causing pollution from both
point and non point sources. Care must be exercised to avoid ground water development that leads to the
degradation of quality or the depletion of supplies. Regulatory and technological measures must cover all categories
of point and industrial landfills, mining operations and agricultural practice over exploitation of aquifers leading to
quality degradation must be prevented.
A unique study has been made for Anekal Taluk, one of the three taluks of Bangalore urban district, Karnataka,
India. It is alarming to note that the quality of water has deteriorated and aquifers are recharged with low quality
water. The pollution potential of the study area is assessed by “DRASTIC” methodology, where in hydrogeological
setting is given more importance besides, each alphabet representing a parameter.
STUDY AREA:
Anekal Taluk is geographically located between 12° 39" 39” to 12° 56! 30” North latitude and 77° 32! to 77° 50!
East Latitude. The Taluk measures 512 Sq. km. Anekal Taluk represents an uneven landscape with intermingling of
hills and valleys. The ground is much dissected and is a region of rapid erosion. The eastern portion of the Taluk is a
258 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.
