Abstract:
Groundwater contamination and vulnerability
in urbanized areas are of major concern and need proper
attention. Several models including the DRASTIC model
are used to evaluate groundwater vulnerability. In the
present study, a modified DRASTIC model named as
DRASTICA was used, by including anthropogenic influence
as a model parameter. The study included an innovative
methodology to characterize the anthropogenic
influence by using satellite observations of night-lights
from human settlements as a proxy and land-use/landcover
surrounding the urbanized area in Lucknow, the
capital city of the most populous State of Uttar Pradesh in
India. Geographical information system was used for spatial
integration of different parameter maps. The groundwater
vulnerability to pollution indicated that about 0.7 %
area is covered under very high vulnerable zone, 24.5 %
area under high vulnerable zone, 66.6 % area under moderately
vulnerable zone and 8.2 % area under low vulnerable
zone. The results were validated using nitrate
concentration in ground water. It was shown that the proposed
DRASTICA model performed better than conventional
DRASTIC model in an urbanized environment.
Sensitivity analysis indicated that anthropogenic impact
and depth to water table largely influenced the groundwater
vulnerability to pollution, thereby signifying that
anthropogenic influence has to be addressed precisely in
such studies. The modified-DRASTIC/DRASTICA model
proposed in this study will help in better categorization of
groundwater vulnerable zones to pollution where anthropogenic
contamination is high, particularly in and around
urban centers.
