Groundwater is vulnerable to contamination by
anthropological activities. Vulnerability mapping is considered
as a fundamental aspect of groundwater management.
The aim of this study was to estimate aquifer
vulnerability by applying the DRASTIC and GOD models
in Abarkooh plain, Yazd province, center of Iran. The
DRASTIC model uses seven environmental parameters
(depth to water, net recharge, aquifer media, soil media,
topography, impact of vadose zone, and hydraulic conductivity)
to characterize the hydrogeological setting and
evaluate aquifer vulnerability. GOD is an overlay and index
method designed to map groundwater vulnerability
over large regions based on three parameters (groundwater
confinement, overlying strata, and depth to groundwater).
The information layers for models were provided via
geographic information system. The overlap techniques
were used to provide and produce the vulnerability map of
the study areas considering weight coefficients of each
layer. Accuracy of the models was evaluated using linear
regression between observations values of nitrate and estimated
vulnerability to pollution in the measured wells. A
significant correlation was observed between measured
nitrate and pollution potential evaluated by DRASTIC
model (P\0.01), but no significant correlation was observed
for GOD model (P\0.05). The results showed that
the DRASTIC model is better than GOD model to estimate
groundwater vulnerability to pollution in the measured
wells. For DRASTIC model, the correlation coefficient
between vulnerability index and nitrate concentration was
68 % that was substantially higher than 28 % obtained for
the GOD model. We can conclude that nitrate concentration
should be a suitable parameter to inves