The classification of groundwater samples from the study area with respect to percent sodium
and EC are shown in Figure.2. Results show that the wel s belonging to the 1 st layer, that is, 500 m away from the River Noyyal is found to fal in the unsuitable and doubtful to
unsuitable region which clearly indicate that these wel s are not suitable for irrigation. In the
case of 2 nd
layer wel s (about 1000 m away from River Noyyal), it is observed that except one
wel , al other wel s are found to fal in the permissible to doubtful and doubtful to unsuitable
region indicating that most of the wels in this region also not fuly suitable for irrigation. Wels belonging to 3rd layer (about 1500 m away from River Noyyal) demonstrate that 40%
of the wel s are found to be good for irrigation and the remaining 60% fal in the region of
permissible to doubtful. In the case of wels belonging to 4 th and 5th layers, most of them fal
in the very good to good and good to permissible region indicating that these wels are very
much suitable for irrigation. The results of the present study clearly demonstrate that the
influence of pol uted riverwater to the groundwater aquifers is highly significant only within
1 km from River Noyyal on both north and south directions.