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Aquifer performance was tested in 24 locations to assess the groundwater potential of the hard rock terrain in the Chittar-Uppodai watershed of the Tambaraparani River basin. Geologically, the area consists of biotite gneiss, charnockite, and quartzite. The aquifer characteristics, such as transmissivity (T), the storage coefficient, specific capacity, optimum yield, and the recovery rate were calculated. The drawdown transmissivity was determined using Jacob's straight-line method, while the recovery transmissivity was determined by the Theis method. The drawdown transmissivity was low in the western areas, particularly at Kadayanallur, and was higher in the other areas. The recovery transmissivity was high in the western area, and, with the exception of Gangaikondan, was low at other locations. The assessment indicates that there is groundwater potential in the western part of the study area because of favorable results for recovery drawdown, aquifer thickness, and specific capacity.

Spatial and temporal precipitation changeability in Tamil Nadu State in India was analyzed by utilizing month to month precipitation information for a long time (1901-2002) from 29 stations. Tamil Nadu is one of the southern states of India which has a farming-based economy. Sen’s slope method has been used to estimate the magnitude of trend, whose statistical significance was assessed by the Mann-Kendall test, the highest decreases were observed in a summer precipitation and annual precipitation decreasing trends were detected at many stations in January, February and June. The coefficient of variation (CV) was used to analyze precipitation variability. The Slope test depicts a decreasing trend at all Stations over the past 102 years, from the results obtained by both Parametric and Non-parametric tests for annual and monsoon precipitation at 5% level of significance. The Weakening precipitation of the monsoon circulation parameters caused by global warming appears to be the main causes of recent changes. The most elevated inconstancy was seen in the monsoon precipitation and least fluctuation was seen in the late summer over the 102 years (1901-2002). The weakening precipitation of the monsoon circulation parameters caused by gradual increase in the overall temperature of the earth is the major cause of recent changes.