Comparative Analysis of Rainfall Occurrence and Groundwater Level Fluctuations in Theni District of Tamil Nadu

Abstract

Groundwater is the primary source for drinking, irrigation, and industrial purposes. Groundwater provides about 24 per cent of global water supply. Groundwater level fluctuates depending on the groundwater recharge and discharge from the aquifer. The climate change, changing rainfall pattern and growing water demand lead to the groundwater level variation year by year. Rainfall is the major source for groundwater recharge. As rainfall increases, groundwater level also increases. Theni District also called Cardamom city located in the foot of Western Ghats is chosen as the study area. The major source of irrigation was well. For analysis of groundwater level status, the Average-Ground Water Level data and Categorization of the firkas in Theni district was collected from State Ground and Surface Water Resources Data Center. Arithmetic averages of Rainfall of stations under the Theni district was collected from India Meteorological Department. Groundwater level rise and fall analysis of Average-Groundwater level data (2011 to 2019) was carried out using the line chart. Comparative analysis was done using Rainfall data Vs Average-Groundwater level data (2014-2018). Considering the last five years, the groundwater level in Theni District has increased. The statistical correlation between the rainfall and groundwater level fluctuation was poor. Categorization of firkas was used as a performance indicator. It was observed that the Safe Firkas increased from 18% to 41% and the Critical Firkas increased from 6% to 12%. In Periyakulam and Theni Taluk there is no change in Firkas category and remains the same as on 2011. This helps in focusing groundwater development in those taluks which are in the fringe of groundwater status.