Comparative Analysis of Rainfall Occurrence and Groundwater Level Fluctuations in Theni District of Tamil Nadu
Author:Ponnuchakkammal P, Ramachandran J, Raviraj A
Groundwater is the primary source for drinking, irrigation, and industrialpurposes. Groundwater provides about 24 per cent of global water supply.Groundwater level fluctuates depending on the groundwater recharge anddischarge from the aquifer. The climate change, changing rainfall pattern andgrowing 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 citylocated in the foot of Western Ghats is chosen as the study area. The majorsource of irrigation was well. For analysis of groundwater level status, theAverage - Ground Water Level data and Categorization of the firkas in Thenidistrict was collected from State Ground and Surface Water Resources DataCenter. Arithmetic averages of Rainfall of stations under the Theni districtwas collected from India Meteorological Department. Groundwater levelrise and fall analysis of Average-Groundwater level data (2011 to 2019)was carried out using the line chart. Comparative analysis was done usingRainfall data Vs Average – Groundwater level data (2014-2018). Consideringthe last five years, the groundwater level in Theni District has increased. Thestatistical correlation between the rainfall and groundwater level fluctuationwas poor. Categorization of firkas was used as a performance indicator.It was observed that the Safe Firkas increased from 18% to 41% and theCritical Firkas increased from 6% to 12%. In Periyakulam and Theni Talukthere is no change in Firkas category and remains the same as on 2011.This helps in focusing groundwater development in those taluks which arein the fringe of groundwater status.
Key words : Groundwater, Theni district, Over Exploited Firkas, Rainfall