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

Ponnuchakkammal P,Ramachandran J,Raviraj A

doi:10.29321/maj.2020.000337

Abstract

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.

Highlights

IntroductionIt is that part of the water below the earth’s surface, which flows naturally out of the Earth’s surface
The water coming through rainfall is not completely flowing as runoff, while some part of it is going as groundwater recharge (Saraf et al, 2004)
The analysis reveals that there is a poor correlation between the rainfall and groundwater level

Summary

Introduction

It is that part of the water below the earth’s surface, which flows naturally out of the Earth’s surface. Most of the groundwater is derived from precipitation. Groundwater recharged from atmospheric precipitation is called “meteoric water”. Groundwater is an annually replenishable resource, but its availability is nonuniform in space and time. Most of the Earth’s liquid fresh water is stored as groundwater. Groundwater provides about 24 per cent of the global water supply. According to Chow et al, (1988), 30.1% of the freshwater exists as groundwater in the hydrosphere. The water coming through rainfall is not completely flowing as runoff, while some part of it is going as groundwater recharge (Saraf et al, 2004). In the presence of interconnected fractures, cracks, joints, crushed zones (such as faults zones or shear zones), or

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Results

Conclusion