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K. Karthikeyan ¹, S. Poongothai ¹

Affiliations
1 Department of Civil Engineering, Annamalai University, Annamalainagar-608 002, T. N., IN

Abstract

Groundwater quality from a part of lower Vellar watershed has been examined to characterize the geochemical conditions and its suitability for domestic and agricultural uses. The water samples were collected from shallow bore wells at different locations of the study area. The physico-chemical attributes such as pH, electrical conductivity, Ca²⁺, Na⁺, Mg²⁺, K⁺, HCO₃^-, Cl^-, SO₄^2-, hardness, total dissolved solids (TDS) and nitrate were analysed using standard laboratory tests. The other determinants such as sodium adsorption ratio, percent sodium (Na %), residual sodium carbonate (RSC) were calculated from the observed data. The pH and electrical conductivity varied from 4.47 to 9.46 and 500 μmhos/cm to 6710 μ mhos/cm respectively. The TDS and total hardness ranged from 323.0 mg/L to 4363.0 mg/L and 18.2 mg/L to 964.0 mg/L respectively. The range of chemical concentration of cations such as Ca²⁺, Na⁺, Mg²⁺, K⁺ was traces to 62.2 mg/L, 19.4 to 196.9 mg/L, 6.3 to 333.90 mg/L, 0.08 to 167.70 mg/L, while that of anions HCO₃^-, Cl^- and SO₄^2- was traces to 6.0 mg/L, 38.0 to 1392.0 mg/L and 5.0 to 80.0 mg/L respectively. Nitrate varied from traces to 1.0 mg/L. The graphical interpretation of modified Piper trilinear, USSL and Gibb's diagrams represent Ca²⁺ > Na⁺ and Cl^- > SO₄^2- facies, C₁S₁ field and rock-water interaction respectively. The result shows that most of the samples were not exceeded the maximum permissible limit of prescribed standard for drinking by ISI and hence, it is suitable for drinking, industrial and irrigational purposes. The level of precipitation, interaction with formation and discharge nature of the study area could have considerable contribution.

Keywords

Groundwater Quality, Geo-Chemical Parameters, Piper Trilinear Diagram, Gibb’s Diagram, USSL Diagram.

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N. Ravisankar ¹, S. Poongothai ¹

Affiliations
1 Department of Civil Engineering, Annamalai University, Annamalainagar-608 002, T. N., IN

Abstract

Groundwater is a precious resource lying beneath the earth's surface. More than 50% of Indian population depends on groundwater for drinking water supplies. Problems due to groundwater pollution have been amplified due to urbanization, industrialization, solid and hazardous waste disposal, fertilizers, chemicals, and natural calamities such as cyclones, earthquakes and tsunami etc. In India, recent tsunami has affected most of the coastal regions of Tamilnadu. Therefore, it is very important to study the effect of tsunami on coastal water quality and to implement necessary water management strategies for sustainable development.

The study area is the coastal region of Sirkazhi taluk, Nagapattinam district, Tamilnadu, India. The water quality in this coastal region has been affected significantly by December 26, 2004 tsunami, and this study has attempted to find out the source, degree, extent and nature of the groundwater pollution in the study area. Historical data on groundwater quality of observation wells of the study area were collected from the year 1970 to 2000. Groundwater samples after tsunami were collected from the study area and analysed for water quality parameters. Various maps were prepared using ILWIS-GIS package. It was observed that the major pollution is due to conductivity, sodium and chloride. Results show that there is significant degradation in the water quality due to tsunami in the study area. A micro level study is to be carried out to manage efficiently the groundwater quality of the study area for sustainable development.

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