Application of Geoinformatics for Groundwater Characterization

Abstract

Groundwater is the main source of irrigation in most arid and semi-arid regions of India. Therefore, there is a need to appraise quality of groundwater for sustainable crop production in these regions. In present study eighty one groundwater samples collected from tubewells across the block Gohana were analyzed for pH, electrical conductivity (EC), major cations namely, sodium (Na+), potassium (K+), calcium (Ca2+) and magnesium (Mg2+), and anions namely, carbonate (CO32-), bicarbonate (HCO3-), chloride (Cl-), sulphate (SO42-), nitrate (NO3-) and fluoride (F-) and specific irrigation water quality indices viz., sodium adsorption ratio (SAR) and residual sodium carbonate (RSC). The pH of groundwater varied from 7.19 to 9.72 with a mean value of 8.18 and EC from 0.29 to 15.76 dS m-1 with a mean value of 2.74 dS m-1. Among different cations, Na+ was found as the most dominant cation followed by Mg2+, Ca2+ and K+. In case of anions, Cl- was the dominant anion followed by SO42-, HCO3-, CO32-, NO3- and F-. The SAR of groundwater varied from 4.03 to 24.16 (mmol L-1)1/2 with a mean value of 10.59 (mmol L-1)1/2. Correlation matrix indicated that EC is highly correlated with Cl-, CO32-, SO42-, Na+, Mg2+, Ca2+ and K+. The results from the laboratory were imported to ArcGIS (Arc Map 9.2 software) to generate the spatial variability maps of EC, SAR, RSC and water quality. The water quality map will furnish firsthand information to authorities and devisers about the ground water quality of the study area. Hence, geoinformatics plays a pivotal role in the study of earth resources.