Geohydrological studies in part of Gadilam River Basin,India

This book is an attempt to test the spatial analyst tool of Arc/ GIS 9.3 to map hydrogeochemical mapping in the part of Gadilam River basin especially to develop hydro geochemical spatial information,to determine the cause for water table fluctuation and to identify the groundwater recharge zones for the above basin. Sulphate concentration is found to be poor in South central and North west part of the study area around Thiruvamur and Alagappasamudram. Source of sulphate can be attributed to weathering of sulpher from Terteary upland in the south.Concentration of alkalies in groundwater was represented as per WHO’s standards most of the samples represent good category as they are less than 100 ppm. Two samples in south east are moderately suitable for drinking as they are less than 400 ppm in concentration. Based on WHO’s standard less than 100 ppm is categorized as safer zone, which is suitable for irrigation of crops. By considering the concentration more 500ppm.South western part is categorized under poor suitable zones, where south west upland persist.pH value is ranging from 7.2 to 8.6 along the western fringe Southern corner.pH values of 8.6 represent noncarbonate hardness.