Groundwater quality assessment and mapping in coastal blocks of Ramanathapuram district, Tamil Nadu

Abstract

Block wise categorization of groundwater quality in coastal region of Ramanathapuram district for its optimal usage for minimize the soil salinity was undertaken during September 2018. A total of 70 underground water samples representing different coastal blocks viz., Ramanathapuram (12 samples), Kadaladi (14), Tirupullani (10), Mandapam (15), Tiruvadanai (13) and RS Mangalam (6) were collected, analyzed for quality parameter and categorized into different water quality as per the standard procedure. The investigation revealed that groundwater samples with respect to pH and EC ranged from 7.17 to 8.57 and 0.29 to 80.1 dSm-1, respectively. Residual Sodium Carbonate (RSC) varied from nil to 22.8 meqL-1 and Sodium Adsorption Ratio (SAR) ranged from 0.51 to 9.31. Frequency of occurrence of good quality water in the blocks surveyed were in the order of Mandapam (20%)>Tirupullani (10%)>Tiruvadani (7.6%)> kadaladi (7.1%) based on the CSSRI, Karnal water quality classification In coastal blocks of Ramanathapuarm district, 7.45 per cent of groundwater samples were in good quality, Saline water was found in Tiruvadani and RS Mangalam to the extent of 4.03 per cent. Alkali water was found in Manadapam, Tiruvadani and RS Managalam blocks to the extent of 33.3, 15.3 and 16.6 per cent respectively. Among the coastal blocks of Ramanathapuram districts surveyed, Kadaladi blocks falls under high SAR saline (71.4%) and lowest good quality of groundwater (7.1%).