Delineation and Mapping of Groundwater Quality in Chengalpattu District of Tamil Nadu, India

Groundwater is a major natural source of water supply all around the world. It's utilised for irrigation, industry, and even household purposes. The quality of groundwater is important for irrigation. Irrigation water quality plays a critical role in long-term soil productivity. To assess the quality of the groundwater, 149 samples were taken in May 2022 from the coastal blocks of the Chengalpattu district: Chithamur (42), Lathur (37), Thirukalukundram (31), and Thiruporur (39). The samples were analysed in accordance with the appropriate protocol. The study revealed that the coastline blocks pH ranges from 8.92 to 7.52 and their EC ranges from 11.50 to 0.13 dS m-1. The Sodium Absorption Ratio (SAR) ranges from 20.00 to -6.80, while the Residual Sodium Carbonate (RSC) ranges from 14.77 to 0.26 meq/L. The Chengalpattu district has a high concentration of alkali water, according to CSSRI, Karnal classification. Among the coastal blocks, the Thiruporur block contains more alkali water compared to other coastal blocks (46%).