{"title":"Hydrochemical investigation and prediction of groundwater quality in a tropical semi-arid region of southern India using machine learning","authors":"","doi":"10.1016/j.gsd.2024.101343","DOIUrl":null,"url":null,"abstract":"<div><p>Monitoring and predicting groundwater quality is essential for managing water resources, protecting public health, and mitigating environmental impacts. This study presents a comprehensive hydrogeochemical investigation aimed at understanding the general hydrochemistry, identifying the extent of saltwater intrusion and prediction of groundwater quality in the semi-arid coastal aquifers of Tuticorin, Tamil Nadu, India. Groundwater samples were collected during both pre- and post-monsoon seasons to capture seasonal variations and groundwater quality was evaluated using the entropy weighted water quality index (EWQI) and predicted through the Random Forest (RF) machine learning technique. The findings revealed that total dissolved solids (TDS) exceeded WHO limits in 85% of samples during the pre-monsoon season and 61% during the post-monsoon season, indicating significant groundwater quality issues. Hydrogeochemical facies analysis identified Na-Cl as the dominant water type across all seasons, with a higher prevalence in coastal alluvium regions, suggesting a strong lithological influence and ongoing saline water intrusion. The EWQI coupled RF method provided high predictive accuracy, with R<sup>2</sup> values of 0.955 and 0.975 and RMSE values of 6.1 and 5.5 for the pre- and post-monsoon periods, respectively. In addition, results obtained from the RF-EWQI model indicated that ∼11.24% of the study area falls within the extremely poor water quality category. This zone is primarily associated with fluvial, fluvial-marine, and aeolian formations. In terms of spatial distribution, the RF-EWQI values for both seasons exhibit a parallel trend with the seawater mixing index (SMI), suggesting that the poor groundwater quality is primarily linked to the coastal alluvium aquifer. This underscores the significant impact of saline water intrusion on groundwater quality, particularly in the coastal alluvium aquifer. This integrated approach presented here offers valuable insights for improving groundwater quality assessment and management.</p></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":4.9000,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Groundwater for Sustainable Development","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2352801X24002662","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, ENVIRONMENTAL","Score":null,"Total":0}
引用次数: 0
Abstract
Monitoring and predicting groundwater quality is essential for managing water resources, protecting public health, and mitigating environmental impacts. This study presents a comprehensive hydrogeochemical investigation aimed at understanding the general hydrochemistry, identifying the extent of saltwater intrusion and prediction of groundwater quality in the semi-arid coastal aquifers of Tuticorin, Tamil Nadu, India. Groundwater samples were collected during both pre- and post-monsoon seasons to capture seasonal variations and groundwater quality was evaluated using the entropy weighted water quality index (EWQI) and predicted through the Random Forest (RF) machine learning technique. The findings revealed that total dissolved solids (TDS) exceeded WHO limits in 85% of samples during the pre-monsoon season and 61% during the post-monsoon season, indicating significant groundwater quality issues. Hydrogeochemical facies analysis identified Na-Cl as the dominant water type across all seasons, with a higher prevalence in coastal alluvium regions, suggesting a strong lithological influence and ongoing saline water intrusion. The EWQI coupled RF method provided high predictive accuracy, with R2 values of 0.955 and 0.975 and RMSE values of 6.1 and 5.5 for the pre- and post-monsoon periods, respectively. In addition, results obtained from the RF-EWQI model indicated that ∼11.24% of the study area falls within the extremely poor water quality category. This zone is primarily associated with fluvial, fluvial-marine, and aeolian formations. In terms of spatial distribution, the RF-EWQI values for both seasons exhibit a parallel trend with the seawater mixing index (SMI), suggesting that the poor groundwater quality is primarily linked to the coastal alluvium aquifer. This underscores the significant impact of saline water intrusion on groundwater quality, particularly in the coastal alluvium aquifer. This integrated approach presented here offers valuable insights for improving groundwater quality assessment and management.
期刊介绍:
Groundwater for Sustainable Development is directed to different stakeholders and professionals, including government and non-governmental organizations, international funding agencies, universities, public water institutions, public health and other public/private sector professionals, and other relevant institutions. It is aimed at professionals, academics and students in the fields of disciplines such as: groundwater and its connection to surface hydrology and environment, soil sciences, engineering, ecology, microbiology, atmospheric sciences, analytical chemistry, hydro-engineering, water technology, environmental ethics, economics, public health, policy, as well as social sciences, legal disciplines, or any other area connected with water issues. The objectives of this journal are to facilitate: • The improvement of effective and sustainable management of water resources across the globe. • The improvement of human access to groundwater resources in adequate quantity and good quality. • The meeting of the increasing demand for drinking and irrigation water needed for food security to contribute to a social and economically sound human development. • The creation of a global inter- and multidisciplinary platform and forum to improve our understanding of groundwater resources and to advocate their effective and sustainable management and protection against contamination. • Interdisciplinary information exchange and to stimulate scientific research in the fields of groundwater related sciences and social and health sciences required to achieve the United Nations Millennium Development Goals for sustainable development.