Predictive Integrated Groundwater Quality Index in Central Terai of Nepal for Drinking and Agriculture Use: An Advanced Geospatial Analysis with Indices (EWQI, IWQI) and ANN Modelling

Abstract

The availability of clean and safe drinking water sources has come under scrutiny due to the degradation of water quality caused by a variety of anthropogenic and natural factors. In Nepal's Central Terai region, water quality is crucial to sustaining the environment and public health, 25 samples of shallow groundwater a thorough analysis were carried out to evaluate the quality of groundwater in Central Terai, Nepal, where it is crucial for fulfilling these basic requirements. To assist the integrated groundwater quality index of the study area the groundwater quality index such as Sodium Adsorption Ratio (SAR), Magnesium Absorption Ratio (MAR), Sodium Percentage (Na%), Permeability index (PI), Kelly’s ratio (KR), Irrigation water quality index (IWQI) and Entropy Weighted Water Quality Index (EWQI) was determine which sows the value of water quality is moderate (76%) to highly (16%) vulnerable of the study area. The discovery that a number of chemical characteristics, including calcium, magnesium, iron, phosphate, sodium, potassium, and salt, exceeded WHO criteria raises concerns since it may be the result of uncontrolled fertiliser usage and geological interactions. One encouraging finding was that the EWQI determined that most groundwater samples were fit for human consumption. A small percentage of the samples, nonetheless, did not meet the suggested standards, underscoring the importance of exercising caution while safeguarding this essential resource. The IWQI showed that several of the samples ware suitable when it came to irrigation. The use of Artificial Neural Network (ANN) for the prediction of the integrated groundwater quality index vulnerability is significant with the validation value R=0.998 and the regression coefficient (R2) is 0.996. To stop the quality of the groundwater from further declining and to safeguard public health, these zones need specific solutions. For, the purpose of developing efficient plans for managing water resources and mitigating causes of pollution, this research is a great resource for those in charge of making decisions in the area.