Groundwater quality assessment for drinking and irrigation purposes in the Ayad river basin, Udaipur (India)

Globally, about 5.25 billion people depend on groundwater for their water needs. However, groundwater quality significantly impacts human health and agriculture, influenced by factors such as land use, waste seepage, soil properties, and geological settings. In Rajasthan, the primary groundwater quality issues involve fluoride, nitrate, chloride, and calcium. This study addresses the gap in the understanding of the spatial and temporal variations of these contaminants and how the variations are linked to geology and land use. The basis for the analysis is data spanning 2000 to 2021from the Ground Water Department (GWD), the Central Ground Water Board (CGWB), and citizen science data from 2022-2023, focusing on the Ayad River Basin. The research aims to evaluate groundwater quality for drinking and irrigation by assessing physico-chemical parameters and using the Weighted Arithmetic Water Quality Index (WAWQI) method to calculate the Groundwater Quality Index (GWQI) from 2000 to 2023. The findings suggest a decreasing GWQI trend from west to east in the basin, with good groundwater quality (GWQI below 50) in the southern regions near the cities Umarda, Ramgiri, Undri, and Hariyab. The highest index values were near Bhoyana, Khemli, and Sisarma. The results of the salinity hazard test showed that salinity is a major issue in the eastern part of the basin. Though the groundwater is notably hard, a comprehensive analysis of various parameters nevertheless suggested its suitability for irrigation purposes. These results provide new insights in the quality of the groundwater resources in the Ayad River basin and valuable insights for policymakers and for decision-makers to develop strategies to preserve the groundwater quality. • A groundwater quality analysis presented for the semi-arid Ayad River Basin. • The available data is scarce in time and space as is common for semi-arid regions. • A Groundwater Quality Index (GWQI) is developed. • GWQI used to evaluate the groundwater quality for drinking water and irrigation. • GWQI exhibited a west-to-east decreasing trend in groundwater quality.