Entropy-weighted Irrigation Water Quality Index (EIWQI) for the Analysis of Irrigation Water Quality of Kerala, India

Raicy M C^a , Mohammed Maharoof P^a, Olivia Maria ^b, C D Aju ^c, A. L Achu ^d

^a Hydrology and Climatology Research Group, Centre for Water Resources Development and Management (CWRDM), Kunnamangalam, Kozhikode-673 570, Kerala, India
^b School of Earth Sciences, Central University of Karnataka, Kalaburagi, Karnataka, India
^c Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune, India
^d Department of Climate Variability and Aquatic Ecosystems, Kerala University of Fisheries and Ocean Studies (KUFOS), Kochi, Kerala, India

Abstract

Irrigation water quality assessment is critical in ensuring optimal crop productivity, maintaining soil health, protecting ecosystems, and promoting sustainable agricultural practices. This study assesses the irrigation water quality of groundwater in Kerala State, South India using various irrigation water quality indices such as Sodium Absorption Ratio (SAR), Residual Sodium Carbonate (RSC), Percentage of Sodium (Na%), Permeability Index (PI), Magnesium Adsorption Ratio (MAR), and Entropy Weighted Irrigation Water Quality Index (EIWQI). For this purpose, hydrochemical data from 620 observation wells for a period of five years (2018–2022) were procured from the Central Groundwater Board, Government of India, and spatiotemporal variations in various irrigation water quality indices were analysed using GIS. SAR of groundwater samples varied from 0.2 to 11 indicating varying levels of sodium hazard, while RSC ranged from −7 to 2.2 and Na% ranged from 14 to 84. PI values ranged from 20 to 200, and MAR values ranged from 5.3 to 98. The EIWQI zonation indicates that irrigation water quality varies not only based on physiography but also between northern and southern parts of the state. The study concludes that highland areas, particularly central Kerala, are more affected in terms of irrigation groundwater quality compared to midland and lowland regions. Most water samples fall into a category requiring careful management to prevent further deterioration. This study highlights the importance of regular monitoring and comprehensive analysis of irrigation water quality to ensure sustainable agricultural practices and long-term soil fertility in the state.

Keywords

Irrigation Water Quality; Hydrochemistry; Kerala; Entropy-weighted Irrigation Water Quality Index

How to Cite

Raicy M. C., Mohammed Maharoof P., Olivia Maria, Aju C. D., & Achu A. L. (2026). Entropy-weighted Irrigation Water Quality Index (EIWQI) for the Analysis of Irrigation Water Quality of Kerala, India. Journal of Integrated Earth Sciences, 1(1), 72–82. https://doi.org/10.5281/zenodo.18594158