GROUNDWATER QUALITY EVALUATION IN TAMIL NADU USING CRITIC METHOD IN MADM

European Summit on Interdisciplinary Research and Development - An International Research Conference Published By Crystal Pen Publication, Perambalur, Tamil Nadu, India - www.crystalpen.in ESIRD - 2025 Proceedings, Date: November 30, 2025, ISBN Number: 978-93-49435-80-3 74 GROUNDWATER QUALITY EVALUATION IN TAMIL NADU USING CRITIC METHOD IN MADM G. Sugapriya* & S. Indrakala** * Ph.D Research Scholar, Department of Mathematics, K.N. Government Arts College (Affiliated to Bharathidasan University), Thanjavur, Tamil Nadu, India ** Associate Professor & Research Advisor, Department of Mathematics, K.N. Government Arts College (Affiliated to Bharathidasan University), Thanjavur, Tamil Nadu, India Cite This Article: G. Sugapriya, S. Indrakala. (November 2025). Groundwater Quality Evaluation in Tamil Nadu Using CRITIC Method in MADM. In Proceedings of the European Summit on Interdisciplinary Research and Development (pp. 74-76). Perambalur, Tamil Nadu, India: Crystal Pen Publication. ISBN: 978-93-49435-80-3 Publisher Website: www.crystalpen.in Copy Right: © 2025 Crystal Pen Publication (CPP). All rights reserved. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. DOI: Abstract: Groundwater is a vital resource for domestic, agricultural, and industrial use in Tamil Nadu, where surface water availability is limited and rainfall is highly variable. Assessing groundwater quality is essential for sustainable management and safe utilization. This study evaluates the groundwater quality of selected districts in Tamil Nadu using the CRITIC (Criteria Importance through Intercriteria Correlation) method within the MultiAttribute Decision-Making (MADM) framework. Key physicochemical parameters such as pH, chloride, nitrate, and fluoride were analyzed. The CRITIC method was applied to objectively determine the weights of these parameters based on their contrast intensity and inter-criteria correlation, eliminating subjective bias. Groundwater quality indices were then computed to rank sampling locations according to their suitability for drinking and irrigation purposes. The results reveal spatial variations in groundwater quality, highlighting regions with higher contamination risks due to anthropogenic activities and geogenic factors. The integrated CRITIC-MADM approach proves to be an effective and robust decision-support tool for groundwater quality assessment and regional water resource planning in Tamil Nadu. Key Words: MADM, CRITIC, WQI, Physicochemical Parameters. Introduction: Groundwater is one of the most essential natural resources, playing a vital role in sustaining human life, agriculture, and industrial development. In Tamil Nadu, groundwater serves as the primary source of drinking water and irrigation, especially in rural and semi-urban areas where surface water availability is limited. Due to increasing population, rapid urbanization, and intensive agricultural activities, the demand for groundwater has grown significantly, leading to overexploitation and deterioration of water quality in many regions. Therefore, a systematic assessment of groundwater quality is crucial for ensuring its sustainable utilization. The evaluation of groundwater quality involves the analysis of various physicochemical parameters such as pH, chlorides, nitrates, and fluoride. However, these parameters vary spatially and temporally, making it difficult to interpret water quality directly. Multi-Attribute Decision-Making (MADM) techniques provide an effective framework for analyzing complex environmental data by integrating multiple indicators into a single decision model. Among various MADM weighting methods, the CRITIC (Criteria Importance through Intercriteria Correlation) method is an objective approach that determines the relative importance of each parameter based on its contrast intensity and correlation with other parameters. Unlike subjective weighting techniques, the CRITIC method minimizes human bias and improves the reliability of groundwater quality assessment. By applying the CRITIC method within the MADM framework, this study aims to evaluate and rank groundwater quality across selected districts of Tamil Nadu. The results will help identify regions with poor water quality and support policymakers in implementing effective groundwater management strategies. Critic Method: The CRITIC (Criteria Importance through Intercriteria Correlation) method, developed by Diakoulaki et al. (1995), is one of the most effective objective weighting techniques. It determines the importance of each criterion by considering two key aspects: the contrast intensity (variability of each criterion) and the conflict (correlation) among criteria. A criterion with higher variability and lower correlation with others is assigned a greater weight, indicating its higher contribution to decision differentiation. In the context of environmental and water resource studies, the CRITIC method helps eliminate subjective bias and ensures a more balanced assessment of multiple water quality parameters. When integrated within the MADM framework, the CRITIC method enhances the accuracy and robustness of decision-making by objectively prioritizing the influencing factors. European Summit on Interdisciplinary Research and Development - An International Research Conference Published By Crystal Pen Publication, Perambalur, Tamil Nadu, India - www.crystalpen.in ESIRD - 2025 Proceedings, Date: November 30, 2025, ISBN Number: 978-93-49435-80-3 75 Step 1: The decision matrix X is formed. It shows the performance of different alternatives with respect to various criteria. X = [𝑟𝑖𝑗]𝑚×𝑛 = 𝑟11 𝑟12 ⋯ 𝑟1𝑛 𝑟21 𝑟22 ⋯𝑟2𝑛 ⋮ 𝑟𝑚1⋮ 𝑟𝑚2⋯ ⋮ 𝑟𝑚𝑛 ; 𝑖= 1,2, …,𝑚 𝑎𝑛𝑑 𝑗= 1,2, …,𝑛 Where 𝑟𝑖𝑗 presents the performance value of ith alternatives on jth criterion. Step 2: Decision matrix is normalized using the following equation. 𝑋𝑖𝑗∗= 𝑟𝑖𝑗−𝑚𝑖𝑛 𝑟𝑖𝑗 max 𝑟𝑖𝑗 −𝑚𝑖𝑛 𝑟𝑖𝑗 𝑖= 1,2, …,𝑚 𝑎𝑛𝑑 𝑗= 1,2, …,𝑛 𝑋𝑖𝑗∗is the normalized performance value of ith alternative on jth criterion. Step 3: Correlation coefficient among attributes is determined. 𝜌𝑗𝑘= 𝑥𝑖𝑗−𝑥 𝑗 𝑚 𝑖=1 𝑥𝑗𝑘−𝑥 𝑘 / 𝑥𝑖𝑗−𝑥 𝑗 2 𝑚 𝑖=1 𝑥𝑗𝑘−𝑥 𝑘 2 𝑚 𝑖=1 𝑥 𝑗 and 𝑥 𝑘display the mean of jth and kth attributes.𝜌𝑗𝑘 is the correlation coefficient between jth and kth attributes. 𝑥 𝑗=1 𝑛 𝑥𝑖𝑗 𝑛𝑗=1 ; 𝑖= 1,2, …,𝑚 Step 4: Standard deviation of each attribute is estimated. 𝜎𝑗= 1 𝑛−1 𝑥𝑖𝑗−𝑥 𝑗 2 𝑛𝑗=1 ; 𝑖= 1,2, …,𝑚 Then, the index (C) is calculated 𝐶𝑗=𝜎𝑗 1−𝜌𝑗𝑘 𝑛𝑘=1 ; 𝑗= 1,2, …,𝑛 Step 5: Weight of attributes are determined. 𝑤𝑗=𝐶𝑗 𝐶𝑗 𝑛𝑗=1 Example: To illustrate the application of the CRITIC method within the MADM framework, a study was conducted on groundwater samples collected from different districts of Tamil Nadu, such as Coimbatore, Madurai, Trichy, and Thanjavur. Groundwater quality was evaluated based on key physicochemical parameters including pH, Chloride (Cl⁻), Nitrate (NO₃⁻), and Fluoride (F⁻). Solution: Step 1: Decision matrix ph Cl NO₃ F Coimbatore 8.05 127.63 39.63 0.49 Madurai 7.75 340.33 31 0.69 Trichy 8.32 402.2 9.82 0.5 Thanjavur 7.99 225.78 5.62 0.4 Step 2: Normalized values of decision matrix ph Cl NO₃ F Coimbatore 0.526316 0 1 0.310345 Madurai 0 0.774666 0.746251 1 Trichy 1 1 0.123493 0.344828 Thanjavur 0.421053 0.357468 0 0 Step 3: Correlation Coefficient ph Cl NO₃ F Coimbatore 1 0.205608 -0.43812 -0.57444 Madurai 0.2056085 1 -0.45918 0.423608 Trichy -0.438119 -0.45918 1 0.534928 Thanjavur -0.574444 0.423608 0.534928 1 European Summit on Interdisciplinary Research and Development - An International Research Conference Published By Crystal Pen Publication, Perambalur, Tamil Nadu, India - www.crystalpen.in ESIRD - 2025 Proceedings, Date: November 30, 2025, ISBN Number: 978-93-49435-80-3 76 Step 4: Standard Deviation ph Cl NO₃ F Coimbatore 0 0.352705 0.693762 0.661967 Madurai 0.326324 0 0.703919 0.242341 Trichy 0.590758 0.647865 0 0.195537 Thanjavur 0.646758 0.255914 0.224355 0 Cj 1.563839 1.256485 1.622036 1.099844 Step 5: Weights W1 4.978365 W2 4.781826 W3 5.015578 W4 4.681662 The Final Ranking of Attributes: The weights of the attributes are arranged in descending order 𝑊 3> 𝑊 1> 𝑊 2> 𝑊 4 Therefore, it is concluded that the third attributes C3 (Trichy)is highly preferred than the other attributes and the final ranking of attributes is as follows: 𝐶 3> 𝐶 1> 𝐶 2> 𝐶 4 Conclusion: The results indicated that attributes 𝐶 3had the highest influence on groundwater quality, reflecting both natural and anthropogenic impacts. The integrated CRITIC - MADM approach successfully identified regions with poor water quality and potential contamination risks, thereby highlighting the need for effective monitoring and management practices. References: 1. Alinezhad, Alireza, and Javad Khalili. New Methods and Applications in Multiple Attribute Decision Making (MADM). Springer, 2020. 2. Hugo Loaiciga, Omid Bozorg-Haddad, and Babak Zolghadr - Asli. A Handbook on Multi - Attribute Decision - Making Methods. March 2021, Wiley. 3. Shoba, et al. “Applications of Multi Attribute Decision Making Problem.” E3S Web of Conferences 491. Accessed 15 June 2025. 4. Adalı, Esra Aytaç, and Ayşegül Tuş Işık. “Critic and Maut Methods for the Contract Manufacturer Selection Problem.” European Journal of Multidisciplinary Studies, no. 1, EUSER, May 2017, p. 93. 5. Krishnan, Anath Rau, et al. “A Modified CRITIC Method to Estimate the Objective Weights of Decision Criteria.” Symmetry, no. 6, MDPI AG, May 2021, p. 973.