Bulletin of the Geological Society of Malaysia, Volume 79, May 2025, pp. 45 – 56
Vulnerability assessment of coastal groundwater wells in Terengganu using TRUST Index
Ummi Qiyaadah Naajihah Ostadi1, Siti Nurnazurah Shaharudin1, Rasyduddin Gani1, Effi Helmy Ariffin2, Muhd Nur Ismail Abdul Rahman1, Nor Bakhiah Baharim1,2,*
1 Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
2 Institute Of Oceanography & Environment (INOS), Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
*Corresponding author email address: n.bakhiah@umt.edu.my
Abstract: Coastal aquifers in Terengganu, Malaysia, face increasing challenges in groundwater quality and availability, necessitating a comprehensive assessment of their vulnerability. This study investigated groundwater vulnerability and susceptibility in the coastal region of Terengganu, Malaysia, where coastal aquifers face threats to groundwater quality and availability. A comprehensive groundwater vulnerability assessment was conducted using the TRUST Index. This index-based approach considers the lithology, river proximity, well usage, distance to the seashore, and well type. Field investigations were undertaken to obtain real-time measurements of well behavior. This included conducting constant-rate pumping tests on four private wells to gauge hydraulic conductivity. Consequently, flow rates were meticulously monitored throughout these tests, and water level measurements and physicochemical assessments were conducted over a 120-minute duration. Following this, the data was analyzed utilizing AQTESOLV software to determine the hydraulic conductivity, transmissivity, and storativity of the aquifer. The data from MW4, MW16, and MW20 collectively indicate favorable hydraulic characteristics, suggesting water movement within the aquifer, ranging from 4.02 m3/day to 11.39 m3/day. In contrast, MW7 displays an unexpectedly high discharge rate of 19.77 m3/day, suggesting a highly permeable and efficient water-transmitting unconfined aquifer with limited water storage capacity. The vulnerability assessment classified the wells as Low, Moderate, and High vulnerability. Wells MW1, MW6, MW7, and MW20 were categorized as low vulnerability, indicating relatively secure groundwater quality and availability. Wells MW2, MW3, MW8, MW9, MW12, MW13, and MW14 were classified as moderately vulnerable, suggesting a moderate level of potential risk. Meanwhile, wells MW4, MW5, MW10, MW11, MW15, MW16, MW17, MW18, and MW19 were labeled as highly vulnerable, signifying a higher susceptibility to threats. The correlation matrix revealed insightful connections between hydrological and water quality parameters. The distance from the seashore is inversely correlated with salinity and specific conductance, signifying a reduced seawater water impact farther inland. Note that wells near rivers exhibit higher salinity, likely due to potential saltwater intrusion, emphasizing the importance of understanding these relationships in coastal aquifer systems. This study comprehensively assesses coastal groundwater vulnerability, behavior, and water quality. Its unique contributions lie in the meticulous hydraulic characterization and identification of unconventional well behavior. These findings emphasize the importance of considering temporal variations, local influences, and tailored management strategies for sustainable coastal groundwater resource utilization.
Keywords: Coastal aquifers, groundwater vulnerability, TRUST Index, hydraulic characteristics, groundwater quality
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Manuscript received 10 May 2023;
Received in revised form 13 September 2023;
Accepted 13 June 2024
Available online 30 May 2025
https://doi.org/10.7186/bgsm79202506
0126-6187; 2637-109X / Published by the Geological Society of Malaysia.
© 2025 by the Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC-BY) License 4.0.
