An Assessment of Saltwater Intrusion in Coastal Regions of Lagos, Nigeria

Abstract

This paper explains various factors that contribute to saltwater intrusion, including overexploitation of freshwater resources and climate change as well as the different techniques essential for effective saltwater intrusion management. The impact of saltwater intrusion along coastal regions and its impact on the environment, hydrogeology and groundwater contamination. It suggests potential solutions to mitigate the impact of saltwater intrusion, including effective water management and techniques for managing SWI. The application of A.I (assessment index) serves as a guideline to correctly identify wells with SWI ranging from no intrusion, slight intrusion and strong intrusion. The challenges of saltwater intrusion in Lagos and the salinization of wells were investigated using the hydro-chemical parameters. The study identifies four wells ("AA", "CMS", "OBA" and "VIL") as having high electric conductivities, indicating saline water intrusion, while other wells ("EBM", "IKJ, and "IKO") with lower electric conductivities, indicate little or no salt-water intrusion, and "AJ" well shows slight intrusion. The elevation of the wells also played a vital role in the SWI across coastal regions of Lagos. The study recommends continuous monitoring of coastal wells to help sustain and reduce saline intrusion. The findings of the study are important for policymakers, researchers, and practitioners who are interested in addressing the challenges of saltwater intrusion along coastal regions. We assessed the SWI across the eight (8) wells using the Assessment Index to identify wells with SWI. Wells in "CMS" and "VIL" has strong intrusions. A proposed classification system based on specific ion ratios categorizes water quality from good (+) to highly (−) contaminated (refer to Table 4

Detection and Delineation of Lateral and Vertical Extent to Fresh-Saline Water Boundary: Recent Development in Badagary Axis of the Dahomey Basin, Nigeria

“…In Nigeria, this challenge has affected over 1000 km of the coastline of Nigeria extending from Rivers and passes through Bayelsa, Akwa Ibom, Cross Rivers State, Delta, Ondo, Ogun and Lagos States, all of which share their southern border with the Atlantic Ocean and has been reported in several literatures. [Adeyemo et al, 2017[16]; Ohwoghere-Asuma, and Oghenevovwero 2017 [17]; Oloruntola et al, 2019[18]; Yusuf et al, 2021[19]; Atuluchukwu et al, 2022 [20]; A ah et al, 2018 [21]; Edet 2017 [22], Akerele et al, 2023[23], Inim et al, 2020 [24], Obunadike et al, 2024 [25]]. The works of Oteri and Atolagbe (2003) [26] reported that salt water incursion has been occurring especially in coastal areas of the Niger Delta, Nigeria.…”