Isotopic Characterisation and Conceptualisation of Linthipe River Basin to underpin Sustainable Groundwater Development and Management
Authors: Chitsundi Banda Limbikani ,   Limbikani Chitsundi Banda
Published: February 2023

The future of Malawi depends on the sustainable development of groundwater resources, and this study provides a detailed stable isotopic-hydrochemical baseline characterisation and conceptualisation of the Linthipe River Basin in the Lake Malawi Basin at the southern extreme of the East Africa Rift System. The Linthipe River Basin is essential for Lilongwe, Malawi's capital city, when it comes to key water supplies. It is also critical to the water supplies for the rural population whose reliance on groundwater resources is predominant. The study flagged groundwater as a potential source of water supply because the key source of water supply in the basin, the Kamuzu Dam along Lilongwe River, is constrained and imperilled by severe catchment degradation among other adverse factors. Sustainable groundwater resource development and management require proper monitoring and assessment, and isotope hydrology is a valuable tool for conducting comprehensive groundwater monitoring and assessment. The study showed the usefulness of isotope hydrology as an effective tool for examining groundwater conditions, its seasonal variations over time, its interactions with surface water, and its replenishment. The study also showed that isotope hydrology is a good way to look at the saltiness of groundwater and other chemical contaminants, considering that high salinity and other chemical contaminants limit and threaten its availability and quality, making it harder to reach the Sustainable Development Goals (SGDs). The study demonstrated how an understanding of the relationship between the stable isotopic composition of groundwater and surface water is crucial for the development of a conceptual model in a hydrologically complex river basin The study developed a stable isotopic-hydrochemical signature conceptual model that has the potential to shed new light on the most pressing issues in Integrated Water Resources Management (IWRM) systems in Malawi. The hydraulic complexity of the groundwater and surface water interactions revealed by the study is critical to IWRM and warrants high-resolution studies, for which the use of isotopic tools plays a critical role in tracking SDG 6 targets. The stable isotopic-hydrochemical baselines developed will improve the forensic study of potential future consequences stemming from environmental drivers like land development, climate change, and water mixing, all of which influence IWRM systems. Hence, the study valuably contributes to Malawi&#8217;s drive of achieving SDG 6 by 2030.Key references:Monjerezi, M.; Vogt, R.D.; Aagaard, P.; Saka, J.D.K. Using &#948;87Sr/&#948;86Sr, &#948;18O and &#948;2H isotope data along with major chemistry composition to assess groundwater salinization in lower Shire River Valley, Appl. Geochem. 2011, 26, 2201&#8211;2214. [CrossRef]
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