Comparative Research Progress on Hydrogeological Potential of Major Geological Complexes : A Case Study of Togo and ChinaComparative Research Progress on Hydrogeological Potential of Major Geological Complexes : A Case Study of Togo and China

Abstract

Groundwater is one of the most important sources of freshwater globally, but its availability and sustainability vary greatly depending on geology and climate. This study provides a comparative analysis of groundwater potential in Togo and China, with particular attention to lithology, aquifer characteristics, and management challenges. In Togo, aquifers are largely developed within fractured Precambrian crystalline rocks, where water storage is confined to weathered layers and fracture systems. These aquifers generally display low transmissivity (10⁻⁴–10⁻² m²/s), storage coefficients below 0.01, and average specific yields of about 2%. Recharge is mainly linked to seasonal rainfall, typically ranging from 50 to 150 mm per year, which makes these systems highly sensitive to climate variability and limits their ability to support long-term water supply. Moreover, China has extensive sedimentary basins, alluvial plains, and karst aquifers that are considerably more productive. Transmissivity values often exceed 10⁻² m²/s, specific yields commonly reach 10–15%, and recharge averages around 120 mm per year, with values above 500 mm per year in humid karst regions. While these aquifers provide large storage and high yields, they are under intense pressure from long-term overuse, particularly in the North China Plain where groundwater levels are dropping by 0.5–1.5 m annually. Water quality is also a major concern, with widespread nitrate, salinity, and heavy metal contamination. The comparison shows two distinct challenges: Togo faces localized limitations and severe data gaps, while China struggles with systemic depletion despite having advanced monitoring and modelling systems. Nonetheless, both regions offer lessons for one another. Techniques such as numerical modelling, isotope hydrology, and machine learning used in China could enhance groundwater assessment in Togo, while Togo’s low-cost, field-based methods may provide useful approaches for rural or data-inadequate areas in China. Therefore, the study demonstrates that effective groundwater management depends not only on geological conditions but also on institutional capacity and the adoption of appropriate technologies to balance recharge, abstraction, and quality protection. These insights support the development of cross-regional strategies aimed at improving groundwater resilience in the face of growing climate and socio-economic pressures.