Earth Science Malaysia (ESMY)

The multi-decadal dynamics of hydrological components in the Tamne Catchment of Ghana play a pivotal rolein the region’s water resource management and agricultural sustainability. This study evaluates these dynamics using the water balance approach, providing a comprehensive understanding of how key hydrological elements, including precipitation, evapotranspiration, runoff, and groundwater recharge, have evolved over several decades. Additionally, the study assesses the inter-annual variability of Potential Evapotranspiration (PET) and Actual Evapotranspiration (ETₐ) within the Tamne Catchment over a defined period of 1992-2022. By analyzing long-term climate data, land use changes, and hydrological records, we constructed a detailed water balance model to quantify the variations in each component. The results indicate a marked shift in the catchment’s hydrological regime, characterized by increasing variability in precipitation and significant alterations in runoff patterns. Utilizing climate data, soil moisture levels, and vegetation indices, remote sensing techniques were applied to estimate PET and ETₐ. The findings revealed significant inter-annual fluctuations influenced by variations in rainfall, temperature, and land cover changes. PET exhibited a general increasing trend, suggesting heightened atmospheric demand due to rising temperatures, while ETₐ demonstrated variability closely tied to annual precipitation and soil moisture availability. The discrepancy between PET and ETₐ highlights the critical role of water availability in limiting actual evapotranspiration, with implications for irrigation practices and water resource planning in the catchment. These results underscore the need for adaptive water management strategies to cope with the variability in evapotranspiration, ensuring sustainable agricultural practices and water use in the region.