Estimation of Evapotranspiration and its relationship to Land use and Water resources in Luapula Catchment, Zambia

This study delves into the estimation of evapotranspiration (ET) and its intricate relationship with land use and water resources in Zambia's Luapula catchment. Utilizing data from DIVA-GIS and AppEEARS, based on MOD16-A2GF data, the analysis reveals a consistent increase in average evapotranspiration from 2000 to 2021, albeit persistently lower than potential evapotranspiration, indicative of water stress. This observation aligns with global findings, underscoring the prevalence of water limitations and stress in various ecosystems. Employing a vector autoregression (VAR) model incorporating MOD16-A2GF and Global Forest Watch data, the study scrutinizes the impacts of tree cover loss due to deforestation and gross emissions on water availability (precipitation) in Luapula catchment. The analysis demonstrates statistically significant results at a 5% level of significance, revealing that tree cover loss initially exhibits a positive impact on average precipitation at lag 1 (Coef= .026, P-value = 0.000), followed by a significant negative effect at lag 2 (Coef= -.012). Similarly, non-CO2 gross emissions display negative impacts on average precipitation (Coef= -.005, P=0.000), while CO2 equivalent emissions, particularly CO2 and Mg, show positive effects (Coef= .0002, P=0.000). Furthermore, the study assessed the impact of land use on evapotranspiration and results showed that tree cover loss due to deforestation initially stimulates average evapotranspiration at lag 1 (Coef= .009, P-value = 0.000), but later leads to negative impacts at lag 2 (Coef= -0.004, P=0.000). Similarly, non-CO2 gross emissions negatively influence average evapotranspiration at both lags, while CO2 equivalent emissions exhibit mixed effects, initially positive at lag 1 and turning negative at lag 2 (P-value = 0.000). These findings underscore the urgent need for policy interventions to mitigate the adverse effects of deforestation and emissions on water resources. Strengthening forest protection laws, promoting sustainable agriculture, and fostering afforestation and reforestation efforts are essential to ensure water availability and ecosystem services. Transitioning to renewable energy sources and reducing greenhouse gas emissions across sectors are vital steps in addressing climate change impacts and promoting sustainable land use practices.