Assessment of Groundwater Quality under Changing Climate in Ngorongoro Conservation Area, Tanzania

Abstract

Understanding the hydrochemical composition of water resources in the Ngorongoro Conservation Area (NCA, Dodoma, Tanzania) related to climate variability is essential for sustainable development. Thus, the current study used the HYDRUS-1D model to assess the groundwater quality change due to the leaching of hydrochemicals from surface water under the climate variability of the NCA. This study observed that the area’s surface water had varying hydrochemical contaminants, whereas the groundwater is currently most suitable for drinking and domestic purposes. However, it is predicted that two anions (Cl−1 and PO4−3) and two cations (Na+ and K+) are expected to exceed the permissible limits from 2036 to 2050, considering the anticipated climatic conditions. Changes in groundwater quality for cations and anions are significantly correlated to evapotranspiration and temperature, with Pearson’s coefficient of determinations r between 0.35 and 0.66. The findings of this study are necessary to benchmark better water resources management planning. Understanding the hydrochemical composition of water resources in the Ngorongoro Conservation Area (NCA, Dodoma, Tanzania) related to climate variability is essential for sustainable development. Thus, the current study used the HYDRUS-1D model to assess the groundwater quality change due to the leaching of hydrochemicals from surface water under the climate variability of the NCA. The hydrochemical assessment results for the composition of major cations and anions to the subsurface indicate the significant influence of future changes in the climate of the study area. The results indicate, two cations (Na+ and K+) and two anions (Cl−1 and PO4−) would exceed the World Health Organization (WHO) and Tanzania Bureau of Standards (TBS) permissible limits between 2036 and 2050. Statistically, changes in groundwater quality for both cations and anions are significantly correlated with evapotranspiration and temperature. Therefore, apart from other factors such as volcanic activities and accelerated human interventions that could affect water quality, climate change can be considered the main driver for hydrochemical movements to the groundwater. Hence, a detailed climate change study should be conducted to precisely inform the impacts of future changes in climate parameters on water quality deterioration. The findings from such studies can be used for sustainable management of the water resources in this area.