Assessment of Groundwater Vulnerability and Water Quality of Ngwerere Sub-Catchment Urban Aquifers in Lusaka, Zambia

This study is aimed at evaluation of the protection and management of groundwater quality for aquifers in Ngwerere sub-catchment, as a case study. This was achieved through the development of a vulnerability map using inherent hydrogeological and landuse data, as well as analysis of groundwater quality. The results revealed that most of the aquifers in the study area have very low protective effectiveness of the soil and rock cover, which are supposed to act as barriers against pollution. This was validated from physicochemical and microbial analyses of randomly sampled boreholes in the study area, which indicated high levels of nitrates, Escherichia coli, and total coliforms, which are above the recommended standards for drinking water. Nitrate exceeded the recommended value in one of the eight boreholes, but feacal pollution was observed in nearly all boreholes. The calculated Water Quality Index (WQI) of water in five of the eight borehole samples indicated a WQI of 1.8 to 13.2, which indicates that water quality was excellent. However, two of the eight boreholes had WQI exceeding 50, which indicated that water was not suitable for drinking without treatment. The analysis of Internal Factor Evaluation (IFE) and External Factor Evaluation (EFE) indicated overall weighted scores of 2.61 and 2.57, respectively. These values suggests that the legal, policies and institutional frameworks in Zambia, using the Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis revea...
Source: Physics and Chemistry of the Earth, Parts ABC - Category: Science Source Type: research