Use of geophysics to map saline groundwater areas in rural water supply: a case study of Luangwa district, Lusaka province, Zambia.

Water is finite and essential to sustaining human life. It plays a vital role in many human activities including industrial production, agriculture, energy, sanitation, and transportation, in addition to sustaining ecosystems that provide valuable services to both environment and human. The objective of this study is to map the saline groundwater area in Luangwa District through the use of geophysics survey which measures variation in the electrical resistivity of the ground. The study aims to promote the use of geophysics survey to site location where to sink boreholes with the view of minimising chances of boreholes that produce saline water. This study undertook an analysis of water samples in 16 out of the 25 suspected saline
boreholes in Luangwa district. Out of the 25 boreholes suspected by MWDSEP to have saline water, 16 boreholes were randomly selected for this study. The Ministry of Water Development Sanitation and Environmental Protection database on the boreholes in Luangwa District acted as the sampling frame. Luangwa has 176 boreholes. Results showed that 14 out of the 16 sampled boreholes had saline water. Result further showed different depths at which low resistivity is prominent within the District, further underscoring the need for undertaking geophysics surveys before sinking boreholes as saline water is of no economic values resulting in loss of investment and increasing the burden on women to walk long distances to fetch fresh water. The study recommends that Government and all stakeholders in the water and sanitation sub-sector should undertake geophysics surveys before sinking boreholes, especially in basins prone to salinity.