Groundwater Quality Assessment Using Hydrochemical and GIS-BasedApproaches in Heliwaa District, Mogadishu, Somalia

Abstract

Groundwater is the primary source of domestic water supply in Somalia, particularly in urban areas such as Mogadishu. However, little is known about its quality and spatial variation. This study investigated groundwater quality in Heliwaa District, Mogadishu, Somalia, using hydrochemical testing and GIS mapping. Groundwater samples from nine borehole wells were analyzed for pH, total dissolved solids (TDS), and electrical conductivity (EC), and the results were compared with World Health Organization (WHO) drinking-water guidelines. Spatial mapping was used to identify patterns for each parameter. pH averaged 8.29 (SD 0.57; range 7.54–8.90), exceeding WHO's upper limit of 8.5 at four wells. TDS averaged 1019.7 mg/L (SD 439.1; range 601–1789 mg/L), exceeding the 1000 mg/L guideline at three wells, while EC averaged 1555.9 µS/cm (SD 453.1; range 950–2400 µS/cm), exceeding the 1500 µS/cm threshold at five wells. Spatial mapping revealed clear hotspots of poor groundwater quality in boreholes located in Mama Muxibo, Buulo Maxaay, SOS, and Tawakal in Heliwaa District, likely associated with mineral dissolution, groundwater over-abstraction, and inadequate waste management rather than district-wide contamination. While the investigated groundwater in Heliwaa District remains largely suitable for domestic use, the assessment is based on only nine borehole wells, which represents a relatively limited spatial coverage of the district. Therefore, the findings should be interpreted with caution and further investigation involving a larger number of boreholes and more extensive spatial and temporal sampling is recommended to provide a more comprehensive assessment of groundwater quality.