Abstract

Mali, like other Sahelian countries, has experienced a drought in the last 15 years that has caused the exodus of the rural population towards Bamako. As the population of this city doubled a great many new outskirt neighbourhoods sprang up. In each of them, cesspools in the vicinity of recently built wells caused pollution of the water sheet and the spread of diseases. This project will concentrate on problems of urban hydrogeology in West Africa and will study the problem of groundwater management and contamination in different geological and climatic condition and in various socioeconomic environments. Specifically, it proposes to examine, through geological studies, the exposure of the Bamako aquiferous underwater sheet to human and animal pollution; determine the dimension of the pollution; and estimate its evolution in order to propose inexpensive corrective measures for use in wells and waste disposal.

Post-Project Summary

The researchers carried out studies of the geological and hydro-geological structure of the water table on the basis of available data. They selected 180 wells which they used to study variations in piezometric heights; they tested the permeability at 14 of these sites and took samples regularly from 30 of them, to determine the water contamination level as a result of human and animal waste. Finally, the researchers made a model of the hydrodynamic flow from the water table at low water and high water periods. The study showed that the contamination of subterranean waters at Bamako was generalized and that it was both chemical and bacteriological in nature. The chemical contaminants consisted of high concentrations of dissolved salts, especially chlorides and nitrates. The level of bacteriological pollution was very high, making the waters unfit for human consumption. They made recommendations with respect to the treatment of well water and water supplies in outlying areas; and the disposal of waste water, including water from latrines and cesspools.

Recipient Institution(s)