Impact of climate change on water supply in the city of Niamey (Niger): Case of Niamey III and V communal districts

Código

I-EBHE0218

Tema

WG 1.11: Water Quality Under Global Changes

Resumo

Like many African cities, the capital of Niger (Niamey), located in the extreme west of the country, faces enormous challenges in terms of water supply, particularly in the Niamey III and IV districts. The exponential growth of its population and uncontrolled urbanization are the major factors that unbalance the supply and demand for drinking water. In addition, climate change is causing severe low water levels or flooding of the city's main water supply (Niger River). Indeed, the city's main water supply system is unable to meet water needs. This failure is characterized by an outdated, poorly sized network and a water production of 130,000 m3/day for an average need of 180,000 m3/day. Consequently, the population resorts to alternative systems (wells, boreholes, Niger River) of dubious quality. The objective of this study is to evaluate the efficiency of the water supply systems of the Niamey III and IV communal districts. The methodology adopted during this study is based on an inventory of water supply systems, household surveys and sampling for water quality assessment. The results of the study highlight four main alternative systems (Niger River, SEEN water supply system, borehole, well) from which sub-systems have developed (autonomous water station, PMH, mini-water supply network). The mapping of water supply systems reveals that areas with poor coverage of the Société d'Exploitation des Eaux du Niger (SEEN) distribution network (peripheral areas, precarious housing areas, areas where the city is expanding) constitute areas where these alternative systems are used extensively. During hot periods (March, April, May, June), the population's water needs increase by 37.92%. Chemical analyses reveal relatively high concentrations of nitrate ions in 50% of the wells and 37.5% of the boreholes, but remain below the standards recommended by the WHO. The dominant chemical facies of the wells and boreholes is chloride and sulphate-calcium-magnesium. Bacteriological analyses show the presence of bacteria such as Escherichia Coli, faecal Streptococci, Salmonella and total Coliforms in 100% of the well water and 88% of the borehole water.