The adaptability of a rural water supply system to extreme rainfall anomalies in central Sudan

Abstract

Rural water supply in semi-arid Sudan is closely dependent upon annual rainfall. Yet in discussions on the consequences of rainfall anomalies in this climatically marginal zone, the impact on rural water availability is rarely examined in detail. A case study is presented from the White Nile Province of the impact of two anomalous wet seasons on the rural water system: 1978, the second wettest year this century in north-central Sudan and 1983, one of the six driest. The major sources of water for the rural community are identified as being Nile water, hand-dug wells and mechanized boreholes. The operation of a rural water supply system is outlined which focuses on physical and managerial components and the mobility of population and livestock. Although 1983 produced barely one large fall of > 25mm compared to five such falls in 1978, in several localities water was as abundant in April 1984 as in April 1979. The physical and managerial components are shown to be unable to cope fully with such rainfall surplus or deficit, but the variable pattern of human migration and transhumance results in the balancing of water supply and demand. It is suggested that rural water planning should capitalize on this human flexibility and also that studies be initiated on the impact of decadal rainfall anomalies on rural water supply.