Stream Dynamics in Semi-Arid Regions: An Assessment of Sokoto-Rima River, Nigeria, 1965 - 2005

The surface water of Nigeria is argued to be under threat in most parts of the country, especially in the rural environment where it is a main life support system. The level of surface water recession within the Sokoto-Rima River Basin in the northwest Sudano-Sahelian environment of Nigeria is assessed in the study. Interactive remote sensing and Geographic Information System (GIS) techniques are used to map and analyze the hydrology of the basin over a 40-year period (1965 to 2005). The results show alarming reductions in the floodplain area, as well as the lengths, orders, and densities of the river segments and tributaries. The floodplain was reduced by about 40% in areal extent and the length of stream channels by 90%. More recessions are identified around stream headways. The implication for water security and sustainability in the close settled and desert encroached rural areas are reviewed in the conclusion.