STREAM DYNAMICS IN SEMI-ARID REGIONS: AN ASSESSMENT OF SOKOTO-RIMA RIVER, NIGERIA, 1965 – 2005

摘要

The surface water of Nigeria in liquid state is estimated atrnabout 193billion m3 annually. It is argued to be underrnthreat in most parts of the country, especially in the ruralrnenvironment where it is a main life support system. Thernlevel of surface water recession within Sokoto - RimarnRiver Basin in the northwest Sudano-Sahellianrnenvironment of Nigeria is assessed in the study.rnInteractive remote sensing and Geographic InformationrnSystem (GIS) techniques are used to map and analyze thernhydrology of the basin over a 40-year period, 1965 torn2005. The results show alarming reductions in thernfloodplain area, as well as the lengths, orders andrndensities of the river segments and tributaries. Thernfloodplain reduced by about 40% in areal extent and thernlength of stream channels by 90%. More recessions arernidentified around stream headways. The implication forrnwater security and sustainability in the close settled andrndesert encroached rural areas are reviewed in thernconclusion.