期刊名称：Science et changements planétaires / Sécheresse
印刷版ISSN：1147-7806
电子版ISSN：1777-5922
出版年度：2009
卷号：20
期号：1
页码：139-144
DOI：10.1684/sec.2009.0167
出版社：John Libbey Eurotext
摘要：Figures See all figures Authors Gaston Liénou , Gil Mahé , Jean-Emmanuel Paturel , Eric Servat , Georges Emmanuel Ekodeck , Félix Tchoua Département des sciences de la terre Université de Yaoundé-I BP 812 Yaoundé Cameroun, IRD UMR hydrosciences Montpellier BP 64 501 34394 Montpellier cedex 05 France Key words: climatic variability, hydrology, North Cameroon, suspended matter DOI : 10.1684/sec.2009.0167 Page(s) : 139-44 Published in: 2009 Considering the knowledge acquired on the variability of rainfall and stream flow in Africa, it is interesting to study their impact on the quality of the transport of materials, notably that of suspended matter. For most streams, this analysis depends on the availability and the presence of a long and systematic series of data on suspended matter. However, such systematic and continuous measurements require long and tedious field and laboratory measurements. The small Mayo-Tsanaga basin in the Extreme–North Cameroon, with a surface area of 1,535 km 2, have benefited from successive research programmes which have enabled the basin to be followed at different periods providing four series of data on suspended matter (1968-1969, 1973, 1985-1986 et 2002-2004). Analysis of river flow has shown that the discharges have decreased from above an average of 8.7 m 3/s at the end of the year 1960 to 3.6 m 3/s at the beginning of 2000, a drop of more than 50%. At the same time, the average value for the concentration of suspended matter has changed in the reverse order, passing from 1,088 to 2,100 mg/L, with a minimum of 3,027 mg/L observed in 1983. However, the flux of material does not follow the trend of concentration but rather remains constant globally, combining high concentrations with low flows. This finding gives information on the actual context of desertification, on the degradation of the environment and the impacts on the transport of suspended matter. The increase in concentration indicates the availability of large volumes of suspended matter in the basin. However, the quantity of suspended matter transported remains almost the same when compared with that before desertification due to the low flow rates.
关键词：climatic variability; hydrology; North Cameroon; suspended matter
