Degradation of Loumou Track through Ruts In Brazzaville Western Periphery: Forms Characterization, Traffic And Rainfall Aggressiveness Analysis (Republic Of Congo)

Idriss M'bouka Milandou, Leonard Sitou
2017 International Journal of Basic Sciences & Applied Research   unpublished
The Sadelmie-Loumou-Nguidi trail, known as the Loumou Road, located in Pool department, in the south of the Congo and nearly 35 km long, has been affected by the rutting phenomenon for more than 10 years mostly in Case Barnier-Ntoba ilele section. This anthropogenic erosion phenomenon, which impedes the mobility of people and their goods, access to basic social services, the disposal of a few agricultural products and trade with Brazzaville, is due, on the one hand, to traffic aggressiveness
more » ... c aggressiveness and rains aggressiveness. Between 2014 and 2016, the Daily Average Traffic (DAT) on this runway was 88 vehicles per day (V /D). This DAT > 50V/D expresses a strong traffic aggressiveness on this track. The traffic and vehicles weight about all categories leave marked traces of wheels on the wet road during the rainy period from September to May. The concentrated runoffs exploit these traces which rapidly evolve into ruts and later into gullies. These runoffs are due to the 1 400 mm mean yearly rainfall volume (MYRV) recorded to Maya-Maya Climate Station in 10 years (2005-2014). The rainfall aggressive indices evaluated from this MYRV yield 67 for Fournier index (FI) and 7,757 MJ.mm / ha.h.an for rainfall erosivity index (R). These indices express a strong aggressiveness of the rains in the area. But these parameters influence largely the running surface sensitivity of this track, whose reworked material is dominated by Batékés sands, very erodible about rainfall, with an erodibility index (K) between 0.35 and 0.45 t.ha.h / ha.MJ.mm. The aim of this study is to show that this minor erosion phenomenon is part of the main models of anthropogenic erosion that degrade the Loumou road and seriously affects the socioeconomic development of villages along this track. To this end, it characterizes the ruts and analyzes the signs of traffic and rainfull aggressiveness, which are genesis and evolution factors of the ruts on this track.
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