Dynamique du transport solide dans le bassin versant de l'Oued Isser au droit du barrage de Koudiat Acerdoune (Nord Algérie)

摘要

Erosion and solid transport are serious problems on a global scale but they are much more worrying in some parts of the world, as is the case in the Maghreb and more particularly in Algeria. Precipitation and flow phenomena are complex and are directly involved in the processes of water erosion and solid transport. The present study aims to control, criticize and analyze suspended sediment concentration data measured at La Traille hydrometric station. The study strives to find and highlight regressive relationships between suspended sediment discharges and flow discharges, applicable in Wadi Isser watershed and likely to be applied to regions (or watersheds) located in tellian and semi-arid North African environments, and subject to similar phenomena. The optimisation of the retained intra-annual sediment rating curves, explaining the greatest part of the variance, is validated by comparing the estimated values with the observed values and by fitting normal distribution to residues dataset. Corrected rating curves are used to rectify bias in the transformed log data, especially around the upper part of the high flows which contribute very strongly to the annual sediment load, and estimate the variation of solid contributions (fines and coarses) conveyed by Wadi Isser at La Traille hydrometric station during the period (1970/71-1984/85), and deposited in Koudiat Acerdoune reservoir since being in service in 2013. They also made it possible to estimate the annual surface degradation of the basin beyond the period of solid transport observations, which is in the range of 2142 t.km(-2).year(-1)at the dam of Kodiat Acerdoune. Finally, the extrapolation of solid inputs made it possible to predict the silting up of the dam, classify it among those with a very high filling rate, to measure the extent of the soil erosion-solid transport-silting of the dam phenomenon and to propose some actions to remediate it.