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Assessment of sediment transport in the wadi Haddad watershed (North West Algeria) Volume 15, issue 4, OCTOBRE-NOVEMBRE-DÉCEMBRE 2004

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Authors
Université des sciences et de la technologie d’Oran, Faculté de génie civil et d’architecture, Département d’hydraulique, Laboratoire Eau – Environnement. El M’naouar, BP 1505, Oran 31000, Algérie, Laboratoire Eau, roche et plante, Centre universitaire de Khemis Miliana, 44225 Khemis Miliana, Algérie

Silting and solid transport constitute, by their importance, a major problem in Algeria (agricultural land degradation, silting up of reservoirs). Hydrotechnique design and planning studies very often come up against the problem of the lack or of the reduced number of data on solid transport. Many researchers try to find a workaround to/tackle this problem by using two different approaches. In the first one, general models (for numerous watersheds) have been developed to assess solid transport at the level of a site that has no measuring station. In the second approach, models specific to the watersheds studied have been designed. These are used to fill the gaps due to lacking measurement data and to extend the existing series according to the liquid flow often measured. The work presented here falls into the second category of models. The watershed of wadi Haddad, a tributary of the wadi Mina, contributes to the silting of the Es-Saâda dam. Understanding the phenomenon of solid transport will help dams’ managers to minimise silting. The methodological approach adopted consists in finding a regressive model capable of explaining the sediment load as a function of the discharge measured at the level of Sidi Abdelakader El Djillali station, by studying this relation at various scales : annual, seasonal, monthly, and daily to establish the relation which best represents the phenomenon. The data available covers the years 1973-1974 to 1994-1995, that is to say 22 years. The results show that the power model explains the greatest part of the variance (more than 70% of the variance). The models obtained at daily and instantaneous (grouped on a monthly basis) scales gave the best correlation coefficient. The liquid flow explains, at these scales, the variation of the sediment load in time. Thus, in view of the fact that daily data are available, solid transport was evaluated using the daily model. This result confirms those found by various researchers in Algeria and in Morocco.