Abstract

LOPEZ, Raúl; VERICAT, Damià  and  BATALLA, Ramon J.. Assessment of Bed Load Transport Formula for an Armoured Gravel-Bed River. Tecnol. cienc. agua [online]. 2015, vol.6, n.2, pp.5-20. ISSN 2007-2422.

The lower Ebro River (NE Iberian peninsula) has a gravel bed which flows downstream from a reservoir complex. In this section of the river, the armoured surface of the bed undergoes cycles of breaking and reestablishment as a result of natural and control floods. The objective of the present work is two-fold. First, to evaluate the capacity of three formulas to predict bed load transport under conditions in which the armour is broken or disturbed. Second, to analyze the ability of the formulas to predict the breakage or disturbance threshold of the armour. This was all based on a comparison between predictions and measurements of the bed load transport in the study section for two hydrological years. Based on the characteristics of the study section, the formulas which were finally selected were the equations developed by Parker, Klingeman and McLean (1982) (P-K-M), Bathurst (2007) (B) and Recking (2010) (R). Given the results, the P-K-M and R formulas are recommended to predict bed load transport when there is breakage or disturbance of the amour, and not formula B because of its considerable tendency to underestimate. Formulas B and R are recommended to predict the breakage or disruption threshold of the armour. Nevertheless, it is worth cautioning that in this case both formulas tended to predict thresholds much lower than those measured.

Keywords : Bed load formulae; bed load transport; sediment transport; gravel bed-river; armoured bed; River Ebro.

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