épi de navigation

CONT: L'espacement [...] des épis de navigation est généralement de l'ordre de 0,5 à 1 fois la largeur de la rivière (mesurée entre les têtes). La longueur des épis est de 0,7 à 1 fois leur espacement côté concave, de 0,3 à 0,5 fois leur espacement côté convexe.
OBS: épi de navigation : désignation habituellement utilisée au pluriel.

CONT: Bendway weirs are discontinuous, redirective structures usually constructed of rock, designed to capture and then safely direct the flow through a meander bend. A minimum of five structures are typically placed in series (the series are known as ""weir fields"") along straight or convex bank lines. Bendway weirs differ from spurs and vanes in that they form a control system that captures and directs the streamflow through the weir field, usually all the way through the bend (hence the name bendway weirs). Bendway weirs are generally longer ... and lower than barbs or spurs, flat crested, and designed to be continuously submerged or at least overtopped by the design flows.
OBS: bendway weir: designation usually used in the plural.