afflux

noun

1. An upward rush of fluid.

   “The vis viva of these affluxes is employed almost wholly in turning the mass of intermediate gas […]”

2. The rise in water level (above normal) on the upstream side of a bridge or obstruction caused when the effective flow area at the obstruction is less than the natural width of the stream immediately upstream of the obstruction.

   “Backwater due to the crossing as a whole should not be confused with local afflux at piers due to pileup of flow against the hydraulic stagnation point […]”