BT BB 73b(25) :איהו בדלא ואנן בשפלא‏ : [the fish] was against the current and we were with the current
See the entire entry for *dell, dellā n.m. woof; direction of movement

BT BB 73b(25) :איהו בדלא ואנן בשפלא‏ : it was upstream (or: upwind? on the high side?) and we were downstream (or: downwind? on the low side?)
See the entire entry for dlˀy adj. on high

BT BB 73b(25) :איהו בדלא ואנן בשפלא‏ : he was upstream while we were going downstream
See the entire entry for šp̄el, šep̄lā n.m. humiliation