thanks guys
no complicated mathematics involved, these were shot in the riverbed at a rapid, where the riverbed falls a couple feet down from the higher section. most plants in the riverbed die off during this time, exposing the bedrocks and allowing access into slightly more ''dangerous'' portions of the river (will be really dangerous if there were periods of rain before as the river can flood quickly) lots of rocks getting into the way, so it's not a single moment of splash that got ''frozen'' but an accumulation of continuous splashes on the rocks.
sun was low so contrast was especially high, the resulting files gave some good amount of latitude to work with for black and white tones, though some hotspots still arise, but reflections off carbonate deposits on the stones can't be helped anyway since they are totally white. those wrenches in the water are actually concrete embankments by the sides of the river (this is the downstream portion of the river, so it's some 100m+ wide from bank to bank.)