ROILING ON THE RIVER.(Local)

Byline: Fred LeBrun

Surging down the frothy white water of the upper Hudson River is becoming quite the thing to do in some circles.

By the calendar, this should be a big- deal weekend in the frenzied world of white watering. Normally, we say, because it takes heavy water to do that, and the river isn't up where it should be for that sought-after ecstasy you get when you're scared witless and know you're going to drown.

Otherwise garden-variety humans don wet suits and safety helmets, put their affairs in order, then pay $75 a piece for this kind of abuse. Not cheap thrills.

At the peak of the white-water season - which is soon - 1,000 …