To whitewater snobs, the phrase "Dallas whitewater" might seem like an oxymoron, sort of like "desert snorkeling" or "honest politician." But anybody who saw the White Rock spillway this spring saw some ferocious waves that few kayakers would tackle. What most people don't know is that after any sizable rain, the creek that fills the lake at the other end is suddenly festooned with surfable waves and tricky holes that allow experienced boaters to strut their stuff (spectators can check them out at the great play spot where Forest Lane crosses the creek). Sure, it's no Grand Canyon, but it beats driving to Arizona.