High Rock Lake supposedly cannot flood, knock on wood. At least it hasn't since I built my dock there in or around 2002. I built the stationary part only about 1.5ft above full pond. I've heard Wylie and Lake Norman can have flooding problems. I guess High Rock is more like Hartwell in that the water goes WAY DOWN in the off season. But, rarely 17' tho! That's pretty serious drawdown. I feel for ya Daydreamer!
Here's a shot of my dock from a while back. As you can see the water is probably 3' or so below full pond in the pic: