'whitewater golf" is right on the mark here. My group ran thru the right side of House Rock on Sat 7-21-07 at a flow of 920 cfs. The water was amazingly muddy for the Arkansas, apparently due to the big rains on the previous Thursday. After running the first big drop I saw the butt end of a limb, post, whatever just at the surface, right at the eddy line, and obviously lodged in the eddy. It was about 3" diameter.
Anyone flipped or swimming after the first drop could really get some serious injury here. SCOUTING RECOMMENDED!
I also saw on far river left a chunk of large log angling down deep and sticking about halfway out into the left channel. I think it would only be a danger to a swimmer who got pushed very deep on the far left .
Sorry I won't be able to help pull it out.