One month late, but I will answer you anyway.
I have dove there on 2 seperate ocassions with a buddy of mine. Both times were 3 years ago (summer 2001). As far as current: When you first enter the water upstream there is a slight current, probably to much to swim against once you are in, but that is becsause it is relatively shallow. As soon as the depth reachs about 20 feet (under the bridge) the current ceases to be an issue. You will need 2 vehicles to dive, one upstream where you will enter, and one down stream to get you back. I guess you could make the walk back on the road, but it is a long hike after completing a dive when you are tired.
Water Temps are not to bad, I don't remember exactly, but it can be done with a 7ml wetsuit. Both my body and I dive dry but it was not extremely cold, although if was mid July.
Vis is terrible after about 20 ft depth. If you venture down deep into the hole 80+ feet you will only have about 1ft vis. Be carful at that depth as there is a great deal of tree branches and debree (garbage ie. old car tires, old barbed wire) as entanglement hazards. Not much to see because of the vis. If you stick close to the wall, you can see some fish and lots of eals in small cracks and hols in the rock. I did see a HUGE catfish once. He was easily 3 - 4 feet in length. It scared the daylights out of me because my mask was about 6 inches from its face before I relized what I was looking at. It just sat there and looked at me.
Hope that helps
