I'm new to Austin, and went out there yesterday for the first time on a reconnaissance trip for the white bass run. Used my fly rod. Nice place, but I didn't realize how much bigger the river is there than just a few miles upstream at Perdenales Falls State Park.
Water was cold and moving pretty well. The banks are deep and drop away significantly just a few steps from the shore. Practically impossible to wade unless you find a opportune rock sticking out. The river has to be running fairly high because there are lots of submerged trees and grass all around, so I will be interested to see if the level drops as spring approaches.
I went hoping to find some carp but didn't see any although I did see a couple of splashes which were likely carp. I managed a pull out a couple of small bass from classic spots, the first larger one from a drop off and a second tiny one hiding in some structure behind the giant rock on the river bank.
Given the size and depth of the river, I think to be really effective at fishing it, you'd need some sort of watercraft to cover all the water. Personally, I like the shallower and narrower water at the state park a little bit more than the wide open spaces at Reimer's.