Is there any simple method of slowing moving water in a stream channel that does not interfere with particle flow along the bottom of the stream bed and does not require the stream bed shape to be modified in any way? An example that I have been considering is a float tied off to the shore with a lot of chains or some other kind of turbulence inducing device dangling into the stream. I need to brake the water flow around 50% over a distance of about 10 meters if it can be done. The channel is only a meter across and 1/3 meter deep, with a constant drop of around 8 cm per meter. Paddle wheels on top the water?? Any brilliant simple ideas?