I have seen glass eels swimming through the grass on the river forth in Scotland in the last week of October last year whilst salmon fishing.. Or put a worm in the Clyde won't have to wait long
You can also rethink the design of hydro turbines. Instead of a spin, use the flow, the power of the water, and earth's gravity, this time, for a push, and pull action. Than it is just a matter of, figuring out the right gear mechanical design, for a powerful spin, of the right helices, out of the water, you could even use the wind created from such spin outside of the water, to add more tension on the gears, or whatever you want, send it down, or up, a tunnel, the engineering is there for such work. If a material, designed just right, is being pushed, on one side, than pulled on the other side, by the same water, you should get, great powers of tension, if then you apply that tension, to a gear mechanism, the right gear mechanism, than the same types of helices, should spin out of the water. add the design of the dam's, and you have hydro power, with a safe passage for all types of life, maintaining the rivers in the process, easy for managing the dams without interruption, and much more possibly. If I am not wrong it is how fish, and birds actually fly, and swim, which means that there is hope for flying as well. We will have to see.
