River power

If I had my way, many river banks would have aqua ducts that syphon off some of the river's water to generate power. The openings of the aquaducts would have a metal mesh or grill on the front of them to stop fish from swimming through. The aqua ducts would be below the ground, you can see them on the sketch for illustration purposes.

The water would zig zag through the aqua ducts and pass over a water wheel that is down stream, the water wheel would turn a large dynamo that is at a lower elevation and generate electricity. The water would then flow back into the river. There would be many of these aquaducts throughout the length of the whole river. 

There would also be openings on top parts of the aqua ducts that allow some of the water to flow into large tanks when the water level is too high to prevent flooding. When the water level is lower the water tanks would empty out and help keep the dynamos running at full speed.