You might be interested in Baltimore Harbor's Water Wheel https://www.youtube.com/watch?v=v5l7s6wC50g https://www.youtube.com/watch?v=v5l7s6wC50g It uses the

You might be interested in Baltimore Harbor's Water Wheel https://www.youtube.com/watch?v=v5l7s6wC50g https://www.youtube.com/watch?v=v5l7s6wC50g It uses the water flow, solar, some pontoons and a clever design to fill up a dumpster with debris. This seems like the real issue: someone still needs to take it from the dumpster, but at that point it's a manageable problem.