When turning a major river into a conduit for flood prevention, water storage and electricity production, upstream and downstream navigation, plus.

        Fish habitat, (both for migration and food production)  soil replenishment for farms, recreational purposes, and most importantly, as an opportunity of using its waters for replanting arid and semi-arid areas of the planet. this means that the river must be completely tamed and controlled. Yes, controlled means even swamps and wildlife areas must be designed to prevent floods or make controlled floods it that is what is needed for both local and passing wildlife.                                                                                                            In doing this the river will actually hold much more water than it would hold if it was not controlled. Perhaps the biggest change would be how we would use the controlled river for the commercial movement of materials. instead of huge barges, container ships, and liquid or gas transports, there would be railroad type cars that could be loaded on and off at each terminal onto rail transportation to minimize transfer problems, and since you can not derail a floating transfer vehicle and there would only be one-way traffic accidents would be kept to a minimal, and in the case of an accident it would already be in an enclosed lane of traffic easily contained and locked down by the river locks. The main channel would be dug out sometimes even to bedrock and silts and sediments would now be collected prior to the materials entering the main river. By cleaning the rivers prior to mixing with the massive amounts of water in the major river, clean-up will be much more efficient. The sediments would be cleaned and returned to the farmlands for increasing yields, and less need for fertilization. Many rivers once out of the hills and mountains in America have an average drop of around 10 feet per mile of run. Meaning that if we make on average 30-foot tall dams every 3 miles, and dig out the sediment for 3/4 of that distance to an average depth of 40 feet deep we would end up keeping 2-3 times as much water in that river system as the river would normally hold at any one time, that would remain there and could be drawn upon at need. Each dam would be kept at a level that would allow a large safety margin in times of flooding The production of electricity would be greatly increased, however that increase would be offset by the need to move so much water a fairly large distance to where it could be put to the best use for replanting the arid and semi-arid areas of the planet. In America, many of the deserts can be reached by keeping the flow of water at much of the same elevation as both input and output, as much of the waters start very high in the mountainous areas of the region. Tunneling to help prevent long-term energy use in moving water would help greatly in lowering those long-term energy needs, long into the future. (yes that was a little redundant) This whole idea is to prevent as much freshwater from entering the seas and oceans of the planet, to both start to clean up the oceans but even more important to replant the arid and semi-arid areas of the planet and in so doing reduce the carbon dioxide in the atmosphere but even more important to re-establish the planet ability for temperature regulation by decreasing unprotected soils and increasing cloud cover and the corresponding rainfall that comes with it. Dan, I can be reached at 402-890-7946 or by G-mail at daniel.kadavy212@gmail.com for more information you can go to https://lifecycleofaplanet.blogspot.com Thank you