I wonder if anyone has tried to build a Power Water Tower? Best built on a wide river, in a (suspended/hollow) dam format for the foundation.
To power the pumps that run the water upwards and onwards you will need a secondary/auxillary power source to power the initalizers (pump stacks); enough to power according to the volume per second you want to pump, and a secondary gear mechanism that can then merge the auxillary power source to the main power source, and amplify it by just that much. Of course, the initializers will have to connect to the main river itself, and the remaining power stacks, can be nothing but waterwheels every 1 or 2 levels. You can expand the waterwheels as you make it descend, provided the spouts per-floor keep expanding, but just enough to keep the flow at an adequate rate/depth. 1-2 tiles per floor seems decent enough expansion, depending on the inflow rate. You may need to make a pre-fill reservoir so that you can have enough in reserve, and being filled to prevent the water being spread too thin across the board as it makes it's descent down the power-water-tower.
With the kind of design I have in mind, it can be a modular building design that can be stacked, and another tower can be built next to the other one and attached, and lather, rinse, and repeat, just minus the initializer, but having it's own reservoir to power the second one. You can always, provided too much flow, set aside a pipeline to divert a small amount of the flow via aqueduct into the second's reservoir, or main system. Dropping from above, as to not back-flow.
Actually, if one reservoir overflows, allow it to start filling the next one, and so on; of course, the overflow is only to really serve as a recycler, and a secondary means of filling the other reservoir(s) nearby; not to be used as a primary means of powering the next power tower.