Leonardo also devised a water wheel. It combines elements of the more effective overshot water wheel with the more conventional water wheel. Here water falling from an aquifer would turn a wheel, which would then turn the blades of a large screw. In this sense, the invention would generate power. However, as water would need to be conveyed up to his aquifer, it was still reliant on human energy. While not practical, the invention makes important theoretical progress. That the wheel is not connected to a millstone, shows Leonardo’s fascination with water and his desire to use it in ways not previously conceived of. He called water the “driver of nature.” He imagined using water to power various processes, including in this case, a drill, possibly in an urban environment. This invention could be seen as a precursor to the modern water turbine. 

Cooper, Margaret. "The Inventions of Leonardo Da Vini." New York: The MacMillan Company, 1965.

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