A helical blade turning inside a close-fitting inclined cylinder lifts water continuously as it rotates, moving large volumes over a modest head with a hand crank, treadle or animal drive. Ancient sources credit Archimedes; the device was used to drain Egyptian fields, dewater Spanish silver mines and lift bilge water in ships. It was later coupled to windmills and then to steam engines, which is how it became the workhorse of Dutch polder drainage and of early sewage pumping. Modern screw pumps in wastewater plants use the same geometry.
Mechanical lift broke the constraint that water only moves downhill, making it possible to drain low ground for building and to raise supply into cisterns and conduits above street level. Every reclaimed delta city and every pumped drainage district rests on this principle. It is the mechanical link between gravity-fed antique hydraulics and the pumped water and sewerage networks of the industrial city.
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