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>> On 20. Jun 2020, at 20:39, Joseph Eisenberg <[email protected]> >> wrote: > The immediate source of water is groundwater (aquifer or well), not a spring, > stream or river > Water flows by gravity in free flow (not pressurized or pipe flow) > The channel is underground (minimising evaporation) > Construction and maintenance is through vertical shafts, which are then > visible on the surface according to pictures I found they are tall enough so that a person can walk inside? In other types of aqueducts the water channel is often enclosed/inside pipes so that evaporation shouldn’t be an issue either, but the underground position will keep the water more chilled in a qanat. In case of a well, as the aquifer is below your starting point, I’d think you would need some kind of pump and not just gravity (at the beginning)? They are clearly not pressurized, but this is common for sewer pipes as well (i.e. the same kind of “free flow” in pipes, not sure about the definition of pipe, couldn’t you call a qanat also a kind of “pipe”?) I think I would remove the word “pipe” in the paragraph that explains free flow, because I believe you can have “free flow” in pipes, but I am not sure of both, the definitions of free flow and pipe. Cheers Martin
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