I'll do my best.
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║▓▓▓╚╗╔═══════════╗╔╝▓▓▓║ V = downward ramp
║▓▓▓▒╚╣▒▒▒▒VVV▒▒▒▒╠╝▒▓▓▓║ X = Floodgate
║▓▓▓▒▒╚╗▒▒▒▒▒▒▒▒▒╔╝▒▒▓▓▓║ ▒▓ = Water
╚╗▒▒▒▒▒╚╗▒▒▒▒▒▒▒╔╝▒▒▒▒▒╔╝
█╚╗▒▒▒▒▒╚╗▒▒▒▒▒╔╝▒▒▒▒▒╔╝ Basically, this is the lower level of the two level system. The entire system is pressurized to
█╔╩╗▒▒▒▒▒╚╗XXX╔╝▒▒▒▒▒╔╩╗ one level above, with the water going through a diagonal gate two levels above to re-pressurize
█║▒╚╗▒▒▒▒▒║VVV║▒▒▒▒▒╔╝▒║ it at a level that won't flood my fort.
█║▒▒╚╗▒▒▒▒╚═══╝▒▒▒▒╔╝▒▒║ The top ramps lead down into the water supply channel, and when pressure is being calculated
█║▒▒▒╚╗▒▒▒▒▒▒▒▒▒▒▒╔╝▒▒▒║ water flows out of it as fast as the spring tiles above can supply it.
█║▒▒▒▒╚═╗▒▒▒▒▒▒▒╔═╝▒▒▒▒║ The central ramps/floodgates have a floor on the tile directly above and drain into my magma
█║▒▒▒▒XV║▒▒▓▓▓▒▒║VX▒▒▒▒║ farm below.
█║▒▒▒▒XV║▒▒▓▓▓▒▒║VX▒▒▒▒║ The idea of the system is that draining the cistern will leave all water in the X-shaped well
█║▒▒▒▒XV║▒▒▓▓▓▒▒║VX▒▒▒▒║ channel, but the cistern itself can fill up the full z level above. I suppose i could have left the
█║▒▒▒▒╔═╝▒▒▒▒▒▒▒╚═╗▒▒▒▒║ well areas separate, but could potentially have allowed my dwarves to dry out their preferred
█║▒▒▒╔╝▒▒▒▒▒▒▒▒▒▒▒╚╗▒▒▒║ well while the others were barely untouched. As it stands, they each have an isolated upper
█║▒▒╔╝▒▒▒▒╔═══╗▒▒▒▒╚╗▒▒║ level but a linked lower channel, so they can only dry a well out halfway before the others start
█║▒╔╝▒▒▒▒▒║VVV║▒▒▒▒▒╚╗▒║ feeding into it.
█╚╦╝▒▒▒▒▒╔╝XXX╚╗▒▒▒▒▒╚╦╝ The system filled up fine when i first dug it, as expected, but each time it fills up all the way,
█╔╝▒▒▒▒▒╔╝▒▒▒▒▒╚╗▒▒▒▒▒╚╗ subsequent draining won't refill - i have to jump-start the process by sending an air bubble
╔╝▒▒▒▒▒╔╝▒▒▒▒▒▒▒╚╗▒▒▒▒▒╚╗ back up the feeder pipe to drop water level at the diagnonal depressurizer - at which point new
║▓▓▓▒▒╔╝▒▒▒▒▒▒▒▒▒╚╗▒▒▓▓▓║ water flowing through will pressurize back into the cistern.
║▓▓▓▒╔╣▒▒▒▒▒▒▒▒▒▒▒╠╗▒▓▓▓║ The light water is where the wells dip into the channel.
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