Thank you, Jingles, for posting the map.
Fedor, I got the PM, and the savegame from RapidShare. Thank you kindly. I'll post the new version on DFFD, once I get around to fixing a few things, testing the aqueduct system and waiting for spring to arrive (the bridge does look a little unsightly with all the snow on it).
I'll describe a few noteworthy features of the fortress, referencing each foot of the bridge as "tower #X", "tower #1" being the southernmost tower and "tower#10" being the northernmost.
The aqueduct system is actually meant to provide irrigation for the farmland under each tower. In theory, most of that farmland is built over sandy terrain, which means it's permanently fertile, but I find that horribly unrealistic. Another purpose of the aqueduct system is to flood attackers as they travel the bridge (three floodgates exist for this purpose), to fill the currently empty fishery in tower #9, to fill the reservoir in tower #8, to bring horrible watery death upon all who survive the fall into tower #10's depths, to drown the prisoners in tower #7 (on the floor above the as-yet-unelected guard captain's quarters), and to clean the blood off the 80 steel spikes in tower #5's deathtrap.
I was considering installing floodgates along several of the drainage shafts, to provide a means for the dwarves to defecate (and therefore fertilize the farmland far below) or to dump garbage, but decided it was silly. I also intended to create two-z-level-deep moats around several of the towers, which could be filled via the drainage shafts and emptied via the pumps, but never got around to it.
The main reason I built farmlands under every tower was so that, in the event of goblin invasion, the inhabitants of each tower could survive independently, even if all other towers were cut off. This is aided by the design of the bridges on the second-highest levels, as the halves of these bridges can be raised separately.
Unfortunately, the aqueduct systems can easily be disabled, because:
*only three towers (#8, #9 and #10) can have their own reservoirs; all of them are horribly close to the goblins.
*Only one tower (#6) connects the left aqueduct (where water falls into the drains) to the right aqueduct (where water rises from the farmlands). Pull one little lever, and you can prevent flooded farmlands from ever being drained, especially since only one floodgate (in tower #5's deathtrap, on the left side) allows water to permanently leave the system, whereas a single floodgate keeps the pump system in tower #4 from continually bringing water into the aqueducts.
*Breaching only one wall tile is enough to compromise the whole aqueduct system, which lies on the outside of the bridge. This was remedied by ensuring that firm ground does not directly lie anywhere east or west of the aqueduct (which means ballistae and trolls cannot, in theory, target it), but it still is a vulnerability.
*I built only standard-issue pump towers, the kind that collapse into a heap if the bottom pump is removed.
Also disappointing about the whole mechanical sprawl is that only one millstone exists in the whole fortress. This is poor design (and over-reliance on plump helmets) on my part.
Keeping in line with the gameworld's story, no fort exists on the northern end of the bridge, as that particular side would be constantly threatened by goblin attacks. However, I wish I had channeled part of the ground there and built bridges spanning the abyss just north of it, to force potential enemies to charge into the line of fire of the two ballistae.
Likewise, for thematic reasons, I built a sort of military temple/theater on the highest levels of tower #7. Coffins lie behind the front seats, so that dead soldiers can be honored by the frequent sparring matches of their living kin. It's pretty small, but I liked it.
If I had enough spare time for it, I'd call a new Engineering Challenge to construct a heavily-trapped mausoleum, within the span of one year, using only supplies imported via the embark screen, or to carve a massive sculpture from a huge cliff using 7 miners, again in only one year. I would rather devote the rest of my vacation to preparing for my master's course, though.