He's talking out loud / to Alcimus, so they'll probably pick up on at least the outline. He'll also have given them a rough summary as part of telling them to move out of the way.
After they look at one another for a couple of minutes with trepidation, one of the grogs steps forward, a bit timidly. "Uh, sir, don't ya think it might be easier to drain the water from down where it's blocked? That way you won't have to push it up hill, you know?"
Scott
"I'd have to remove the blockage to get it to drain away normally that way, though, which is the entire problem in the first place - unless you mean dig up and break into the aqueduct?"
"Well, yeah, I'm sure you would have to break into it somehow. Is that really harder than sending someone crawling all the way up it, though?"
Scott
"The breaking into it isn't so much the problem as putting it back together again afterwards, especially with water trying to come out of it at the same time. Although I suppose we could block off this end to try and help with that problem..."
How is the aqueduct constructed? Is it cemented blocks of stone? Would the covenant be reasonably able to replicate it?
It's made of limestone blocks. There's mortar between them to make a seal, but yes, you could put it back together. And the grog points out that if you dam the upper end, like you were planning, you could prevent the water from flowing after it's drained.
Scott
All right - I'd been trying to avoid breaking the aqueduct. In that case, Gregorius will relocate his Rego Terram spell to the area of the blockage to uncover the aqueduct, and then get the covenant's mason involved. If he doesn't need the channel, he's think of just freezing the part of the water at the entrance to the tunnel to create the blockage (not too much, and carefully - he wants to avoid the expanding ice causing problems, but that's what finesse is for), as that'll cause less permanent damage, but wants the mason's assessment of how much time things will need before he does that.
You're going to need a channel in this case; if you drain the water from the top, I think you can drain it into the stream itself, provided you can move that much water--but I think that's gonna be beyond what Gregorius can accomplish: "extremely gentle" isn't going to be enough to push water uphill (by way of comparision, Push of the Gentle Wave is base 4, and all it's doing is pushing a boat slowly, though you could argue it should be base 3 instead).
I can't find where you mentioned the ice before--what's that for?
The mason tells you it shouldn't take longer than hour or so to make a good-sized hole in the aqueduct, once it's uncovered.
Scott
I didn't mention the ice before - this was an alternative way of blocking the entrance to the pipe, since he didn't have to be tearing up the river bank to make the channel anyway.
How long does the mason think it'll take to put the aqueduct back together again?
A couple of hours, at most. In other words, it's fairly trivial in the scheme of things.
Scott
Okay. Gregorius will make sure the mason is set up with everyone and everything he needs, and that his Rego Terram spell means the water coming out of the aqueduct is going to be coming out in a suitable place. Then he will block the mouth of the aqueduct by turning the water around it to ice:
[OOC: Base 3 + 1 Touch + 1 Part = 5. Casting total (Re 7 + Aq 0 + Sta 1 + Aura 1 +die 4)/2 = 6.5, so suceeds.
Finesse roll on placement of the ice (not sure if this is really necessary, but to be on the safe side): Per 3 + Finesse 7 + die 5 = 15 - I would assume this is more than enough.]
Then he'll head back to the mason and tell him to get cracking. He's meant to be opening the aqueduct just before the blockage, so that they can drain the water first and then worry about the blockage, rather than having to worry about it coming through as they remove the blockage. If the mason has any specific suggestions, though, he'll listen to them.
The mason needs to understand at least a little about how water flows, since it's something you have to think about when building buildings. He inspects the channel, an reassures Gregorius that it should do nicely.
OK, that works. Depending on how long it takes to clear the blockage, it's possible you'll get some leakage as the ice melts, but a little leakage should give you warning before the dam breaks catastrophically.
OK, the mason removes a few blocks, allowing the aqueduct to drain through the channel. It takes a while for all of the water to exit, so Gregorius finds he has to recast the ice spell, but that works fine (anything but a 0 would): invisiblecastle.com/roller/view/4434936/.
However, since the water is being diverted into the channel, Gregorius and the mason can see the blockage almost immediately, even if they can't get to it without enlarging the hole (since, right now, the hole is mostly filled with outrushing water). It looks like the aqueduct is blocked with a wall of solid stone. It fits the passage so perfectly that no water at all can get through.
Scott
Hmmm. The timing had already made Gregorius suspicious on the origins of the blockage, but this seems to confirm magic was involved. The question is - why? Why bloack off the aqueduct just when the covenant is coming under attack? And was it done by the magi or the attackers?
Also, why is the block still present? That would take some doing with Hermetic magic.
He'll attempt to determine if the "wall" is actually a magic item:
Base 1 (Detect the presence of spun vis) + 2 Voice = 3. (In 6 + Vi 6 + Aura 1 + Sta 1 + G 1)/5 = 3. (Or if Voice isn't going to work he'll use sight, but will need to roll for that.)
No, there's no spun vis in the blockage. Aside from the possibility of non-Hermetic magic, remember that even in Hermetic magic, stone can be made more pliable with Muto and then shaped with Rego, and then not show up as magical later. Mind you, they'd need to get a rock (or rocks) all the way down there in the first place, unless whoever did it used part of the aqueduct itself to form part of the blockage.
Scott
Actually, thinking about it, the wall would probably be generated by a magic item rather than a magic item itself, so it's no surprise there's no spun vis in it.
I'd been assuming the wall looked fairly solid and smooth - does it actually look like it's been moulded? And is there any change to the walls?
Gregorius is still curious to know why the wall exists. He can't see any good reason based off what he knows at the moment for cutting off the water to the fountains to be particularly important - yes it might be damaging the aura for some reason, but why would that matter that much on an "assault the covenant" timescale? Is there an agreement with some entity involved? One possibility that he can think of is that someone wanted the cavity behind the blockage to exist for some reason, so let's check that before removing the blockage.
Once the water has finished coming out of the aqueduct, he'll have the mason remove stones so he can access the other side of the blockage as well.
The part of the wall facing outward is rough--not that that necessarily means anything, since whoever did it likely didn't care how it looked.
OK. That requires renewing the ice dam, though: invisiblecastle.com/roller/view/4435753/
Having a look at the other side, Gregorius doesn't see anything of interest--just empty aqueduct.
Scott
Gregorius will have a quick look around in the blocked off side of the aqueduct (I assume it's a fairly short stretch before it turns into pipes?) Then assuming he doesn't find anything of interest, he'll go back to the point of this exercise and get the blockage removed. Can the mason's team just remove it? If not, do I need a part target, or is the wall a sufficiently distinct object that individual will do?
They could chisel away at it, but yes, magic would be much easier (as is usually the case, destruction is easier than construction--though that doesn't imply Gregorius needs to use Perdo, of course). Yes, the blockage can be considered a single target, though it's a little hard to estimate its exact size (it doesn't appear to be thicker than a foot or two, though).
Scott
In that case, Gregorius will try casting a 'Rock of Viscid Clay' variant.
Base 3 (turn dirt to stone or vice versa) + 1 Touch + 1 Conc =5. Any extra levels will be spent on enlargening the target if it needs it, although the base target for stone is a cubic pace so I don't think it should be necessary.
Casting total is: (Mu 0 + Te 7 + Sta 1 + Aura 1 + W&G 2 + die 2x5)/2 =10.5 So works.
So, he'll start tearing down the wall.
OK, that works. With a couple of hours (and after one more renewal of the ice spell (invisiblecastle.com/roller/view/4436754/), the mason and his team have the blockage dug out and the aqueduct fixed, and water is flowing again.
The fountain in the center of town immediately starts flowing again--apparently, it was undamaged. Smaller fountains begin to flow in the kitchen and several of the old labs, as well, including Tasia's and the lab on the second level of the caves; the one in Gregorius' lab is among those that are broken, but the mason thinks he can get them working easily enough.
Not all of Patrick's aura-measuring "significant lamps" are still working, since some of the circles have been broken by this point, but the one in the kitchen immediately registers a jump in the aura there; a little spellcasting reveals that the aura in that location (for about 5 paces around the kitchen fountain) has increased from 3 to 5. The aura remains at 5 in the caves, but the addition of fresh, running water to the labs provides a useful convenience, and the possibility of a Feature or Focus for any magus wanting to incorporate one into the lab.
Scott