So, for the first time in my DF career, I decided to get ambitious. I'm absolutely still a newb, though, and I screwed up. My ultimate goal is to make a majestic dining room/meeting hall in my fortress with a small waterfall descending into a pool in the center. I found a setup that worked temporarily. I made three long tunnels, each with a channel on one end, and a single connection to the river on the other. This connection is made diagonally at a corner, as I figured this may slow the flow. At the end of a long tunnel, I made two branches to take some water to the other two channels. On the level immediately below, I put one block channels underneath. On the third level down, I mined out a cave, then made a 5x5 channel underneath that. So, the whole thing takes up four z-levels. The original plan was to have my dining room two levels below the river, but the room flooded. I guess this should have been a sign. The level immediately below looked fine, so I made the dining room there. It's been functional for a few seasons now, providing a cool, misty environment for my dwarves to eat in. Sadly, the room is beginning to flood.
Do I have any options to stop it? Is this perhaps a problem related to building this room in a peat environment? And, most importantly, any tips on making the dining room of my dreams?
I should also add, as a n00b, I don't have any experience messing with water. This is the first I've ever tried to re-route it. I've never used and flood gates or anything.
Thanks for your help!