I kind of have this problem with my fortress, i tried digging an indoor water supply, but the river current(im used to settling near brooks, using dams to store the water) was so strong it basically went like when you turn on the knob on the sink too high and the water just splutters everywhere. My friend tried helping me but he couldnt figure it out, what could i do?
Like Sheb said, first make sure you
understand how pressure works. Also,
cisterns. If you have an aquifer, it's a lot easier. If you have a river, it's a bit more work.
First, mine out a tunnel to your water source, but stop before you actually breach it. My preferred method is to set up a fortification and floodgate at the end. Once the floodgate is installed, you can channel out the last block from above. The fortification will keep building destroyers from reaching the floodgate, and the floodgate allows you to shut off the water supply at will. Connect floodgates to appropriately placed levers, and make use of the note system to track what lever goes to what floodgate.
Run this tunnel to a first cistern for "untreated" water. Make sure to equalize the pressure, so it doesn't overflow. I like to have a method to empty this cistern, in case I have to do work in it. Build a second cistern for your "clean" water - use a pump to pull from the first cistern into this one. I like to build a "pressure equalizer" into this point, so I can automate the pump later and never worry about overflows:
Top: (w - wall, Pp - pump going right to left, . - open air)
www
w.Pp.
www
Bottom: (w- wall, . - floor, r - ramp up)
.ww
wrw <- water drops into the center, flows out through the diagonals.
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It's a good idea to have ways to block inflowing water and empty the water system, in case you need to go into it for repairs. Also, don't just smooth the floors of your waterways, or you will eventually get trees growing on them - be sure to use constructed floors to prevent that. Read up on contaminants, and build walls (instead of smoothing) as needed. In areas where you don't need to worry about contaminants, smoothing & engraving the walls is good practice for your low-skill Stone Detailers.
I also like to dig out a few extra tunnels leading out of the cistern, and install floodgates to them - in case you want to expand your waterworks in the future, or add drowning traps.