I was building a small reservoir to support a well, and so had a tunnel from this to my local river to act as a filling pipe. All was ready, so I marked the last square between the tunnel and river to be channelled.
A short while later I spotted a lone dwarf running down the pipe tunnel being chased by a wall of water. Luckily I was able to shut the flood gate and build some steps for him to escape before he drowned, but I'd rather avoid this situation in the future!
I presume this dwarf channelled the square and somehow ended up on the ramp square, then decided to run away from the water - straight in to the pipe tunnel?
How can I prevent my dwarfs from doing this in the future?
Or, is there a safer way to connect a "pipe" tunnel to a water source?