40d:Murky pool

Murky pools are small pools of water one Z-Level deep on the surface of the map. Dwarves with the fishing job active will attempt to fish in them. Murky pool can (will?) completely drain in summer. In some climates during winter, they will refill themselves fully about the time that snow melts. This is because any ice that melts will always melt to 1 square of 7/7 water regardless of the amount of water that froze. Drinking from a murky pool will give dwarves an unhappy thought.

Removing

A murky pool is difficult to remove. Once drained, murky pools cannot be dug out or into. Channel designations cannot be placed on top of murky water tiles, and they cannot be dug out from beneath.

There are a few known ways to remove murky pools:

1. Drain the pool and build a dirt road on the murky tiles. When removed, the murky pool tiles will be gone. (Leaving silty clay loam or some such). This is the preferred method.
2. Dig underneath the murky pool, then dig a channel around the edge so that the pool tiles are connected to nothing. The tiles will collapse in a pile of rubble, job done. This method does not always work; sometimes the muck will simply splatter onto the next level.
3. Build a floor tile on each space of the murky pool, then remove the floor tiles. This is much slower than simply using roads, but will work.