I have a river I want dammed. Ordinarily this wouldn't be a huge issue, but I have two big constraints:
* Everything must be done non-permanently, with the exception of digging access tunnels (since it lies at Z-1 compared to ground level) and new flow paths (ideally these should be kept to a minimum, but as long as they aren't visible from the surface I don't really care).
* The river never freezes.
I was able to dam a similar river using this setup to reduce the depth long enough to install floodgates (idea and diagram stolen from ToxicFrog):
code:
#####
~~~#+++<<~~ *: gear mechanism
~~~#+++<<~~ W: water wheel
~~~#+++<<~~ ~: water
~~~#+++<<~~ <<: pump
#### #* W =: axle
#*======W +: floor
# W #: wall
########
However, that river was already shallow thanks to the nearby rapids, and even then it barely worked. The basic concept here is to re-route part of the river's flow into the nearby mini-lake (a confluence of rivers, actually) so that the amount of water flowing through any actual point is less. I tried setting up a similar set of four pumps on this river, and while they did move an impressive amount of water, they didn't make any noticeable difference in the depth of the river. This makes a certain amount of sense; if I were to distribute the water of the river evenly to a depth of 1, I'd need seven times the volume for it to flow through.Before I go to the rather massive effort of making seven of these setups, does anyone have any better ideas?