Ok, first, i've searched the forums and the top suggestions list and didnt see this anywhere, but then again i didnt spend an hour looking through every post ever to mention "aquifer", so if this has been posted before i aplogize in advance.
Aquifers are a fairly contentious topic from what i've seen on the forums. People either love them or absolutely hate them. Personally, i quite like them in theory but am not a huge fan in how they affect the game in execution. The main issues i see with aquifers, as they currently sit, are their capacity and pressure/velocities. Capacity seems to be an issue which is best ignored for game purposes, as I doubt anyone wants to have the game spend time calculating replenishment due to rain or more advanced concepts like hydrolic conductivity and porosity. For that reason it seems completely rational to describe an in-game aquifer as infinite.
However, what seems off and (hopefully easily) adjustable to me would be the velocity at which an average aquifer flows. Now, i'm no expert in the matter (i could ask one at work if it would help the discussion) but my experience has been that water tends to move out of an aquifer at a very low rate, typically less than a meter per day. The flow in DF seems to be on the increadibly high side. Almost more like striking an underground river than an aquifer.
Admittedly, it may be my perception of DF Time
http://df.magmawiki.com/index.php/Time that is off, i'm not sure and maybe someone with more understanding of DF time could chime in here. In any event, i would love to see the aquifer flow rate reduced to allow for a little reaction time as is typically seen in the real world (then again ... i've never seen anyone build a waterproof wall so quickly in the real world either!
).
Thoughts?
Edit: I guess i should add the idea here being to keep the usefulness, annoyance
and planning required when dealing with aquifers while reducing how effectively they can destroy an entire fort in such a short time (like tunneling into the Amazon)