@oceanotter it's possible but really annoying. you have to dig out the aquifer layer by layer and drop constructed walls into it from above (because constructing them in situ is impossible if the aquifer is too strong)
your dwarves will get wet in the process. do not attempt to build bedrooms or anything inside an aquifer layer, that will just end in frustration
-F
@oceanotter how many layers deep is your aquifer? because the construction area gets really big if it's more than a handful of layers deep (you have to dig into it like an inverted pyramid sort of thing)
-F