Here are the Wild life regs for our great state:

001.01B It shall be unlawful:

001.01B12 to take mountain sheep, elk, deer or pronghorn within 200 yards of a site which is included in the same ownership as the site of take and upon which feed, feed supplement, or bait has been placed within the last sixty (60) days except for those instances where said food, supplement or bait has been placed in the active operation of husbandry for domesticated livestock
other than domesticated cervidae and provided that the Commission may, by special permit, allow take otherwise prohibited by these regulations.


They kind of give them selves a catch-all by not really defining ''Bait" but I surely don't believe for a second that making a watering hole would fall under that. The actual regs might say something more http://www.ngpc.state.ne.us/admin/re...egulations.asp
But I'll let you look over the 200 pages.
Water sources can be a great hunting tool, even better if there is not much water arround. Deer arround here seem to prefer clean pools of water over the muddy creeks or rivers. Unless you are planing to do something rather large scale, or keep water flowing in the pool it will get stagnet fairly quick and not work for what you are looking for. Another option would be a shallow depresion that would fill a couple of inches when it rains and drain off in a couple of days, Deer love to drink out of these, but depending on the weather it may be dry most of the season.