you may mean a Cubic Foot of water ?
which weighs a little over 60 lbs not 112 lbs
Water is 62.3 pounds per cubic foot and if we are talking about a six foot fence there would be 6 cubic feet of water on top of every linear foot of a fence one foot wide.
So I did make an error. That should be roughly 374 pounds per square foot of fence that must be supported by some kind of footer or foundation.
When I wrote that post for a second I thought that doesnt seem right but I didnt stop.