It's all about loading it up properly and knowing what you can load.
70 x 16oz bottles of water - 73 pounds (not counting the packaging.) You need panniers to distribute that lower, or a full on cargo bike or trailer.

Check out this haul:
Those panniers are full of gatorade bottles. That's a 17 pound sack of dog food across the top. The whole bundle is lashed with some rope. All said and done I had about 50 pounds of crap loaded up; but I kept the heaviest stuff lower using the panniers.

utility cruiser loaded 2..jpgutility cruiser rear angle..jpg