The end of the rope should be looped around the other side and then looped around itself several times. 

The looping allows the rope to be easily tightened and loosened. The rock creates a super-strong tie point without putting a hole in the outside material. Some AquaDams® have integrated straps to be used as tie-off points, but nothing works as well as a rock.

The rope is then tied off to a suitably immovable object to help secure the AquaDam®. (in this case a cement road divider) The dirt fill berm provides a starting point for the AquaDam®, which extends down the other side.