The water walls can be used many ways. You can keep them empty, or you can use sand or water as a ballast in them. It all depends on your need. The walls can connect with one another, which allow you to create an actual and effective wall. It is also possible to use them separately so you can create a pathway with openings for vehicles and pedestrians. They are very durable, and they are versatile as well, making them an ideal choice for many different types of situations.