Abstract: A liquid filled dike is described. The dike is formed of a flexible material selected to contain water. The dike includes at least two bladders which extend at least a portion of the length of the dike. The dike can be transported in empty condition and filled on site. When it is no longer required at a particular site, the dike can be emptied and stored for later use. The dike is self-leveling and may include a leak detection system.