In recent years, global climate anomalies (such as ENSO; global warming; and human damage), whenever heavy rains or typhoons, floods often make big disasters, not only cause loss of life and property, but also spend a lot of social costs. In general, most people use sandbags as a transient barrier, but need to spend a lot of manpower to do the transport. Bags may be due to exposure to cause brittle and hourglass, or unused for long time and solidified into a massive. A watertight device like undulating waves, it can replace sandbags. People fill it with water, and move to door positioning for cross-pricked. After the floods, the water can be used for mud cleaning. They can tread it to get internal water. It also a flag stand for advertising in usual time.