Water Dams quickly absorb and gel water, swelling to create a barrier to control problem floodwater. Compact, water-activated dams swell and gel when wet. They are lightweight, quick and easy to deploy. Each one expands to 2.5" high in minutes to contain, control and divert problem water. Long continuous lengths are perfect for wraparound protection. Durable knit keeps inner gel contained. Water dams can be left in place for maintenance or discarded into regular trash.