Impervious containment walls, also called bund walls, are a constructed retaining wall designed to prevent inundation or breaches from a known source. It is a secondary containment system commonly used to protect environments from spills where chemicals are stored. Sheet piles have been used for many years to construct water retaining cofferdams.
In recent years the same flow-restricting properties have been used in the environmental sector. Sheet piles can be driven deep to cut off groundwater far below the surface. Sheet pile barrier walls are far less disruptive than slurry walls, drilling, and other methods. The inherent tightness of the Larssen interlock of the sheet piles, the width of the piles, and the possibilities for prefabricated sealing and welding measures all contribute to decreasing a possible flow.
Sheet piles are recognized by environmental engineers as an excellent method for containing spills and polluted groundwater and have enjoyed success in many environmental projects.