Protection dykes or levees are used to control the movement of water in confined areas to prevent flooding and water damage. Where protection dykes are used to continually control and constrict the flow of water, they are designed in a similar way to embankment dams where the raised water level is prevented from seeping through the protection dyke and causing inundation of the surrounding land. For this application, the dyke consists of at least one zone of fine-grained soil to act as a hydraulic barrier to the seepage water. To prevent erosion of the water-exposed face of the protection dyke, a revetment is normally used.

Protection dykes also may be used to protect low-lying land from infrequent flooding due to storms, high tides etc. In this application, the time over which the high water level occurs is relatively short, thus the dyke-fill does not have to be too impermeable. Here, Geotube® units can be used as the core protection dykes. The Geotube® dyke core is covered with a sand or soil mound that blends in with the local scenery. During periods of high water level and heavy storms, the water-side surface of the dyke may be eroded exposing the Geotube® units, but the dyke cannot be breached. Following the storms, the Geotube® core can be regenerated either naturally or artificially.

Containment dykes are used to retain water borne sediments, hydraulic fills and other fills. To reclaim land from the sea, or to provide a storage facility for spoil or other soil materials, it is common practice to first construct a containment dyke around the extremity of the area to be filled. The function of the containment dyke is to prevent loss of the fill into the surrounding water. Geotube® units may be used to construct the dyke using locally available sand as the dyke fill. In some instances, underwater containment dykes are constructed to retain spoil and other fills in an environmentally acceptable manner. Here, Geocontainer® units can be used to construct the dyke walls.