Levees are often critical components of water conveyance systems in that they expand the flow capacity of natural river and stream channels. Water conveyed down a natural waterway may or may not be impounded against levees. For example, in locations where levees are constructed to retain flood waters, the levees are often dry when the river is flowing at non-flood or normal stages. In other locations—for instance, low-lying delta areas—levees are a required feature that allows normal flow levels to pass. GEOTILL has a long history, association with, and project experience in all types of levee work, ranging from studies and evaluations, to design and construction.