Inflatable dams

A special group of geosystems are flexible geo-dams, which are made of a synthetic membrane or geotextile secured to the channel bed. There are a variety of flexible dams (see Figures 9.1 and 9.2 ). Parachute dams (open type), in which the upper end of the membrane is fixed to a floating boom and restrained by guys ( Watson, 1985 ), are similar to the bottom screens discussed in Chapter 8 . In this chapter, only inflatable (closed type) flexible dams are discussed. Inflatable dams are made of a synthetic membrane (or impregnated fabric) and filled with air or water. Both types of flexible dams (open and closed types) are usually used as both temporary and permanent structures for river regulation, flood protection, irrigation and increase of reservoir capacity. They can also be used as submerged breakwaters near harbour entrances. Most often, inflatable dams are used for water regulation as part of a water management scheme or an irrigation project ( Tam, 1998 ). In a few cases these dams function as flood protection.