A NEW METHOD OF SEDIMENT DUMPING TO REDUCE ENVIRONMENTAL IMPACT

A new method for sediment dumping, “Double Tremie Tubes” was developed to reduce environmental impacts such as dispersion of suspended solids. Its functions to decrease both occurrence and dispersion of suspended solids are derived from unique flow pattern in the tubes caused by structural properties. Orifices, double tubes and interaction of water and sediment motion in tubes are fundamentally responsible for the effect. We confirmed all functions experimentally or by field observation in actual practices. Furthermore, a few important points to be considered in design and construction management are presented.