Method and plant for storing fresh water

A tank for storage of a confined quantity of freshwater in a large body of saltwater comprising

• an upper annular support having flotation means so that said annular support can freely float in said body of salt water, vertically supported only by said flotation means;
• a non-expandable flexible skirt of sheet material extending downwardly from said annular support to define an open-bottomed storage tank;
• means on said skirt to maintain said skirt in a generally vertical downward orientation from the annular support while said support floats in the saltwater;
• means for adding freshwater and removing freshwater from the top of said storage tank;
• a horizontal boundary layer being formed and maintained between the freshwater and the saltwater with the freshwater floating above the boundary layer and on top of the saltwater that is within the tank, said boundary layer being provided with a plurality of solid bodies having a density intermediate the density of said freshwater and the density of said saltwater, said bodies floating in the region of said boundary layer for reducing the contact area between the freshwater and the saltwater, said boundary layer being lowered as freshwater is added and the excess saltwater within the storage tank is freely displaced through said open bottom, that open bottom also permitting any particulate matter in the freshwater to settle out of the tank and into the surrounding body of saltwater.