The engineers at Synthetex have recently completed the design of custom fabric structures to allow for filling with fine aggregate concrete to form a seal of an underwater tunnel at a power facility.  The system allows for 1 deployment of divers to place all the units as a single unit, but filling will occur at 3 separate times.  Each pour will result in a 6.5-foot height per unit.  Upon filling the 3 units, the finished unit will extend up to 19.5 feet in height and laterally 12 feet to the side walls of the tunnel.  Parallel to the tunnel direction the units will be a pyramid stack ... the lower unit will be 14 feet in depth, the center unit 11 feet, and the upper unit 8 feet.  Internal reinforcements are incorporated in the tunnel direction and vertical direction, providing both tensile strength reinforcement as well as fabric wall depth/height control.  And ... all of the above will have a filling system able to be filled from the surface without divers.