TWO EMPLOYEES WERE REPAIRING ON 4"" AQUALINE DISCHARGE WATER LINE. THEY USED COME A LONGS TO PULL THE LINE TOGETHER AND WERE INSTALLING STRAW CONNECTORS. THEY BELIEVED THEY HAD DEPRESSURIZED THE LINE BUT THE LINE CAME APART AND THE WATER PRESSURE IN THE LINE WHIPPED THE PIPE AND HIT ONE EMPLOYEE KNOCKINGHIM TO THE GROUND.