 Once the beachhead had been secured , Omaha became the location of one of the two Mulberry harbours , prefabricated artificial harbors towed in pieces across the English Channel and assembled just off shore . Construction of ' Mulberry A ' at Omaha began the day after D @-@ Day with the scuttling of ships to form a breakwater . By D + 10 the harbor became operational when the first pier was completed ; LST 342 docking and unloading 78 vehicles in 38 minutes . Three days later the worst storm to hit Normandy in 40 years began to blow , raging for three days and not abating until the night of June 22 . The harbor was so badly damaged that the decision was taken not to repair it ; supplies being subsequently landed directly on the beach until fixed port facilities were captured . In the few days that the harbor was operational , 11 @,@ 000 troops , 2 @,@ 000 vehicles and 9 @,@ 000 tons of equipment and supplies were brought ashore . Over the 100 days following D @-@ Day more than 1 @,@ 000 @,@ 000 tons of supplies , 100 @,@ 000 vehicles and 600 @,@ 000 men were landed , and 93 @,@ 000 casualties were evacuated , via Omaha . 
