During this interval, the region was periodically submerged beneath shallow seas. Numerous villages were either completely submerged in floodwaters or destroyed. Before then, it was submerged and was part a shallow ocean floor. LVTs were also employed as guide boats for tanks unloading onto submerged reefs. The only angiosperms capable of growing completely submerged in seawater are the seagrasses. In many aquatic species, the leaves are submerged in water. It is composed of partially submerged volcanic mountains. Several houses had submerged into water, leaving many people homeless. Consequently, over 100 villages were submerged in water and destroyed. Today this confluence is submerged beneath Lake Hartwell. Many floats had been partially submerged in floodwaters for weeks. The rising sea levels had also submerged around of forest areas. This leads to a situation known as a submerged or drowned hydraulic jump. Several islands were not completely submerged at high tide. They will eat both the leaves and stems of submerged and emergent vegetation.