Storms, sea-states, flooding, and seasonal sedimentation adversely affect navigability. The accumulation of silt has diminished the depth, and thus navigability, of the Lower Hackensack. The Ganges carries a long oar, representing the river's navigability. In 1785, Washington founded the Potowmack Company to improve the navigability of the Potomac River. The major function of the dam is to improve navigability. In 1850 he demonstrated the navigability of the Red River. Its "dynamic stability" enables improved navigability in narrow, crowded and dynamic environments. The atoll has several passages with varying degrees of navigability that lead into the lagoon. In 1510 another storm surge widened and deepened that gat to navigability. At this depth, navigability between the Pacific Ocean and the Rogue Valley is limited. Year-round navigability begins above Maramec Spring, just south of St. James.