The creation of dams does have negative impacts. Communities on the river edge are displaced, such as Conowingo, Bald Friar, and Glen Cove, Maryland in 1928. Longitudinal river navigation is impeded. Although the historic Susquehanna was very difficult to navigate most of the year. Timber rafts could come down in the spring high water, but very few boats went up the river, before the canals were built. The Conowingo Dam is located near "Smith's Falls", where John Smith had to turn back while exploring the region in the early 17th century due to the impassable rapids.