Two important local industries with conflicting needs brought about construction of Roebling's Delaware and Lackawaxen Aqueducts: canal traffic and timber rafting. Since the mid-18th century, timber from the Delaware valley had been floated down the river to shipyards and industries in Trenton and Philadelphia. The D&H Canal's rope ferry crossing of the Delaware at Lackawaxen created a bottleneck, and there were numerous collisions with timber rafts headed downstream. In 1846, to alleviate both problems, the D&H Canal Company approved Russell F. Lord's plan to substitute two new aqueducts in place of the rope ferry.