Construction of the Erie Canal began on July 4, 1817, in Rome, New York, with digging proceeding west toward Buffalo and east toward Albany at the same time, and each completed section opening to navigation as soon as it was finished. The section between Schoharie Creek and Schenectady opened in 1822, and the canal was routed here so its builders could use the bridge spanning the creek at this point. A dam across the creek created a pool of calm water, allowing draft animals to cross on the bridge and tow barges across the pool. Completed in 1825, the 40-foot-wide and 4-foot-deep canal connected the Hudson River to Lake Erie. More than 80 locks, each 90 feet long and 15 feet wide, overcame the 565-foot elevation difference between those bodies of water. Construction cost more than $7 million, but tolls had paid off that debt by 1835.