to the river in downtown Buffalo.
Problems developed but were quickly solved. Leaks developed along the entire length of the canal, but these were sealed with a newly invented concrete that hardened under water. Erosion on the clay bottom proved to be a problem and the speed was limited to 4 mph (6 km/h).
The original design planned for an annual tonnage of 1.5 million tons (1.36 million tonnes), but this was exceeded immediately. An ambitious program to improve the canal began in 1834. During this massive series of construction projects, known as the First Enlargement, the canal was widened to and deepened to . Locks were widened and/or rebuilt in new locations, and many new aqueducts were constructed. The canal was also straightened and slightly re-routed in some stretches, resulting in the abandonment of short segments of the original 1825 canal. The First Enlargement was completed in 1862, with further minor enlargements in later decades.
Today, the reconfiguration of the canal created during the First Enlargement is commonly referred to as the Improved Erie Canal or the Old Erie Canal, to distinguish it from the canal's modern-day course. Existing remains of the 1825 canal abandoned during the Enlargement are sometimes referred to today as Clinton's Ditch (which was also the popular nickname for the entire Erie Canal project during its original 1817-1825 construction).
Additional feeder canals soon extended the Erie Canal into a system. These included the Cayuga-Seneca Canal south to the Finger Lakes, the Oswego Canal from Three Rivers north to Lake Ontario at Oswego, and the Champlain Canal from Troy north to Lake Champlain. From 1833 to 1877, the short Crooked Lake Canal connected Keuka Lake and Seneca Lake. The Chemung Canal connected the south end of Seneca Lake to Elmira in 1833, and was an important route for Pennsylvania coal and timber into the canal system. The Chenango Canal in 1836 connected the Erie Canal at Utica to Binghamton and caused a business boom in the Chenango River valley. The Chenango and Chemung canals linked the Erie with the Susquehanna River system. The Black River Canal connected the Black River to the Erie Canal at Rome and remained in operation until the 1920s. The Genesee Valley Canal was run along the Genesee River to connect with the Allegheny River at Olean, but the Allegheny section which would have connected to the Ohio and Mississippi was never built. The Genesee Valley Canal was later abandoned and became the Genesee Valley Canal Railroad.
In 1903, the New York state legislature authorized construction of the New York State Barge Canal as the "Improvement of the Erie, the Oswego, the Champlain, and the Cayuga and Seneca Canals". In 1905, construction of the Barge Canal began, which was completed in 1918, at a cost of $96.7 million. Freight traffic reached a total of 5.2 million tons by 1951, before declining in the face of combined rail and truck competition.
Competition also came from inside New York state. The Mohawk and Hudson Railroad opened in 1831, providing a bypass to the slowest part of the canal between Albany and Schenectady. Other railroads were soon chartered and built to continue the line west to Buffalo, and in 1842 a continuous line (which later became the New York Central Railroad and its Auburn Road in 1853) was open the whole way to Buffalo. As the railroad served the same general route as the canal, but provided for faster travel, passengers soon switched to it. However as late as 1852, the canal carried thirteen times more freight tonnage than all the railroads in New York state, combined; it continued to compete well with the railroads through 1882, when tolls were abolished.
The New York, West Shore and Buffalo Railway was completed in 1884, as a route running closely parallel to both the canal and the New York Central Railroad. However, it went bankrupt and was acquired the next year by the New York Central.
Because so many immigrants traveled on the canal, many genealogists would like to find copies of canal passenger lists. Unfortunately, apart from th