so that the water would not flow too fast down the canal and impede the progress of upstream boats. Rivers were often dammed to raise the water's height so that the canal could be fed, for instance, the Chesapeake and Ohio canal had 7 dams built to feed water. If a dam was not built, often water had to be pumped. The Chesapeake and Ohio put a steam pump near the South Branch, near mile 174, which had a capacity of about , since the water from Dam No. 8 was insufficient. This problem is particularly acute on summit pounds (see below). On the Delaware Division canal, the Delaware River was made to pump its own water into the canal, using an undershot water wheel which was connected to another wheel which had buckets attached, thereby lifting the river water up to the canal. Winter Where ice would form during winter, the canal prism would usually be closed and drained. During this time, sand bars would be dug out, locks and other structures would be fixed. Exceptions to this would include wartime necessities, i.e. the Chesapeake and Ohio Canal was left open in the winters of 1861–1862 because of the American Civil War. Level walkers and repairs American canals often had a man called a "level walker" (Chesapeake and Ohio Canal), "bank watchman" (Erie Canal), towpath walker or inspector whose job was to walk along the pound (level) with a shovel, checking for leaks and repairing minor ones before the leak could cause major damage, and calling the section work crew for major ones. His rounds were about 20 to 24 miles daily. Muskrats would cause leaks by burrowing in the canal, as well as competitors such as stage coach lines or teamsters who would sabotage the canal by digging holes in the bank. Other duties included checking the waste weir gates to see if they were letting out the correct amount of water, checking aqueducts for damage, as well as being called in the night to search for missing persons supposedly drowned in the canal. If a break or leak was discovered and the level walker could not do repair it himself, he sent a message to the section superintendent or headquarters, and the section crew with a repair scow would come. These boats carried clay straw, takes, rope, wooden boards, and tools (picks & shovels). For culverts and