I came across an article about the drought conditions in the Mississippi/Missouri Rivers recently. It noted the volume of steamboat traffic on the river systems in the post Civil War era. This author notes that "it wasn't uncommon in the 1800's to have hundreds of steamboats pass by St. Louis each day..." (that number seems hard to believe). He also noted that the boats were "sometimes lined up two miles deep and four boats wide in both directions...". The average life span on a riverboat was about five years but that if a boat make one run from St Louis to Fort Benton, Montana and back it made enough money to pay for itself with a profit. This created a situation where the owners were not that concerned if they lost a boat to the hazards of the river. The drought has now turned up the "remains of 500 to 700 steamboats...at the bottom of the Missouri river" with just as many in the Mississippi river. It is interesting to me to note the level of river traffic occurring at that time.
(Source: "Drought-plagued rivers reveal sunken troves" by Jim Salter of The AP. In The Record on 12/23/12)
