Transportation was a key issue and the Army (especially the Army Corps of Engineers) was given full responsibility for facilitating navigation on the rivers. The steamboat, first used on the Ohio River in 1811, made possible inexpensive travel using the river systems, especially the Mississippi and Missouri rivers and their tributaries. Army expeditions up the Missouri River in 1818–25 allowed engineers to improve the technology. For example, the Army's steamboat "Western Engineer" of 1819 combined a very shallow draft with one of the earliest stern wheels. In 1819–25, Colonel Henry Atkinson developed keelboats with hand-powered paddle wheels.