The rivers were used as transportation routes for trading and travel. The introduction of steamboats to the Mississippi and other major rivers led to deforestation of the river banks in the 19th century. The steamboats consumed much wood for fuel, leading to dramatic environmental effects along the Mississippi River between St. Louis and the confluence with the Ohio River. With so many trees taken down, the banks became unstable, collapsing into the river due to the powerful current. In this area, the Mississippi became wider and more shallow, which resulted in more severe flooding and lateral changes of the major channel. Several French colonial towns in the 19th century, such as Kaskaskia, Cahokia, and St. Philippe, Illinois, were flooded and destroyed. Kaskaskia was rebuilt but, after the channel of the Mississippi shifted, it was cut off from the mainland of Illinois and is connected to Missouri land.