Erosion is the primary force that the Cahaba river exerts on the landscape. The Cahaba is considered a mature stream. It has lateral deposits of sediments that have built a broad flood plain and a meandering course.
Natural levees of sediment are deposited along the sides of the river.
The picture to the right is Perry Lake. It is an oxbow lake which
formed about 150 years ago.
A watershed is defined by the EPA as "A watershed is the area of land where all of the water that is under it or drains off of it goes into the same place."
The Cahaba River is 306 kilometers long and has a drainage area of 1825 square miles. The Cahaba has 11 tributaries that flow into it. It is the primary water source for a quarter of Alabama. Here are some statistics from Legacy, Inc. Alabama ranks seconds in the nation in the number of fish species and also second in the number of extinct species. It has some of the cleanest drinking water in the United States. There are more species of fish in the Cahaba River than in the entire state of California.
The Cahaba serves eight counties. The majority of the land cover is forest. This watershed is used more recreational activities than any other river in the state.
Several monitoring sites are set up along the river where real time
data for discharge, water temperature and gage height can be accessed.
The figure to the right shows the water temperature for a 31 day period.
More data is available here.
