Drainage Basins: Definition & Characteristics

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Laminar & Turbulent Streamflows

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:07 What Is a Drainage Basin?
  • 1:42 Developing a River System
  • 3:11 Examples of Drainage Basins
  • 4:08 Lesson Summary
Add to Add to Add to

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Login or Sign up


Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Margaret Cunningham

Margaret has taught many Biology and Environmental Science courses and has Master's degrees in Environmental Science and Education.

Do you know where the water in your area flows? In this lesson, we will explore the system of drainage basins and how they help develop river systems. We will also investigate some extreme examples of drainage basins.

What Is a Drainage Basin?

If you follow a small stream downhill, where do you think it will lead? In most cases, a small stream will lead to a bigger stream, which will then lead to a river, and finally an open body of water. All of these waterways are connected and rely on precipitation to flow properly. When it rains, water falls on all surfaces, not just in the waterways. But how does the water that falls on the ground get to the stream or river?

This type of water is referred to as runoff, because it is water that falls on the ground and flows across the surface until it hits a stream. Each waterway has a drainage basin, or watershed, which is an area of land where all precipitation that falls will drain or flow downhill into a specific stream. Based on where rain falls, and in what drainage basin, determines what waterway it will end up traveling to.

Drainage basins often have well-defined boundaries. The line that separates two adjacent drainage basins is called a drainage divide. Drainage divides are often steep mountain ranges or hills. When rain falls on one side of the divide, it will flow into a certain drainage basin, and if the water falls on the opposite side of the divide, it will flow into a different drainage basin. Within a drainage basin, sometimes water that is moving downhill is stopped due to a depression in the land. This process creates ponds, which are small bodies of standing water, and lakes, which are much larger bodies of standing water.

Developing a River System

Although each individual stream has its own drainage basin, a larger river system is made up of all of the smaller streams and their respective drainage basins. As mentioned before, small streams flow into larger streams, then rivers and finally, open bodies of water. The drainage basin of a larger river system is comprised of many branching networks. It starts at high elevation with first-order streams, which are small streams that originate from springs. First-order streams are where the system begins, and they do not have any other streams flowing into them.

Next, there are second-order streams, which are streams that are created when two first-order streams meet. These streams are slightly larger and more downhill from first-order streams. When two second-order streams meet, they create a third-order stream. This process can continue until a large network of waterways is created. All of the branches of the system will eventually come together and lead to the final large waterway that will empty into the open body of water.

The drainage basin for this entire river system would be very large and incorporate each drainage basin from individual waterways. These systems can be very complex. We can think of it as a tree with many branches. The smaller, twig-like branches lead to larger branches, and finally they all meet at the trunk of the tree.

Examples of Drainage Basins

There are many drainage basins in the United States. Technically, wherever you are currently standing or sitting is within a drainage basin. The United States is home to several very large drainage basins, including the Columbia River drainage basin, the Colorado River basin and the Mississippi River drainage basin.

To unlock this lesson you must be a Study.com Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back
What teachers are saying about Study.com
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 160 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create An Account