Lecture
The confluence of the Mississippi and Ohio rivers in Cairo, Illinois during
a flood. Looking south, the Ohio River is muddier. (Photo: USACE Memphis District.)First let’s get a definition out of the way. While we call any major channel where water flows a river, geologists refer to any (naturally or anthropogenically) channelized body of flowing water a stream. You might notice the larger streams like the White River, Wabash River, and the Ohio River, but what about the stream that is most likely less than a mile or two from where you live? In this part of the Midwest, most of us live within one to two miles of a small stream. If you don’t believe me, go to this site (geodata.gov) and type in your city and state. Under “Content Type,” click on “Selected Types,” then “Geographic Services.” Then, under “My Geography,” select your place. All those little blue lines represent a stream. (Even if you do believe me, go to the site and see the streams in your area. This shouldn’t take more than five minutes.)
So, while they are nearby, we often don’t pay too much attention to them except maybe during extreme rainstorms when streams flood. Unless you live in a rural area, you are mostly immune to streams, they sit hidden behind a shopping plaza or obscured by bridges that quickly carry you over them. In many cities (including Indianapolis) the streams have been simply buried under the ground in concrete pipes.
But streams are everywhere; they are nature’s method of quickly organizing and moving surface water towards the ocean. Just as roads are built to quickly get you places, streams help water to quickly get to the ocean. Big streams, like the Ohio River, Mississippi River, are like our interstates, they move large volumes of water over long distances. A local stream in a neighborhood is like a neighborhood alley, it only helps move water over a short distance.
But before we get all wet, you’ll want to know this section is organized into three sections:
- Streams: Geologic Time and Stream Formation, Stream Terminology, Stream Measurement
- Humans Impact: River Management, Lakes, Urbanization
- Flooding: Causes of Flooding, Flooding Hazards, Flooding Prevention
Use the arrows at the bottom of each page to scroll through all pages of the lecture. You can click the tabs at the top of the page to access the three modules of the rivers and floods lecture. Use the arrows at the bottom of each page to scroll through all pages of the lecture, each section has several pages. You may want to review the previous module on Air, Water, and Ice that covered water resources of Earth.