If you can't wait for our primer to come on-line check out:

Minnesota Rivers: A Primer

found in the:

mn shoreland management guide

Stream Primer

We are in the process of developing an on-line stream primer that will explain the physical, chemical, and biological workings of streams.

Meanwhile, you can learn more about stream ecology on our companion website -- WaterOntheWeb.org

More about how streams work here 

discharge diagram
Fig 1-18: Stream Corridor Restoration Handbook
FISRWG (10/1998). Stream Corridor Restoration: Principles, Processes, and Practices. By the Federal Interagency Stream Restoration Working Group (FISRWG)(15 Federal agencies of the US gov't). GPO Item No. 0120-A; SuDocs No. A 57.6/2:EN 3/PT.653.