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Hydrological Process
Definition
A proper stream generally consists of concentrated, channelized flow, even if it only carries water for a few days of the year. In contrast, an upland system may have surface water flow, but the flow is more akin to sheet flow and typically not concentrated into channels.
![Example of sheet flow.](/earth111/sites/www.e-education.psu.edu.earth111/files/Module3/Earth111Mod3StreamsFig2A.png)
![Example of Channelized Flow](/earth111/sites/www.e-education.psu.edu.earth111/files/Module3/Earth111Mod3StreamsFig2B.png)
Figure 17. Examples of Sheet Flow and Channelized Flow
Photo credits: Top panel: Kelly Caylor, licensed under Creative Commons; Attribution-Noncommercial-NoDerivs 2.0 Generic (CC BY-NC-ND 2.0). Bottom panel: Source: Brian Laub