World Library  
Flag as Inappropriate
Email this Article

Perennial stream

Article Id: WHEBN0010325214
Reproduction Date:

Title: Perennial stream  
Author: World Heritage Encyclopedia
Language: English
Subject: Agnes River (Australia), Ada River (East Gippsland, Victoria), Ada River (Baw Baw, Victoria), Arte River, Barkly River (Victoria)
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Perennial stream

A perennial stream or perennial river is a stream or river (channel) that has continuous flow in parts of its stream bed all year round during years of normal rainfall.[1] "Perennial" streams are contrasted with "intermittent" streams which normally cease flowing for weeks or months each year, and with "ephemeral" channels that flow only for hours or days following rainfall. During unusually dry years, a normally perennial stream may cease flowing, becoming intermittent for days, weeks, or months depending on severity of the drought. The boundaries between perennial, intermittent, and ephemeral channels are indefinite, and subject to a variety of identification methods adopted by local governments, academics, and others with a need to classify stream-flow permanence.

As stream flow decreases in dry weather, visible flow above the stream bed may not be readily evident, especially in streams with coarse substrate (gravel and rocks), where water is flowing beneath and between these particles (hyporheic flow). From a biological perspective, a stream may be considered flowing if sufficient water is available to support flow-dependent aquatic life, including fish and gill-breathing amphibians, benthic insects, crustaceans, and mollusks, many of which survive in shallow hyporheic flow beneath rocks or logs. This extreme low flow may not be detectable on typical USGS stream-flow gages, but is vital to stream ecology.[2]

See also

  • Winterbourne, a stream or river that flows only in winter.

References

  1. ^ Meinzer, Oscar E. (1923). Outline of ground-water hydrology, with definitions. Washington, DC: US Geological Survey (USGS). p. 57.  Water Supply Paper 494.
  2. ^ """Definition of "Perennial Stream. Office of Surface Mining - US Department of the Interior. Archived from the original on October 7, 2006. Retrieved March 28, 2007. 


This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.