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Riparian Area Restoration in Arid Western North America

June 6, 2012

Riparian zone along the Columbia River, Oregon.  Picture used with permission from Cristina Francisco.

Stompled and Trampled.  Neglected and left for drought.  Plants in the arid regions of North America (west of the Rocky Mountains and east of the Cascade Mountains) are under extreme stress for survival. One of the ways that plants win this battle is by living close to rivers and streams. This zone of more dense plants along waterways is called the riparian zone and is often measured to a specific distance from the water’s edge.  However, even along waterways the plants in these areas must survive extreme droughts, as surface soil dries, both on a seasonal and occasionally on multi-year time spans.  With water stress on the plants, rates of transpiration (water loss and carbon intake), carbon assimilation (making of energy) and growth are generally diminished (A. Porporato, 2002).

Riparian zone subject to rock fall and landslides along the Deschutes River, Oregon. Picture used with permission from Cristina Francisco.


These riparian zones are extremely important to humans because of our dependence on clean air and water.  Without plants along waterways holding back mud, debris, and chemicals (such as pesticides and nitrate rich fertilizers) water prices would skyrocket due to the increased filtering required before it could be consumed. Riparian zones with established stream banks increase stability of the area.  With increased stability, developed areas are going to see less damage from stream bank erosion and ground area loss because of erosion.

Polluted water from mine tailings in Colorado. Picture from US National Archives on Flickr.

Riparian zones in the western United States have been subject to much damage by many factors such as overgrazing by cattle and expanding populations of wild animals, such as deer and elk.  Additionally irrigation, development of structures along waterways and regional warming are degrading many riparian areas.

Many organizations are trying to repair damage done to riparian areas. One of the common methods is to fence off areas so that fewer animals, especially cattle, can trample the area.  Often only small sections of the waterway are left unfenced so that animals can drink some water while diminishing the amount of area that they are trampling and destroying. Similarly, buffer zones which are specified widths of plant growth that are not used for agricultural or structural development use are used to protect waterways.  These can be buffer zones (wider and more regulated) or buffer strips (narrow with fewer regulations). The use of buffer zones/strips and their width from the edge of the water depend on nearby land use and abiotic factors such as slope of surrounding area (Mander, 2008).

Generally these two management types are used to:

  1. Filter water flow into the main waterway
  2. Reduce erosion along the stream bank
  3. Filter the nearby air
  4. Improve climate in the water and surrounding area
  5. Prohibit growth of unwanted plants that prefer warm, unshaded water

Protected riparian zones along the Bighorn River. Picture from Flicker Commons.

More methods of riparian area management include: placing seeds in the habitat for native and beneficial plants, though this occurs less often when ample moisture is available for local plant populations to reseed themselves. Also, proper management such as monitoring the amount of time and when animals are allowed to graze an area is a common practice. This allows proper hardwood populations to develop before grazing animals have a chance to trample them. Furthermore, artificial barriers can be placed in the water as bank stabilizers or sediment catchers. In this method, bank stabilization is increased so that less sediment pollutes and clogs the waterway while allowing increased growth of plants since their habitat isn’t sinking falling into the waterway (Romasko, 2012). In my opinion, riparian areas must be protected so that our air and water is kept clean, and so that we have more natural scenery during recreation events such as fishing and rafting down waterways.

Water was too contaminated to drink along Interstate 25 in Colorado. Something we desperately need to avoid today. Picture from Flickr Commons.


References and Further Reading

Hamerlynck, Erik P., Russel L., et al. “Soil Moisture and Ecosystem Function Responses of Desert Grassland Varying in Vegetative Cover to a Saturating Precipitation Pulse.” Ecohydrology (2011). Web.

Mander, U. “Riparian Zone Management and Restoration.” Encyclopedia of Ecology. Elsevier. 3044-061. Elsevier, 2008. Web. 5 June 2012.

Porporato, A., P. D’Odorico, et al. “Ecohydrology of Water-Controlled Ecosystems.” Advances in Water Resources (2002): 1335-348. Elsevier, Mar. 2002. Web. 5 June 2012.

Romasko, Theresa. “Riparian Area Managment.” Telephone interview. June 2012.

Shafroth, Patrick B., Vanessa B. Beauchamp et. al. “Planning Riparian Restoration in the Context of Tamarix Control in Western North America.” Restoration Ecology 16.1 (2008): 97-112. Web.

Shafroth, Patrick B., and Mark K. Briggs. “Restoration Ecology and Invasive Riparian Plants: An Introduction to the Special Section on Tamarix Spp. in Western North America.” Restoration Ecology 16 (2008): 94-96. Web.

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One Comment leave one →
  1. August 12, 2012 10:32 am

    In the Midwest stream bank restoration efforts are hampered by layers of government agencies that have a preference for allowing streams to follow their “natural meanders” even if it involves massive washout and introduction of silt into streams. See our blog, Saving Our Silt: Streambanks and Bureaucrats at http://savingoursilt.us for a discussion of these issues.

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