Riparian Areas Functions and Strategies for Management (2002) / Chapter Skim
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1. Introduction
1. Introduction
Pages 23-48
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From page 23... ...
They include assemblages of riparian plant communities and wildlife that depend upon the natural hydrologic regimes representative of a particular landscape. In the absence of human alteration, riparian plant communities support numerous functions including bank stabilization through root strength, sediment deposition on floodplains during periods of overbank flow, interstitial flow through the sediments, and large wood supply, which has a substantial influence on channel complexity and instream habitat features.
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From page 24... ...
, creating significant impacts to riparian systems including removal of riparian vegetation; "hardening" of streambanks with concrete, rip-rap, or other means; realignment of channels; and increased sediment production. In the western United States, the construction of dams and other water control structures for power generation and irrigation diversions followed by the subsequent alteration to downstream hydrologic regimes have additionally influenced the extent, quality, and functioning of many riparian systems (Reisner, 1987~.
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From page 25... ...
An expanding population base coupled with an increasing standard of living has ensured a high and increasing demand upon the productivity not only of riparian areas, but also of all the nation's natural resources. Continued population growth and increasing resource demands remain a dominant force in the national agenda.
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From page 26... ...
Although in the National Forest Management Act (NFMA) of 1976, the production of timber and other resources were indicated as important multiple uses of federal forestlands, Congress emphasized that "the Forest Service has both a responsibility and an opportunity to be a leader in assuring that the Nation maintains a natural resource conservation posture that will meet the requirements of our people in perpetuity." Congress further indicated a need to ensure that "protection is provided for streams, streambanks, shorelines, lakes, wetlands, or other bodies of water from detrimental changes in water temperatures, blockages of water courses, and deposit of sediment." Although riparian areas are not explicitly identified in NFMA, it has been increasingly accepted in agency practice that water resources protection cannot occur without the protection of riparian systems.
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From page 27... ...
This database contains over 11,000 references to journal articles, government documents, monographs, conference proceedings, and other papers associated with streams, rivers, streamside vegetation, water quality, and other riparian-related topics. This database has a western bias because most national forests and rangelands are located in the western states, and many ecological studies associated with western streams and rivers have occurred in recent decades.
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From page 28... ...
Forest Service and University of Washington (College of Forest Resources) database as of December 2000.
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From page 29... ...
Trends revealed by these databases are consistent with the relatively recent mushrooming of scientific information that specifically addresses riparian and riparian-related topics. Although much fundamental biological, geomorphic, and hydrologic research undoubtedly preceded this recent period of riparian research and provided a useful context for understanding many riparian issues, the last few decades have shown an exceptional trend toward increased research productivity on a wide variety of riparian topics.
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From page 30... ...
Soil characteristics and vegetation in riparian areas are frequently noted as being different or distinguishable from adjacent upland areas, particularly in semiarid and arid regions of the country. Invariably, the soils and vegetation of riparian areas are noted as being adapted to distinct hydrologic regimes such as elevated water tables, relatively high levels of soil moisture, or frequent flooding.
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From page 31... ...
resource values and characteristics, that are comprised of the aquatic and riparian ecosystems, floodplains, and wetlands. They include all areas within a horizontal distance of 100 feet from the edge of perennial streams or other water bodies....A riparian ecosystem is a transition between the aquatic ecosystem and the adjacent terrestrial ecosystem and is identified by soil characteristics and distinctive vegetation communities that require free and unbound water.
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From page 32... ...
It should be noted that for management and regulatory purposes, riparian areas are frequently given distinct spatial boundaries in order to achieve specific goals and are thereby called "riparian zones" or "riparian management areas." Such management designations incorporate inherent trade-offs between proportions of riparian functions included within and outside of the boundaries of the zone. The working definition developed in this report is broad in the sense that it encompasses all the characteristics mentioned above, including reference to location, hydrology, vegetation, soils, and the concept of gradients:
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From page 33... ...
where flood waters spread out laterally. Clearly part of riparian areas, floodplains are dynamic structures composed of the channel system and adjacent depositional levees, interfluvial bars and low-lying, depositional shelves, often with ridge and swale topography reflecting backfilling of ancient river channels.
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From page 34... ...
An alluvial aquifer underlies the channel and includes both a hyporheic zone and a deeper phreatic zone of groundwater. The phreatic zone contains groundwater that has had no contact or mixing from surface sources for very long time periods, often hundreds of years or longer.
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From page 40... ...
The aquatic boundary of riparian areas could be established where permanent water begins. For bodies of water that have relatively constant elevations, such as estuarine shorelines influenced by slowly changing sea level, a boundary such as mean high tide or mean low tide is relatively easy to identify.
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From page 41... ...
The minimum essential characteristics of a wetland are recurrent, sustained inundation or saturation at or near the surface and the presence of physical, chemical, and biological features reflective of recurrent, sustained inundation or saturation. Common diagnostic features of wetlands are hydric soils and hydrophytic vegetation.
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From page 42... ...
Water enters riparian areas from uplands in the form of groundwater discharge, shallow subsurface flow, and overland flow (see Chapter 2~. From the aquatic side, water is supplied by overbank flow, infiltration through adjacent channel banks (bank storage)
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From page 43... ...
Riparian forests persist in arid regions where there is insufficient precipitation to support upland forests (Brinson, 1990) , thus creating a distinct boundary.
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From page 44... ...
Field testing found the 1991 proposed revisions not only to be technically wanting, but to propose a much narrower definition of wetlands. Unlike the 1989 Manual, the 1991 proposed revisions would substantially reduce the surface area of wetlands that would fall under jurisdiction of Section 404 of the Clean Water Act.
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From page 45... ...
The following was one of the recommendations of the committee: "If national policy extends to protection of riparian zones pursuant to the goals of the Clean Water Act, regulation must be achieved through legislation that recognizes the special attributes of these landscape features, and not by attempting to define them as wetlands." The purpose of the present study is to recognize and identify the attributes of riparian areas and make recommendations for managing and maintaining these attributes. Chapter 2 describes riparian structure and how riparian areas affect water quality, provide habitat for fish and wildlife, and serve as corridors for species movement, among many other functions.
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From page 46... ...
CONCLUSION A large body of scientific information on riparian areas has developed over the last several decades documenting their importance as elements of regional landscapes. Early publications on riparian topics focused predominantly on water law.
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From page 47... ...
General Technical Report RMRS-GTR54. Ogden, UT: USDA Forest Service.
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From page 48... ...
Section 2526.05. Washington, DC: USDA Forest Service.
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