Temporal and geomorphic variations of stream stability and morphology: Mahogany Creek, Nevada
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Authors: T. J. Myers, and S. Swanson
Date: 1996
Journal: Water Resources Bulletin
Volume: 32
Number: 2
Pages: 253-265
Summary of Methods: Intensive data collected by the Summit Lake Indian tribe and the Nevada Department of wildlife was used to detect changes in stream stability rating (SSR), ocular stability, and stream morphologic and aquatic habitat variables in response to management, low flows and geomorphic differences on stream reaches in northwestern Nevada over 4 years. Reach 1 had been grazed annually for many years with one year of rest; reach 2 had been rested for 2 years and reach 3 rested for 14 years when the study began. Over the course of the study reach 1 and 3 were rested, reach 2 was only grazed in the summer of one year for 2 months.
Article Summary / Main Points: Channel capacity and landform slope differed among reaches as Reach 1 was a different stream type than Reaches 2 and 3. Reach 1, dominated by shrubs and grasses had a low debris jam potential when compared to reaches 2 and 3 that were classified as aspen riparian areas. Transport distance among reaches effected rock angularity, the further the transport distance the less angular the rocks present. Overall mass wasting improved over the course of the study though the least improvement was found on reach 2 that was grazed once during the study. Vegetative bank protection increased on all reaches. Deposition improved variably on Reaches 1 and 3 and was stable on Reach 2. Brightness and aquatic vegetation improved the most on Reach 1 and rated the best on undamaged sites. Scouring and deposition improved on all reaches, reflecting a lack of scour during low flows. Reestablishment of riparian vegetation with controlled livestock grazing improved aquatic habitat. The rate of recovery was limited when sediment from livestock disturbances and road crossings were coupled with very low stream flows.
Vegetation Types: Riparian and Wetlands
MLRA Ecoregions: 23 Malheur High Plateau
Agrovoc Control Words: Riparian zones Grazing Streams
Article Review Type: Refereed
Article Type: Documented Case History
Keywords: grazing, aquatic habitat, stream morphology, rangeland streams, watershed management
Annotation: The results of this non-replicated study conducted over 4 years are applicable to only this stream in northwestern Nevada. As is true for all grazing research, the results are most directly applicable to areas with similar landscapes, species, level and season of use, and weather conditions. Additional research is needed to make it applicable to other areas. Thought this study mentioned management upstream and on adjacent lands will affect the characteristics of sites downstream. Another idea that came from this and other studies by Myers and Swanson (1991, Water Resour Bull 27:667-677; 1992 Water Resour Bull 28:743-754) is that stream types effects and can limit the effectiveness of management.
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