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Robert H Webb

Landscape Change in the Southwest
Understanding the effects of climatic variability is important to development of water resources, mitigation of flood hazards, and interpretation of geomorphic surfaces. Climatic variability, which is characterized by temporal changes in variability of seasonal climate that spans decades or centuries, may be more important to water-resources evaluations than changes in mean climatic conditions. Changes in variability of climate has a large effect on the probability of occurrence of extreme events, such as floods or droughts. Understanding of climatic variability and its effect on the landscape is of paramount importance for estimation of flood frequency, sediment transport rates, and long-term watershed and channel...
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This metadata references a comma-delimited file describing 492 digitized prints of large-format photographs from 160 viewpoints. The photographic images themselves are referenced in a separate metadata file entitled "Photographs Showing Change in Riparian Vegetation in the Grand Canyon, 1889-2012". The viewpoints were first photographed by Stanton in 1889-1890, and then re-photographed in about 1989-1992 and 2010-2012. This set of photos focuses on change in riparian vegetation and partially overlaps a larger set of Stanton viewpoints re-photographed by Webb and others and available at http://wwwpaztcn.wr.usgs.gov/fscc/stanton-repeat-photography/index.php. The file of descriptive information gives viewpoint stake...
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Photographs Showing Change in Riparian Vegetation in the Grand Canyon, 1889, 1991, 2010 and other years
The viewpoints were first photographed by Stanton in 1889, and then re-photographed in about 1991, 2010 and sometimes other years. This set of photos focuses on change in riparian vegetation and partially overlaps a larger set of Stanton viewpoints re-photographed by Webb and others and available at http://wwwpaztcn.wr.usgs.gov/fscc/stanton-repeat-photography/index.php. The file of descriptive information gives viewpoint stake number, name, and river mile, and documents occurrence of the exotic shrub Tamarix ramosissima, changes in cover of native and invasive woody riparian vegetation, occurrence of Diorhabda spp., the beetle introduced to control Tamarix, reductions in cover of native Prosopis glandulosa, changes...
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The dataset includes 492 digitized prints of large-format photographs from 160 viewpoints. A separate metadata file "Photographs Showing Change in Riparian Vegetation in the Grand Canyon, 1889-2012" describes a comma-delimited file of descriptive information. The viewpoints were first photographed by Stanton in 1889, and then re-photographed in about 1991, 2010 and sometimes other years. This set of photos focuses on change in riparian vegetation and partially overlaps a larger set of Stanton viewpoints re-photographed by Webb and others and available at http://wwwpaztcn.wr.usgs.gov/fscc/stanton-repeat-photography/index.php. The file of descriptive information gives viewpoint stake number, name, and river mile,...
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