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• 1. [Article] Using Landsat TM Imagery to Monitor Vegetation Change Following Flow Restoration to the Lower Owens River, California

  Rehabilitating river corridors to restore valuable riparian habitat consumes significant resources from both governments and private companies. Given these considerable expenditures, it is important to ...

  Citation × Citation Citation Abstract Copy Title: Using Landsat TM Imagery to Monitor Vegetation Change Following Flow Restoration to the Lower Owens River, California Author: Bross, Lesley Crandell Year: 2015 Rehabilitating river corridors to restore valuable riparian habitat consumes significant resources from both governments and private companies. Given these considerable expenditures, it is important to monitor the progress of such projects. This study evaluated the utility of using Landsat Thematic Mapper remotely-sensed data from 2002 and 2009 to monitor vegetation change induced by instream flow restoration to the Lower Owens River in central California. This study compared the results of an unsupervised classification with an NDVI threshold classification to appraise the resources required and effectiveness of each analysis method. The results were inspected by creating standard remote sensing accuracy error matrices and by correlating landscape pattern metrics with bird indicator species. Both sets of classified maps show a noticeable increase in riparian vegetation in the study area following flow restoration in 2006, indicating an improvement of the quality of bird habitat. The study concluded that analyzing vegetation change using the unsupervised classification technique required more effort, expert knowledge, and supplementary data than using the NDVI threshold method. If these prerequisites are met, the output from the unsupervised classification process produces a more precise map of land cover change than the NDVI threshold method. However, if an analyst is lacking either resources or ground verification data, the NDVI threshold technique is capable of providing a generalized, but still valid evaluation of vegetation change. This conclusion is supported by higher correlations between indicator bird species under the unsupervised classification method than were found with the NDVI threshold method. Title: Using Landsat TM Imagery to Monitor Vegetation Change Following Flow Restoration to the Lower Owens River, California Author: Bross, Lesley Crandell Year: 2015 Rehabilitating river corridors to restore valuable riparian habitat consumes significant resources from both governments and private companies. Given these considerable expenditures, it is important to monitor the progress of such projects. This study evaluated the utility of using Landsat Thematic Mapper remotely-sensed data from 2002 and 2009 to monitor vegetation change induced by instream flow restoration to the Lower Owens River in central California. This study compared the results of an unsupervised classification with an NDVI threshold classification to appraise the resources required and effectiveness of each analysis method. The results were inspected by creating standard remote sensing accuracy error matrices and by correlating landscape pattern metrics with bird indicator species. Both sets of classified maps show a noticeable increase in riparian vegetation in the study area following flow restoration in 2006, indicating an improvement of the quality of bird habitat. The study concluded that analyzing vegetation change using the unsupervised classification technique required more effort, expert knowledge, and supplementary data than using the NDVI threshold method. If these prerequisites are met, the output from the unsupervised classification process produces a more precise map of land cover change than the NDVI threshold method. However, if an analyst is lacking either resources or ground verification data, the NDVI threshold technique is capable of providing a generalized, but still valid evaluation of vegetation change. This conclusion is supported by higher correlations between indicator bird species under the unsupervised classification method than were found with the NDVI threshold method. Close

• 2. [Article] Analyzing Dam Feasibility in the Willamette River Watershed

  This study conducts a dam-scale cost versus benefit analysis in order to explore the feasibility of each the 13 U.S. Army Corps of Engineers (USACE) commissioned dams in Oregon’s Willamette River network. ...

  Citation × Citation Citation Abstract Copy Title: Analyzing Dam Feasibility in the Willamette River Watershed Author: Nagel, Alexander Cameron Year: 2017 This study conducts a dam-scale cost versus benefit analysis in order to explore the feasibility of each the 13 U.S. Army Corps of Engineers (USACE) commissioned dams in Oregon’s Willamette River network. Constructed between 1941 and 1969, these structures function in collaboration to comprise the Willamette River Basin Reservoir System (WRBRS). The motivation for this project derives from a growing awareness of the biophysical impacts that dam structures can have on riparian habitats. This project compares each of the 13 dams being assessed, to prioritize their level of utility within the system. The study takes the metrics from the top three services (flood regulation, hydropower generation and recreation) and disservices (fish mortality, structural risk and water temperature hazards) and creates a rubric that scores the feasibility of each dam within the system. Within a range between 0 to 3 for three dam services and 0 to -4.5 for two disservices, the overall calculated score elucidates for each structure whether its contribution to the WRBRS is positive or negative. Further analysis searches for spatiotemporal trends such as anomalous tributaries or magnified structural risk for structures exceeding a certain age. GIS data from the National Inventory of Dams (NID), U.S. Geologic Survey (USGS) water measurements, raw data from USACE, and peer-reviewed studies comprise the statistics that generate results for this analysis. The computed scores for each dam yield an average overall score of -1.31, and nine of the 13 structures have negative results, indicating that the WRBRS faces challenges going forward. The study seeks to contribute to the increasingly relevant examination of dam networks at the watershed scale. Title: Analyzing Dam Feasibility in the Willamette River Watershed Author: Nagel, Alexander Cameron Year: 2017 This study conducts a dam-scale cost versus benefit analysis in order to explore the feasibility of each the 13 U.S. Army Corps of Engineers (USACE) commissioned dams in Oregon’s Willamette River network. Constructed between 1941 and 1969, these structures function in collaboration to comprise the Willamette River Basin Reservoir System (WRBRS). The motivation for this project derives from a growing awareness of the biophysical impacts that dam structures can have on riparian habitats. This project compares each of the 13 dams being assessed, to prioritize their level of utility within the system. The study takes the metrics from the top three services (flood regulation, hydropower generation and recreation) and disservices (fish mortality, structural risk and water temperature hazards) and creates a rubric that scores the feasibility of each dam within the system. Within a range between 0 to 3 for three dam services and 0 to -4.5 for two disservices, the overall calculated score elucidates for each structure whether its contribution to the WRBRS is positive or negative. Further analysis searches for spatiotemporal trends such as anomalous tributaries or magnified structural risk for structures exceeding a certain age. GIS data from the National Inventory of Dams (NID), U.S. Geologic Survey (USGS) water measurements, raw data from USACE, and peer-reviewed studies comprise the statistics that generate results for this analysis. The computed scores for each dam yield an average overall score of -1.31, and nine of the 13 structures have negative results, indicating that the WRBRS faces challenges going forward. The study seeks to contribute to the increasingly relevant examination of dam networks at the watershed scale. Close