The Middle Fork Willamette River Basin encompasses 3,548 square kilometers of western Oregon and drains to the mainstem Willamette River. Fall Creek Basin encompasses 653 square kilometers and drains to the Middle Fork Willamette River. In cooperation with the U.S. Army Corps of Engineers, the U.S. Geological Survey evaluated geomorphic responses of downstream river corridors to annual drawdowns to streambed at Fall Creek Lake. This study of geomorphic change is focused on the major alluvial channel segments downstream of the U.S. Army Corps of Engineers dams including the lowermost 11.5 km of Fall Creek and 27.3 km of the Middle Fork Willamette River, as well as Fall Creek Lake. This dataset is delivered as one excel workbook with two tabs, and associated metadata includes separate entity sections for each workbook tab. These tables document grain-size distributions and sediment depths collected as a part of a study to document the geomorphic responses to the Fall Creek Lake streambed drawdowns. Surficial grain size distributions and fine sediment deposit depths were measured for this study over 2015 through 2017 to support analyses tracking geomorphic change in the reaches downstream of Fall Creek Lake. Particle counts were collected at 6 gravel bars along Fall Creek and the Middle Fork Willamette River in September 2015. Counts were repeated at 5 of those sites and at 5 additional sites along the Middle Fork Willamette River in October 2016. Multiple clay horizon markers were deployed at 10 sites in October 2015. Deposition depths were measured multiple times throughout the year. Clay horizon markers were deployed again at 9 of the 2015 sites plus one additional site in October-November 2016 and, again, measured throughout the year. Sediment measurements are summarized in spreadsheet tables.

The Middle Fork Willamette River Basin encompasses 3,548 square kilometers of western Oregon and drains to the mainstem Willamette River. Fall Creek Basin encompasses 653 square kilometers and drains to the Middle Fork Willamette River. In cooperation with the U.S. Army Corps of Engineers, the U.S. Geological Survey evaluated geomorphic responses of downstream river corridors to annual drawdowns to streambed at Fall Creek Lake. This study of geomorphic change is focused on the major alluvial channel segments downstream of the U.S. Army Corps of Engineers dams including the lowermost 11.5 km of Fall Creek and 27.3 km of the Middle Fork Willamette River, as well as Fall Creek Lake. GIS layers defining the landforms, cover type, vegetation density, and secondary water type throughout the active channel study area were developed for six time periods: 1936, 2005, 2011, 2012, 2014, and 2016. GIS layers defining the wetted channel centerline throughout the active channel study area were developed for three time periods: 1936, 2005, and 2016. For this study, the active channel was defined as area typically inundated during annual high flows and includes the low-flow channel as well as side channels, and gravel bars. We also include floodplain islands that have a substantial area surrounded by active channel features in the mapping. The datasets were developed by digitizing from aerial photographs. Aerial photographs from 1936 were scanned, rectified, and mosaicked for this project. Digital channel traces were also produced to depict channel conditions along Fall Creek and the Middle Fork Willamette River floodplains from historical surveys. Plan and profile maps from 1926 (USGS, 1927) provide a basis from which to evaluate spatial and temporal changes that may result from multiple factors and place changes such as aggradation related to annual drawdown to streambed at Fall Creek Lake within historical context. GIS layers defining the outline of the 1926 Middle Fork Willamette River from the confluence with the Coast Fork Willamette River to the North Fork of the Middle Fork Willamette River were digitized. See individual FGDC metadata xml files for more information on the specifications, location, attributes and definitions, and processing descriptions.

The Middle Fork Willamette River Basin encompasses 3,548 square kilometers of western Oregon and drains to the mainstem Willamette River. Fall Creek Basin encompasses 653 square kilometers and drains to the Middle Fork Willamette River. In cooperation with the U.S. Army Corps of Engineers, the U.S. Geological Survey evaluated geomorphic responses of downstream river corridors to annual drawdowns to streambed at Fall Creek Lake. This study of geomorphic change is focused on the major alluvial channel segments downstream of the U.S. Army Corps of Engineers dams including the lowermost 11.5 km of Fall Creek and 27.3 km of the Middle Fork Willamette River, as well as Fall Creek Lake. GIS layers defining the landforms, cover type, vegetation density, and secondary water type throughout the active channel study area were developed for six time periods: 1936, 2005, 2011, 2012, 2014, and 2016. GIS layers defining the wetted channel centerline throughout the active channel study area were developed for three time periods: 1936, 2005, and 2016. For this study, the active channel was defined as area typically inundated during annual high flows and includes the low-flow channel as well as side channels, and gravel bars. We also include floodplain islands that have a substantial area surrounded by active channel features in the mapping. The datasets were developed by digitizing from aerial photographs. Aerial photographs from 1936 were scanned, rectified, and mosaicked for this project. Digital channel traces were also produced to depict channel conditions along Fall Creek and the Middle Fork Willamette River floodplains from historical surveys. Plan and profile maps from 1926 (USGS, 1927) provide a basis from which to evaluate spatial and temporal changes that may result from multiple factors and place changes such as aggradation related to annual drawdown to streambed at Fall Creek Lake within historical context. GIS layers defining the outline of the 1926 Middle Fork Willamette River from the confluence with the Coast Fork Willamette River to the North Fork of the Middle Fork Willamette River were digitized. See individual FGDC metadata xml files for more information on the specifications, location, attributes and definitions, and processing descriptions.

The Siletz River Basin encompasses 970 square kilometers of western Oregon and drains to the Pacific Ocean. In cooperation with the Confederated Tribes of the Siletz Indians of Oregon (CTSI), the U.S. Geological Survey is evaluating how streamflow and bedload sediment conditions may influence mainstem spawning habitats for spring Chinook Salmon (Oncorhynchus tshawytschya) and Pacific Lamprey (Entosphenus tridentatus). This study encompasses approximately 105 kilometers of the Siletz River, including bedrock and alluvial reaches, between Elk Creek and the Pacific Ocean. More detailed evaluation for this study focuses on a 18.8-kilometer segment of the Siletz River between Wildcat Creek near Moonshine County Park and the town of Siletz. To support sediment transport and habitat analyses and provide information on the character of sediment along the river corridor, surface and subsurface particle size data were collected in August 2017 and July 2018 between Moonshine County Park and the town of Siletz. Surficial particle sizes on gravel bar surfaces were measured at ten locations. Five additional surface measurements were made within riffle segments of the wetted channel adjacent to the gravel bars and in locations where the CTSI has observed spawning by spring Chinook salmon or Pacific lamprey in the past. Eight bulk subsurface samples coinciding with the surficial particle counts were collected in the field and analyzed for size at the USGS Cascade Volcano Observatory sediment lab.

The Siletz River Basin encompasses 970 square kilometers of western Oregon and drains to the Pacific Ocean. In cooperation with the Confederated Tribes of the Siletz Indians of Oregon (CTSI), the U.S. Geological Survey is evaluating how streamflow and bedload sediment conditions may influence mainstem spawning habitats for spring Chinook Salmon (Oncorhynchus tshawytschya) and Pacific Lamprey (Entosphenus tridentatus). This study encompasses approximately 105 kilometers of the Siletz River, including bedrock and alluvial reaches, between Elk Creek and the Pacific Ocean. More detailed evaluation for this study focuses on a 18.8-kilometer segment of the Siletz River between Wildcat Creek near Moonshine County Park and the town of Siletz. To support sediment transport and habitat analyses and provide information on the character of sediment along the river corridor, surface and subsurface particle size data were collected in August 2017 and July 2018 between Moonshine County Park and the town of Siletz. Surficial particle sizes on gravel bar surfaces were measured at ten locations. Five additional surface measurements were made within riffle segments of the wetted channel adjacent to the gravel bars and in locations where the CTSI has observed spawning by spring Chinook salmon or Pacific lamprey in the past. Eight bulk subsurface samples coinciding with the surficial particle counts were collected in the field and analyzed for size at the USGS Cascade Volcano Observatory sediment lab.

This data release will consist of 40 Excel files (one file for each cross section) containing worksheets corresponding to each channel cross-section survey (from 2 to about 40). Worksheets contain the basic survey data (dates, equipment, reference elevations, foresights, distances from reference pins, and elevations).

This data release will consist of 40 Excel files (one file for each cross section) containing worksheets corresponding to each channel cross-section survey (from 2 to about 40). Worksheets contain the basic survey data (dates, equipment, reference elevations, foresights, distances from reference pins, and elevations).

Since 2008, large-scale restoration programs have been implemented along the Willamette River, Oregon, to address historical losses of floodplain habitats for native fish. For much of the Willamette River floodplain, direct enhancement of floodplain habitats through restoration activities is needed because the underlying hydrologic, geomorphic, and vegetation processes that historically created and sustained complex floodplain habitats have been fundamentally altered by dam construction, bank protection, large wood removal, land conversion, and other influences (for example, Hulse and others, 2002; Wallick and others, 2013). For gravel-bed rivers like the Willamette River, planimetric changes (defined here as geomorphic changes related to horizontal adjustments independent of elevation and that can be observed using aerial photographs and other two-dimensional maps) include changes in channel position, gravel bars, and side channels. Restoration activities likely to cause planimetric changes in channel features include revetment removal, construction of off-channels features, modifications to floodplain topography, and gravel pit enhancements. Repeat planimetric mapping, provides a basis for quantifying channel changes and relating those changes to restoration projects or other natural or anthropogenic influences affecting geomorphic processes. Repeat mapping also can be used to quantify planimetric changes resulting directly from implementation of restoration projects, as well as subsequent geomorphic evolution of those features. In this study, repeat geomorphic mapping was completed for 2018 and 2020 along the lower 6.8 kilometers of the Middle Fork Willamette River (river mile 187.5 to 191.5 on USGS topographic maps) to support an assessment of geomorphic changes resulting from restoration activities implemented from 2014 to 2017. These datasets can be combined with previously published mapping (Keith and Gordon, 2019) in which the lower 11.6 km of Fall Creek and lower 27.3 km of Middle Fork Willamette were mapped for six periods (1936, 2005, 2011, 2012, 2014, and 2016). The 2018 and 2020 mapping was completed in the vicinity of large-scale restoration projects at the Willamette Confluence Preserve where gravel ponds and revetments were modified to improve floodplain habitats. The repeat mapping datasets include GIS layers defining the landforms and water features, as well as the types of cover and vegetation density on landforms, and types of secondary channel features mapped throughout the active channel. For this study, the active channel was defined as area typically inundated during annual high flows and includes the low-flow channel as well as side channels and gravel bars. Floodplain islands that have a substantial area surrounded by active channel features in the mapping were also included.

Since 2008, large-scale restoration programs have been implemented along the Willamette River, Oregon, to address historical losses of floodplain habitats for native fish. For much of the Willamette River floodplain, direct enhancement of floodplain habitats through restoration activities is needed because the underlying hydrologic, geomorphic, and vegetation processes that historically created and sustained complex floodplain habitats have been fundamentally altered by dam construction, bank protection, large wood removal, land conversion, and other influences (for example, Hulse and others, 2002; Wallick and others, 2013). For gravel-bed rivers like the Willamette River, planimetric changes (defined here as geomorphic changes related to horizontal adjustments independent of elevation and that can be observed using aerial photographs and other two-dimensional maps) include changes in channel position, gravel bars, and side channels. Restoration activities likely to cause planimetric changes in channel features include revetment removal, construction of off-channels features, modifications to floodplain topography, and gravel pit enhancements. Repeat planimetric mapping, provides a basis for quantifying channel changes and relating those changes to restoration projects or other natural or anthropogenic influences affecting geomorphic processes. Repeat mapping also can be used to quantify planimetric changes resulting directly from implementation of restoration projects, as well as subsequent geomorphic evolution of those features. In this study, repeat geomorphic mapping was completed for 2018 and 2020 along the lower 6.8 kilometers of the Middle Fork Willamette River (river mile 187.5 to 191.5 on USGS topographic maps) to support an assessment of geomorphic changes resulting from restoration activities implemented from 2014 to 2017. These datasets can be combined with previously published mapping (Keith and Gordon, 2019) in which the lower 11.6 km of Fall Creek and lower 27.3 km of Middle Fork Willamette were mapped for six periods (1936, 2005, 2011, 2012, 2014, and 2016). The 2018 and 2020 mapping was completed in the vicinity of large-scale restoration projects at the Willamette Confluence Preserve where gravel ponds and revetments were modified to improve floodplain habitats. The repeat mapping datasets include GIS layers defining the landforms and water features, as well as the types of cover and vegetation density on landforms, and types of secondary channel features mapped throughout the active channel. For this study, the active channel was defined as area typically inundated during annual high flows and includes the low-flow channel as well as side channels and gravel bars. Floodplain islands that have a substantial area surrounded by active channel features in the mapping were also included.

This dataset contains cross-section geometry and sediment-size data collected in the fall of 2019 from Muddy Creek and North Fork Gunnison River below Paonia Reservoir, western Colorado. Six cross sections were surveyed using Real-Time Kinematic Global Navigation Satellite System (RTK-GNSS) methods to document channel geometry below Paonia Reservoir. One cross section was surveyed on Muddy Creek below Paonia Reservoir, and five cross sections were surveyed from North Fork Gunnison River below Paonia Reservoir. All six cross sections are incorporated in this data release within one shapefile. Pebble counts were performed at each of the six cross sections to document sediment-size downstream from the reservoir. Four transects were completed at each cross section, where sediment size was measured and recorded. Sediment-size data are presented in .CSV files, with one file for each cross-section location, incorporating all of the data for each of the four transects at that location.