Filters: Tags: Channel Narrowing (X)
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We used the 1981 historical imagery of the Escalante River, Utah in ArcGIS to quantify channel area and average width and quantify woody riparian vegetation cover in two reaches of the river. Reach 1 was approximately 15 river kilometers (rkms) long and located between Sand and Boulder creeks within Grand Staircase Escalante National Monument. Reach 2 was approximately 16 rkms in length, extending from the Glen Canyon National Recreation Area boundary to just upstream of Choprock Canyon. We delineated the extent of active channel. Active channel was defined as the portion of the channel free of vegetation. We also delineated fluvial geomorphic features such as point bars, mid-channel bars, lateral bars and floodplain....
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Escalante River, Utah,
Riparian ecosystems,
Southwestern U.S.,
biota,
channel narrowing,
These data were compiled to perform analyses of hydrologic change, changes in sediment transport, and channel change within Moenkopi Wash, Arizona. Objective(s) of our study were to quantify the magnitude and timing of changes in hydrology, sediment transport, and channel form within Moenkopi Wash and to determine the downstream effects of those changes on sediment delivery downstream to the Little Colorado River, and the Colorado River. These data represent instantaneous discharge records, suspended-sediment sample records, topographic survey data, historical aerial imagery, and channel polygons and centerlines mapped on the historical imagery. Instantaneous discharge records in this study began in 1926 and extend...
We used the 1951/1960 historical imagery of the Escalante River, Utah in ArcGIS to quantify channel area and average width and quantify woody riparian vegetation cover in two reaches of the river. Reach 1 was approximately 15 river kilometers (rkms) long and located between Sand and Boulder creeks within Grand Staircase Escalante National Monument. For Reach 1 we used the earliest available imagery which was from 1960. Reach 2 was approximately 16 rkms in length, extending from the Glen Canyon National Recreation Area boundary to just upstream of Choprock Canyon. For Reach 2 the earliest imagery was from 1951. We delineated the extent of active channel. Active channel was defined as the portion of the channel free...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Escalante River, Utah,
Riparian ecosystems,
Southwestern U.S.,
biota,
channel narrowing,
These data were compiled to perform analyses of hydrologic change, changes in sediment transport, and channel change within Moenkopi Wash, Arizona. Objective(s) of our study were to quantify the magnitude and timing of changes in hydrology, sediment transport, and channel form within Moenkopi Wash and to determine the downstream effects of those changes on sediment delivery downstream to the Little Colorado River, and the Colorado River. These data represent instantaneous discharge records, suspended-sediment sample records, topographic survey data, historical aerial imagery, and channel polygons and centerlines mapped on the historical imagery. Instantaneous discharge records in this study began in 1926 and extend...
Significant ecological, hydrologic, and geomorphic changes have occurred during the 20th century along many large floodplain rivers in the American Southwest. Native Populus forests have declined, while the exotic Eurasian shrub, Tamarix, has proliferated and now dominates most floodplain ecosystems. Photographs from late 19th and early 20th centuries illustrate wide river channels with largely bare in-channel landforms and shrubby higher channel margin floodplains. However, by the mid-20th century, floodplains supporting dense Tamarix stands had expanded, and river channels had narrowed. Along the lower Green River in eastern Utah, the causal mechanism of channel and floodplain changes remains ambiguous due to...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: American Southwest,
Ecological Applications,
Green River,
Populus deltoides,
Tamarix ramosissima.,
Point locations for Russian olive stems aged in the field in two reaches along the Escalante River in fall of 2014 and spring through fall of 2015. Dataset includes information for each stem on diameter at stump height (DSH), age when the tree was cut, year it was cut, estimated year of establishment, and ArcGIS-estimated distances to the mapped 1981 active stream channel of the Escalante River.
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Boulder, Utah,
Cottonwood,
Elaeagnus angustifolia,
Escalante River,
Escalante River, Utah,
The geomorphic effectiveness of extreme floods increases with aridity and decreasing watershed size. Therefore, in small dry watersheds extreme floods should control the age structure and spatial distribution of populations of disturbance-dependent riparian trees. We examined the influence of extreme floods on the bottomland morphology and forest of ephemeral streams in a semiarid region. Along six stream reaches on the Colorado Piedmont we examined channel changes by analyzing a rectified sequence of aerial photographs spanning 56 yr, and we investigated the spatial distribution of different-aged patches of forest by aging 189 randomly sampled cottonwood trees. Channel change in these ephemeral sand-bed streams...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Bottomland Forest,
Channel Narrowing,
Colorado,
Cottonwood,
Disturbance,
These data were compiled to perform analyses of hydrologic change, changes in sediment transport, and channel change within Moenkopi Wash, Arizona. Objective(s) of our study were to quantify the magnitude and timing of changes in hydrology, sediment transport, and channel form within Moenkopi Wash and to determine the downstream effects of those changes on sediment delivery downstream to the Little Colorado River, and the Colorado River. These data represent instantaneous discharge records, suspended-sediment sample records, topographic survey data, historical aerial imagery, and channel polygons and centerlines mapped on the historical imagery. Instantaneous discharge records in this study began in 1926 and extend...
These data were compiled to perform analyses of hydrologic change, changes in sediment transport, and channel change within Moenkopi Wash, Arizona. Objective(s) of our study were to quantify the magnitude and timing of changes in hydrology, sediment transport, and channel form within Moenkopi Wash and to determine the downstream effects of those changes on sediment delivery downstream to the Little Colorado River, and the Colorado River. These data represent instantaneous discharge records, suspended-sediment sample records, topographic survey data, historical aerial imagery, and channel polygons and centerlines mapped on the historical imagery. Instantaneous discharge records in this study began in 1926 and extend...
We analyzed historical aerial photography and used dendrochronology to quantify long-term spatial and temporal patterns of narrowing and vegetation expansion, including native cottonwood (Populus fremontii) and non-native Russian olive (Elaeagnus angustifolia), along the largely unregulated Escalante River in Utah, USA. Our general study area was between the town of Escalante and Choprock Canyon, and we focused on two detailed study reaches within this broader area. The study reaches were in long, entrenched meander sections of river: an upper reach, Reach 1, was approximately 15 river kilometers (rkms) long and located between Sand and Boulder creeks within Grand Staircase Escalante National Monument; and a lower...
Significant ecological, hydrologic, and geomorphic changes have occurred during the 20th century along many large floodplain rivers in the American Southwest. Native Populus forests have declined, while the exotic Eurasian shrub, Tamarix, has proliferated and now dominates most floodplain ecosystems. Photographs from late 19th and early 20th centuries illustrate wide river channels with largely bare in-channel landforms and shrubby higher channel margin floodplains. However, by the mid-20th century, floodplains supporting dense Tamarix stands had expanded, and river channels had narrowed. Along the lower Green River in eastern Utah, the causal mechanism of channel and floodplain changes remains ambiguous due to...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Ecological Applications,
Green River,
Populus deltoides,
Tamarix ramosissima,
american southwest,
These data include geospatial files (shapefiles and orthorectified raster images) and an input hydrograph (csv) for a 1-dimensional unsteady hydrologic model. Shapefiles consist of active channel boundarys and channel centerlines of six reaches of the LCR beginning ~4.5 km above Grand Falls, AZ, and ending ~12.8 km downstream from Cameron, AZ. These reaches are (1) the ~4.5 km above Grand Falls reach, (2) the 1.5km below Grand Falls reach, (3) the ~18.8 km Black Falls reach, (4) the ~16.5 km above Cameron reach, (5) the ~4.7 km Cameron to Moenkopi reach, and (6) the ~8.1 km below Moenkopi reach. Raster images consist of orthorectified aerial photograph mosaics between 1933/34 and 1992. Scans of the images were acquired...
We used the 2010 historical imagery of the Escalante River, Utah in ArcGIS to quantify channel area and average width and quantify woody riparian vegetation cover in two reaches of the river. Reach 1 was approximately 15 river kilometers (rkms) long and located between Sand and Boulder creeks within Grand Staircase Escalante National Monument. Reach 2 was approximately 16 rkms in length, extending from the Glen Canyon National Recreation Area boundary to just upstream of Choprock Canyon. We delineated the extent of active channel. Active channel was defined as the portion of the channel free of vegetation. We also delineated fluvial geomorphic features such as point bars, mid-channel bars, lateral bars and floodplain....
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Escalante River, Utah,
Riparian ecosystems,
Southwestern U.S,
biota,
channel narrowing,
This study examines bed and bank adjustment in the 105-km reach of the Green River immediately downstream from Flaming Gorge Dam by the use of historical aerial and oblique photographs, analysis of current and abandoned stream-gaging records, and field observations. Although this segment has been previously characterized as sediment deficient, these data show that sediment is accumulating in all reaches and that the bed has not degraded at any location where historical data are available. Adjustment is occurring through a combination of deposition of post-dam sediment and stabilization of pre-dam deposits, resulting in a 10?30% reduction in average width of the channel. All post-dam surfaces are colonized by woody...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Geomorphology,
channel adjustment,
channel narrowing,
dams,
degradation,
These data include geospatial files (shapefiles and orthorectified raster images) and an input hydrograph (csv) for a 1-dimensional unsteady hydrologic model. Shapefiles consist of active channel boundarys and channel centerlines of six reaches of the LCR beginning ~4.5 km above Grand Falls, AZ, and ending ~12.8 km downstream from Cameron, AZ. These reaches are (1) the ~4.5 km above Grand Falls reach, (2) the 1.5km below Grand Falls reach, (3) the ~18.8 km Black Falls reach, (4) the ~16.5 km above Cameron reach, (5) the ~4.7 km Cameron to Moenkopi reach, and (6) the ~8.1 km below Moenkopi reach. Raster images consist of orthorectified aerial photograph mosaics between 1933/34 and 1992. Scans of the images were acquired...
These data were compiled to perform analyses of hydrologic change, changes in sediment transport, and channel change within Moenkopi Wash, Arizona. Objective(s) of our study were to quantify the magnitude and timing of changes in hydrology, sediment transport, and channel form within Moenkopi Wash and to determine the downstream effects of those changes on sediment delivery downstream to the Little Colorado River, and the Colorado River. These data represent instantaneous discharge records, suspended-sediment sample records, topographic survey data, historical aerial imagery, and channel polygons and centerlines mapped on the historical imagery. Instantaneous discharge records in this study began in 1926 and extend...
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