Sand classifications along the Colorado River in Grand Canyon derived from 2002, 2009, and 2013 high-resolution multispectral airborne imagery
Dates
Publication Date
2018-10-10
Time Period
2002
Time Period
2013-05-30
Citation
Sankey, J.B., Chain, G.R., Solazzo, D., Durning, L.E., Bedford, A., Grams, P.E., and Ross, R.P., 2018, Sand classifications along the Colorado River in Grand Canyon derived from 2002, 2009, and 2013 high-resolution multispectral airborne imagery: U.S. Geological Survey data release, https://doi.org/10.5066/P99TN424.
Summary
These data are remote sensing image-based classification maps of unvegetated river-derived sand along the Colorado River. One map is based on imagery acquired in May 2013 and is a classification of sand located above the wetted river channel in the imagery which was acquired at the approximate contemporary low-flow river discharge of 8,000 cubic feet per second (227 cubic meters per second) and extends from Glen Canyon Dam at Lake Powell to Separation Canyon at Lake Mead, a total distance of approximately 255 river miles (410 river kilometer). Three other maps are based on imagery acquired in May 2002, 2009, and 2013, respectively, and are classifications of sand located above the wetted river channel (at river discharge of approximately [...]
Summary
These data are remote sensing image-based classification maps of unvegetated river-derived sand along the Colorado River. One map is based on imagery acquired in May 2013 and is a classification of sand located above the wetted river channel in the imagery which was acquired at the approximate contemporary low-flow river discharge of 8,000 cubic feet per second (227 cubic meters per second) and extends from Glen Canyon Dam at Lake Powell to Separation Canyon at Lake Mead, a total distance of approximately 255 river miles (410 river kilometer). Three other maps are based on imagery acquired in May 2002, 2009, and 2013, respectively, and are classifications of sand located above the wetted river channel (at river discharge of approximately 8,000 cubic feet per second, or 227 cubic meters per second) and below the approximate maximum contemporary flood stage of the river at a discharge of 45,000 cubic feet per second (1,274 cubic meters per second). Those three maps extend from Lees Ferry (approximately 15 miles downstream of Glen Canyon Dam) to Diamond Creek, a total distance of approximately 226 river miles (364 river kilometers). These three maps only have sand classified within large sand deposition zones (SDZs) in the river corridor. Sand transported by the Colorado River through Grand Canyon is stored on the river bed and in recirculation zones, or eddies, that typically house separation or reattachment sandbars in the lee of debris fans (Schmidt, 1990; Hazel et al., 2006). Alternatively, sand can also be found lining pools and channel margins upstream of debris fans (Schmidt, 1990). The SDZs were identified by delineating individual large eddies and adjacent debris fans, pools and channel margins which contain a majority of the areas of exposed unvegetated river-derived sand that can be classified by multispectral image analysis. The more comprehensive 2013 sand map extends outside of the SDZs and encompasses all river-derived sand within the entire width and length of the river corridor above the low-flow river stage. Each classification map was derived from a combination of unsupervised and supervised image classification methods followed by exhaustive image interpretation and map editing to identify river-derived sand that was not vegetated and not obviously colonized by biologic soil crust. The sand classifications have the same 0.2-meter ground resolution as the imagery. No formal accuracy assessment has been completed at this time for these data.
These data are intended to be useful for management, monitoring, and research of sediment-related resources in the Colorado River downstream of Glen Canyon Dam in Glen Canyon National Recreation Area and Grand Canyon National Park. These data can be used in GIS analyses and for change detection with other classification datasets to assess dynamics of sand distribution in the Colorado River ecosystem.
Rights
The author(s) of these data request that data users contact them regarding intended use and to assist with understanding limitations and interpretation. Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty.
